Showing papers in "Canadian Journal of Zoology in 2010"

Chemical ecology of predator–prey interactions in aquatic ecosystems: a review and prospectusThe present review is one in the special series of reviews on animal–plant interactions.

Abstract: The interaction between predator and prey is an evolutionary arms race, for which early detection by either party is often the key to success. In aquatic ecosystems, olfaction is an essential sourc...

Variation in natural plant products and the attraction of bodyguards involved in indirect plant defense

Abstract: Plants can respond to feeding or egg deposition by herbivorous arthropods by changing the volatile blend that they emit These herbivore-induced plant volatiles (HIPVs) can attract carnivorous natu

Hair cortisol concentration as a noninvasive measure of long-term stress in free-ranging grizzly bears (Ursus arctos): considerations with implications for other wildlife

Abstract: Human-caused landscape change negatively affects the sustainability of many wildlife populations. In Alberta, Canada, grizzly bears (Ursus arctos L., 1758) live in one of the most populated and hea...

The chemical ecology and evolution of bee-flower interactions: a review and perspectives'

Abstract: Bees and angiosperms have shared a long and intertwined evolutionary history and their interactions have resulted in remarkable adaptations. Yet, at a time when the “pollination crisis” is of major...

Coping with human disturbance: spatial and temporal tactics of the brown bear (Ursus arctos)

Abstract: In human-dominated landscapes, species with large spatial requirements, such as large carnivores, have to deal with human infrastructure and activities within their home ranges. This is the case fo...

The bioclimatic envelope of the wolverine (Gulo gulo): do climatic constraints limit its geographic distribution?

Abstract: We propose a fundamental geographic distribution for the wolverine (Gulo gulo (L., 1758)) based on the hypothesis that the occurrence of wolverines is constrained by their obligate association with...

Roads, logging, and the large-mammal community of an eastern Canadian boreal forest

Abstract: We evaluated hypotheses concerning the distributions of large mammals in a 60 000 km2 study area that encompassed the contact zone between Ontario’s roadless north and the postlogging southern land...

Metabolic power budgeting and adaptive strategies in zoology: examples from scallops and fishThe present review is one of a series of occasional review articles that have been invited by the Editors and will feature the broad range of disciplines and expertise represented in our Editorial Advisory Board.

Abstract: Evolutionary explanations of the adaptive value of animal characteristics are often expressed in energetic terms, but unless they are accompanied by demonstrations of limited energy availability, they remain speculative. In this review, we argue that metabolic power budgeting provides easily testable mechanisms through which energetically efficient attributes could become adaptive. Given each organism’s maximal aerobic (and metabolic) capacity, available metabolic power (energy use per unit time) is limited and must be partitioned between different processes. This leads to compromises among the major fitness functions of growth, locomotor activity, and reproductive investment. As examples of such conflicts, we examine the compromise among growth, reproduction, and predator avoidance in scallops, as well as the means whereby thermal limitations on oxygen uptake reflect the geographical distribution limits and associated energetic trade-offs of temperate zone and polar fishes. These examples show several me...

Cheaters and liars: Chemical mimicry at its finest

Abstract: Chemical mimicry is an essential part of certain interspecific interactions, where the outcome for both species may depend on the degree to which the original signals are mimicked. In this review, ...

Artificial maturation, fertilization, and early development of the American eel (Anguilla rostrata)

Abstract: Spawning for the American eel (Anguilla rostrata (Le Sueur, 1817)) takes place in secretive locations within the Sargasso Sea, which has thus far prevented investigations of gametogenesis and early

Rumen physiology constrains diet niche: linking digestive physiology and food selection across wild ruminant species

Abstract: We propose a hypothesis for digestive constraints on the browsing and grazing options available to ruminants: that the diet-niche range (maximum and minimum grass intake) of a species is dependent

Lack of behavioral responses of moose (Alces alces) to high ambient temperatures near the southern periphery of their range

Abstract: Although fundamental factors limiting geographic ranges are understood for many animal species, there is less certainty regarding how such factors influence the behavior of individuals near distributional edges. We tested the hypothe- sis that climate limits the southern distribution of moose (Alces alces (L., 1758)) by documenting space use and behavior of 36 females at the margin of the species' range in Ontario, Canada. We assessed temperature differences among habitats and related changes in seasonal habitat use and daily movement patterns in response to temperature. Ambient temperatures frequently exceeded the thresholds of -5 8C (winter) and 14 8C (summer), above which moose are supposed to be ther- mally stressed. We detected no differences in habitat use relative to thermoregulation thresholds. However, moose exhib- ited reduced movement when snow was deep and were more active at dawn and dusk. Low variability in temperature among habitat types implied that functional thermal shelters were absent. We suggest that moose in their southern range either ameliorate heat stress at a finer resolution than we measured or are more resilient to temperature than previously thought. Additional evidence linking temperatures with negative responses is necessary before the prevalent hypothesis of heat stress limiting the southern distribution of moose can be fully assessed. Resume´ : Alors que les facteurs fondamentaux qui limitent les aires geographiques sont bien connus pour plusieurs espe `- ces animales, il est moins clair comment ces facteurs influencent les individus habitant pres des marges de ces aires de re ´- partition. Nous testons l'hypothese qui veut que les conditions climatiques limitent la repartition vers le sud de l'orignal (Alces alces (L., 1758)) en etudiant l'utilisation de l'espace et le comportement de 36 femelles a la limite de l'aire de re ´- partition de l'espece en Ontario, Canada. Nous avons mesureles differences de temperature entre les habitats et noteles changements associes dans l'utilisation saisonniere des habitats et les patrons de deplacements journaliers en reaction ala temperature. Les temperatures depassaient souvent les seuils de -5 8C (hiver) et 14 8 C( ete ´), en-decaet au-deladesquels les orignaux sont senses subir un stress thermique. Nous ne decelons aucune difference dans l'utilisation de l'habitat en fonction des seuils de thermoregulation. Cependant, les orignaux se deplacent moins quand la neige est profonde et ils sont plus actifs al'aube et a la tombee du jour. La faible variabiliteentre les types d'habitats fait qu'il n'existe pas de re- fuges thermiques fonctionnels. Nous croyons que les orignaux dans le sud de leur aire de repartition ou bien mitigent leur stress thermique a une echelle plus fine que celle que nous utilisons ou alors sont plus resistants ala temperature qu'on ne le croyait anterieurement. Il faudra des donnees supplementaires reliant les temperatures ades reactions negatives avant que l'hypothese actuelle selon laquelle le stress duala chaleur limite la repartition des orignaux vers le sud puisse etre completement evaluee. (Traduit par la Redaction)

The diving behaviour of mammal-eating killer whales (Orcinus orca): variations with ecological not physiological factors

Abstract: Mammal-eating killer whales (Orcinus orca (L., 1758)) are a rare example of social predators that hunt together in groups of sexually dimorphic adults and juveniles with diverse physiological diving capacities. Day-night ecological differences should also affect diving as their prey show diel variation in activity and mammal-eating killer whales do not rely on echolocation for prey detection. Our objective was to explore the extent to which physiological aerobic capacities versus ecological factors shape the diving behaviour of this breath-hold diver. We used suction-cup-attached depth record- ers (Dtags) to record 7608 dives of 11 animals in southeast Alaska. Analysis of dive sequences revealed a strong bout structure in both dive depth and duration. Day-night comparisons revealed reduced rates of deep dives, longer shallow dives, and shallower long-duration dives at night. In contrast, dive variables did not differ by age-sex class. Estimates of the aerobic dive limit (cADL) suggest that juveniles exceeded their cADL during as much as 15% of long dives, whereas adult males and females never exceeded their cADL. Mammal-eating killer whales in this area appear to employ a strategy of physiological compromise, with smaller group members diving nearer their physiological limits and large-bodied males scaling down their physiological performance. Resume´ : Les orques (Orcinus orca (L., 1758)) mangeurs de mammiferes representent un rare cas de predateurs sociaux qui chassent ensemble dans des groupes d'adultes adimorphisme sexuel et de jeunes et qui possedent des capacites phy- siologiques de plongee differentes. Les differences ecologiques jour-nuit devraient aussi affecter la plongee parce que leurs proies ont une variation journaliere d'activiteet les orques mangeurs de mammiferes n'utilisent pas l'echolocation pour la detection de leurs proies. Notre objectif est d'explorer de quelle maniere le rapport entre les capacites physiologiques aero- bies et les facteurs ecologiques faconne le comportement de plongee de ce plongeur en apnee. Des etiquettes enregistreu- ses de profondeur (Dtags) munies de ventouses nous ont permis d'enregistrer 7608 plongees chez 11 animaux dans le sud- est de l'Alaska. L'analyse des sequences de plongeer evele une forte structure des episodes, tant en ce qui concerne la pro- fondeur que la duree. Les comparaisons jour-nuit montrent un taux reduit de plongees profondes, des plongees peu profon- des de plus longue duree et des plongees de longue duree moins profondes la nuit. En revanche, les variables de la plongee ne different pas en fonction des classes d'age et de sexe. Les estimations de la limite de la plongeea erobie (cADL) laissent croire que les jeunes depassent leur cADL durant jusqu'a ` 15 % des plongees prolongees, alors que les adultes males et femelles n'excedent jamais leur cADL. Les orques mangeurs de mammiferes dans cette region semblent utiliser une strategie comportant un compromis physiologique, dans lequel les plus petits membres du groupe plongent pres de leurs limites physiologiques et les males de grande taille reduisent leur performance physiologique en proportion. (Traduit par la Redaction)

Feeding-crater selection by high-arctic reindeer facing ice-blocked pastures

Abstract: Increased frequency of ground-icing events is likely to influence population dynamics in arctic ungulates, but their behavioural responses remain unexplored. During a record-mild winter with heavy rainfall, we analysed snow and ice characteristics and foraging trade-offs by Svalbard reindeer (Rangifer tarandus platyrhynchus Vrolik, 1829) on a semi-isolated, recently occupied range. Snow depths were well within thresholds for cratering, but >90% of low altitudes was covered by a thick ice coat on the ground (median thickness 9 cm). Different strategies to cope with these conditions appeared. Part of the population sought mountainous habitat with very sparse vegetation. Individuals remaining at lower altitudes either used sparsely vegetated, wind-blown ridges partially covered with ice, or apparently applied olfactory senses to locate vegetation in ice-free microhabitat beneath the snowpack. No feeding craters were covered by ground ice, compared with most nearby controls. Following ground-ice avoidance, ve...

Influence of patch- and landscape-level attributes on the movement behavior of raccoons in agriculturally fragmented landscapes

Abstract: We tested the hypotheses that movement rates and home range sizes of raccoons (Procyon lotor (L., 1758)) inhabiting a highly fragmented landscape would vary in response to local and landscape-level...

Does food abundance explain altitudinal migration in a tropical frugivorous bird

Abstract: Many animals undergo annual migrations. These movements are well studied at proximate levels, but their fundamental causes are poorly understood. Among tropical frugivorous birds, annual migration is thought to have evolved in the context of exploiting reciprocal peaks in fruit abundance among locations and seasons, yet previous tests of this hypothesis have yielded equivocal results. In this paper, I tested whether protein and (or) fruit limitation explain both uphill and downhill migratory movements in a tropical frugivorous bird, the White-ruffed Manakin (Corapipo altera Hellmayer, 1906). While White-ruffed Manakins likely migrate uphill to exploit peaks in fruit abundance, I found no evidence that elevational differences in fruit abundance explain the downhill portion of the migratory cycle. This result challenges long-standing ideas regarding the causes of altitudinal migration because it implies that birds seeking to maximize fruit intake should remain sedentary at higher elevations. Data are also i...

The relative effects of mating status and age on the mating behaviour of female field crickets

Abstract: Intrinsic factors such as female age and mating status have been found to affect female choosiness. However, as these factors are often confounded in the wild because mated females are usually older individuals, the relative influence of these two factors on female behaviour is unclear. Using a fully factorial design, we tested the relative effects of age and mating status of female field crickets (Gryllus pennsylvanicus Burmeister, 1838) on both (i) the probability that she would mate and (ii) her latency to mate. We found that virgin females were both more likely to mate and copulated more quickly than mated females, but female age had no significant effect on either the probability of mating or the latency to copulate. These results clearly show that mating status is more important in determining female mating behaviour than age. We suggest that previous work which showed an age effect on female choosiness in virgins alone might be of reduced relevance if most females do not remain unmated for long.

Denning-area fidelity and mitochondrial DNA diversity of female polar bears (Ursus maritimus) in the Barents Sea

Abstract: Polar bears (Ursus maritimus Phipps, 1774) show fidelity to general denning areas in subsequent reproductive events. Studying the level and spatio-temporal scale of denning-area fidelity is critical to determine the adaptability of po- lar bears to climate change. We used mark-recapture data in conjunction with mitochondrial DNA (mtDNA) data to inves- tigate the level of fidelity of polar bears from the Barents Sea population to five maternal denning areas. There was no differentiation in mtDNA haplotype frequencies between denning areas. The fidelity of females to denning areas is at a lo- cal geographic scale and small groups of neighboring females (3-13) shared similar haplotypes with higher probability than expected by chance. The transmission of denning-area fidelity is supported by the short distances (£60.0 km) ob- served between capture locations of six (out of eight) denning mother-daughter pairs. Moreover, our results suggested that some females (3 out of 13) used different denning areas in subsequent denning events. This behavioral plasticity implies that females are likely to be able to change denning locations if unsuitable ice conditions prevent them from reaching their preferred denning areas. We consider this plasticity an important attribute of polar bears when facing climate change. Resume´ : Les ours blancs (Ursus maritimus Phipps, 1774) sont fideles a des zones generales ouils construisent leurs tanie `- res maternelles, lors de reproductions consecutives. Etudier le degreet l'echelle spatio-temporelle de la fideliteaux zones de tanieres maternelles est primordial dans l'optique de determiner l'adaptabilitedes ours blancs au changement climatique. Nous avons utilisedes donnees de marquage-recapture conjointement avec des donnees d'ADN mitochondrial pour exami- ner le degrede fidelitedes ours blancs de la population de la mer de Barents acinq zones de tanieres maternelles. Il n'y avait pas de difference de frequence haplotypique entre les zones de tanieres maternelles. La fidelitedes femelles aux zones de tanieres maternelles est a une echelle geographique relativement petite, et de petits groupes de femelles voisines (3-13) ont une plus forte probablitede partager des haplotypes similaires qu'attendu par chance. La transmission de la fideliteaux zones de tanieres maternelles est soutenue par les courtes distances (£60,0 km) observees entre les localites de capture de six (parmi huit) paires mere-fille, ayant etedans des tanieres maternelles. De plus, nos resultats ont demontreque quelques femelles (3 parmi 13) ont changede zone de tanieres maternelles entre des evenements de reproduction consecutifs. Cette plasticitecomportementale implique que les femelles sont probablement capables de changer de zone de tanieres maternel- les si des conditions de glace defavorables les empechent de rejoindre leur zone preferee. Nous considerons cette elasticite ´ comme un attribut important des ours blancs lorsque confrontes au changement climatique.

Den-site selection is critical for Pallas's cats (Otocolobus manul).

Abstract: We evaluated the habitat selection of 101 den sites used by 21 individual Pallas’s cats (Otocolobus manul (Pallas, 1776) = Felis manul Pallas, 1776) in summer, winter, and the maternal period in central Mongolia using generalized linear mixed models. Pallas’s cats used rock crevices and marmot burrows as dens for giving birth, raising young, thermoregulation, feeding, mating, and as important cover from predators. Den sites were selected with higher proportions of rocky and ravine habitats in the surroundings, and in winter Pallas’s cats avoided the presence of humans. Habitat and structural features suggested that dens were selected to minimize predation risk. Selection of dens in shade in summer and the use of insulated dens of Siberian marmots (Marmota sibirica (Radde, 1862)) in winter indicated that thermal properties may also be important. We contend that dens are a critical habitat for Pallas’s cats and the availability of suitable den sites is critical for the conservation of the species. Repeated ...

Partial seasonal migration in high-arctic Svalbard reindeer (Rangifer tarandus platyrhynchus)

Abstract: We examined seasonal range use and calving success in wild Svalbard reindeer (Rangifer tarandus platyrhynchus Vrolik, 1829) on two contrasting ranges separated by risky barriers (open sea, thin sea ice, and glaciers). One (“poor”) range had a depleted lichen resource and negative reindeer population trend, whereas the neighbouring (“rich”) range was recently occupied with initially high lichen abundance and positive population trend. Winter foraging conditions limit survival and reproduction in this predator-free system and lichens are the preferred winter food by reindeer. Accordingly, marked female reindeer that switched between the ranges (“migrants”) spent most winters on the lichen-rich range, yet most summers on the poor range (possibly owing to fidelity to calving area). While facing high mortality risk along the migration route, migrants spending the winter on the rich range and subsequent summer on the poor range had improved calving success compared with residents on the poor range. The partial ...

Dietary response of Barn Owls (Tyto alba) to large variations in populations of common voles (Microtus arvalis) and European water voles (Arvicola terrestris)

Abstract: The diet of the Barn Owl (Tyto alba (Scopoli, 1769)) was studied over an 8-year period in the Jura mountains of France, during two population surges of its main rodent prey (common voles (Microtus arvalis (Pallas, 1778)) and European water voles (Arvicola terrestris (L.,1758))), allowing us to test whether T. alba is an opportunistic predator as is often cited in the literature or exhibits more complex patterns of prey selection as is reported in arid environments. Small mammals were sampled by trapping and index methods. We observed (i) significant correlations between the proportions of A. terrestris and M. arvalis and woodland rodents in the diet and their respective densities in the field; (ii) interactions between populations of A. terrestris and M. arvalis, indicating that the proportion of each species in diet was affected by the density of the other; (iii) proportions of red-toothed shrews (genus Sorex (L., 1758)) in the diet did not correlate with their abundance in the field, indicating that those species were likely to be preyed upon when others were no longer available. This confirms that T. alba is generally opportunistic; however, prey selection of a focal species (e.g., Sorex spp., grassland species) can be affected by the density or availability of the other prey species

The impact of tannins on protein, dry matter, and energy digestion in moose (Alces alces)

Abstract: Recent work suggests that moose (Alces alces (L., 1758)) in the boreal ecoregion may be nutritionally limited by the availability of protein as a consequence of both low nitrogen (N) concentrations and high tannin levels in their principal foods. However, the ability of moose to digest protein in the presence of tannins is unknown. We undertook a series of digestion trials with captive moose to quantify the effects of tannins and compare the digestive capabilities of moose to other browsing cervids. We fed four moose 14 single-species diets including 10 native tannin-containing forages and 4 non-tanniferous foods over four winters. True protein digestibility in moose was 92%, and metabolic fecal N excretion was estimated at 0.389 g N/100 g dry matter (DM) intake. Tannins reduced protein digestion, on average, by 38%, and the rate of reduction in protein digestion was estimated to be 8.28 g protein/100 g DM per unit protein-precipitating capacity. The digestion of protein, neutral detergent fiber, DM, and ...

Variability in the growth patterns of the cornified claw sheath among vertebrates: implications for using biogeochemistry to study animal movement

Abstract: We review the role of biogeochemical signatures, such as stable isotopes and trace elements, in the cornified claw tissue as a means of studying movement and foraging behaviour of vertebrates because this approach is noninvasive and can capture contemporary and historic signatures. Because biogeochemical techniques are still relatively new in studies of animal movement, we are only beginning to understand how the growth patterns of the cornified claw sheath may affect our ability to interpret the biogeochemical signals in these tissues. To move towards resolving this, we review the morphology of the epidermal cornified claw sheath in several taxa that illustrate substantial variation in growth patterns both between taxa and between individual distinct claw regions. For instance, in mammalian claws, deposition of keratinizing cells from the epidermis is nonlinear because the claw tip is composed of old and new cornified epidermal cells, whereas the cornified blade horn covering the claw’s lateral walls is ...

Influence of incubation temperature on morphology and locomotion performance of Leatherback (Dermochelys coriacea) hatchlings

Abstract: The journey of Leatherback (Dermochelys coriacea (Vandelli, 1761)) hatchlings from nest to the sea is a vulnerable life-history stage. Studies have shown that nest incubation temperatures influence...

Interactions between parasites and pollutants in yellow perch (Perca flavescens) in the St. Lawrence River, Canada: implications for resistance and tolerance to parasites

Abstract: Parasites were examined in yellow perch, Perca flavescens (Mitchill, 1814), from four localities ranging in degree of pollution in the St. Lawrence River, Quebec, Canada, to examine the effects of the most prevalent parasite species on expression of biomarkers of oxidative stress. Various biomarkers appeared to be affected by the infection levels of Apophallus brevis Ransom, 1920 and genus Diplostomum von Nordmann, 1832. For certain biomarkers, interactions between infection level and pollution type were detected for A. brevis, Diplostomum spp., and genus Ichthyocotylurus Odening, 1969. Activity of glutathione reductase in gill tissue decreased with increasing numbers of A. brevis, but only at the two most polluted localities. Catalase activity in kidney increased with numbers of Diplostomum spp. at the polluted localities, but not at the two least contaminated sites. Results suggest that parasites may affect expression of biomarkers of pollution and that pathogenicity of parasites may be enhanced under p...

Differential forage use makes carrying capacity equivocal on ranges of Scandinavian moose (Alces alces)

Abstract: Availability of preferred forage is hypothesized to be positively related to demographic performance in selective ungulates. Comparing two regions with high density of moose (Alces alces (L., 1758)) having contrasting demographic performance and different composition of available plant species, we show that such a positive relationship may not always apply. The high-performance region (HP) had an estimated 41% higher total availability of browse per capita than the low-performance region (LP), but the availability of preferred species did not differ between the two regions. Although birch (genus Betula L.) was the most abundant browse in both regions (comprising 66% and 50% of the shoot amount available per m2 in HP and LP, respectively), it dominated the diet of moose only in HP (constituting, e.g., 69% of all trees browsed in summer compared with 22% in LP). Further research is needed to identify the cause of the seemingly suboptimal use of birch in LP. We also quantified factors that determine forage a...

Tissue–diet discrimination factors and turnover of stable carbon and nitrogen isotopes in white-footed mice (Peromyscus leucopus)

Abstract: Stable isotope analysis has become an increasingly valuable tool in investigating animal ecology. Here we docu- ment the turnover rates for carbon in the liver, muscle, and whole blood tissue, as well as the tissue-diet discrimination values for carbon and nitrogen isotopes in the liver, whole blood, muscle, and hair, of the white-footed mouse (Peromyscus leucopus (Rafinesque, 1818)). A 168-day diet-switching experiment was conducted with a laboratory population of white- footed mice. The d 13 C values for all tissues deviated less than 1% from those of the diet except for whole blood, which had a slightly higher tissue-diet discrimination factor of 1.8%. All tissues were enriched in 15 N by approximately 3% rela- tive to the diet except for liver tissue, which was 4.5% higher than the dietary d 15 N value. Turnover rates for tissues of white-footed mice were ranked liver > whole blood > muscle. The half-lives calculated for liver tissue differed signifi- cantly between the two diet switches performed in this experiment. We demonstrate that there is potential for variation in tissue-diet discrimination values and tissue turnover rates between even closely related species. These findings highlight the importance of determining species-specific estimates of these parameters prior to the use of stable isotope analysis in field investigations of animal ecology. Resume´ : L'analyse des isotopes stables devient un outil de plus en plus precieux dans l'etude ecologique des animaux. Nous determinons ici les taux de remplacement du carbone dans les tissus du foie, du muscle et du sang entier, ainsi que les valeurs de discrimination tissu-regime des isotopes de carbone et d'azote dans le foie, le sang entier, le muscle et le poil chez la souris a pieds blancs (Peromyscus leucopus (Rafinesque, 1818)). Nous avons meneune experience de change- ment de regime alimentaire de 168 jours avec une population de laboratoire de souris a pieds blancs. Les valeurs de d 13 C dans tous les tissus different de moins de 1 % de celles du regime, exceptedans le sang entier qui possede un facteur de discrimination tissu-regime legerement plus elevede 1,8 %. Tous les tissus sont enrichis en 15 N d'environ 3 % par rap-

Cross-population responses to conspecific chemical alarm cues in wild Trinidadian guppies, Poecilia reticulata: evidence for local conservation of cue production

Abstract: Within freshwater fishes, closely related species produce alarm cues that are chemically similar, leading to conserved antipredator responses. Similar conservation trends are predicted for species with geographically isolated populations. Here, we tested this hypothesis with the guppy (Poecilia reticulata Peters, 1859) from two populations within the Aripo River, Trinidad. Free-ranging guppies in the Lower Aripo (high-predation population) exhibited more risk-aversive inspection behaviour towards a fish predator model paired with the alarm cues of guppies collected from the same population versus a river water control. In comparison, when paired with the alarm cues of guppies from the Upper Aripo (low-predation population), the response was intermediate. In the laboratory, we tested Upper and Lower Aripo guppies to the alarm cues of the same or different Aripo River donors, Quare River guppies (a high-predation population from a different drainage), or a water control. Both Upper and Lower Aripo River guppies exhibited the highest intensity response to donors from the same population and the lowest intensity response to Quare River donors, with the response to different Aripo donors being intermediate. Collectively, these results demonstrate a trend of intraspecific conservation of chemical alarm cue production, leading to population-specific responses to conspecific cues.

Nutrient allocation for egg production in six Atlantic seabirds

Abstract: How species allocate nutrients to egg production is an important question in contaminant analyses. Seabird eggs are sampled frequently in such studies, so it is important to know the source of nutrients in these eggs if the source of the contaminants is to be traced. We used a stable-isotope approach to evaluate the relative importance of locally derived nutrients (income breeding) and stored nutrient reserves (capital breeding) in six species of Atlantic seabirds (Arctic Tern, Sterna paradisaea Pontoppidan, 1763; Common Tern, Sterna hirundo L., 1758; Atlantic Puffin, Fratercula arctica (L., 1758); Common Murre, Uria aalge (Pontoppidan, 1763); Razorbill, Alca torda L., 1758; Leach’s Storm-Petrel, Oceanodroma leucorhoa (Vieillot, 1818)) breeding in the Bay of Fundy. We found that all species either were income breeders or adopted an intermediate strategy whereby varying proportions of locally derived nutrients were incorporated into eggs. Each species’ migratory behaviour is likely a main factor in determi...

Regulatory actions of neuropeptides and peptide hormones on the reproduction of molluscsThe present review is one of a series of occasional review articles that have been invited by the Editors and will feature the broad range of disciplines and expertise represented in our Editorial Advisory Board.

Abstract: Reproductive success of individual animals is essential for the survival of any species. Molluscs have adapted to a wide variety of environments (freshwater, brackish water, seawater, and terrestri...