Showing papers in "Biological Journal of The Linnean Society in 2005"

Towards integrative taxonomy

Abstract: Delineating species boundaries correctly is crucial to the discovery of life’s diversity because it determines whether or not different individual organisms are members of the same entity. The gap in communication between the different disciplines currently involved in delimiting species is an important and overlooked problem in the so-called ‘taxonomy crisis’. To solve this problem, it is suggested that taxonomy become integrative, and this integration is seen as the real challenge for the future of taxonomy. ‘Integrative taxonomy’ is defined as the science that aims to delimit the units of life’s diversity from multiple and complementary perspectives (phylogeography, comparative morphology, population genetics, ecology, development, behaviour, etc.). Some workers have already collaborated and successfully adopted an integrative approach to taxonomy. However, it is now time for the whole discipline to evolve. A radical change in mentality is needed concerning the creation of names in order to achieve this integration and to prevent the over-abundance of both synonyms and names of doubtful application from worsening. Integrative taxonomy gives priority to species delineation over the creation of new species names. Furthermore, it is emphasized that describing morphological diversity, referred to as ‘morphodiversity’, does not require the naming of any single set of specimens. Seven guidelines are proposed to help integrative taxonomists recognize cases when species are supported by broad biological evidence and therefore are deserving of an official name. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society , 2005, 85 , 407‐415. ADDITIONAL KEYWORDS: biodiversity ‐ character variation ‐ DNA barcoding ‐ ecology ‐ morphodiversity ‐ phylogenetics ‐ phylogeography ‐ population biology ‐ species delineation ‐ systematics.

Comparing entire colour patterns as birds see them

Abstract: Colour patterns and their visual backgrounds consist of a mosaic of patches that vary in colour, brightness, size, shape and position. Most studies of crypsis, aposematism, sexual selection, or other forms of signalling concentrate on one or two patch classes (colours), either ignoring the rest of the colour pattern, or analysing the patches separately. We summarize methods of comparing colour patterns making use of known properties of bird eyes. The methods are easily modifiable for other animal visual systems. We present a new statistical method to compare entire colour patterns rather than comparing multiple pairs of patches. Unlike previous methods, the new method detects differences in the relationships among the colours, not just differences in colours. We present tests of the method's ability to detect a variety of kinds of differences between natural colour patterns and provide suggestions for analysis.

One hundred years of eruptions of house mice in Australia: a natural biological curio

Abstract: The house mouse has adapted well to the cereal crops of south-eastern Australia where populations show aperiodic outbreaks over large areas. A 20-year population study has provided a wealth of information on breeding ecology, demographic changes, spatial behaviour and epidemiology. The breeding season can be as short as 4.5 months and as long as 10 months with litter size changing seasonally from high values in spring to low values in autumn. There are marked changes in litter size between years. Rates of increase of populations also vary between years. The rate of change of populations during the breeding season is independent of density effects, but if the population density is high at the commencement of breeding then the litter size is depressed throughout that breeding season. There are density-dependent effects on survival during the non-breeding season. Rates of increase of populations over spring and summer are highly correlated with accumulated rainfall from the previous winter-spring (April-October). Studies of helminths and viruses indicate that Australian mice carry only a subset of the helminths found in Europe. There have been no published studies on murine viruses in Europe. Perhaps a reduced diversity of diseases partially accounts for the ability of mice to increase rapidly to extreme population densities in cereal-growing areas of south-eastern Australia.

Phylogeography and species limits in the Gymnodactylus darwinii complex (Gekkonidae, Squamata): genetic structure coincides with river systems in the Brazilian Atlantic Forest

Abstract: Phylogenetic analyses based on mtDNA cytochrome b were performed in 42 lizards of the Gymnodactylus darwinii complex from three regions within Brazil's Atlantic Forest. Mainland regions and continental shelf islands in the south-eastern range and mainland areas from the north-east were sampled. The criteria of maximum parsimony (MP), maximum likelihood (ML) and Bayesian methods were explored, with the robustness for nodes assessed by bootstrapping (MP and ML) and posterior probabilities (Bayesian searches). By all methods, three distinctive phylogroups were recovered: a south-eastern clade (SE) and two clades from northern regions (NE1 and NE2). The pattern of genetic structure of the major clades coincided with the presence of river systems in the Atlantic Forest, and based on corrected genetic distances between those clades, divergence times were tentatively estimated using mtDNA rates calibrated for squamate reptiles. The putative role of Atlantic Forest rivers in generating differentiation is discussed. We present a hypothesis of species limits for G. darwinii, based on concordant lines of evidence including cytogenetic and mtDNA analyses. Two chromosome races (cytotype A, 2n = 38; and cytotype B, 2n = 40) had distributions concordant with clades SE and NE1 + NE2, respectively. These races are interpreted to be full species on the basis of a number of empirical criteria. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society, 2005, 85, 13–26.

First occurrence of the house mouse (Mus musculus domesticus Schwarz & Schwarz, 1943) in the Western Mediterranean: a zooarchaeological revision of subfossil occurrences

Abstract: This paper provides a critical analysis of archaeological small mammal collections in the Mediterranean area, from the Late Glacial to the first centuries AD, to validate the presence/absence of the house mouse through zooarchaeological criteria. The results have been synthesized through a diachronic map, whose chronological phases are related to socio-economic and cultural human evolution. The house mouse (Mus musculus domesticus) progression in the Mediterranean begins with a quick but limited diffusion in the Eastern Mediterranean Basin achieved around the 8th millennium BC. Until the 1st millennium BC, the invasive process seems to have stopped or drastically slowed, despite the increasing opportunities of passive transport during the Bronze Age. During the 1st millennium BC, there was mass colonization by the house mouse of the entire Western Mediterranean Basin and Northern Europe. We propose to explain this chronological gap in the colonization of the Eastern and Western Mediterranean using source-sink theory considering that the western environments acted like sinks until the first millennium BC. At that time the Western Mediterranean was fully opened to Eastern influences and migrations, and the human pressures on the environment drastically increased. This may have favoured definitively the adaptation of the house mouse to the Western commensal niches.

Chromosomal variation in the house mouse

Abstract: Although the standard karyotype of the western house mouse, Mus musculus domesticus, consists entirely of acrocentric chromosomes, there are 97 distinct 'populations' that are characterized by various combinations of metacentric chromosomes that have arisen by Robertsonian (Rb) fusions and whole-arm reciprocal translocations (WARTs). In this review we discuss the processes behind the origin and fixation of these rearrangements and then present a unified list of all known metacentric populations and evaluate their phylogenetic relationships. Eleven independent phylogeographical 'systems', each consisting of 2-25 metacentric populations, were identified in Scotland, Denmark, Northern Europe-Northern Switzerland, Southern Switzerland, Northern Italy, Croatia, Spain, Central-Southern Italy, Peloponnesus, Mainland Greece and Madeira. There are six isolated metacentric populations that do not belong to any of these systems. To generate phylogenies of the metacentric populations within each system, we determined those outcomes with the fewest steps regarding accumulation of metacentrics by Rb fusions, WARTs and zonal raciation and taking into account geographical proximity. These phylogenies should be viewed as working hypotheses that will be refined with further chromosomal and molecular data and improvements in methods of phylogenetic reconstruction. The list of metacentric populations and our phylogenies are also published electronically and can be accessed at http://www.studenec.ivb.cz/Projects/RobertsonianMice/.

Dispersal in house mice

Abstract: This review evaluates direct (live-trapping) and indirect (genetic) methods to study dispersal in wild house mice (Mus musculus) and summarizes field and experimental data to examine the causes and consequences of dispersal. Commensal house mice (associated with human habitations, farms, food stores and other anthropogenic habitats) typically show lower rates of dispersal than feral house mice (living in crops, natural and semi-natural habitats). However, early claims of long-term fine-scale genetic structure in commensal house mice (due to low rates of dispersal) are not supported by recent data. Dispersal becomes obligatory when habitat conditions deteriorate, but most dispersal occurs below the local environmental carrying capacity and is due to social interactions with conspecifics. Excursions are relatively frequent and probably allow mice to assess the quality of habitats before dispersing. Young males have the greatest tendency to disperse, apparently prompted mainly by aggressive interactions with dominant males. If they do disperse, females integrate into new groups more easily than do males. Dispersing house mice risk loss of condition or death, but may gain reproductive opportunities on arrival in a new location. House mice can be transported passively as stowaways with humans; this contributes to population persistence and genetic structure at regional scales and has allowed house mice to spread world-wide.

The phylogenetic position of toadfishes (order Batrachoidiformes) in the higher ray-finned fish as inferred from partitioned Bayesian analysis of 102 whole mitochondrial genome sequences

Abstract: In a previous study based on 100 whole mitochondrial genome (mitogenome) sequences, we sought to provide a new perspective on the ordinal relationships of higher ray-finned fish (Actinopterygii). The study left unexplored the phylogenetic position of toadfishes (order Batrachoidiformes), as data were unavailable owing to technical difficulties. In the present study, we successfully determined mitogenomic sequences for two toadfish species (Batrachomoeus trispinosus and Porichthys myriaster) and found that the difficulties resulted from unusual gene arrangements and associated repetitive non-coding sequences. Unambiguously aligned, concatenated mitogenomic sequences (13 461 bp) from 102 higher actinopterygians (excluding the ND6 gene and control region) were divided into five partitions (1st, 2nd and 3rd codon positions of the protein-coding genes, tRNA genes and rRNA genes) and partitioned Bayesian analyses were conducted. The resultant phylogenies strongly suggest that the toadfishes are not members of relatively primitive higher actinopterygians (Paracanthopterygii), but belong to a crown group of actinopterygians (Percomorpha), as was demonstrated for ophidiiform eels (Ophidiiformes) and anglerfishes (Lophiiformes) in the previous study. We propose revised limits of major unranked categories for higher actinopterygians and a new name (Berycomorpha) for a clade comprising two reciprocally paraphyletic orders (Beryciformes and Stephanoberyciformes) based on the present mitogenomic phylogenies. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society, 2005, 85, 289–306.

Phylogenetic relationships and historical biogeography of tribes and genera in the subfamily Nymphalinae (Lepidoptera: Nymphalidae)

Abstract: We infer for the first time the phylogenetic relationships of genera and tribes in the ecologically and evolutionarily well-studied subfamily Nymphalinae using DNA sequence data from three genes: 1450 bp of cytochrome oxidase subunit I (COI) (in the mitochondrial genome), 1077 bp of elongation factor 1-alpha (EF1- a ) and 400-403 bp of wing- less (both in the nuclear genome). We explore the influence of each gene region on the support given to each node of the most parsimonious tree derived from a combined analysis of all three genes using Partitioned Bremer Support. We also explore the influence of assuming equal weights for all characters in the combined analysis by investigating the stability of clades to different transition/transversion weighting schemes. We find many strongly supported and stable clades in the Nymphalinae. We are also able to identify 'rogue' taxa whose positions are weakly supported (the different gene regions are in conflict with each other) and unstable. Our main conclusions are: (1) the tribe Coeini as currently constituted is untenable, and Smyrna, Colobura and Tigridia are part of Nymphalini; (2) 'Kallimini' is paraphyletic with regard to Melitaeini and should be split into three tribes: Kallimini s.s. , Junoniini and Victorinini; (3) Junoniini, Victorinini, Melitaeini and the newly circumscribed Nymphalini are strongly supported monophyletic groups, and (4) Precis and Junonia are not synonymous or even sister groups. The species Junonia coenia , a model system in developmental biology, clearly belongs in the genus Junonia . A dispersal-vicariance analysis suggests that dispersal has had a major effect on the distributions of extant species, and three biotic regions are identified as being centres of diversification of three major clades: the Palaearctic for the Nymphalis -group, the Afrotropics for Junoniini and the Nearctic for Melitaeini. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society , 2005, 86 , 227-251. ADDITIONAL KEYWORDS: DIVA - molecular phylogeny - Partitioned Bremer Support - sensitivity analysis.

Hybridization and the inheritance of female colour polymorphism in two ischnurid damselflies (Odonata: Coenagrionidae)

Abstract: a> p i > p ∞ ). Five interspecific crossings between female I. graellsii and male I. elegans , five crossings between hybrid females and male I. elegans and one crossing between female I. graellsii and a hybrid male further confirmed that the genetic system is the same in both species. A survey of morph frequencies in north-west Spain revealed that I. elegans shows high variability in androchrome frequency (4‐91%) between nearby populations, whereas in I. graellsii androchromes never are the majority morph (5‐40%). The highest androchrome frequency in I. graellsii was found in populations closest to a locality where both species have hybridized, and that now has the highest androchrome frequency of I. elegans . We hypothesize that I. elegans genes have been incorporated into the genome of I. graellsii resulting in increased androchrome frequency in the latter species. Low androchrome frequency in I. elegans seems also related to the influence of I. graellsii genes. Therefore, we suggest that hybridization between both taxa is contributing to the temporal maintenance of contrasting androchrome frequencies in nearby populations. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society , 2005, 85 , 471‐481. ADDITIONAL KEYWORDS: allopatry ‐ female-limited polychromatism ‐ hybrid zone ‐ introgression sympatry ‐ Ischnura elegans ‐ Ischnura graellsii ‐ laboratory crosses.

Postzygotic isolation between the two European subspecies of the house mouse: estimates from fertility patterns in wild and laboratory-bred hybrids

Abstract: We assessed the fertility (reproductive success, litter size, testis weight, spermatocyte-to-spermatid ratio) of F 1 s and backcrosses between different wild-derived outbred and inbred strains of two mouse subspecies, Mus musculus domesticus and M. m. musculus. A significant proportion of the F 1 females between the outbred crosses did not reproduce, suggesting that female infertility was present. As the spermatocyte-to-spermatid ratio was correlated with testis weight, the latter was used to attribute a sterile vs. fertile phenotype to all males. Segregation proportions in the backcrosses of F 1 females yielded 11 (inbred) to 17% (outbred) sterile males, suggesting the contribution of two to three major genetic factors to hybrid male sterility. Only one direction of cross between the inbred strains produced sterile F 1 males, indicating that one factor was borne by the musculus X-chromosome. No such differences were observed between reciprocal crosses in the outbred strains. The involvement of the X chromosome in male sterility thus could not be assessed, but its contribution appears likely given the limited introgression of X-linked markers through the hybrid zone between the subspecies. However, we observed no sterile phenotypes in wild males from the hybrid zone, although testis weight tended to decrease in the centre of the transect.

A comparison of habitat use, morphology, clinging performance and escape behaviour among two divergent green anole lizard ( Anolis carolinensis ) populations

Abstract: We measured available and actual habitat use, morphology, escape behaviour and clinging ability in a large sample(N = 242) of green anoles, Anolis carolinensis, in a habitat consisting primarily of segregated dense clumps of broadleaves, Aspidistra elatior (Tulane University campus, LA) to compare against similar data collected previously froma more typical habitat c. 30 km away, consisting of continuous strands of bushes and trees (Good Hope Field, St.Charles Parish, LA). At Tulane the anoles perched primarily on the broad, smooth leaves of broad leaves, whereasin Good Hope Field (GHF) they predominantly perched on branches and tree trunks. The two populations differedsignificantly in morphology. In Tulane, the anoles tended to have shorter distal hindlimb elements, longer forelimbelements, and were more ‘slender’ than those at GHF. A comparison of escape behaviour showed population and sexdifferences. In both populations, females had significantly longer approach distances (i.e. were more ‘wary’) thanmales. These distances were, in addition, significantly longer at GHF than at Tulane for both sexes; this may be dueto the potentially higher diversity and abundance of predators at GHF, although habituation to humans may alsoplay a role. Anoles at Tulane had significantly larger toepads and higher clinging abilities than those at GHF. Theenhanced clinging abilities of anoles at Tulane may have arisen due to their propensity to use smooth leaves as theirprimary substrate. Overall, our data reveal substantial ecological, behavioural, morphological, and functional dif-ferences among populations, some of which may be adaptive. © 2005 The Linnean Society of London, BiologicalJournal of the Linnean Society, 2005, 85, 223–234.

Inferences of selection and migration in the Danish house mouse hybrid zone

Abstract: We analysed the patterns of allele frequency change for ten diagnostic autosomal allozyme loci in the hybrid zone between the house mouse subspecies Mus musculus domesticus and M. m. musculus in central Jutland. After determining the general orientation of the clines of allele frequencies, we analysed the dine shapes along the direction of maximum gradient. Eight of the ten clines are best described by steep central steps with coincident positions and an average width of 8.9 km (support limits 7.6-12.4) flanked by tails of introgression, indicating the existence of a barrier to gene flow and only weak selection on the loci studied. We derived estimates of migration from linkage disequilibrium in the centre of the zone, and by applying isolation by distance methods to microsatellite data from some of these populations. These give concordant estimates of σ = 0.5-0.8 km generation -1/2 . The barrier to gene flow is of the order of 20 km (support limits 14-28), and could be explained by selection of a few per cent at 43-120 under-dominant loci that reduces the mean fitness in the central populations to 0.45. Some of the clines appear symmetrical, whereas others are strongly asymmetrical, and two loci appear to have escaped the central barrier to gene flow, reflecting the differential action of selection on different parts of the genome. Asymmetry is always in the direction of more introgression into musculus, indicating either a general progression of domesticus into the musculus territory, possibly mediated by differential behaviour, or past movement of the hybrid zone in the opposite direction, impeded by potential geographical barriers to migration in domesticus territory.

Molecular phylogeny of the genus Mus (Rodentia: Murinae) based on mitochondrial and nuclear data

Abstract: The genus Mus encompasses at least 38 species divided into four subgenera: Mus, Pyromys, Nannomys and Co-elomys. The subgenus Mus, which comprises the house mouse and related species, is by far the most extensively studied, although the subgenus Nannomys is the most speciose. Although the relationships within the subgenus Mus are rather well characterized, those between subgenera are still unclear. In the present study, phylogenetic analyses of the whole genus were performed using a larger species sample of Nannomys than in previous studies, and a nuclear gene (IRBP) in addition to mitochondrial data (cytochrome b and 12S rRNA). Members of the Acomyinae and Murinae were used as outgroups. Separate and combined analyses were performed with maximum parsimony, maximum likelihood and Bayesian methods, and divergence times were estimated. The results showed that the monophyly of the genus Mus and of each subgenus was strongly supported by the three genes and the combined analysis. The phylogenies derived from the three genes were on the whole congruent; however, several conflicting topologies were observed such as the relationships between the three Asian species of the subgenus Mus (caroli, cervicolor and cookii). Increasing the taxonomic sampling of Nannomys did not satisfactorily improve the resolution of relationships between the four subgenera. In addition, molecular calibrations indicate that the Mus and Nannomys radiation coincided with major environmental changes.

Correlations between lizard cranial shape and diet: A quantitative, phylogenetically informed analysis

Abstract: Although the relationship between dietary and phenotypic specialization has been well documented for many vertebrate groups, it has been stated that few such general trends can be established for lizards This is often thought to be due to the lack of dietary specialization in many lizards For example, many species that are reported to be insectivorous may also consume a variety of plant materials, and the reverse is often true as well In this study, we investigate whether a correlation exists between general cranial form and dietary niche in lizards Additionally, we test previously proposed hypotheses suggesting that herbivorous lizards should be larger bodied than lizards with other diets Our data indicate that lizards specializing in food items imposing different mechanical demands on the feeding system show clear patterns of morphological specialization in their cranial morphology True herbivores (diet of fibrous and tough foliage) are clearly distinguished from omnivorous and carnivorous lizards by having taller skulls and shorter snouts, likely related to the need for high bite forces This allows herbivores to mechanically reduce relatively less digestible foliage Carnivores have relatively longer snouts and retroarticular processes, which may result in more efficient capture and processing of elusive prey When analysed in an explicit phylogenetic context, only snout length and skull mass remained significantly different between dietary groups The small number of differences in the phylogenetic analyses is likely the result of shared evolutionary history and the relative paucity of independent origins of herbivory and omnivory in our sample Analyses of the relationship between diet and body size show that on average herbivores have a larger body size than carnivores, with omnivores intermediate between the two other dietary groups

Towards a panbiogeography of the seas

Abstract: A contrast is drawn between the concept of speciation favoured in the Darwin–Wallace biogeographic paradigm (founder dispersal from a centre of origin) and in panbiogeography (vicariance or allopatry). Ordinary ecological dispersal is distinguished from founder dispersal. A survey of recent literature indicates that ideas on many aspects of marine biology are converging on a panbiogeographic view. Panbiogeographic conclusions supported in recent work include the following observations: fossils give minimum ages for groups and most taxa are considerably older than their earliest known fossil; Pacific/Atlantic divergence calibrations based on the rise of the Isthmus of Panama at 3 Ma are flawed; for these two reasons most molecular clock calibrations for marine groups are also flawed; the means of dispersal of taxa do not correlate with their actual distributions; populations of marine species may be closed systems because of self-recruitment; most marine taxa show at least some degree of vicariant differentiation and vicariance is surprisingly common among what were previously assumed to be uniform, widespread taxa; mangrove and seagrass biogeography and migration patterns in marine taxa are best explained by vicariance; the Indian Ocean and the Pacific Ocean represent major biogeographic regions and diversity in the Indo-Australian Archipelago is related to Indian Ocean/Pacific Ocean vicariance; distribution in the Pacific is not the result of founder dispersal; distribution in the south-west Pacific is accounted for by accretion tectonics which bring about distribution by accumulation and juxtaposition of communities; tectonic uplift and subsidence can directly affect vertical distribution of marine communities; substantial parallels exist between the biogeography of terrestrial and marine taxa; biogeographically and geologically composite areas are tractable using panbiogeographic analysis; metapopulation models are more realistic than the mainland/island dispersal models used in the equilibrium theory of island biogeography; and regional biogeography is a major determinant of local community composition. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society, 2005, 84, 675–723.

Pollen fates and the limits on male reproductive success in an orchid population

Abstract: Male reproductive success in higher plants depends largely on the fates of pollen, but current methodologies have given only partial insights into this important aspect of plant mating. We present a detailed analysis of the proportions and absolute amounts of stained pollen involved in six key fates for the hawkmoth-pollinated African orchid Disa cooperi. Despite being packaged into pollinaria, high proportions (> 0.95) of the pollen removed from anthers were lost during transport by hawkmoths in both years. The proportion of pollen lost correlated positively with the number of pollinaria removed from a plant, so that pollen export did not vary with pollen removal. Most pollen was dispersed to neighbouring plants, with rare long-distance dispersal up to 65 m. Of the pollen that reached stigmas during both years, roughly equal amounts were involved in facilitated self-pollination vs. cross-pollination, but the relative proportions of these fates differed between years. Contrary to expectation, we found that self-pollination between flowers did not increase with the number of open flowers, even though moths probed significantly more flowers on larger plants. However, during both years the fraction of removed pollen exported to other plants declined significantly with increasing self-pollination on the source plant, indicating that once self-pollination occurred it reduced (discounted) subsequent pollen export opportunities. The packaging of pollen into pollinaria in orchids appears to increase overall transfer efficiency by at least an order of magnitude relative to plants with granular pollen. Nevertheless, considerable uncertainties remain in the male reproductive success of individual orchids. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society, 2005, 86, 175–190.

Intraspecific correlations among morphology, performance and habitat use within a green anole lizard ( Anolis carolinensis ) population

Abstract: We examined habitat use, morphology, jumping and clinging ability for 403 juvenile, female and male green anole lizards, Anolis carolinensis, in a population in south-eastern Louisiana. We sought to answer three questions: (1) Do age/sex classes differ in habitat use, morphology and performance ability? (2) Do habitat use, morphology and performance correlate among all individuals across three age/sex classes (juveniles, females and males)? (3) Do juveniles compensate for their poor absolute performance capacities by being better performers on a relative scale? The three age/sex classes were found to differ significantly in size-adjusted morphology, habitat use and size-adjusted performance capacity. Juveniles tended to occupy perches which were closer together than those of adult males and females. The distal elements of the hindlimb (femur, tibia) were significantly longer in males than in females and juveniles, while females were more stocky than males and juveniles. The only significant overall ecomorphological relationship detected was between the lengths of the distal hindlimb elements and maximum jump acceleration. Our hypothesis that juveniles should be better performers (relative to size) compared to adults was disproved, as adult females were always the best performers relative to size. Our analysis of a mainland anole population presents a different view of population structure compared to similar studies involving Caribbean Anolis lizards, which show more ecological differentiation among age/sex classes, and also show that juveniles are relatively good performers.

The influence of recent geography, palaeogeography and climate on the composition of the fauna of the central Aegean Islands

Abstract: Partial Mantel tests and structural equation models were used to investigate the influence of recent geography, palaeogeography and climate on the composition of the fauna of the central Aegean Islands. The composition of land snail and isopod island faunas was significantly influenced by recent and by Pliocene geography. Only Pleistocene palaeogeography had a significant influence on the composition of tenebrionid beetle island faunas. The composition of butterfly island faunas was influenced by recent and by Miocene geographical distances. The composition of reptile island faunas was correlated with recent and Pliocene geography as well as with Pleistocene and/or Miocene geographical distances. Island area influenced only the composition of the island faunas of the volant butterflies, and not that of the less mobile land snails, land isopods, tenebrionid beetles and reptiles. This might indicate that butterflies are able to colonize large islands with suitable habitats even if such islands are comparatively far from source areas more frequently than can the nonvolant groups. Influence of a climatic parameter, namely annual precipitation, on faunal composition was found only for reptiles. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society, 2005, 84, 785–795.

Pollen‐host specificity and evolutionary patterns of host switching in a clade of specialist bees (Apoidea: Diadasia)

Abstract: We examined the levels of pollen-host specificity in North American Diadasia (Hymenoptera: Apoidea), a clade of specialist bees. We analysed the scopal pollen loads of 409 individuals representing 25 of the 30 species of Diadasia that occur in North America. Each Diadasia species showed a preference for one of five plant families. However, the 25 species varied in their level of host specificity: the average percentage by volume of the preferred host in pollen loads ranged from > 99% to < 75%. In 17 of the 25 species, all or most individuals examined contained pure loads of one host taxon, while in eight species individuals were less specialized and carried mixtures of several unrelated host taxa. Mapping these host preferences onto a phylogenetic tree indicated that Malvaceae is the most likely ancestral host for the genus, and use of other hosts can be explained by a single switch to each of the other four host-plant families. Thus, most speciation events were not associated with a host switch; this pattern does not support host switching as a niche partitioning strategy to avoid competition. Diadasia species are more likely to use host-plant families that are used by other Diadasia and Emphorine bees; however, there was no evidence of residual adaptation to ancestral hosts. Diet breadth appears to be a labile trait: transitions from narrower to broader host use, as well as vice versa, were observed. The observed patterns of host-use evolution may be driven, in part, by host morphology and/or chemistry. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society , 2005, 86 , 487‐ 505.

Is the last glaciation the only relevant event for the present genetic population structure of the meadow brown butterfly Maniola jurtina (Lepidoptera: Nymphalidae)?

Abstract: Phylogeographical studies are available for a considerable number of European species, but few analyses exist for temperate species with very large and fairly continuous populations that are also absent from Northern Europe. Therefore, we studied the butterfly Maniola jurtina as a model for this group. The species has two major genetic lineages (mean genetic distance between lineages: 0.033; FCT: 0.052), most probably evolving in glacial differentiation centres in the western and eastern Mediterranean. The onset of this differentiation might have been the beginning of the last glacial stage maximum some 40 kyr bp. A hybrid zone between these two lineages exists in western Central Europe. No genetic substructures have been found within the two lineages (FSC: 0.017) and average genetic distances are very small. Therefore, it is highly probable that postglacial expansion was of the phalanx type. There is, at most, very limited differentiation at regional and local scales. However, the genetic diversity within populations is high (means: A: 2.68; HE: 17.2%; P: 78%), as would be predicted for such a common species. Comparison of these results with a published allozyme analysis revealed a similar phylogeographical pattern, but lower genetic diversity in the latter. Morphological patterns of wings and genitalia show similar geographical patterns as allozyme data. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society, 2005, 85, 419–431.

Survey-gap analysis in expeditionary research: where do we go from here?

Abstract: Research expeditions into remote areas to collect biological specimens provide vital information for understanding biodiversity. However, major expeditions to little-known areas are expensive and time consuming, time is short, and well-trained people are difficult to find. In addition, processing the collections and obtaining accurate identifications takes time and money. In order to get the maximum return for the investment, we need to determine the location of the collecting expeditions carefully. In this study we used environmental variables and information on existing col- lecting localities to help determine the sites of future expeditions. Results from other studies were used to aid in the selection of the environmental variables, including variables relating to temperature, rainfall, lithology and distance between sites. A survey gap analysis tool based on 'ED complementarity' was employed to select the sites that would most likely contribute the most new taxa. The tool does not evaluate how well collected a previously visited site sur- vey site might be; however, collecting effort was estimated based on species accumulation curves. We used the num- ber of collections and/or number of species at each collecting site to eliminate those we deemed poorly collected. Plants, birds, and insects from Guyana were examined using the survey gap analysis tool, and sites for future col- lecting expeditions were determined. The south-east section of Guyana had virtually no collecting information avail- able. It has been inaccessible for many years for political reasons and as a result, eight of the first ten sites selected were in that area. In order to evaluate the remainder of the country, and because there are no immediate plans by the Government of Guyana to open that area to exploration, that section of the country was not included in the remainder of the study. The range of the ED complementarity values dropped sharply after the first ten sites were selected. For plants, the group for which we had the most records, areas selected included several localities in the Pakaraima Mountains, the border with the south-east, and one site in the north-west. For birds, a moderately col- lected group, the strongest need was in the north-west followed by the east. Insects had the smallest data set and the largest range of ED complementarity values; the results gave strong emphasis to the southern parts of the coun- try, but most of the locations appeared to be equidistant from one another, most likely because of insufficient data. Results demonstrate that the use of a survey gap analysis tool designed to solve a locational problem using contin- uous environmental data can help maximize our resources for gathering new information on biodiversity. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society , 2005, 85 , 549-567.

The great tit (Parus major) — a misclassified ring species

Abstract: The great tit (Parus major) has been considered to be the most typical example of an avian ring species The terminal taxa of the ring (major and minor sectors) are supposed to be reproductively isolated in a zone of secondary contact in the middle Amur valley, Siberia Our study combines molecular markers (cytochrome-b), bioacoustic analyses and morphological characters to judge the ring species status of the great tit complex Despite a notable percentage of intermediately coloured birds in the mixed population of middle Amur, a lack of mitochondrial introgression between the major and minor sectors and a small number of true hybrids among voucher specimens from this area suggest at least a partial reproductive barrier between both sectors In contrast, variation of morphological and especially acoustic characters along the ring-shaped area and the phylogenetic structure of the P major group do not match the ring species concept Bioacoustic and molecular data (cytochrome-b sequences) reveal two large and closely related subspecies blocks, the sectors major and bokharensis in the Western Palaearctic and central Asia, and the sectors minor and cinereus in the Eastern Palaearctic and South-east Asia, respectively The two western sectors diverged only recently (05 Mya) and they were separated from the eastern group by Pleistocene events about 15 Mya Songs from allopatric regions of the two subspecies blocks differ distinctly in frequency parameters and element composition In the area of secondary contact, males of all phenotypes share the same frequency range of song, close to the range of the typical minor song Hybrids and major males sing mixed repertoires of typical major and minor strophe types as well as mixed strophes In contrast, phenotypic minor males display only pure minor strophes Differences in mate choice and mating success based on repertoire size are believed to uphold the reproductive barrier between major and minor birds in the area of sympatry Taxonomic consequences suggest three separate species in the Parus major complex: Parus major ss (including the very closely related bokharensis sector), Parus minor and Parus cinereus © 2005 The Linnean Society of London, Biological Journal of the Linnean Society, 2005, 86, 153–174

Identifying sources of variation in reproductive and life-history traits among five populations of a Chinese lizard (Takydromus septentrionalis, Lacertidae)

Abstract: Research on life-history traits of squamate reptiles has focused on North American species, while Asian taxa have been virtually ignored. In order to understand general patterns in reptile life histories, we need a broader data base. Our study on the slender-bodied lacertid lizard Takydromus septentrionalis provides the first detailed information on factors responsible for intraspecific variation in reproductive output and life history in a Chinese reptile. Clutches of recently collected lizards from five widely separated localities in China revealed major divergences in female body size at maturation, mean adult female body size, body condition after oviposition, size-adjusted fecundity, relative clutch mass, and mass and shape of eggs. Most of these geographical differences persisted when the same groups of females were maintained in identical conditions in captivity. Additionally, reproductive frequency during maintenance under laboratory conditions differed according to the animals’ place of origin. Thus, the extensive geographical variation in reproductive and life-history traits that occurs within T. septentrionalis is exhibited even in long-term captives, suggesting that proximate factors that vary among localities (local conditions of weather and food supply) are less important determinants of life-history variation than are intrinsic (presumably genetic) influences. The maternal abdominal volume available to hold the clutch may be one such factor, based on low levels of variation in Relative Clutch Mass among populations, and geographical variation in the position of trade-off lines linking offspring size to fecundity. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society, 2005, 85, 443–453.

Effects of substrate structure on speed and acceleration capacity in climbing geckos

Abstract: We studied the effects of substrate structure on locomotor performance in a climbing gecko, Hemidactylus garnoti. We quantified three performance traits (acceleration capacity, instantaneous speed, and final speed) on three substrates: (i) smooth wood, (ii) a cloth surface, and (iii) a wire mesh. While acceleration capacity and instantaneous speed were highest on the wooden surface, final speed did not differ significantly among substrates. Using scanning electron microscopy (SEM) pictures, we estimated that 98% of the wooden surface is available for adhesion by the setae on the toepads, while this percentage is much lower for the mesh and cloth (41 and 37%, respectively). We suggest that when a gecko climbs up a gap-filled substrate, such as the wire mesh or cloth, adhesion will only happen between part of the toepad and the substrate, resulting in a diminished acceleration capacity. The higher acceleration capacity on the wooden substrate and the fact that the geckos tend to slip less often on this particular surface, may explain the difference in instantaneous speed. As for final speed, geckos might achieve similar final speeds on all three substrates by employing different locomotor strategies. Our results suggest that microhabitat use in nature might have a profound effect on locomotor performance and survival for climbing lizards such as geckos. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society, 2005, 85, 385–393.

Ecological opportunity and levels of morphological variance within freshwater stickleback populations

Abstract: The ‘ecological opportunity’ hypothesis predicts that when interspecific competition or predation is reduced, populations will exhibit increases in phenotypic variance as a result of colonization and adaptation to vacant or underutilized ecological niches (i.e. character release). We assessed this hypothesis by examining morphological diversity within stickleback populations in 40 undisturbed lakes from six islands off the mid-coast of British Columbia, Canada. Because larger lakes with well-developed littoral and limnetic zones will have greater trophic niche diversity than smaller lakes with only littoral zones, we predicted a positive association between lake size and variation in trophic morphology. Conversely, reduced vertebrate predation in small bog lakes allows increased variance in defensive structures without costs to fitness. Consistent with both predictions, we observed that phenotypic variance in two traits that are involved in feeding (gape width and pectoral fin length) increased with lake size while variability in defence structures (lateral plate number and dorsal spine length) was inversely related to lake size. Moreover, increased variance in defence morphology was accentuated in populations with severe armour reduction (spine loss, decreased plate overlap), another strong indicator of reduced vertebrate predation. In the majority of cases, these patterns were repeatable among islands, independent from the geographical distance between lakes, and arose from a combination of high variance within each of the sexes and increases in sexual dimorphism. These findings suggest that character release can be trait-specific and reflect the combined effects of competition, predation and habitat heterogeneity. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society, 2005, 86, 297–308.

Geometric morphometrics as a tool for understanding Dactylorhiza (Orchidaceae) diversity in European Russia

Abstract: Geometric morphometric techniques were employed to assess the diversity of lip shapes (305 samples from 83 populations) in flowers of European Russian Dactylorhiza (Orchidaceae: Orchidinae). We found significant agreement between the results from geometric morphometrics, classic morphometrics and the distribution of certain nuclear DNA markers. The lip shapes from Arctic Dactylorhiza samples occupied an intermediate position between D. maculata and D. fuchsii samples from Central Russia, supporting a hybrid origin of ‘northern tetraploids’. Lip shapes of the taxonomically controversial allotetraploid D. baltica were found to form a distinct group, with members having definite relationships with diploid D. incarnata samples from the same localities, indicating either their local origin or introgression with D. incarnata . In addition to demonstrating the value of geometric morphometric methods in studies of plant taxonomy and hybridization, we suggest future applications designed to explore pollinator-driven directional selection, developmental constraints and fluctuating asymmetry. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society , 2005, 85 , 1‐12.

Genomic microsatellite adaptive divergence of wild barley by microclimatic stress in ‘Evolution Canyon’, Israel

Abstract: We examined diversity levels and patterns of 19 nuclear microsatellites and four chloroplast microsatellites in 275 genotypes of wild barley Hordeum spontaneum, in seven stations at the ‘Evolution Canyon’ (EC) microsite, Lower Nahal Oren, Mt. Carmel, Israel. EC is sharply subdivided ecologically into a tropical savannoid, ‘African’, xeric, south-facing slope (SFS) abutting the temperate, dense, liveoak, brushwood, ‘European’, mesic, north-facing slope (NFS). We found the following. (i) 17 of 19 (89.5%) nuDNA simple sequence repeats (SSRs) were polymorphic across all seven subpopulations and three chDNA SSRs were polymorphic. (ii) A total of 216 nuDNA SSR alleles, with a maximum of 23 alleles in a nuclear locus, and ten chDNA SSRs, with a maximum of four alleles in a locus, were registered. (iii) There were striking and significant inter- and intraslope diversities, based on the 19 nuDNA SSRs, climaxing with a remarkable genetic distance between the mid-slope stations on opposite slopes (DA = 0.481), across a distance of 200 m. This genetic distance is as large as that between the H. spontaneum populations of Jerusalem and Sede Boqer, which are separated by 100 km (× 500 larger in transect length). (iv) Slope-unique alleles (103 = 45.6%) were higher on the ‘European’ than on the ‘African’ slope. Slope-specific (predominant) alleles (17) were equal on opposite slopes. (v) nuDNA SSR gene diversity was higher on the ‘European’ slope and the opposite was found for the chDNA SSR. (vi) nuDNA SSR genic differentiation was very high between opposite slopes, with Gst = 0.187; for chDNA SSR this value was 0.127. Our results are inexplicable by stochastic processes and suggest that: (i) microclimatic diversifying selection is the major evolutionary, fast-acting, interslope force, overriding migration and drift, and (ii) ecological stress can generate local, regional and global adaptive patterns, suggesting that natural selection is a major differentiating force of both coding and noncoding SSRs linking micro- and macroevolutionary processes. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society, 2005, 84, 205–224.

Phylogenetic relationships of the north-eastern Atlantic and Mediterranean blenniids

Abstract: The phylogenetic relationships of 27 north-eastern Atlantic and Mediterranean blennioids are analysed based on a total of 1001 bp from a combined fragment of the 12S and 16S mitochondrial rDNA. The most relevant results with implications in current blenniid taxonomy are: (1) Lipophrys pholis and Lipophrys (= Paralipophrys) trigloides are included in a well-supported clade that by the rule of precedence must be named Lipophrys; (2) the sister species of this clade are not the remaining species of the genus Lipophrys but instead a monotypic genus comprising Coryphoblennius galerita; (3) the smaller species of Lipophrys were recovered in another well-supported and independent clade, which we propose to be recognized as Microlipophrys; (4) although some authors included the genera Salaria and Lipophrys in a single group we have never recovered such a relationship. Instead, Salaria is more closely related to the genera Scartella and Parablennius; (5) the genus Parablennius, which was never recovered as a monophyletic clade, is very diverse and may include several distinct lineages; (6) the relative position of Aidablennius sphynx casts some doubts on the currently recognized relationships between the different blenniid tribes. Meristic, morphological, behavioural and ecological characters support our results and are also discussed. The possible roles of the tropical West African coast and the Mediterranean in the diversification of blenniids are discussed. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society, 2005, 86, 283–295.

Foraging mode of the chameleon, Bradypodion pumilum: a challenge to the sit-and-wait versus active forager paradigm?

Abstract: Foraging mode is an important aspect of life history, often associated with traits such as locomotor mode, energy budget, risk of predation and reproductive effort. Because of these life-history associations, classification of foraging mode can be conceptually useful. Lizards figured prominently in the historical development of foraging mode concepts, yet our current understanding is dominated by only two lizard families which are good examples of the two extreme modes, sit-and-wait vs. active foraging. A great deal of lizard phylogenetic diversity remains unrepresented. Chameleons are a highly derived lizard taxon for which we have very little behavioural or ecological data, and no foraging mode data. Because chameleons are so unusual, it is not possible to predict where they will fit within the bimodal paradigm. I studied time budget and foraging mode in the Cape dwarf chameleon, Bradypodion pumilum, in Stellenbosch, South Africa. Several approaches were taken to assess foraging behaviour. First, lag-sequential analysis was applied to compare rates behaviours associated with observed eating events, which did not support a sit-and-wait foraging mode. Second, the number of moves per minute (MPM) and per cent time moving (%TM) were compared with those of other lizard taxa from the literature. Foraging in B. pumilum was found to be most consistent with an active foraging mode, although the MPM is unusually low. Thus I propose classification of B. pumilum as a cruise forager. Sufficient data are available to define a discriminant function for active vs. sit-and-wait modes among lizard speries, which classifys B. pumilum as active and additionally lends statistical support for good separation between foraging modes. These findings are discussed in relation to the evolution of foraging modes in chameleons and other lizard families. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society, 2005, 84, 797–808.