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991.
992.
Drosophila melanogaster larvae are used to examine habitat choice behavior and its effect on a component of preadult fitness (pupal survivorship). We established strains of flies by collecting pupae from two microhabitats from an orchard. Strain differences in pupation site choice (on versus off fruit) persisted in a field-like laboratory assay without artificial selection. To produce heterogeneous environments, air temperature and soil water content were varied in these assays. A habitat suitability difference measure was used to determine for each environment, which microhabitat (on or off fruit) resulted in greater pupal survivorship. We found 1) that habitat choice behavior had both plastic and heritable components, 2) that strain-by-environment interactions influenced habitat choice behavior and pupal survivorship and, 3) a significant positive correlation between habitat suitability and larval habitat choice behavior. 相似文献
993.
Data on developmental characteristics from fertilization to 2 days post‐hatching during captivity of the anoxia tolerant bearded goby Sufflogobius bibarbatus, one of the keystone prey species for many of the commercial fish populations, sea mammals and birds in south‐west Africa, are presented. 相似文献
994.
Noriyuki Endo Kana Sato Kiyotaka Matsumura † Erina Yoshimura Yukiko Odaka Yasuyuki Nogata 《Biofouling》2013,29(8):901-911
Species-specific detection and quantification methods for barnacle larvae using quantitative real-time polymerase chain reaction (qPCR) were developed. Species-specific primers for qPCR were designed for 13 barnacle species in the mitochondrial 12S ribosomal RNA gene region. Primer specificity was examined by PCR using template DNA extracted from each of the 13 barnacle species, other unidentified barnacle species, and field collected zooplankton samples. The resulting PCR products comprised single bands following agarose gel electrophoresis when the templates corresponded to primers. The amplifications were highly species-specific even for the field plankton samples. The field plankton samples were subjected to qPCR assay. The calculated DNA contents for each barnacle species were closely correlated with the number of larvae measured by microscopic examination. The method could be applied to quantify barnacle larvae in natural plankton samples. 相似文献
995.
Can ultraviolet radiation influence cod Gadus morhua L. year class strength: a model study 总被引:1,自引:0,他引:1
To simulate the UVR dose that eggs and larvae of cod Gadus morhua receive during spring in Lofoten, the main spawning area of north-east Arctic cod, a model driven by wind, tides and surface heat flux was applied. The model was forced using in situ measured hydrographical data while underwater UVR doses were calculated using satellite data, ozone measurements, meteorological data and in situ diffuse extinction coefficients. The model was run with data from 1934 to the present and indicated that UVR induced mortality has little effect on cod year class strength. When thin ozone layers and slack winds coincide with meagre phytoplankton stocks, UVR induced mortality may be harmful to eggs and larvae. As these events are highly episodic, and since the spawning period of cod is long ( c. 3 months), they are believed to have only a minor influence on the overall survival of cod eggs and larvae. 相似文献
996.
Matthew R. Gilligan 《Environmental Biology of Fishes》1980,5(2):109-116
Synopsis Reef fish community composition in three segments of a peninsular rocky shoreline in the Gulf of California was estimated
over four periods by visual observation. ‘Point’ and ‘bay’ segments had regular and distinct species compositions over most
periods while a ‘middle’ segment was least distinct but consistently had the greatest number of species. Compositional change
along the peninsula was least regular during the coldest sea temperature period (April). Mean species turnover between segments
was highest between point and bay. Within segments, the point had greater compositional predictable composition (lowest species
turnover). When species with regular frequency of encounter were classified into ‘point’, ‘middle’, ‘bay’, and ‘no trend’
groups it was found that comparatively more ‘point’ species had pelagic eggs and comparatively more ‘bay’ species had demersal
eggs. Beta diversity of rocky-shore fishes along the physical gradient of the Punta Doble peninsula reflects a transition
between exposed and protected rocky shoreline communities. The correlated physical environmental characteristics associated
with exposed and protected habitats are discussed in relation to diversity regulation and dispersal strategies in reef fishes. 相似文献
997.
Michael J. Miller 《Environmental Biology of Fishes》2002,63(3):235-252
A total of 4589 leptocephali of the congrid eel, Ariosoma balearicum, were examined from 17 cruises in the western North Atlantic Ocean. Myomere counts made on 915 of these indicated there were two ranges of number of myomeres that appear to be associated with separate spawning populations. Those with the higher range (high count: 128–137) were consistently 70–100mm in length in the Sargasso Sea from February to April and 20–80mm in length in the northern Sargasso Sea and Gulf Stream from September to October. Those with the lower range (low count: 120–130) were rare in the northern and eastern Sargasso Sea where they had consistently greater lengths than high count leptocephali and were most abundant in the Florida Current and Providence Channel. The geographic distributions of size and myomere ranges in relation to hydrography provide strong support for the hypothesis that high count eels found along the South Atlantic Bight (SAB) migrate across the Florida Current to spawn in the northwest Sargasso Sea. This migratory pattern is similar to those of Anguilla rostrata and Conger oceanicus, which use the southern Sargasso Sea for development as larvae. However, the distribution of high count leptocephali suggests that they use the entire Sargasso Sea gyre as a development area as larvae before crossing the Florida Current and recruiting to the SAB. The low count eels inhabiting the Bahamas appear to spawn near the banks and their abundance in the Providence Channel and southwest Sargasso Sea suggests most are retained close to the Bahamas. These two distinct styles of spawning, distribution and recruitment of larvae are hypothesized to be related to the different hydrographic regimes of the two juvenile habitats and the resulting constraints on growth and recruitment of larvae. Vertebral and myomere counts reported from other areas suggest there are distinct populations in other regions of the North Atlantic Ocean. 相似文献
998.
999.
Although variation within populations in plasticity to time constraints is expected with regard to hatching date, empirical studies are largely lacking. We studied life-history responses to time constraints manipulated by photoperiod and associated with hatching date in larvae of the damselfly Lestes viridis for two populations with a different hydroperiod. In a common garden experiment, early- and late-hatched larvae from both populations were reared at two photoperiods mimicking the start and the end of the egg-hatching season. In a reciprocal transplant experiment, early- and late-hatched larvae from both populations were reared in both ponds. In all these experiments, larvae were reared from egg hatching until adult emergence. Within both populations, larvae reared at the photoperiod indicating a late time point in the growing season, reduced development time to compensate for their perceived shorter development period. Growth rate, however, did not respond to photoperiod, resulting in a lower mass at emergence. As expected, both in the laboratory and in the field, larvae from eggs that hatched later in the season generally had a shorter development time and a faster growth rate, resulting in a higher mass at emergence compared to early-hatched larvae. This may explain the intriguing seasonal increase in mass at emergence in this species, and affect the predictions of optimality models. None of these life-history responses differed between the two populations, despite clear differences in time constraints linked to hydroperiod, suggesting the robustness of the observed patterns. Given the ubiquity of asynchronous hatching in nature, and the adaptive value of the observed differences between early- and late-hatched larvae, we expect the effects of hatching date on life-history plasticity to be widespread. 相似文献
1000.