Showing papers in "Biotropica in 1974"

Flowering Phenology and Diversity in Tropical Bignoniaceae

Abstract: Central American Bignoniaceae show five distinct patterns of flowering phenology. Four of these phenol6gical types characterize different bee-pollinated species. Only the generalized "cornucopia" strategy is employed by temperate Bignoniaceae. In the tropics this strategy is also prevalent and is often associated with a seasonal sequence of flowering by related species. The more specialized phenological strategies employed by many tropical species of Bignoniaceae are viewed as making possible differential and essentially contemporaneous attraction of similar pollinators from the same limited pollinator resource. The high diversity of tropical Bignoniaceae appears to be facilitated by use of a variety of phenological strategies by the different species. It is suggested that such mechanisms may be an important factor in maintaining increased tropical diversity in other groups of plants. DIFFERENCES IN flowering phenology among Central American Bignoniaceae illustrate an overlooked mechanism for maintenance of high species diversity in tropical plant communities. The ecological importance of these differences in phenology is in making possible effective and often contemporaneous sharing by numerous plant species of a limited pollinator resource. Evolutionary diversification of floral morphology in the Bignoniaceae has, of course, given rise to genera employing most of the potential pollen vectors available in a tropical community (Gentry 1972, 1973). But although bats (in Parmentiera, Crescentia, Dendrosicus), hummingbirds (in Mawrtinella), hawkmoths (in Tanaecium), and butterflies and small bees (in Tynnanthus and Arrabidaea florida) are the principal pollinators of some Bignoniaceae, the majority of the 76 species occurring naturally in Costa Rica and Panama are pollinated by large and medium-sized bees, especially female euglossines. In some bee-pollinated species additional morphologic specializations further restrict potential pollen vectors as in Amphilophium where pseudocleistogamous flowers which never open spontaneously can be entered only by the strongest members of the apifauna (Megachile, large anthophorids, presumably xylocopids). However, most bee-pollinated species of Bignoniaceae secure their requisite pollinators by different strategies of flower production rather than morphologic differentiation.

Carrion reduction by animals in contrasting tropical habitats

Abstract: Decomposition of lizard (Iguana iguana, Ctenosaura similis) and toad (Bufo marinus) carrion open to arthropods was studied in a tropical dry and a tropical wet forest in Costa Rica. Carcass fates, feeding interactions of necrophagous animals and their predators, temporal succession patterns, and species compositions differed between sites. More than 170 species representing 49 families were associated with the carrion baits; calliphorid and sarcophagid larvae and adults and adult Formicidae and Scarabaeidae were most important in reducing carcasses to the dry skin stage. The significance of these results is discussed in relation to nutrient cycles and the decomposition submodel of a tropical forest ecosystem. SYNTHESES OF ENERGY and elemental transfers in tropical forest ecosystems are now available (Golley et al. 1969, McGinnis et al. 1969, Odum and Pigeon 1970, Malaisse et al. 1972, Fittkau and Klinge 1973). The grazing and detritus food chains are the two major pathways for the movement of nutrients in such ecosystems (Odum and de la Cruz 1963, Wiegert and Owen 1971). Nutrients enter the decomposer subsystem via such detritus pathways as annual leaf fall (de la Cruz 1964); total plant death (Richards 1952); seed and fruit drop (Smythe 1970); animal defecation (Watling 1963, Nicholson, Bocock, and Heal 1966); and animal death (Heatwole 1971). Nutrients tied up in dead animals of various sizes are released in large part by activities of necrophagous bacteria, fungi, and animals. Research on carrion bacteria and fungi is scant (Okafor 1966), but this is not true for investigations of the role of scavenger birds (Chapman 1938, Stager 1964), omnivorous mammals (Koepcke and Koepcke 1952), and arthropods (Chapman and Sankey 1955, Reed 1958). In addition, Fuller (1934), Bornemissza (1957), Payne (1965), and Payne and Crossley (1966) report results of studies on faunas associated with carrion. More specialized research discusses carrion-associated Coleoptera (Pessoa and Lane 1941, Howden 1950, Halffter and Matthews 1966, Shubeck 1969, Payne and King 1969a); Diptera (Hepburn 1943); and Lepidoptera (Payne and King 1969b). These investigations have increased our understanding of the intricate food webs, temporal patterns, and identity of arthropods associated with the carrion microcosm in temperate regions of the world. Virtually nothing is known about similar phenomena in tropical environments. The purpose of this research is (1) to document relative durations of the various stages of lizard and toad decomposition in two different tropical forests; (2) to structure preliminary trophic interactions and discuss them in terms of resource partitioning; (3) to detail temporal succession patterns; and (4) to establish an inventory of species attending these carriotn. Information about the carrion microcosm will be useful in elucidating detritus compartments of the above-mentioned models of ecosystems. SITES, MATERIALS AND METHODS This research was conducted at a tropical dry lowland forest at Finca La Pacifica, 5 km N of Las Cafias, Guanacaste Prov., Costa Rica, and a tropical wet lowland forest 5 km W of Rincon de Osa, Puntarenas Prov., Costa Rica, in the dry season during parts of February and March 1968. From February 8 to February 17 temperatures measured at ground level at the Guanacaste site ranged from 21.8 to 38.50 C with a typical daily fluctuation from 240 C (0400 hr) to 340 C (1300 hr). Ten-year averages of rainfall at Las Cafias (Scott 1966) ranged from a low of 5 mm in January and March, through an average of 17 mm during February to a high of 375 mm in October. In February, the soil was rather dry and loose, and the depth of the dry leaf litter, where existent, averaged 5 cm. The Osa site exhibited temperature extremes of 22.0 and 28.50 C at ground level for the period February 29 to March 9; typical daily fluctuations ranged from 23 to 270 C. Rainfall profile by ten-year averages for nearby Coto, Puntarenas Prov., ranged from 39 mm (February) to 579 mm (October) with 60 mm as the average for March (Scott 1966). The soil was moist, somewhat compact and rocky. Litter depth averaged 1 Present address: Battelle-Columbus Laboratories, 505 King Avenue, Columbus, Ohio 43201 U.S.A. This study was conducted under the auspices of the Organization for Tropical Studies, Inc., Apartado 16, Universidad de Costa Rica, C. A. BIOTROPICA 6(1): 51-63 1974 51 This content downloaded from 157.55.39.104 on Sun, 19 Jun 2016 06:46:14 UTC All use subject to http://about.jstor.org/terms 4 cm. Minimal selective cutting of large trees had occurred at both forest sites within the last 20 years. Both study areas were at least 200 m from remote human habitations. Animals native to the respective forests were killed and served as carrion baits: two Bufo marinui m4rinus (Linnaeus) (1 ?, 61 g (wet weights taken immediately after death), 90 mm (snout to vent); 1 ?, 303 g, 130 mm) and two medium-sized Ctenosama similis similis Gray ( 3, 88 g, 145 mm; ?, 124 g, 168 mm) were studied at Guanacaste; two medium-sized Igzana igaana iguana Linnaeus ( 3, 261 g, 210 mm; 3', 291 g, 180 mm) and two B. m. marinus (3', 71 g, 95 mm; 3', 222 g, 115 mm) were used at Osa. At the sites it was impossible to locate lizard and toads whose sizes exactly matched. Toads were hand retrieved and pithed. Lizards were either noosed and strangled or shot from a tree with a shotgun; there were a few, small perforations in the skin of the latter specimens. Each carcass was placed at the center of a 1 m2 square area. The area was cleared of most leaf and twig litter to facilitate observations at the lizardground interface as has been done in other carrion studies (Payne 1963, 1965). It was assumed that the carrion fauna was not affected by the partial clearing of such a small area on the forest floor. Individual plots were at least 35 m apart at each site. Carcasses were protected from molestation by vertebrate scavengers by small bottomless wire cages (2 cm x 3 cm mesh size), which permitted large cockroaches and beetles access to the rotting animals. One lizard and one toad were killed and placed in the field on day one, another pair readied on day four; this staggered placement schedule permitted over 100 hours of observation for the total study and maximized observation time per carcass during the first 3 days of the decay sequence. Numerous observations were made daily at each carcass primarily between 0600 and 1900 hr; several night observations were made also. Each observation lasted from 5 to 180 min with an average of ca. 70 min per observation. The study was conducted at Guanacaste during the following dates in February: 8-15, lizard 1; 11-16, lizard 2; 8-14, toad 1; 11-14, toad 2. Osa dates are as follows: February 29-March 9, lizard 3; March 5-March 12, lizard 4; February 29March 8, toad 3; March 5-March 12, toad 4. During observation times the cage was lifted away from the carcass. Once placed, carcasses were not moved. The following phenomena were scrutinized at each carrion: decay state of carcass; arrivals, abundances during residency and departures of arthropod taxa; feeding habits by animals on carcass proper and on each other. One feeding observation represents either the removal of flesh or fluid from the carcass or the capture and ingestion of one organism by a predator(s). Ants and fly larvae ate holes through the body walls of some dead toads and lizards; these breaks permitted observation of the abundances of necrophagous animals inside the carcasses. Activities also were noted as maggots en masse undulated under the skin and body walls. Limited voucher specimens of each recognized morpho-species associated with each kind of carcass were collected and labelled daily.

Epiphytic myrmecophytes in Sarawak : mutualism through the feeding of plants by ants

Abstract: Hydnophytum /C»'micfNium, Myrmecodia tuberosa, Phymatodes sinuosa, and Dischidia rafflesiana are described as epi· phytic myrmecophytes in low·productivity vegetation, growing on Sarawak white sand soils, which are fed by the relative· ly unaggressive ant Iridomyrmex myrmecodiae. The ants place large quantities of insect parts in the plants, which prob· ably take up their decomposition products. Virtually all epiphytes in this community are trophically associated with a colony of I. myrmecodiae and one or more myrmecophytes, and it appears that there are not enough nutrients to support epiphytes unless they obtain extra nutrients from ants. Two conspicuous plant parasites, Dischidia gaudichaudii and Pachycentria tuberosa, take root in the debris dumps. In the light of these findings, it seems likely that the neotropical myrmecophytes with relatively unaggressive ant occupants are involved in a similar relationship. Experiments are needed to compare seed production or growth rate in epiphytic myrmecophytes that are occupied and unoccupied by I. myrmecodiae. THE MORE SPECTACULAR EXAMPLES of neotropical and African ant-plants (myrmecophytes) represent mutualisms whereby the ants protect the plant from herbivores and competitors, and are fed and housed by the plant (Bequaert 1922; Wheeler 1942; Janzen 1966, 1967, 1969, 1972, 1974a; Hocking 1970; Rehr et at. 1973). While it may be the case that some Southeast Asian myrmecophytic mutualisms are based on protection of the plant by ants (e.g., Macaranga, Bequaert 1922; Takahashi 1951), the Southeast Asian epiphytic myrmecophytes clearly have a different kind of interaction with ants. It appears that the ant species regularly living in these epiphytic myrmecophytes are of greatest importance in feeding the plant rather than in protecting it. The natural history and taxonomy of Southeast Asian myrmecophytic epiphytes (Hydnophytum, Myrmecodia, Dischidia, Phymatodes, and Lectmopteris) have been examined with highly variable intensity by numerous authors (e.g., Treub 1888; Groom 1893; Scott and Sargant 1893; Heim 1898; Ridley 1910; Kerr 1912; Mann 1921; Bequaert 1922; Blatter 1928; van Leeuwen 1928, 1929; Holttum 1954a,b; van der Pijl 1955; Teuscher 1956, 1967, and others cited by these authors). As was usual in times when the interplay of morphology, ecology, and evolution was poorly understood and incompletely accepted, many of these authors remained indecisive as to the nature of the interaction and often attributed fanciful processes to it. The situation was not helped by the fact that not one of the more than 500 pages written on the subject deals in detail with the behavior of the ants, and no one attempted to view the interaction in the context of the habitat containing it. Here, I wish to try to place the interaction in an ecological perspective by describing it as it currently occurs in vegetation growing on very poor white sand soils in Sarawak (d. Janzen 1974b).

Floral Ecology of Coastal Scrub in Southeast Jamaica

Abstract: Species flowering during the dry season (late December to early April) form three main pollinator groups, namely, butterfly, solitary bee, and hummingbird flowers. The animal vectors present match these three flower syndromes. The daily and seasonal rhythms of flower opening and pollination activity are synchronized. Butterflies and solitary bees, active chiefly in the morning, visit flowers blooming only half a day. The number of seeds per fruit and the pollencarrying capacity of the pollen vector are correlated. Butterflies, carrying few pollen grains, chiefly pollinate flowers with one to four seeds. Solitary bees, carrying many grains, chiefly pollinate flowers with many seeds per flower. These close links between the flowers and their visitors result in a high degree of successful pollination and a high percentage fruit set. A group of species, attracting no visitors, was characterized by a very narrow 'pollination gap,' making self-pollination almost inevitable. Heavy fruiting indicated self-fertility. Heterocorollary in Cordia sebestena, a double keel in Stylosanthes hamata, and several examples of andromonoecy are recorded for the first time. The presence of the adventive honeybee, Apis mellifera, in the association appeared detrimental to the native pollinators when forage was scarce. The whole scrub association appears balanced with a distinctive pattern of floral ecology. This circumstance, in terms of pollinators, is designated a Butterfly-Solitary bee-Hummingbird association. STUDIES IN PLANT ECOLOGY seldom include any consideration of the floral ecology. Yet this facet of the life cycle can scarcely be ignored if an assessment of the plant association as a whole is to be reached. Indeed, without the floral data, errors in interpretation of the ecological factors involved may be made. In Salvia, isolation between two species was assigned to edaphic and topographical features, when it was really due to differences in floral morphology and insect vectors (Grant and Grant 1964). Although patterns of floral ecology are tacitly acknowledged to

Prey Capture and Competition in the Ant Lion

Abstract: The parameters of prey capture and competition are remarkably simple to measure in the larval ant lion (Neuroptera: Myrmeliontidae). There exists a thirteen- to fifty-fold difference in food availability (mg. prey available/mg. predator) between the largest and smallest individuals. The larva grows to the optimal size as a food getter, but no larger before metamorphosing. A special distribution of ant lions minimizing competition is hypothesized and observed. The ant lion does not conform to the concepts of limiting similarity or niche variation. THE ANT LION has long been a naturalist's delight in its exotic method of prey captLre. The larva digs a conical pit in loose sand and lies buried at the vertex. When an insect falls in, the ant lion attempts to grab it with its long ice-tong-shaped mandibles. If it fails and the prey starts to scramble up the side of the pit, the ant lion tosses sand with violent flips of its head, creating land slides that carry the prey back into its jaws. After extracting the fluids, it throws the carcass out of the pit, along the rim. Interest in the ant lion died together with interest in simple natural history, for the last nontaxonomic paper was Wheeler's (1930) monograph. What has not been appreciated is the ant lion's elegance for ecological study. Here I show that the searching capacity, prey size range, and success of capturing prey within this range can all be measured by taking the diameter of the pit; the nutritional history, prey size distribution and abundance by collecting the carcasses around the rim of the pit; and the competitive effect of neighbors, in percent prey intercepted, by the spatial configuration of the pits. Also, while not studied here, it is worth noting that when the animal disperses it does so half submerged in the sand, leaving an easily visable trough as a record of its movements.

Bud Temperature in Relation to Nyctinastic Leaf Movement in an Andean Giant Rosette Plant

Abstract: Espeletia schultzii Wedd. (Compositae), a large caulescent rosette species of the paramo zone of the Venezuelan Andes, has strongly nyctinastic leaves. At night, the rosette leaves close around the apical bud, protecting the bud from freezing temperatures, and also preventing rapid heating of young leaves just after sunrise, when water transport to leaves is probably inefficient. If nyctinastic leaf movement is prevented, leaf wilting and death occur. Espeletia schultzii Wedd. (Compositae) is a common caulescent rosette species in the pairamo zone of the Venezuelan Andes. Its large pubescent leaves show distinct nyctinastic movements; they close around the single apical bud at night, and open during the day (figure 1). This species is highly polymorphic with respect to leaf movement; nyctinasty seems to be most pronounced in valley-floor populations subject to nighttime cold-air drainage. Similar growth forms, large rosettes supported by unbranched stems, have evolved independently in the high elevation zones of Hawaii (Argyroxiphium) and East Africa (Lobelia and Senecio). The East African giant rosettes show similar diurnal leaf movements. Hedberg (1964) suggested that "night buds" formed by nyctinastic leaves in the East African plants protect the apical meristem from freezing damage. However, it appears that detailed experimental studies of temperature relations have not been made previously in giant rosette plants of this kind. This paper reports such data in relation to nyctinastic opening and closing of the rosette. MATERIALS AND METHODS Field measurements were made at Mucubaji, Estado Merida, Venezuela (80 45' N.), at an elevation of 3600 m. Four sets of seven plants were located on a level valley floor. Plants were selected which showed particularly strong nyctinastic leaf movement. Average plant height to bud base was 25.2? 1.1 cm; average rosette diameter was 55.2?+1.5 cm. For each plant, one thermocouple was placed inside the apical btud ("bud core") and another in the tissue of an outer bud leaf on the north-facing side of the bud ("bud surface"). The first set of seven plants was used as a control. In the second set of plants, rosette leaves were immobilized in the fully opened position (the position reached in mid-afternoon on a clear day) using stiff wire rings. Comparison of bud temperatures of these plants with those of control plants permitted study of the effects of rosette closure. In the third set of plants, rosette leaves were immobilized in the fully closed position (the position reached just before sunrise after a clear cold night), again using stiff wire rings. Comparison of temperatures of these plants with those of controls permitted study of the effects of rosette expansion during the day. In the fourth set of plants, the rosette leaves were removed, leaving only the apical bud. Comparison of these plant temperatures with those for set number two (rosettes held open) permitted study of the effects of non-nyctinastic leaves on bud temper-

Toxicity in Holothurians: A Geographical Pattern

Abstract: Experiments on the toxicity of holothurians to fishes were conducted at Cocos Island (eastern Pacific), in Mexico, California, and Washington. Six of seven species of holothurians tested at Cocos Island are toxic to fishes. Five species in Mexico are toxic, one of two species in California is mildly toxic, and three of twelve species in Washington are mildly toxic to fishes. Feeding experiments confirm laboratory tests on toxicity. A summary of information is presented on the current status of our knowledge of toxicity in holothurians. The evidence supports the hypothesis that toxicity in tropical holothurians probably has evolved in part as a chemical defense mechanism against predation by fishes. THE PURPOSE of this investigation was to evaluate the hypothesis that toxicity in holothurians is inversely related with latitude and that this phenomenon is in part a reflection of fish predation, which differs in intensity with latitude and habitat (Bakus 1968, 1969). Studies were conducted at the Instituto Technologico de Monterrey, Escuela de Ciencias Maritimas y Technologia de Alimentos, Bahia de Bacochibampo, Guaymas, Sonora, Mexico (28? N), 30 December 1968 to 1 January 1969 and 2-4 April 1969; the University of Southern California Santa Catalina Marine Biological Laboratory (330 N) from 4 May to 11 May 1970; the Allan Hancock Foundation, University of Southern California, during 1969 and 1970; Cocos Island, eastern Pacific (6? N), from 29 March to 8 April 1972 and the University of Washington Friday Harbor Laboratories (48? N) from 24 July to 16 August 1972. MATERIALS AND METHODS Marine fishes and holothurians were collected by skindiving and with SCUBA, using the narcotizer quinaldine, dip-nets, and diving bags. They were maintained in aquaria. Tests were conducted to determine which holothurians are toxic to fishes and to obtain a rough approximation of the level of toxicity. Techniques used to study holothurians generally follow those of Bakus (1968) except where noted. Briefly, pieces of the animals are weighed (2 g) then placed in a beaker. A solvent (usually 95% ethanol) is added to the beaker and the solution is evaporated by boiling for 20 minutes. The extracted residue is dissolved in 100 ml of fresh seawater, distilled water, or tapwater in a fingerbowl. A fish is placed in the fingerbowl, and the time at which it dies is recorded. Experiments were terminated when fish showed consistently normal behavior or had died. Violent escape behavior, paralysis, and loss of equilibrium indicated the presence of a toxin. A strongly toxic holothurian is defined as causing death in fishes within 15 minutes (often < 10 minutes); a weakly toxic holothurian causes death in fishes from 20 to 45 minutes. Temperatures under which experiments were conducted were at or near the ambient for the site of capture, unless otherwise indicated, in order to simulate natural responses to toxins by fishes. Control experiments were conducted simultaneously with every test experiment. They consisted of placing fishes in the same volume of clean seawater or freshwater as that used in the experiments. OBSERVATIONS ON THE BIOLOGY

Vegetative and Reproductive Strategies of Opuntia (Cactaceae) in the Galapagos Islands

Abstract: In the Galapagos Islands, the Opuntia cactus is represented by a large number of endemic species and varieties dis. playing different vegetative and reproductive characteristics on each island. To determine the adaptive significance of this variation in relation to the conditions on each island, studies of Opuntia populations and individuals growing on three islands were carried out; relationships between the dimensions of tree height, trunk diameter, pad numbers and fruit numbers were determined, and seed-fruit energetics were measured for Opuntia trees on Santa Cruz, Santa Fe, and Pinzon Islands. Additional seed collections and analysis of variation in Opuntia from other islands are included. Interisland differences in height-diameter growth, pad production, and reproductive effort of Opuntia are related to the amount of competition for light with other woody plants and possibly to wind intensity. The prolonged and asynchronous dropping of fruit by Opuntia may act both to increase assurance of seed dispersal by iguanas and tortoises and to decrease chances of seed predation by finches. The interisland variation in seed-coat thickness may be affected by predation pressure as determined by the numbers of alternative plant food sources on an island. IN THE GALAPAGOS ISLANDS, the arid zone communities of most islands contain a large and bizarre

Maximum plant species diversity in terrestrial communities

Abstract: THE ORTHODOX VIEW that tropical rain forest has the highest plant species diversity of any terrestrial plant community (Cain and Castro 1959; Walter 1971) has recently been challenged by Richards (1969), who suggests that some non-forest sclerophyll communities like the fynbosch of the Cape Peninsula of South Africa and similar communities in Australia may be even more species-rich. This hypothesis, now being widely referred to (e.g., Greig-Smith 1971), is tested here for the first time using previously unavailable data. Species-area curves including all vascular plant species were obtained from the most species-rich

Relative Isolation and Seed Predation in Calliandra grandiflora, a Mimosaceous Legume from the Highlands of Guatemala

Abstract: The hypothesis that an isolated plant is less prone to attack by insect seed predators than a similar plant growing in dense stand was tested and supported by data derived from a study of the mimosaceous legume Calliandra grandiflora.

Flowering Periodicity at Four Altitudinal Levels in Eastern Ethiopia

Abstract: This report compares flowering seasons in perennial woody plants at four altitudinal levels in the Harar Highlands of eastern Ethiopia. In this area a majority of woody species flower in the dry season only in the montane evergreen forest formation above about 2200 meters altitude. In the other three deciduous formations at lower altitudes flowering is primarily in the wet season. In the drier Acacia (microphyll) formations there is a burst of flowering at the beginning of the rainy season. THE AREA OF the Harar Highlands in eastern Ethiopia above 1000 m altitude and north of latitude 80 30' North experiences a single wet season with two maxima, in April and August. The rains that fall between March and June are called the "little rains" by local people. They may be heavy but vary greatly from year to year and are dependable for agriculture only above about 2200 m elevation. The months of July, August, and September are the period of the "big rains," and these permit the maturation of long-season (90 day) crops at altitudes of about 1700 m and higher. The long dry season, from early October to March or April, may total as little as 50 mm of rain at 2000 m elevation. The dry season in this area of Ethiopia is made more severe by the nature of the prevailing winds. From late September or early October to March the winds are usually quite strong out of the north and northeast. They are part of a large monsoon system bordering the Indian Ocean and sweep across parts of Arabia before moving southward over Ethiopia and Somalia. These winds are thus very dry. The ameliorating effects of higher elevations are pronounced and produce several easily distinguished vegetation types or life zones. The vegetation types in this area range from subdesert grasslands at 700 to 1000 m altitude to elfin forest and subalpine formations above 3000 m. The boundaries of these

The Cost of Being Dormant in the Tropics

Abstract: The roots, stems, and twigs of Jacquinia ptangens were found to lose as much as one-half of their stored carbohydrate reserves when leafless during the rainy season. This finding implies that dormancy can be an expensive way to avoid an inimical environment. Jacquinia pungens A. Gray (Theophrastaceae) is an understory shrubby tree in Central American deciduous forests. In Costa Rica, it produces leaves at the beginning of the dry season (December) and drops them about six months later at the beginning of the rainy season (May-June) (Janzen 1970). In this paper we examine the hypothesis that the rainy (dormant) season is a period of substantial stress to the plant, as measured by metabolic expenditures at this time. The cost to J. pungens of rainy season dormancy is a special case of the general problem of understanding the cost of being dormant at high tropical temperatures. This dormancy contrasts strikingly with the apparent low metabolic cost of dormancy for a poikilothermic tree during the cold season in temperate zones. We chose J. pungens for this study because of its abundance, small size at reproductive maturity, conspicuous starch storage, lack of sexual activity while leafless, and potential for suggesting minimal maintenance costs for a woody plant during the rainy (coolest) time of year in the lowland tropics. METHODS AND STUDY AREA Twig, main stem, and root segments were collected from each of five 1.5-2.0 m tall J. pungens shrubs on seven dates (table 1). Twig segments were from the previous year's growth; main stem segments were 2-4 cm diameter and from about 30 to 80 cm up the trunk; and the root segments were from the tap root at a point 10-20 cm below the ground and the same diameter as the main stem segments. J. pungens is exceptional among tropical deciduous forest understory shrubs in that it has a very deep and large tap root (Janzen 1970). The shrubs were sacrificed when sampled. The woody segments (including the thin bark) TABLE 1. Total available carbohydrate (TAC) in mg per g of Jacquinia pungens twig, stem and root segments. Each value is the average of five samples and the same five shrubs were used for twig, stern and root segments on a given date. See text for calculation of TAC for entire shrub.

A Case for Selection for Delayed Fruit Maturation in Spondias (Anacardiaceae)

Abstract: Spondias radlkoferi J. Donn. Sm. of lower Central America and Panama is believed to have been derived from the more widespread S. mombin L. The fruits of S. mombin are both colorful and sweet, characteristic of the genus. S. radlkoferi, however, has fruits which remain green and are not sweet at maturity. Where the two species occur together on Barro Colorado Island, they are, nevertheless, equally abundant. Selection in S. radlkoferi appears to have favored longer periods of fruit maturation to extend the time of maturation into a period of the year marked by food scarcity. Apparently also because of the dearth of food and the resulting increase in the foraging activities by mammals there has been selection in favor of a fruit which is neither sweet nor colorful. THE GENUS Spondias (Anacardiaceae), with 8-12 species from tropical regions of the world, is renowned for its tasty, edible fruits (Adams 1972, Bailey 1949, Standley 1928). The fruits are customarily also colorful at maturity, usually yellow, orange, purple, or red. Recently, while conducting research toward a new Flora of Barro Colorado Island in the Panama Canal Zone, I encountered a species which is unusual in the genus. The species, S. radlkoferi J. Donn. Sm., was considered synonymous with S. mombin L. by Blackwell (1968) in the Flora of Panama. However, studies conducted on Barro Colorado Island during 1970 and 1971 and at the Missouri Botanical Garden since then have shown that the two species are distinct. Among the more important features distinguishing the two species are differences in flowering and fruiting time, fruit color, endocarp shape, sap color, bark texture, calyx pubescence, flower bud shape, number of styles, disk width, and type of pubescence, all summarized in table 1. Perhaps the most biologically significant feature separating the two species is the difference in flowering time. Initiation of flowering for both species varies somewhat from year to year, perhaps depending on climatic conditions. Spoidias momben begins losing its leaves in the earliest part of the dry season, usually from December to February. Before flowering is initiated, the species usually has a full complement of new but fully matured leaves. Flowering occurs principally between March and July. At the time flowering is initiated in S. radlkoferi its leaves are only partially developed so that flowers develop precociously or simultaneously with the new leaves. Spondias radlkoferi usually loses its leaves later than S. mombin 1 This study was supported in part by N.S.F. Grants GB34502 and GB-36202X. and begins to flower 4-6 weeks after S. mombin, principally April to July. While populations of both species are common on the island and have flowering periods lasting 4 months or more, individuals rarely flower more than 4-6 weeks. Despite the extended period of overlap in their flowering periods, there is no evidence that the two species hybridize. The characters separating them are quite uniform and consistent for two such close cogeners. Fruit development time for Spondias mombin averages about five months with the fruits maturing principally from July to October but especially during August and September. The drupe is obovoid to oblong, 2.5-3 cm long and orange at maturity with a thin exocarp and a fleshy, tasty, sweet mesocarp surrounding the tough, fibrous, apparently inedible seed. In contrast, Spondias radikoferi has fruits which require an average of six months to develop, maturing principally from September to December. At maturity the fruits are somewhat larger than S. mombin and of similar shape but do not turn orange. The mesocarp, though becoming moderately soft and fleshy, is not sweet or tasty like other Spondias species. Spondias radlkofeeri ranges from Guatemala to Panama. It is without question closely related to S. mombin which ranges throughout tropical America. Based on morphological data (Croat 1974), such as the reduction in number of styles, it appears likely to have been derived from S. mombin. It is also appropriate on this basis to presume that the species has lost the generically characteristic ability to develop colored, tasty fruits. This selection against such fruits can be explained by its phenological history. Phenological studies on Barro Colorado Island BIOTROPICA 6(2): 135-137 135 This content downloaded from 157.55.39.215 on Wed, 31 Aug 2016 04:26:57 UTC All use subject to http://about.jstor.org/terms TABLE 1. Characters separating Spondias mombin L. and S. radlkoferi J. Donn. Sm. S. mombin S. radlkoferi Pubescent parts of plant puberulent Pubescent parts of plant villous to (trichomes short and straight) velutinous Bark very coarse, deeply fissured Bark not deeply fissured, the strips the intervening corky periderm of periderm paper-thin, smooth hard and prominently raised Slash not producing cloudy, viscid Slash producing cloudy, viscid droplets droplets on inner bark within 30-60 seconds on inner bark Leaves generally fully developed at Leaves usually young at time of flowering time of flowering Leaves drying greenish Leaves drying blackish Leaf blades with a prominent Leaf blades lacking prominent submarginal submarginal collecting nerve collecting nerve Flowers with 4 or 5 (rarely 3) styles Flowers with 3 or 4 (rarely 5) styles Flower buds globular to obovoid Flower buds ovoid Calyx pubescent Calyx glabrous Pedicels puberulent Pedicels glabrous or with sparse long trichomes Disk ca 1 mm wide, narrower than Disk ca 2.3 mm wide, wider than stylar stylar clump clump Mature fruits orange, sweet and tasty Mature fruits green, edible but not very tasty and reported to be more acidic Old endocarps (persisting on ground Old endocarps oblong beneath tree for most of the year) obovoid (Croat 1969) show that the peak of fruiting for all species of trees is in April (fig. 1) and that, from this period until the end of the rainy season in December, there are fewer species of trees available with fruit. Smythe (1970), in food-trap sampling experiments, has shown that May is the month with the maximum number of species producing fruits on Barro Colorado Island. However, his data also indicate marked paucity of fruits throughout the remainder of the year, nearly all of which is the rainy season. The rainy season begins on Barro Colorado

Helminthiasis as a Measure of Cultural Change in the Amazon Basin

Abstract: Fecal samples were analyzed for helminth eggs to determine level of helminthiasis in representative populations of Tucuna Indians from Puerto Narino and Petuna, Colombia. Although both populations were hyperendemic for roundworm, hookworm, and whipworm, Indians from Petuna village appear to have more severe helminthiasis. Modernization of Puerto Narino has contributed to a reduced incidence and worm burden in the inhabitants. THE EFFECTS of increasing population density on culture in the Amazon Basin have been discussed by Meggers (1971, 1973) and Sioli (1973). Surveys of intestinal parasitic infections in Amazonian Indian tribes were listed by Lowenstein (1973) in his discussion of the biological adaptations of aboriginal man. However, interpretation of behavioral and cultural adaptions of people in terms of data based on parasitic diseases was only recently recognized by Kochar (1973) as an emerging research strategy in social biology. Recent development of natural resources in the Amazon Basin (Sanger 1969 and Smith 1971) has prompted Latin American governments to establish towns along the Amazon River and its tributaries. In Colombia, settlements are encouraged along rivers in the Leticia Corridor. To encourage settlement and extend central government influence, the Colombian government has provided certain villages with piped water, electricity, street and sidewalk improvements, schools, protection and law enforcement, and limited medical and dental care. The result has been rapid growth in existing settlements, the establishment of new villages, and the gradual grouping of isolated Indian families into larger communities. This study compares intestinal helminth infections of people living in two villages, Puerto Narino and Petuna, in southeastern Colombia, to point out the use of helminthiasis as a measure of cultural change since the addition of government facilities. Both villages were initially inhabited by Tucuna Indians brought together from smaller isolated family groups by increasing contact with Europeans. About 1967, Puerto Narino began receiving government support for construction of more modern facilities. Petuna, having a much smaller population and being situated farther from the nearest large city (Leticia), received no such support. Today, Puerto Narino is the provincial capital of Amazonas, Colombia, while Petuna has remained essentially unchanged. Puerto Narino and Petuna are situated in the "habitation zone" (after Camargo 1958, as illustrated in Sioli 1973) of the lower Loreto-Yacu River near its junction with the Amazon River in southeastern Colombia (fig. 1). Elevation in both villages is approximately 95 m above sea level, and the climate in this region is typically tropical, warm and humid, with an average daily temperature of 26.6? C and an annual rainfall exceeding 305 cm. Definite wet and dry seasons occur with little seasonal variation in temperature (perhaps 2.70 C). The predominant soil in both villages is kaolinitic yellow latosol which is almost always acid. The vegetation is tropical forest (Richards 1952).

Saltatorial Orthoptera as Common Visitors to Tropical Flowers

Abstract: In wet tropical regions of Peru and the Panama Canal Zone, saltatorial Orthoptera were found to visit flowers of certain species of Commelinaceae, Compositae, Gramineae, and Euphorbiaceae. Tettigoniids, especially Coinocephalus, were the commonest visitors, though representatives of Tridactylidae, Gryllidae, and Acrididae were also seen on the flowers. Most were nymphs. In the Commelinaceae, the principal family studied, most of the visitors fed only on the anthers, and some were observed to walk from flower to flower. This behavior suggests that they may effect some pollination. However, their destruction of the anthers, which reduces a flower's potential for more efficient bee pollination, would probably make the orthopterans' net effect on the plant deleterious. A GREAT VARIETY of insects visit flowers, but there is rare mention of saltatorial Orthoptera among them. Ramsay (1960) mentions a specimen of Caedidia simplex (Tettigoniidae) found "feeding on chrysanthemum flowers" in New Zealand. Wickler (1968) notes that the juveniles of a cicindellid mimic, Condylodera tricondyloides (Tettigoniidae), are found in the flowers of a tree in Borneo. Tettigoniidae were mentioned as flower visitors to Tripogandra cumanensis' (Kunth) R. E. Woodson (Commelinaceae) in Peru by Schuster and Schuster (1971). Further observations in Peru and the Panama Canal Zone have confirmed and extended the knowledge of saltatorial Orthoptera interractions with tropical flowers. Occasional observations were made of various flowers, particularly Commelinaceae, during the period from June 1970 to late February 1972 in the region of Tingo Maria, Peru, and during April 22-23, 1972 on Barro Colorado Island in the Canal Zone. Tingo Maria, at 670 meters on the eastern slopes of the Andes, is in a region of "Subtropical Wet Forest" (Tosi 1960). Barro Colorado Island is in a region of "Tropical Moist Forest" (Holdridge and Budowski 1959). Both in Peru and on Barro Colorado Island, the usual sites of observation were open weedy areas, such as clearings and roadsides. Such sites were similar floristically and included abundant Tripogandra cumanensis, some Commelina (Commelinaceae), and similar species of Compositae, Acanthaceae, Euphorbiaceae, and Gramineae in bloom. In Peru, one additional site studied was slightly different. This site, an ecotone area between forest and roadside ditch, contained abundant Zebrina pendula Schnizl. (Commelinaceae) in the shadier parts and T. cumanensis in the sunnier. Also present were two species of Urticaceae and a couple of flowering bushes of Hamelia patens (Rubiaceae). The Orthoptera found on flowers are shown in table 1. By far the most common was a species of Conocephalus (Tettigoniidae), of which only nymphs (various instars) were observed on flowers.2 In Peru, it was found on T. cumarnensis during February, May, June, August, September, October, and November, and is probably present on the flowers throughout the year. Clumps of T. cumrnensis produce large quantities of fresh flowers every day in the year. Conocephalus sp. was observed feeding on the anthers, perhaps also consuming stamen hairs, but not eating other parts of the flower. The insects visited a given flower for approximately five to fifteen minutes, and were, at times, observed to pass directly to another flower. Many of the flowers visited would be left without anthers. This situation occurred only while the flowers were open, i.e., from about 9:00 to about 13: 00 (Schuster and Schuster 1971). In the Commelinaceae, flowers which are open on one day do not reopen the following day. This has the result that, at the beginning of any day's open period, all the flowers are unexploited, and the insects do not waste time and energy visiting flowers exploited the previous day. On only one occasion was Conocephalus sp. seen to eat a petal as well as the anthers. This was on a flower of Commelina diffusa Burm. f. in January 1972. Conocephalus sp. was also encountered on the small pale-purple heads of a roadside composite during May 1971. For example, on May 4, 1971 at 10:45 a.m., Conocephalus sp. was found on flower heads of all six plants of this composite growing at a particular site. They were observed to walk from 1 Now T. serrulata (Vahl) Handlos (D. R. Hunt pers comm.). 2 In both Trinidad and Tobago in August 1967 first and second instar nymphs of Conocephalus sp. and Neoconocephalus sp. were observed chewing the anthers of grasses. Crop analyses revealed that anthers and pollen had been ingested. The later instars and adults fed upon the seeds as these became available. M. G. Emsley, Ed. 138 BIOTROPICA 6(2): 138-140 This content downloaded from 157.55.39.78 on Mon, 20 Jun 2016 07:21:09 UTC All use subject to http://about.jstor.org/terms TABLE 1. Species of Orthoptera observed on flowers in Peru (P) and the Canal Zone (C). unidentified ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~~~~~; sp. (Paerperne Pu Pn d) 4'S Anaxq7hv? s p. ( Trigonidiinae ) P ~ ~ ~ s ~ ~ Speiescoflinsec 0 ~ ~ ~ ~~~~~a

The Summit Vegetation of Cerro Autana

Abstract: Cerro Autana is one of the smallest of all the sandstone table mountains of the Guayana Highland. It appears to represent a fragmented portion of the nearby Cerro Sipapo (Paraque) in Territorio Federal Amazonas, Venezuela. One hundred and thirty-two species of plants are now known from the summit, of which seven are new to science, four new to Venezuela, one new to the flora of the Guayana Highland, and sixteen newly recorded for the flora of Territorio Federal Amazonas. The majority of the species found on the sumit prove to be either generally distributed ones common to other mountains of the Guayana Highland or to certain mountains of the Territorio Federal Amazonas or Estado Bolivar. An obvious relationship is shown with the nearby Cerro Sipapo. Of significance is the fair proportion of species represented on the summit of Cerro Autana and elsewhere found commonly in lowland portions of the Venezuelan Guayana, indicating a former geological connection allowing for past migrations and interchange of floras between lowland and summit. It is postulated that this migration of floras has proceeded from top to bottom. CERRO AUTANA, located in Territorio Federal Amazonas of southwestern Venezuela, at Lat. 40 52' N., Long. 670 27' W., about 100 kilometers south-southeast of Puerto Ayacucho, may be likened to a giant tower (fig. 1) rising abruptly from a lowland green rain forest to a height of approximately 1300 meters. It is completely isolated. The upper part of this mountain is completely walled by precipitous salmon-pink and buff-white sandstone cliffs up to 900 meters high. It is one of the smallest of all the sandstone table mountains of the Guayana Highland with its summit about one kilometer long and 200350 meters wide. Near the middle portion of the summit is a boulder-strewn hump about 55 meters higher than the nearly level ends. The large Cerro Sipapo (Paraque) lies 18 kilometers to the south-

Architecture of trees in the rain forest of Morobe district, New Guinea

Abstract: The architectural spectrum of the rain-forest appears to be qualitatively the same in New Guinea as previously reported in tropical Africa or America. However, the study of Asiatic and Melanesian trees leads to a broader understanding of the architectural range in pantropical families of flowering plants, and suggests an approach to the understanding of many problems in taxonomy, phylogeny, biogeography, and forest ecology. THE ARCHITECTURE OF TREES in the tropics, a new subject for botanical research, has already been applied to taxonomy, as, for example, in the Euphorbiaceae (Halle 1971). In the present paper, I wish to introduce another aspect of tree architecture, which is biogeographical rather than taxonomical. The introduction of the topic of tree architecture by Halle and Oldeman (1970) was mainly founded upon African and American records, and was comparatively poor in original data about Asiatic trees. Taking into account the particular richness of the Asiatic flora, and its well-known importance for tropical botany, filling such a gap was a preliminary essential for the satisfactory formulation of the problem of architectural evolution in trees. A visit to Australian New Guinea in 1972 provided an opportunity to make a first study of the architecture of Asiatic and Melanesian trees, the main results of which are summarized below.' All the architectural models previously discovered in Africa and America were found easily in the lowland rain forest around Lae, and in the submontane rain forest around Bulolo, Morobe District. A significant, if negative, result is that-contrary to a priori views-no new architectural models were found during my visit to Asia. Thus, as far as I know, the architectural spectrum of the rain forest appears to be qualitatively the same in all parts of the tropics. Of course, the possibility of quantitative variation within the spectrum cannot be denied, some models being favored in some countries either for historical reasons or by environmental conditions, but this supposition is speculative, as a study which would reveal this still remains to be done. Even if the total number of known models has not been augmented, this study of Asian trees leads to a better understanding of the architectural range in several pantropical families of flowering plants. From the 76 New Guinea species from 45 families whose form was studied, I extract 11 which were observed in particularly good circumstances. Schuurmansia henizgsii K. Schum. OCHNACEAE Cf. NGF 40163 from Red Hill, near Lae, Morobe District. Leeuwenberg's Model. This very common small tree, usually less than 10 meters high, is one of the finest plants around Lae at flowering time. Figure 1 a and b represents a well-grown flowering specimen. All the serial axes are orthotropic and equivalent to one another, the only variation being a quantitative one such that, when the branching increases, the size of the successive axes, and the length of their leaves, progressively decreases, as advanced by Corner (1949) in his Durian Theory. Apical inflorescences appear simultaneously on all the upper axes, the lower ones remaining sterile from then on. Owing to these architectural features, Schuurmansia heningsii belongs to Leeuwenberg's model, as defined by Halle and Oldeman (1970). Apart from the characteristics of the model itself, Schuurmansia heningsii offers some individual morphogenetic features, such as the stilt-roots supporting the seedling axis, and the periodic growth which is indicated by the series of bud-scale scars at each level of temporarily interrupted growth. This is the first record of Leeuwenberg's model in Ochnaceae. However, in the same family, the African Lophi'ra alata Banks possesses an architecture related to the present one, although its aerial axes, after the first growth, are no longer equivalent to one another, since some of them grow upright to form a sympodial trunk (Kwan Koriba's model). 1 I wish to express my gratitude to John S. Womersley, head of the Division of Botany at Lae, to the members of his staff, particularly Mark J. E. Coode, for their help in my field-work, and to Anna Cook and Bokinane, for their assistance. BIOTROPICA 6(1): 43-5

Distribution of Native and Invader Plant Species on the Island of Guam

Abstract: The structure of the vegetation of Guam and the position of invading species is investigated. Three species groups, endemic, native non-endemic, and invader, were found to have characteristic growth forms, ranges, and habitats on the island. Endemic species and native species of limited distribution are largely woody; invaders are generally herbaceous. The proportion of endemic species in each habitat was found to vary inversely with the proportion of invaders. Invasion was most successful in communities with large proportions of widely distributed native species. Invaders originating in the New World outnumber those from the Old World, but Old World invaders proved to be more successful in establishing themselves in highly organized, complex vegetation communities. The type of invading species and the organization of native species into communities appear to be important factors in the success of plant invasion. ONE CURRENTLY HELD IDEA in biogeography is that the place of evolution has some effect on an organism's competitive success. Certain areas may be considered evolutionary centers which, because of large size, high species diversity, and stable ecosystems, produce competitively dominant forms. Dispersal of species occurs from these centers to smaller, peripheral areas which are less likely to produce dominant species, and results in the displacement of the species which evolved in the peripheral areas. Islands are viewed as one type of peripheral area, and it has often been suggested that island forms are competitively inferior to mainland forms, and subject to rapid replacement by invading mainland species. Darlington (1965) maintains that the number of species present is related to area and climate. The more species present in an area, the more effective the evolution of the species. Dispersal of species occurs from these areas to smaller areas which are less likely to produce dominant forms. These dominant organisms have the ability to cross barriers and establish themselves in the peripheral areas, at the expense of organisms which have evolved here. Briggs (1966) draws similar conclusions regarding marine systems and additionally points out the possibility of greater and lesser dominant evolutionary centers. The susceptibility of islands to invasion has also been attributed to other characteristics of island biota. Carlquist (1965) suggests that islands are loosely packed with species and therefore have room for invaders. Thorne (1963) states that island forms are more generalized and therefore poor competitors when faced with the more specialized mainland forms. Although the actual species present may be subject to rapid turnover, it appears that an equilibrium species number and, in animals at least, an equilibrium trophic structure are maintained (MacArthur and Wilson 1967; Heatwole and Levins 1972). The present research investigates this idea of competitive superiority due to place of evolution by analyzing the competitive relationships between native and invading plants on the island of Guam. Most of the literature on the problem of nativeinvader plant interactions draws conclusions in contrast to those cited above. Persistence of native vegetation on islands in the face of invading mainland species has often been noted, and plant invaders appear to be transitory members of the community. Success of invading plant species has been largely attributed to man's disturbance of the native vegetation. Pioneer invading species appear to be most successful and most likely to become fully naturalized. Invasion is least successful in fully developed, highly diverse communities (Elton 1958; Harris 1963, 1965; Sauer 1967; Watts 1970, 1971). In this research two main factors are investigated, species range and growth forms. It is expected that the species most affected by invasion are the endemics, for these are the species which have evolved in the island habitat and should show the least competitive ability. More widespread species should be less affected. Smaller plants are both more likely to be successful invaders and less likely to go extinct than larger forms because of larger populations. Adjustment to invasion resulting in a mixed nativeinvader community is expected among these species. 1 This paper is a section of a Master's thesis presented to the University of Maryland. The author gratefully acknowledges the advice and assistance of Dr. G. J. Vermeij, Department of Zoology, University of Maryland, in the preparation of this paper. 2Present address: Department of Geography, University of Hawaii, Honolulu, Hawaii 96822 U.S.A. 158 BIOTROPICA 6(3): 158-164 1974 This content downloaded from 157.55.39.159 on Sun, 18 Sep 2016 06:42:37 UTC All use subject to http://about.jstor.org/terms

The Use of Two Polymorphic Systems, Nectary Fringe Hairs and Corky Alleles, as Indicators of Phylogenetic Relationships in New World Cottons'

Abstract: An earlier study (Stephens and Phillips 1972) showed that primitive cultivars of Gossypium barbadense L., native to the Americas, could be subdivided into two geographical groups: one west of the Andes which is polymorphic for the corky alleles, cky and ck0, and the other, east of the Andes, which approaches monomorphism for cky, All races of G. hirsutum L., except race maarie-galante, are monomorphic for ck0. In the present study an almost identical grouping is found to hold for the presence or absence of fringe hairs on the floral nectary. The western group of G. barbadense is polymorphic for fringe hairs and the eastern group monomorphic for absence of fringe hair. Virtually all forms of G. hirsutum are monomorphic for presence of fringe hairs. The trivial and inconspicuo,us nature of the fringe hairs makes it difficult to imagine that they have any strong selective value. The corky alleles have no apparent phenotypic expression except in the rare cases where mixed plantings of G. barbadense and G. hirsutum race marie-galante have been established and followed by interspecific hybridization. Both characters, therefore, would seem to provide useful indicators of racial phylogenies. Applying this concept to primitive forms of G. barbadaense now established in Africa, India, and Polynesia, it is found that most of them belong to the eastern group with respect to fringe hairs and corky alleles. This finding is consistent with the commonly held but unsubstantiated opinion that they were introduced over the old Portuguese trade routes from Brazil and the West Indies and not via the old Spanish trade route (Mexico, Guam, Philippines). The origin of modern annual forms of G. barbadense is obscure. The origins of the Sea Island cottons can be traced back only to mid-18th century in the seaboard colonies of North America, and the Egyptian cottons to the early 19th century in the Nile Delta. The Sea Island cottons have the eastern pattern of fringe hairs and corky alleles, contrasting sharply with the Egyptian cottons which have the western pattern. The possible implications of these findings are discussed.

Runway Building and Food Exploration Strategy of Pseudacanthotermes militaris (Insecta: Isoptera)

Abstract: Pseudacanthotermes militaris explores and attacks timber in the vicinity of cracks. Maximum stimulation of the termite was observed when the crack width approximated both the modal height of the runways and the height to which a minor worker could lift a soil particle. OBSERVATIONS ON THE DAMAGE to telegraph poles (Usher and Barnacle 1974) and fencing material in Ghana indicated that termites sometimes preferentially attacked wood in the vicinity of cracks or checks. Such observations posed the question of whether the presence of cracks could act as a termite attractant, the answer to which would influence two aspects of termite research. First, if man's wooden structures (e.g. poles and building timbers) are to be protected from attack, then a smooth continuous surface may be more resistant to attack than one with cracks or badly fitted joints. Secondly, an attractant property could be used as a bait (Fougerousse 1969; Lund 1969) when designing tests on the resistance of materials or treatments to termite attack, or as a lure (Gray 1969) in survey work. In some areas of Kumasi, Ghana, the most frequent wood-destroying termite is Pseudacanthotermej militaris (Hagen), Termitidae: Macrotermitinae. The chewed wood (or other material) is taken underground to the nest, where it is used in the construction of a fungus comb, having passed once through the gut of the worker termite. This species forages on the soil surface at night or when the weather is cool and moist, and when a food resource has been located it is covered by a soil structure and the path leading to it is completely enclosed by a soil tube, referred to as a "runway." In section these runways are approximately semi-elliptical, with the substrate forming the shorter diameter of the ellipse. If a runway or food location is examined, four castes of P. militaris will usually be found, major and minor soldiers and major and minor workers. Observational evidence by Sands (1972), Williams (1973), and myself suggests that minor workers are usually associated with the building of the runways while major workers are the means of transport of the food to the fungus comb. STIMULUS TO EXPLORE To test the response of P. militaris to cracks, 18 strips of wawa or obeche (Triplochiton scleroxylon K. Schum.) 70 x 30 x 15 mm were used between two sheets of glass. The blocks were glued side by side to the glass leaving spaces of 0, 0.5, 1, 1.5, 2, 2.5, 3, 4, and 6 mm. These spaces were randomly arranged, and were repeated once on each side of a plate (a similar plate is shown in figure 1). Each crack was therefore 30 mm high and 70 mm long. Four such plates were made, set level with the ground surface, and covered with roofing felt supported on hollow bricks. Each day the plates were uncovered and the amount of termite penetratioln, as indicated by runway construction, recorded by observation through the glass. Two plates were explored by termites on the first day of exposure, one on the seventh, and one on the nineteenth day. An index of exploration was determined by scoring 3 if the whole crack had been explored, 2 if more than 10 mm of the depth had been explored, 1 if less than 10 mm had been explored, and 0 if there was no exploration. The indices for the first and third days after exploration of the plate had commenced, averaged over all plates, are shown in figure 2. From this graph it is apparent that small cracks do not stimulate termite exploration, probably because they are too narrow for all castes of P. militaris to enter. One question which remained unanswered was whether the smaller index for 6 mm cracks was a real reduction of exploration with crack size. Thus a second experiment was set up, again using 4 plates, but with crack widths of 3, 4, 5, 6, 7, 8, 10, 12, and 15 mm (fig. 1). The crack height, depth, and the scoring system for the index of exploration were the same as before. The plates were exposed in December 1971, which is during the dry, sunny season in Kumasi (Gibbs and Leston 1970), and it was apparent that the level of ground surface activity in P. nzilitaris was reduced at this 1 Present address: Department of Biology, University of York, York YO1 5DD, United Kingdom. 154 BIOTROPICA 6(3): 154-157 1974 This content downloaded from 207.46.13.28 on Tue, 30 Aug 2016 04:57:32 UTC All use subject to http://about.jstor.org/terms time of year. Exploration of the plates began on the first, second, third, and thirty-sixth days of exposure. The data, shown in figure 2, also demonstrate a decrease in the index of exploration at larger crack sizes. With cracks of 12 and 15 mm width it was frequent for P. militaris not to occupy the whole crack width, but to build a runway on the side of one of the wawa blocks. RUNWAY AND WORKER SIZE Runways of P. militaris from the same habitat were collected and measured. Histograms of the maximum height and of the basal width are shown in figure 2. ... * ..... ..** .* .... * * . . .. FIGURE 1. The layout of a plate in the second crackwidths experiment. The outline of the glass sheet is shown, and stippling indicates obeche strips. On each side of the plate the crack widths are arranged randomly. From this data it was found that the mean height is 3.95 mm (S.E. 0.097) with a mode of about 4.75 mm. The mean width is 6.99 mm (S.E.0.216), and the mode is 7 mm. The distribution of heights is strongly skewed to the left, with no runways being greater than 5.5 mm high. The distribution of widths is more nearly normal, though only one runway was found with a width of less than 4.5 mm. Fifteen minor workers have been measured from a collection made on the test site and preserved in ethanol. Experimentation with models yielded two possible mechanisms whereby the minor workers, carrying soil particles in their mouths, could push the particles upward into position. Figure 3 shows the two models, one where the termite is bipedal and one where it is quadripedal. Taking first the bipedal model, the height to which the termite could raise a soil particle is approximately the sum of the lengths of tibia III, femur III, coxa III, the thoracic segments, and the majority of the head capsule. The mean lengths together with their standard errors are recorded in table 1. In interpreting these measurements, it should be noted that the maximum height can only be TABLE 1. Measurements (in mm) of fifteen minor wokers of P. militaris. Quadripedal model Bipedal model Structure Mean S.E. Mean S.E. Tibia (II or III) 0.94 0.014 1.18 0.014 Femur (II or II) 0.79 0.016 1.05 0.018 Coxa (II or III) 0.57 0.013 0.57 0.014 Thoracic segments (I-II or I-III) 0.75 0.030 1.09 0.034 Part of head and mandible 1.22 0.020 1.22 0.020 Total 4.27 0.062 5.11 0.067 realized if the termite is able to bring all five sections measured into a straight line. This practice is certainly possible for the legs, but the forward prolongation dorsally of the first thoracic segment probably prevents the head being raised to more than 300 from the vertical. Assuming 300, then the head and mandibles height will be reduced to a mean of 1.22 cos 30? 1.06 mm, giving a mean total height of 4.95 mm. The maximum total height of the 15 minor workers measured would be reduced from 5.68 to 5.50 mm. Bipedality in these insects is probably less common than quadripedality. Figure 3 illustrates a model Runway Building and Food Exploration in Termites 155 This content downloaded from 207.46.13.28 on Tue, 30 Aug 2016 04:57:32 UTC All use subject to http://about.jstor.org/terms 0 30 0~~~~~~~~~~~~~~/0

Problems in Interpreting Dispersal of Terrestrial Organisms as Related to Continental Drift

Abstract: The interpretation of past movements of land areas and their degree of emergence involves a number of suppositions and uncertainties which are briefly discussed. Evidence seems to indicate that from at least the Mesozoic to the present, water barriers have been present and have served as an isolating mechanism for terrestrial organisms. Further data and interpretation are needed before much of our speculation on the past movements of organisms can be said to have a firm factual basis. WITH THE CURRENT PLETHORA of geological papers discussing continental drift it is not surprising that the evidence and theories relating to drift have influenced thinking in other disciplines. For many years some biogeographers have felt the necessity of proposing either continental drift or land bridges to explain certain types of distribution patterns, particularly those of terrestrial organisms. Now with the current geophysical evidence supporting continental drift, many biologists seem to feel that continental movements can be used to explain most disjunct patterns found in the older groups of terrestrial organisms. While continental movements may help to explain some disjunct distributions, a number of factors that could influence both old and present distribution patterns frequently seem to be overlooked. The purpose of this paper is to summarize some of these factors and consider some of the inherent problems and uncertainties, particularly in relation to continental drift and the occurrence of epicontinental seas. For most biologists the interpretation of geological evidence as an aid to understanding biological patterns and diversity presents many problems. Not the least of these is the voluminous literature concerning continental drift and related subjects. Because of this situation, biologists have tended to utilize review or summary papers such as the series from the Scientific American entitled "Continents Adrift" with an introduction by J. Tuzo Wilson (1972). Unfortunately many of the papers are oversimplifications and tend to present the positive evidence for plate tectonics and drift while neglecting the contrary evidence. A second aspect is that the geological evidence has usually not been presented in a format of optimal usefulness for biologists. The vast majority of geologists now accept the broad picture of continental plate movements. However, there are objections that need to be answered, and biologists should be aware of these. Meyerhoff and Meyerhoff (1972) and Meyerhoff, Meyerhoff, and Briggs (1972) have thoughtfully discussed a number of inconsistencies that need answering such as the position of coal and evaporite beds which can be related to present continental positions and climatic belts but which form an unexplainable mosaic when plotted on drift maps of Pangaea. Ilich (1972) has briefly summarized major problem areas, and Wesson (1972), in a summary manner, has listed six major groupings of problems and 74 objections. Both Meyerhoff and Meyerhoff (1972) and Keith (1972) have proposed alternate interpretations of present evidence, which involve cooling and contraction movements of the earth's crust (e.g., a sea floor narrowing). Of the various objections to present drift theories, Meyerhoff's numerous papers (see bibliography in Meyerhoff et al. 1972) are the best documented. If one assumes that most of the objections can be answered, a consideration of prodrift evidence still poses problems for both geologists and biologists. The Caribbean area presents numerous interpretive problems (Khudoley and Meyerhoff 1971, list 46 major unsolved geological problems) as does the Beringean area (Churkin 1972). One specific example of a problem area involves the debate about the placement of Madagascar (the Malagasy Republic), its direction of movement and time of separation. At least three different positions have been proposed (Heirtzler and Burroughs 1971): first, that it has remained in its present position from Mesozoic time; second, that it has moved eastward since the Cretaceous period from a position adjacent to Mozambique; and third, that it has been moving BIOTROPICA 6(1): 1-6 1974 1 This content downloaded from 157.55.39.243 on Wed, 05 Oct 2016 04:36:49 UTC All use subject to http://about.jstor.org/terms MAP 1. Approximate extent of exposed land (black) and epicontinental seas (white) about 150 million years B.P. (Jurassic) plotted on a continental drift configuration from Wilson (in "Continents Adrift," 1972). The "?" indicates a possibly seaway. south and slightly east from a position against Somalia since the early Cenozoic. In addition, northward movements from a more southerly position have also been proposed. At present the type and direction of movements are unresolved as is the time of separation. Hammond (1973) has stated that recent evidence has shown that Madagascar has been "an independent minicontinent for at least the last 100 million years." Epicontinental sea sediments surrounding the north-south mountain spine of Madagascar seem also to indicate that there has been no dry-land connection to Madagascar from other continental plates for at least the same period of time or longer. Some biologists seem to question this assumption, since according to Fooden (1972) the mammalian relicts indicate that the separation of Madagascar may date from the Paleocene-Eocene. Differences in the time sequence for continental separations are numerous, both among geologists and biologists, with biologists often tending to utilize the dates proposed by geologists that seem most favorable to explain a particular pattern. Recently Phillips and Forsyth (1972) have dated the opening of the North Atlantic at 150 million years B.P. and the opening of the South Atlantic at 130 million years B.P., while some earlier authors have suggested a much later opening. Current geological literature seems generally in accord with the Phillips and Forsyth dates. (Maps 1 and 2 herein show a later separation.) Timing of the Mesozoic (and earlier) continental movements will undoubtedly be debated for some time along with their effect on terrestrial dispersal patterns. However, if the overall major pattern of continental movements is accepted, other geological events must still be considered in assessing the distributional patterns of terrestrial organisms. Present theories of plate movements and continental fits are based, in part, on the shapes of the continental margins. These margins often are now submerged

Zoogeography of the Irenidae (Aves: Passeres)

Abstract: The only family of birds endemic to the Oriental zoogeographical region is the Irenidae (genera Irena, Chloropsis, and Aegithina). The ranges of the 57 races (in 14 species) are described, and some taxonomic and distributional questions are raised. The southern Malay peninsula and Sumatra contain the largest number of species and subspecies, with numbers decreasing outward to their lowest values at the peripheries of the family's range. Several lines of evidence indicate that Malaya-Sumatra has served as the center of evolution of the Irenidae. Water gaps are important barriers to dispersal of birds of this family in which 28.6% of the species and 43.9% of the races are confined to a single island or island group. Mountains also impede dispersal, but ecological factors associated with altitude; latitude, and precipitation are probably more important that elevation per se. Much of the diversity of the Irenidae fauna in the Malaysian subregion may be attributable to Pleistocene sea-level oscillations. Some races and even species probably have evolved since the end of the last glaciation 11,000 years ago, making insular southeast Asia a natural laboratory for the study of bird evolution. Suggestions are made for ecological, ethological, zoogeographical, and taxonomic research to explain the restriction of this family, AUTHORITIES DISAGREE about the precise number of families of birds in existence, but it is generally regarded as approximately 170. Of the 144 families of land birds considered by Barden (1941), 33 occur in all six zoogeographical regions. The Nearctic, Palearctic, and Oriental regions have only one indigenous family each, while the other three regions exhibit considerably more endemicity (Pettingill 1970; Welty 1963), although because of taxonomic and distributional problems, even these generalizations are not accepted by all authorities (e.g. Darlington 1957; Van Tyne and Berger 1959). The more recent treatments of the subject, however, recognize one family of Aves that includes the fairy bluebirds (Irena), the leafbirds (Chloropsis), and the ioras (AegithinnazAethorhynchus) as being endemic to the Oriental zoogeographical region. Particularly in the early literature these genera were often classified within the family Pycnonotidae (bulbuls) (e.g. Caldwell and Caldwell 1931; Chasen 1935), which presumably accounts for Barden's (1941) listing of no family endemic to the Oriental region. When recognized as a separate family, this assemblage of three genera has been referred to as either Aegithinidae or Irenidae. Delacour used the former term in his books of 1946 (with Mayr) and 1947, but the latter in his contribution to Mayr and Greenway (1960), Ripley (1961), and Wildash (1968) also used Irenidae. Wetmore (1960) stated that the generic name Chloropsis antedates the others, hence should be used to designate the family, but he also placed Irena in the family Oriolidae (old world orioles) so that his family Chloropseidae included only Chloropsis and Aegithina. Other arrangements include that of Henry (1971) in which Irena is the sole genus of the Irenidae, the other two genera constituting the subfamily Liotrichinae of the Pycnonotidae, and that of Robinson (1927) in which the Irenidae comprise Irena and the nowsynonymized genus Ire-nella while the Aegithinidae consist of Aegithina and Chloropsis. I shall follow the majority of recent authors in considering Irena, Aegithina, and Chioropsis as comprising the family Irenidae. Aside from taxonomic studies and brief discussions of the species in bird guides, very little has been written about this group, although Ali and Ripley (1971) have recently enhanced our knowledge of the Indian forms. It is hoped that this review will raise questions that will prompt further research into the systematics of the Irenidae, as well as the ecology and ethology with a view toward explaining their distribution. Although the familial position of the genera may have been a subject of some dispute, the genera themselves and the species (with two possible exceptions) seem welldefined. Their geographic distributions are also quite well-known. However, systematics at the subspecific2 level, often based on subtle and apparently variable plumage differences (Hall 1957; Hoogerwerf 1962; Marien 1952; Robinson 1927), are to some extent not yet clear, particularly for Aegithina. The most general consensus of opinion is on races confined to islands or island groups. In this paper I shall, with a few exceptions, accept as valid those subspecies recognized as distinct by Delacour (1960), 1 Present address: School of Biological Sciences, University of Malaya, Kuala Lumpur, Malaysia. 2 The terms "subspecies" and "race" (i.e. geographical race) are used synonymously (Mayr 1969b). BIOTROPICA 6(3): 165-174 1974 165 This content downloaded from 157.55.39.35 on Wed, 31 Aug 2016 04:29:06 UTC All use subject to http://about.jstor.org/terms whose listing agrees with most recent literature on the subject. Aegithina are black and yellowor olive-green, mainly insectivorous birds; Chloropsis, bright green animals, are largely frugivorous, but feed on insects, nectar, and seeds as well; Irena, mainly blue in color, are almost exclusively fruit-eaters (Ali and Ripley 1971; Baker 1922, 1926; Hachisuka 1935; Robinson 1927; Smythies 1960; Whistler and Kinnear 1949). Thus all are tied to areas of abundant vegetation, occurring in forests, plains peripheral to forests, or areas of secondary growth, and most species are rarely resident much above about 1000 m elevation, although they may range higher (Ali and Ripley 1971; Baker 1922, 1926; Ripley 1961; Wait 1925). All are non-migratory although they may undergo altitudinal movements correlated with breeding season, so their ranges are strictly residential (Ali 1943; Ali and Ripley 1971; Deignan 1945; Whistler and Kinnear 1932). Irenidae range from extreme northwestern Pakistan to the easternmost portion of the Philippine Islands, and from the latitude of the Himalayan foothills south to Wallace's line, an area almost precisely coincident with that generally recognized as the Oriental region. However, no one genus spans the entire distance east to west, although all three genera extend to the northern and southern extremes of the range. Irena, the most geographically restricted genus, has only two species. The other genera have about equally wide geographic spans, but Aegithina extends farther west and Chloropsis farther east. Aegithina consists of four species, Chloropsis of eight. Nothing can be deduced about the zoogeography of the Irenidae at the generic level for all three genera are found in lower peninsular India and Ceylon, from Bangladesh eastward through Burma, Thailand, IndochiDa, and into the Malaysian subregion as far east as Palawan. Aegithina alone extends into Pakistan. while both Chloropsis and Irena are represented east of Palawan in the Philippines.