Hatching plasticity occurs in response to a wide range of stimuli across many animal taxa, including annelids, arthropods, mollusks, and chordates. Despite the prominence of echinoderms in developmental biology and more than 100 years of detailed examination of their development under a variety of conditions, environmentally cued hatching plasticity has never been reported in the phylum Echinod...

In this study, the aim was to determine the effect of 12 hours delay and time advancement of Bombyx mori larvae transfer to spinning frames on the economic traits of harvested cocoons. Our experience focused on the transfer of three lots of silkworm mature larvae to cocoon frames with 12 hours delay or advancement from usual spinning time. Commercial silkworm eggs were obtained and thr...

Population dynamics of black-legged kittiwakes Rissa tridactyla in Bering Sea colonies are likely to increasingly experience climate-induced changes in the physical environment. Since adult kittiwakes are central place foragers with high energy requirements, increased variability of forage patch dynamics, as predicted for polar regions, may influence both quantity and quality of food available ...

This study investigated the effects of mate switching on the reproductive performance of the severum cichlid, Herosseverus, by advancing the egg and larval production in hatcheries. Two reproductive tactic treatments of “monogamous pair” and “mate switching” were used for evaluating 4 reproductive traits of egg production, hatching rate, spawning intervals, and starvation tolerance of the larva...

This study investigated the effects of mate switching on the reproductive performance of the severum cichlid, Herosseverus, by advancing the egg and larval production in hatcheries. Two reproductive tactic treatments of “monogamous pair” and “mate switching” were used for evaluating 4 reproductive traits of egg production, hatching rate, spawning intervals, and starvation tolerance of the larva...

Synopsis Incubation temperature plays a prominent role in shaping the phenotypes and fitness of embryos, including affecting developmental rates. In many taxa, including turtles, eggs are deposited in layers such that thermal gradients alter developmental rates within a nest. Despite this thermal effect, a nascent body of experimental work on environmentally cued hatching in turtles has reveale...

A crossbreeding experiment was conducted between the Sinai (SI), an indigenous Egyptian strain, and exotic Lohmann Brown (LB) breeds of chickens. total 790 chicks were produced in four genetic groups, namely SI x SI, LB LB, SI. The objective to estimate direct additive effect (gi), individual heterosis (hi), maternal (gm) for growth reproduction traits. Direct effects positive (P ≤0.01) bodywei...

Life history theory seeks to explain patterns of variation among geographically widespread populations of same species to understand their ecology and adaptations. To date, very few attempts have been made to review and compare life history traits of tropical reptiles, especially those that inhabit the Asian continent. Among tropical reptiles, the agamid lizard Calotes versicolor is widespread,...

We have identified, using composite interval mapping, quantitative trait loci (QTL) affecting a variety of life history traits (LHTs) in the nematode Caenorhabditis elegans. Using recombinant inbred strains assayed on the surface of agar plates, we found QTL for survival, early fertility, age of onset of sexual maturity, and population growth rate. There was no overall correlation between survi...

To test the hypothesis that the variance of incubation temperature may have constituted a significant selective force for reptilian viviparity, we incubated eggs of the slender forest skink Scincella modesta in five thermally different natural nests and at two constant temperatures (18 °C and 21 °C). Our manipulation of incubation temperature had significant effects on incubation length and sev...