Wild-caught Individuals Research Articles

Age structure changes and extraordinary lifespan in wild medfly populations.

The main purpose of this study was to test the hypotheses that major changes in age structure occur in wild populations of the Mediterranean fruit fly (medfly) and that a substantial fraction of individuals survive to middle age and beyond (> 3-4 weeks). We thus brought reference life tables and deconvolution models to bear on medfly mortality data gathered from a 3-year study of field-captured individuals that were monitored in the laboratory. The average time-to-death of captured females differed between sampling dates by 23.9, 22.7, and 37.0 days in the 2003, 2004, and 2005 field seasons, respectively. These shifts in average times-to-death provided evidence of changes in population age structure. Estimates indicated that middle-aged medflies (> 30 days) were common in the population. A surprise in the study was the extraordinary longevity observed in field-captured medflies. For example, 19 captured females but no reference females survived in the laboratory for 140 days or more, and 6 captured but no reference males survived in the laboratory for 170 days or more. This paper advances the study of aging in the wild by introducing a new method for estimating age structure in insect populations, demonstrating that major changes in age structure occur in field populations of insects, showing that middle-aged individuals are common in the wild, and revealing the extraordinary lifespans of wild-caught individuals due to their early life experience in the field.

Pollinator foraging modifies nectar sugar composition in Helleborus foetidus (Ranunculaceae):An experimental test

We experimentally tested the hypothesis that the extensive within-plant variation of nectar sugar composition in Helleborus foetidus (Ranunculaceae) and other species results from differences between flowers and nectaries in pollinator visitation history. Experiments were conducted to mimic single-nectary visits by wild-caught individuals of the main bee pollinators of H. foetidus, which were assayed for their capacity to modify the sugar composition of natural and artificial nectar. Experimental nectar probing with bee mouthparts induced extensive changes in proportional sugar composition 48 h after treatment, and bee taxa differed widely in their effects. Nectar probing by Andrena, medium-sized Anthophoridae, Apis mellifera, and Lasioglossum had no subsequent effects on nectar sugar composition, while probing by Bombus terrestris and B. pratorum induced an extensive reduction in percentage sucrose, a marked increase in percentage fructose, and a slight increase in percentage glucose. Results support the hypothesis that stochastic variations among flowers or nectaries in the taxonomic identity of recent visitors and their relative visitation frequencies may eventually generate very small-scale mosaics in nectar sugar composition. Changes in nectar sugar composition following bumblebee probing may be the consequence of nectar contamination with pollinator-borne nectarivorous yeasts.

Evolution of a behavior-linked microsatellite-containing element in the 5' flanking region of the primate AVPR1A gene

BackgroundThe arginine vasopressin V1a receptor (V1aR) modulates social cognition and behavior in a wide variety of species. Variation in a repetitive microsatellite element in the 5' flanking region of the V1aR gene (AVPR1A) in rodents has been associated with variation in brain V1aR expression and in social behavior. In humans, the 5' flanking region of AVPR1A contains a tandem duplication of two ~350 bp, microsatellite-containing elements located approximately 3.5 kb upstream of the transcription start site. The first block, referred to as DupA, contains a polymorphic (GT)25 microsatellite; the second block, DupB, has a complex (CT)4-(TT)-(CT)8-(GT)24 polymorphic motif, known as RS3. Polymorphisms in RS3 have been associated with variation in sociobehavioral traits in humans, including autism spectrum disorders. Thus, evolution of these regions may have contributed to variation in social behavior in primates. We examined the structure of these regions in six ape, six monkey, and one prosimian species.ResultsBoth tandem repeat blocks are present upstream of the AVPR1A coding region in five of the ape species we investigated, while monkeys have only one copy of this region. As in humans, the microsatellites within DupA and DupB are polymorphic in many primate species. Furthermore, both single (lacking DupB) and duplicated alleles (containing both DupA and DupB) are present in chimpanzee (Pan troglodytes) populations with allele frequencies of 0.795 and 0.205 for the single and duplicated alleles, respectively, based on the analysis of 47 wild-caught individuals. Finally, a phylogenetic reconstruction suggests two alternate evolutionary histories for this locus.ConclusionThere is no obvious relationship between the presence of the RS3 duplication and social organization in primates. However, polymorphisms identified in some species may be useful in future genetic association studies. In particular, the presence of both single and duplicated alleles in chimpanzees provides a unique opportunity to assess the functional role of this duplication in contributing to variation in social behavior in primates. While our initial studies show no signs of directional selection on this locus in chimps, pharmacological and genetic association studies support a potential role for this region in influencing V1aR expression and social behavior.

Directions in reintroduction biology

Reintroductions are attempts to return species to parts of their historical ranges where they were extirpated, and might involve release of either captive-bred or wild-caught individuals. The poor success rate of reintroductions worldwide has led to frequent calls for greater monitoring, and since 1990 there has been an exponential increase in the number of peer-reviewed publications related to reintroduction. However, these publications have largely been descriptive accounts or have addressed questions retrospectively based on the available data. Here, we advocate a more strategic approach where research and monitoring targets questions that are identified a priori. We propose ten key questions for reintroduction biology, with different questions focusing at the population, metapopulation and ecosystem level. We explain the conceptual framework behind each question, provide suggestions for the best methods to address them, and identify links with the related disciplines of restoration ecology and invasion biology. We conclude by showing how the framework of questions can be used to encourage a more integrated approach to reintroduction biology.

Genetic variability in three Amazon parrot species

Parrots of the genus Amazona are among the most threatened species of the Order Pscittaciformes. This work describes allozyme polymorphisms in three Amazon parrot species--the Blue-fronted Amazon (Amazona aestiva), the Orange-winged Amazon (Amazona amazonica), and the Festive Amazon (Amazona festiva) -, and provides useful data for the evaluation of their genetic variability. We electrophoretically analyzed blood samples from 68 wild-caught individuals, maintained in captivity in three Brazilian zoos. Eight of the ten studied enzyme loci exhibited polymorphism. Glucosephosphate isomerase (Gpi) proved to be a diagnostic locus for the identification of these Amazon species. The expected average heterozygosity of the Blue-fronted Amazon (0.060) differed significantly from the expected heterozygosities of the Orange-winged Amazon and the Festive Amazon (0.040 and 0.039, respectively). This result was discussed as a consequence of hybridization between two geographic A. aestiva subspecies, and alternatively as a particular trait of this species. Genetic variability of the Blue-fronted Amazon compared to birds in general is not low on a species-wide level, despite the fact that this parrot is one of the most illegally traded species. Allozyme analysis proved to be an useful tool in monitoring the genetic variation within the genus Amazona and can be applied in the management program of other threatened species of this genus.

Dynamics of colour polymorphism in a changing environment: fire melanism and then what?

Studies of whether disturbance events are associated with the changing genetic compositions of natural populations may provide insights into the importance of local selection events in maintaining diversity, and might inform plans for the conservation and protection of that diversity. We examined the dynamics of a colour pattern polymorphism in a natural population of pygmy grasshoppers Tetrix subulata (Orthoptera: Tetrigidae) inhabiting a previously burnt clear-cut area. Data on morph frequencies for wild-caught and captive-reared individuals indicated that the initial dominance of black phenotypes following the fire event was followed by an increased diversity of the polymorphism. This was manifested as the appearance of a novel morph, a decreased incidence of the black morph, and a more even distribution of individuals across alternative morphs following the recurrence of vegetation. We also found that the colour patterns of captive-reared individuals resembled those of their parents and that the degree of within-clutch diversity increased between generations. Our comparisons of morph frequencies across generations and between environments within generations point to a genetic determination of colour pattern, and indicate that the polymorphism is influenced more strongly by selection than by plasticity or migration.

THE UTILITY OF MOLECULAR MARKERS FROM NON-LETHAL DNA SAMPLES OF THE CITES II PROTECTED “TARANTULA” BRACHYPELMA VAGANS (ARANEAE, THERAPHOSIDAE)

Abstract Tarantula spiders of the genus Brachypelma Simon 1891 are the only complete genus of arachnids protected from international trade under CITES law. To better understand the genetic cohesion of spiders within this genus, we evaluated multiple genetic fragments (totalling about 2200 bp) for their ability to recover population sub-structure among wild-caught Brachypelma vagans (Ausserer 1875) from Belize. We used a novel non-lethal method of tissue sampling, by inducing autospasy of the medial leg. This method allowed us to release wild-caught individuals of this protected species after DNA sampling. We used arachnid specific PCR primers to amplify targeted regions of B. vagans DNA, testing various combinations for consistency. We compared mitochondrial fragments from two populations of B. vagans (∼50 km apart) for variation in mitochondrial 16S lrRNA (plus 5′ ND1), CO1, and the nuclear ITS-2 spacer. Both lrRNA-ND1 and CO1 provided congruent estimates of population subdivision, and indicated that lrR...

Human influences on rates of phenotypic change in wild animal populations

Human activities can expose populations to dramatic environmental perturbations, which may then precipitate adaptive phenotypic change. We ask whether or not phenotypic changes associated with human-disturbed (anthropogenic) contexts are greater than those associated with more 'natural' contexts. Our meta-analysis is based on more than 3000 rates of phenotypic change in 68 'systems', each representing a given species in a particular geographical area. We find that rates of phenotypic change are greater in anthropogenic contexts than in natural contexts. This difference may be influenced by phenotypic plasticity - because it was evident for studies of wild-caught individuals (which integrate both genetic and plastic effects) but not for common-garden or quantitative genetic studies (which minimize plastic effects). We also find that phenotypic changes in response to disturbance can be remarkably abrupt, perhaps again because of plasticity. In short, humans are an important agent driving phenotypic change in contemporary populations. Although these changes sometimes have a genetic basis, our analyses suggest a particularly important contribution from phenotypic plasticity.

Establishment of an Albino Strain of the Bitterling Tanakia signifer (Pisces, Cyprinidae)

An albino strain of the bitterling Tanakia signifer (Pisces, Cyprinidae, Acheilognathinae) was established through interbreeding using an albino male selected from among the offspring produced from the spawning of 18 wild-caught individuals. This is the first report of albinism in this species. Progeny tests demonstrated that inheritance of the trait follows the expected pattern for a simple autosomal recessive. A stock of 200+ individuals is currently being held at the Kannonzaki Nature History Museum, Japan.

Role of larval host plants in the climate‐driven range expansion of the butterfly Polygonia c‐album

1. Some species have expanded their ranges during recent climate warming and the availability of breeding habitat and species' dispersal ability are two important factors determining expansions. The exploitation of a wide range of larval host plants should increase an herbivorous insect species' ability to track climate by increasing habitat availability. Therefore we investigated whether the performance of a species on different host plants changed towards its range boundary, and under warmer temperatures. 2. We studied the polyphagous butterfly Polygonia c-album, which is currently expanding its range in Britain and apparently has altered its host plant preference from Humulus lupulus to include other hosts (particularly Ulmus glabra and Urtica dioica). We investigated insect performance (development time, larval growth rate, adult size, survival) and adult flight morphology on these host plants under four rearing temperatures (18-28.5 degrees C) in populations from core and range margin sites. 3. In general, differences between core and margin populations were small compared with effects of rearing temperature and host plant. In terms of insect performance, host plants were generally ranked U. glabra > or = U. dioica > H. lupulus at all temperatures. Adult P. c-album can either enter diapause or develop directly and higher temperatures resulted in more directly developing adults, but lower survival rates (particularly on the original host H. lupulus) and smaller adult size. 4. Adult flight morphology of wild-caught individuals from range margin populations appeared to be related to increased dispersal potential relative to core populations. However, there was no difference in laboratory reared individuals, and conflicting results were obtained for different measures of flight morphology in relation to larval host plant and temperature effects, making conclusions about dispersal potential difficult. 5. Current range expansion of P. c-album is associated with the exploitation of more widespread host plants on which performance is improved. This study demonstrates how polyphagy may enhance the ability of species to track climate change. Our findings suggest that observed differences in climate-driven range shifts of generalist vs. specialist species may increase in the future and are likely to lead to greatly altered community composition.

Growth rates of young-of-year shovelnose sturgeon in the Upper Missouri River

Summary Information on growth during the larval and young-of-year life stages in natural river environments is generally lacking for most sturgeon species. In this study, methods for estimating ages and quantifying growth were developed for field-sampled larval and young-of-year shovelnose sturgeon Scaphirhynchus platorynchus in the upper Missouri River. First, growth was assessed by partitioning samples of young-of-year shovelnose sturgeon into cohorts, and regressing weekly increases in cohort mean length on sampling date. This method quantified relative growth because ages of the cohorts were unknown. Cohort increases in mean length among sampling dates were positively related (P 0.59 for all cohorts) to sampling date, and yielded growth rate estimates of 0.80–2.95 mm day−1 (2003) and 0.44–2.28 mm day−1 (2004). Highest growth rates occurred in the largest (and earliest spawned) cohorts. Second, a method was developed to estimate cohort hatch dates, thus age on date of sampling could be determined. This method included quantification of post-hatch length increases as a function of water temperature (growth capacity; mm per thermal unit, mm TU−1), and summation of mean daily water temperatures to achieve the required number of thermal units that corresponded to post-hatch lengths of shovelnose sturgeon on sampling dates. For six of seven cohorts of shovelnose sturgeon analyzed, linear growth models (r2 ≥ 0.65, P < 0.0001) or Gompertz growth models (r2 ≥ 0.83, P < 0.0001) quantified length-at-age from hatch through 55 days post-hatch (98–100 mm). Comparisons of length-at-age derived from the growth models indicated that length-at-age was greater for the earlier-hatched cohorts than later-hatched cohorts. Estimated hatch dates for different cohorts were corroborated based on the dates that newly-hatched larval shovelnose sturgeon were sampled in the drift. These results provide the first quantification of growth dynamics for field-sampled age-0 shovelnose sturgeon in a natural river environment, and provide an accurate method for estimating age of wild-caught individuals. Methods of age determination used in this study have applications to sturgeons in other regions, but require additional testing and validation.

Variable growth band deposition leads to age and growth uncertainty in the western wobbegong shark, Orectolobus hutchinsi

Age and growth parameters of Orectolobus hutchinsi were estimated using micro-radiographs of sectioned vertebrae from 182 wild caught individuals. Two fluorochrome marker dyes, calcein and oxytetracycline, were used to validate the timing and periodicity of vertebral band formation in nine individuals held in the laboratory for between 423 and 472 days. Growth bands were difficult to interpret and final counts were obtained from only 98 (53.8%) individuals ranging in total length (TL) from 63 to 146 cm. The timing of growth band formation in the vertebrae of captive animals had no predictable temporal pattern, with formation occurring during all seasons of the year, making age validation difficult. Growth band formation was hypothesised to be influenced by non-periodic changes in centrum or somatic growth rather than seasonal growth, as observed in many other elasmobranch species. Growth rates of nine O. hutchinsi held in captivity varied considerably, ranging from 3.5 cm year–1 to 13.8 cm year–1 in total length (mean = 7.03 cm year–1). Although the periodicity of vertebral band formation in captive animals did not support a synchronous annual pattern, captive growth rates matched those predicted when an annual band pattern was assumed for wild caught individuals. Von Bertalanffy growth parameters estimated from vertebral analysis assuming an annual banding pattern and a mean size of birth of 24.1 cm were: L∞ = 149.45 cm and K = 0.117 year–1 for both sexes combined. These results illustrate the fundamental importance of validating the periodicity of growth band formation in elasmobranch age and growth studies as it has considerable implications for the management of fisheries that exploit shark and ray species that may exhibit asynchronous growth band deposition.

Do cleaning organisms reduce the stress response of client reef fish?

BackgroundMarine cleaning interactions in which cleaner fish or shrimps remove parasites from visiting 'client' reef fish are a textbook example of mutualism. However, there is yet no conclusive evidence that cleaning organisms significantly improve the health of their clients. We tested the stress response of wild caught individuals of two client species, Chromis dimidiata and Pseudanthias squamipinnis, that had either access to a cleaner wrasse Labroides dimidiatus, or to cleaner shrimps Stenopus hispidus and Periclimenes longicarpus, or no access to cleaning organisms.ResultsFor both client species, we found an association between the presence of cleaner organisms and a reduction in the short term stress response of client fish to capture, transport and one hour confinement in small aquaria, as measured with cortisol levels.ConclusionIt is conceivable that individuals who are more easily stressed than others pay a fitness cost in the long run. Thus, our data suggest that marine cleaning mutualisms are indeed mutualistic. More generally, measures of stress responses or basal levels may provide a useful tool to assess the impact of interspecific interactions on the partner species.

Captive Breeding and a Threatened Gecko

In their letter “Scientific description can imperil species” (26 May, p. [1137][1]), B. L. Stuart et al. warn that scientific description can draw attention to newly described species attractive for hobbyists, which could lead to their overexploitation or even extinction. Although this scenario sounds plausible, and taxonomists should keep in mind the conservation impacts of their work, at least one of the three examples given is incorrect. The gecko Goniurosaurus luii from southeastern China was heavily threatened by hunting for pet trade and local medicine purposes and was probably extirpated from its type locality before it was scientifically described. The specimens of G. luii obtained from pet dealers and listed as Goniurosaurus sp. were studied by Japanese molecular phylogenetics before the official description ([1][2]). Lui, the collector of the holotype of G. luii , himself “became aware of the existence of Goniurosaurus luii and G. araneus” from “individuals who specialise in gecko collecting for commercial purposes” ([2][3]). Stuart et al. also claim that immediately after being described in 1999, G. luii reached a breathtaking price of $1500 to $2000 per individual in importing countries. During the last few years, hobbyists perfectly mastered the keeping and breeding of G. luii and closely related G. araneus and established numerous breeding colonies of both species. Recently, hundreds of captive-born juveniles have been available on the world pet market every year for about $40 each, which has two important conservation consequences. First, there is no further demand on the imported, wild-caught animals. Second, as G. luii is a species with limited range still hunted for local medicine trade ([3][4]) and endangered by habitat damage ([2][3]), the captive population will soon outnumber the wild one and can serve as a guarantee that this species will survive at least in captivity with a potential chance for re-introduction. ![Figure][5] A G. luii gecko CREDIT: TONY GAMBLE/UNIVERSITY OF MINNESOTA 1. 1.[↵][6] 1. H. Ota, 2. M. Honda, 3. M. Kobayashi, 4. S. Sengoku, 5. T. Hikida , Zool. Sci. 16, 659 (1999). [OpenUrl][7][CrossRef][8] 2. 2.[↵][9] 1. L. L. Grismer, 2. B. E. Viets, 3. L. J. Boyle , J. Herpetol. 33, 382 (1999). [OpenUrl][10] 3. 3.[↵][11] 1. K. S. Lee, 2. M. W. N. Lau, 3. B. P. L. Chan , “Wild Animal Trade Monitoring in Selected Markets in Guangzhou and Shenzhen, South China 2000–2003” (Kadoorie Farm and Botanic Garden Corporation, Tai Po, Hong Kong SAR, 2004). # Response {#article-title-2} Our letter used three Asian herpetological examples to illustrate the point that publishing scientific descriptions of new species may inadvertently facilitate their overexploitation by advertising “novelties” to hobbyists and providing detailed locality information to commercial collectors. Kratochvil correctly notes that one of our examples, the gecko Goniurosaurus luii , was already being heavily harvested in China for sale in the international pet trade ([1][12], [2][13]) prior to its description as a new species ([1][12]). However, immediately after being described, its value in the U.S. pet trade jumped from approximately $500 under an older name to approximately $1500 under its new name as a result of increased demand from hobbyists seeking a unique addition to their collections (the $2000 quote in our Letter referred to a second reptile example, Chelodina mccordi , provided in the same sentence). Thus, we feel that G. luii remains an appropriate example of how scientifically describing a new species can unintentionally fuel its commercial exploitation ([3][14]). It is fortunate for G. luii that demand for wild-caught individuals has now diminished, owing to the availability of inexpensive, captive-born individuals produced by hobbyists. The conservation merits of unregulated, private, captive breeding programs are beyond the scope of our Letter, but it does seem that G. luii paid a high cost for the end result of inexpensive, captive-born substitutes in the pet trade. 1. 1.[↵][15] 1. L. L. Grismer, 2. B. E. Viets, 3. L. J. Boyle , J. Herpetol. 33, 382 (1999). [OpenUrl][10] 2. 2.[↵][16] 1. H. Ota, 2. M. Honda, 3. M. Kobayashi, 4. S. Sengoku, 5. T. Hikida , Zool. Sci. 16, 659 (1999). [OpenUrl][7][CrossRef][8] 3. 3.[↵][17] 1. L. Guterman , Chron. Higher Educ. 52, A12 For additional plant and animal examples, see (21 July 2006). [1]: /lookup/doi/10.1126/science.312.5777.1137b [2]: #ref-1 [3]: #ref-2 [4]: #ref-3 [5]: pending:yes [6]: #xref-ref-1-1 View reference 1. in text [7]: {openurl}?query=rft.jtitle%253DZool.%2BSci.%26rft.volume%253D16%26rft.spage%253D659%26rft.atitle%253DZOOL%2BSCI%26rft_id%253Dinfo%253Adoi%252F10.2108%252Fzsj.16.659%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [8]: /lookup/external-ref?access_num=10.2108/zsj.16.659&link_type=DOI [9]: #xref-ref-2-1 View reference 2. in text [10]: {openurl}?query=rft.jtitle%253DJ.%2BHerpetol.%26rft.volume%253D33%26rft.spage%253D382%26rft.atitle%253DJ%2BHERPETOL%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [11]: #xref-ref-3-1 View reference 3. in text [12]: #ref-4 [13]: #ref-5 [14]: #ref-6 [15]: #xref-ref-4-1 View reference 1. in text [16]: #xref-ref-5-1 View reference 2. in text [17]: #xref-ref-6-1 View reference 3. in text

MEASUREMENT ERROR ASSOCIATED WITH EXTERNAL MEASUREMENTS COMMONLY USED IN SMALL-MAMMAL STUDIES

Measurement error can occur at both the intra- and interobserver level, result in significant biases in collected data, and increase the likelihood of type II errors. We estimated the intra- and interobserver measurement error associated with 4 commonly used and 1 modified external metric in 4 representative Australian small-mammal species, using both preserved laboratory specimens and live wild-caught individuals. Measurement error was larger in live individuals and was significant in a number of cases in metrics that were difficult to define, were highly flexible, or were relatively small. Observer experience significantly affected precision, and overall, our modified hind foot metric (length of the hind foot, excluding the toes) performed similarly to the currently used metric. The number of replicate measurements significantly affected the size of detectable differences between observers, and we recommend that at least 2 replicate measurements per metric be taken as a matter of course.

Exploitation and trade of Australian seahorses, pipehorses, sea dragons and pipefishes (Family Syngnathidae)

Seahorses and their syngnathid relatives have provided a focus for efforts to ensure sustainable use of marine resources, with new international trade controls (CITES Appendix II) implemented in May 2004. We demonstrate how a study of international trade can be used to assess relative levels of threat and set domestic research and conservation priorities. Australia has remarkably high syngnathid biodiversity with at least 14 seahorse species, two endemic sea dragon species, and 90 species of pipefishes and pipehorses found in its territorial waters. Our objectives were to quantify species, trade routes, volumes, values and temporal trends in syngnathid trade to and from Australia. We found that Australia is probably the major global supplier of dried pipehorses Solegnathus spp.. These fishes, including at least one endemic species, are sourced from trawl bycatch and comprise Australia's largest syngnathid export, by both volume and value. Research is urgently needed to evaluate the impacts and sustainability of trawling on pipehorse populations. Australia is also the sole supplier of two sea dragon species, Phycodurus eques and Phyllopteryx taeniolatus, for the live aquarium trade. Although lucrative, the number of wild-caught individuals involved in this trade was relatively low and probably of low conservation risk relative to habitat loss. Exports of seahorses and other pipefish species, and imports of all syngnathid species, are minor on a global scale, although the burgeoning aquaculture industry for seahorses requires careful evaluation for its potential impacts on wild populations.

Effect of prepared and macroalgal diets and seed stock source on somatic growth of juvenile green sea urchins ( Strongylocentrotus droebachiensis)

Populations of sea urchins, harvested for their gonads, are in decline worldwide and so scientific research is now focusing on full life cycle grow-out. The objective of this study was to compare the growth rates of juvenile (initial test diameter: 4.5–13.7 mm) green sea urchins that were held in laboratory tanks and fed a variety of diets. Two separate experiments were conducted. The first compared juvenile growth on seven different diets: 1) prepared diet, 2) Porphyra purpurea, 3) Palmaria palmata, 4) Ulva linza, 5) a mixture of Ulvaria obscura and Ulva lactuca, 6) Laminaria saccharina collected from an Atlantic salmon aquaculture site, and 7) L. saccharina collected from a site relatively distant from salmon aquaculture operations. The latter two treatments were chosen in order to determine if the nutrient regime in which an alga was grown could affect juvenile growth rate. A second experiment compared the growth rates of wild-caught and hatchery-reared juvenile green sea urchins fed either a prepared diet or fresh kelp ( L. saccharina) collected from a site relatively distant from salmon aquaculture. Test diameter and whole wet weight measurements were taken monthly for a period of 16 months. In the first experiment, feed type significantly affected somatic growth rate, the overall best growth being supported by Porphyra purpurea (mean growth rate ±SE: 0.059±0.001 mm d −1) and the prepared diet (0.056±0.001 mm d −1). L. saccharina collected from the site distant from salmon aquaculture operations (0.019±0.001 mm d −1) produced significantly slower growth than any other feeding treatment including L. saccharina collected from a salmon aquaculture site (0.047±0.001 mm d −1). In the second experiment, feed type also significantly affected growth with the prepared diet (0.058±0.001 mm d −1) supporting better growth than L. saccharina (0.027±0.001 mm d −1). Seed stock source also affected overall growth with the hatchery-reared individuals displaying significantly greater growth (0.045±0.002 mm d −1) than wild-caught individuals (0.040±0.002 mm d −1). Identifying which diets and sources of juvenile sea urchins optimize growth may help aquaculture operations produce market-size sea urchins in a minimum amount of time, thus maximizing profitability.

Behavioural differences between individuals and two populations of stickleback (Gasterosteus aculeatus)

Behavioural syndromes are correlations between behaviours in different functional contexts. Behavioural syndromes are attracting the attention of evolutionary biologists because they mean that different behaviours might not be free to evolve independently of one another. In a landmark study, Huntingford (1976) showed that individual stickleback which were bold toward predators were also aggressive toward conspecifics and active in an unfamiliar environment. Here, I revisited the activity-aggression-boldness syndrome in stickleback and tested the hypothesis that correlations between behaviours might act as evolutionary constraints. I measured a suite of behaviours on wild-caught individuals and their offspring from two different populations and calculated heritabilities and genetic correlations between the different behaviours. I found that these behaviours were phenotypically and genetically correlated in one population but not another. On average, boldness and aggression were negatively related to each other across the populations. These results suggest that behavioural syndromes don't always act as evolutionary constraints.

Fecal Corticosteroid Levels in Free-living Populations of Deer Mice (Peromyscus maniculatus) and Southern Red-backed Voles (Clethrionomys gapperi)

Abstract Fecal corticosteroid levels were monitored in free-living populations of deer mice (Peromyscus maniculatus) and southern red-backed voles (Clethrionomys gapperi) in North-Central Idaho. Sex, reproductive condition and age had no significant effect on fecal corticosteroid level in either species, but fecal corticosteroid levels were significantly higher in deer mice than red-backed voles regardless of sex or age. These data are consistent with the plasma corticosterone level profile exhibited by wild-caught individuals of both species maintained in captivity. In addition, for deer mice estimated population size was significantly correlated with fecal corticosteroid levels. Overall, these data clearly indicate the utility of fecal corticosteroid measures in assessing the adrenal status of wild populations of rodents.

Multiple selection pressures influence Trinidadian guppy (Poecilia reticulata) antipredator behavior

Animals alter their behavior to avoid a variety of different types of predators. Trinidadian guppies (Poecilia reticulata) have been an important system for examining the evolution of antipredator behavior because geographically isolated populations experience different amounts of aquatic predation. Although the influence of aquatic predators has been well documented, selective pressures from other types of predators are less well understood. We examined the response of wild-caught individuals from upstream and downstream populations to an aquatic predator and a simulated aerial predator. As previously documented, fish from the downstream population responded more strongly to the aquatic predator than did fish from the upstream population, inspecting for longer periods of time. Guppies also exhibited a strong behavioral response to the potential aerial predator. Although both populations displayed a similar magnitude of response, they differed in the specific behaviors used. Upstream fish tended to freeze on the tank bottom, whereas downstream fish tended to hide under shelter. Field observations suggest that these strategies are related to habitat features specific to each site. The behaviors used against aerial predators differed substantially from the behaviors used against aquatic predators, suggesting that different types of predators exert conflicting selection pressures. This research demonstrates the importance of considering multiple selection pressures acting on an organism when trying to understand the evolutionary history of behavioral and morphological traits. Key words: aerial predators, aquatic predators, fish, guppy. [Behav Ecol 15:673–678 (2004)]