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Larval Duration (larval + duration)

Distribution by Scientific Domains

Life Sciences	90%

Distribution within Life Sciences

Evolution	66%
Entomology	22%

Selected Abstracts

Characterization of microsatellite multiplexes for population genetic studies of bluehead wrasse (Thalassoma bifasciatum, Pisces: Labridae)

MOLECULAR ECOLOGY RESOURCES, Issue 3 2004
D. A. WILLIAMS
Abstract Bluehead wrasse (Thalassoma bifasciatum) are common coral reef fish found throughout the Caribbean. Larval duration in the plankton is relatively long for this species, which raises the possibility of long-distance transport by ocean currents. Several nongenetic studies suggest, however, that most recruits were spawned locally. Determination of the relative importance of local recruitment vs. immigration for recruitment is needed for the effective management of populations and establishment of marine reserves. We characterized seven new polymorphic microsatellite loci for bluehead wrasse and optimized them into PCR multiplexes with three previously published loci to determine the level of dispersal between populations. [source]

Molecular systematics of cowries (Gastropoda: Cypraeidae) and diversification patterns in the tropics

BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 3 2003
CHRISTOPHER P. MEYER
This study produces a nearly comprehensive phylogeny for the marine gastropod group Cypraeidae (cowries) and uses this topology to examine diversification patterns in the tropics. The dataset is based on molecular sequence data from two mitochondrial genes and includes 210 evolutionary significant units (ESUs) from 170 recognized species (>80%). Systematics for the group is revised based on well-supported clades, and tree topology is generally consistent with previously proposed classification schemes. Three new genera are introduced (Cryptocypraea gen. nov, Palmulacypraea gen. nov, and Contradusta gen. nov) and two previous genera are resurrected (Perisserosa and Eclogavena). One new tribe is proposed (Bistolidini). Topologies produced by a range of transition:transversion (Ti:Tv) weighting schemes in parsimony are pooled and evaluated using maximum likelihood criteria. Extensive geographical coverage shows persistent, large-scale geographical structure in sister-groups. Genetic divergence between subspecies is often equivalent or even greater than that between recognized species. Using ESUs as a metric, diversity throughout the Indo-West Pacific (IWP) increases by 38%. Intra- and inter-regional diversification patterns show that the IWP is the centre for speciation in cowries. The other major tropical regions of the world are inhabited by a predominantly relictual fauna; from a cowrie's eye-view. Good dispersal ability begets larger ranges, increased extinction resistance and morphological stasis; whereas shorter larval duration results in smaller ranges, higher speciation rates, but also higher turnover. Larval duration and dispersal ability appear correlated with ocean productivity as taxa with longer-lived larvae are associated with oligotrophic conditions; whereas taxa with shorter larval durations are associated with eutrophic, continental conditions. This tendency is carried to the extreme in temperate or upwelling regions where a planktonic phase is completely lost and crawl-away larvae evolve multiple times. A strong phylogenetic trend supports these observations as lineages leading up to and including the derived Indo-West Pacific Erroneinae clade contain taxa predominantly restricted to continental habitats and have undergone the greatest evolutionary radiations in their respective regions. © 2003 The Linnean Society of London, Biological Journal of the Linnean Society, 2003, 79, 401, 459. [source]

Effects of elevated CO2 associated with maize on multiple generations of the cotton bollworm, Helicoverpa armigera

ENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 1 2010
Jin Yin
Abstract Under elevated environmental carbon dioxide (CO2), leaf chewers tend to compensate for decreased leaf nutritional quality with increased consumption; mortality and development times also increase and cause a reduction in the fitness of leaf chewers. However, the effect of elevated CO2 on multiple successive generations of these and other insects is not well understood. Furthermore, information about the direct effects of increased environmental CO2 on developmental time and consumption of herbivores is lacking. In this paper, we tested the hypothesis that cascade effects of elevated CO2 through plants, rather than the direct effects of elevated CO2, are the main factors decreasing the fitness of cotton bollworm, Helicoverpa armigera Hübner (Lepidoptera: Noctuidae). We used two series of experiments to quantify the growth, development, and consumption of H. armigera fed on an artificial diet or C4 plants (maize) grown under two CO2 levels (ambient vs. double ambient). In the first series of experiments, elevated CO2 had no effect on the population abundance or individual consumption for three successive generations of cotton bollworms fed on an artificial diet. In the second series of experiments, elevated CO2 reduced population abundance of cotton bollworm larvae for two successive generations when they were fed maize milky grains. The specific effects were longer larval duration, lower fecundity, and decreased rm of cotton bollworms. Furthermore, elevated CO2 increased individual consumption when cotton bollworm was fed maize milky grains for two successive generations and decreased the population's total consumption in the first generation but increased it in the second generation. The results from this study indicate that: (1) The effects of elevated CO2 on three successive generations of cotton bollworm fed on artificial diet were weak, or even non-existent, and (2) elevated CO2 increased the consumption when cotton bollworm were fed maize. Our study also suggests that the damage inflicted by cotton bollworm on maize (a C4 plant) will be seriously affected by the increases in atmospheric CO2, which is unlike our previous results for spring wheat (a C3 plant). [source]

VICARIANCE AND DISPERSAL ACROSS BAJA CALIFORNIA IN DISJUNCT MARINE FISH POPULATIONS

EVOLUTION, Issue 7 2003
Giacomo Bernardi
Abstract., Population disjunctions, as a first step toward complete allopatry, present an interesting situation to study incipient speciation. The geological formation of the Baja California Peninsula currently divides 19 species of fish into disjunct populations that are found on its Pacific Coast and in the northern part of the Gulf of California (also called the Sea of Cortez), but are absent from the Cape (Cabo San Lucas) region. We studied the genetic makeup of disjunct populations for 12 of these 19 fish species. Phylogeographic patterns for the 12 species can be separated into two major classes: a first group (eight species) showed reciprocal monophyly and high genetic divergence between disjunct populations. A second group (four species) displayed what appeared to be panmictic populations. Population structure between Pacific Coast populations, across the Punta Eugenia biogeographic boundary, was also evaluated. While dispersal potential (inferred by pelagic larval duration) was a poor predictor of population structure between Gulf of California and Pacific populations, we found that population genetic subdivision along the Pacific Coast at Punta Eugenia was always positively correlated with differentiation between Pacific and Gulf of California populations. Vicariant events, ongoing gene flow, and ecological characteristics played essential roles in shaping the population structures observed in this study. [source]

Larval transport and retention of the spiny lobster, Panulirus argus, in the coastal zone of the Florida Keys, USA

FISHERIES OCEANOGRAPHY, Issue 5 2002
Cynthia Yeung
Abstract The spiny lobster Panulirus argus is of ecological and commercial importance in the South Florida coast of the continental USA and throughout the Intra-Americas Sea. Essential spiny lobster habitat in South Florida is primarily located in the Florida Keys coastal zone (including the Dry Tortugas), where the dynamic regional circulation coupled with the long planktonic larval duration (6,12 months) of P. argus raises questions of larval retention and recruitment. Locally spawned phyllosomata entrained in the Florida Current are likely to be expatriated out of the Straits of Florida, which implies that the local spiny lobster population is sustained by the transport of larval recruits from upstream locations. We examined the physical processes that may influence recruitment. Transport processes in the Keys coastal zone are spatially variable. Observed and modelled data suggest that the upper Keys is a point of onshore larval transport via the inshore meandering of the Florida Current, and the lower Keys to Dry Tortugas region apoint of retention through wind-driven onshore/countercurrents and eddy recirculation. Eddies that propagate between the Dry Tortugas and the lower Keys facilitate the exchange of larvae between the Florida Current and the coastal zone. Northerly wind events associated with cold fronts can enhance recirculation of larvae in the upper Keys. The association of older larvae with the Florida Current front supports the hypothesis that spiny lobster larval recruits come from upstream sources in the Caribbean. [source]

Production of the green lacewing Chrysoperla caranea (Steph.) (Neuropt., Chrysopidae) reared on semi-artificial diet based on the algae, Chlorella vulgaris

JOURNAL OF APPLIED ENTOMOLOGY, Issue 1-2 2001
F. N. Zaki
The larvae of the aphid lion Chrysoperla carnea (Steph.) were reared on a semi-artificial diet for laboratory rearing. Algae, Chlorella vulgaris Beij was used as a source of protein for the nutrition of the predator. Feeding the newly hatched larvae of the predator on water extract of the algae by using a small piece of sponge, extended the larval duration up to 30 days, and the larvae failed to pupate. The addition of carbohydrates, salts and vitamins was necessary to the larvae to complete their development to reach the pupal and adult stages. Normal adult longevity and egg deposition were obtained after the addition of the carbohydrates, salts and vitamins. [source]

Contrasting demographic history and phylogeographical patterns in two Indo-Pacific gastropods

MOLECULAR ECOLOGY, Issue 2 2008
ERIC D. CRANDALL
Abstract Marine species with ranges that span the Indo-Australian Archipelago (IAA) exhibit a range of phylogeographical patterns, most of which are interpreted in the context of vicariance between Indian and Pacific Ocean populations during Pliocene and Pleistocene low sea-level stands. However, patterns often vary among ecologically similar taxa, sometimes even within genera. This study compares phylogeographical patterns in two species of highly dispersive neritid gastropod, Nerita albicilla and Nerita plicata, with nearly sympatric ranges that span the Indo-Pacific. Mitochondrial COI sequences from > 1000 individuals from 97 sites reveal similar phylogenies in both species (two divergent clades differing by 3.2% and 2.3%, for N. albicilla and N. plicata, respectively). However, despite ecological similarity and congeneric status, the two species exhibit phylogeographical discordance. N. albicilla has maintained reciprocal monophyly of Indian and Pacific Ocean populations, while N. plicata is panmictic between oceans, but displays a genetic cline in the Central Pacific. Although this difference might be explained by qualitatively different demographic histories, parameter estimates from three coalescent models indicate that both species have high levels of gene flow between demes (2Nem > 75), and share a common history of population expansion that is likely associated with cyclical flooding of continental shelves and island lagoons following low sea-level stands. Results indicate that ecologically similar, codistributed species may respond very differently to shared environmental processes, suggesting that relatively minor differences in traits such as pelagic larval duration or microhabitat association may profoundly impact phylogeographical structure. [source]

Development of nine microsatellite markers for Pomacentrus amboinensis

MOLECULAR ECOLOGY RESOURCES, Issue 6 2008
DAVID B. JONES
Abstract The relatively long pelagic larval duration of Pomacentrus amboinensis, a tropical fish, suggests the potential for long-distance dispersal; however, several nongenetic studies have found substantial self-recruitment at one location. To analyse patterns of connectivity of this species, primers for nine independent microsatellite loci were developed for P. amboinensis using a magnetic bead enrichment protocol. Twenty individuals from one location were analysed and observed heterozygosities ranged from 0.7 to 0.95. Eight of nine loci were in Hardy,Weinberg equilibrium and no evidence of linkage or null alleles were found. [source]