Adaptive plasticity at switch points in complex life cycles (e.g., hatching, metamorphosis) is well known, but the evolutionary history of such plasticity is not. Particularly unclear is how a single plastic response (e.g., shifts in hatching timing) evolves to respond to different threats and cues (e.g., abiotic and biotic). We conducted a comparative phylogenetic study of hatching plasticity ...

 Effect of nanosilver particles was studied on the hatchability of rainbow trout (Oncorhynchus mykiss) egg and survival of the produced larvae at about 12ºC. In the first experiment the water-based nanosilver particles was used at concentrations of 0.5, 1, 2 and 4 mgL-1 for 30 minutes per day starting 24 hour post egg incubation until the hatching time. The mean percentage of hatchability reach...

We examined the molecular basis of the circadian control of egg hatching behavior in the silkmoth Antheraea pernyi. Egg hatching is rhythmically gated, persists under constant darkness, and can be entrained by light by midembryogenesis. The time of appearance of photic entrainment by the silkmoth embryo coincides with the appearance of Period (PER) and Timeless (TIM) proteins in eight cells in ...

To study the effects of post-stripping oocyte ageing at low temperatures on the viability of kutum (Rutilus kutum) oocytes, unfertilised eggs of five females were stored in ovarian fluid at temperatures of 4 and 7 degree centigrade for 24 hours post stripping (HPS). The stored ova of five female kutum were separately fertilised at 0 (i.e., control eggs fertilised prior to storage), 4, 8, 12, 16...

Meloidogyne incognita egg masses were immersed in different concentrations of six volaule fatty acids to bioassay their toxic effect on embryonic development and hatching. Exposure to a 250 ppm aqueous solution of volatile fatty, acids completely suppressed egg hatching within 48 hours. When exposed to a 125 ppm concentration hatching was reduced 75 % by acetic acid, 91% by propionic acid, 23% ...

-TO better understand the effects of egg mass and position in the laying sequence on reproductive success of Canada Geese (Brunta canadensis), I determined the fate of eggs, marked embryos near hatching, and recaptured goslings near fledging. Hatching success did not correlate with egg mass and position in the laying sequence. The probability of recapturing marked goslings near fledging was not...

A study was conducted to investigate Fe requirements of broiler breeders. One-hundred-fifty-six Cobb 500 broiler breeder hens were individually placed in electrostatically painted cages at 22 weeks. The study was composed of an adaptation phase, in which hens were fed corn-soy-wheat bran diets until 35 wks. An Fe deficient mash diet (24.6 ppm Fe) was provided from 35 to 46 wk in order to induce...

Doncaster and Shepherd (1) reported that hatching of eggs of Heterodera rostochienis Woll. was preceded by larval movement, by purposeful and accurate stylet thrusts which cut a slit at the end of the egg shell, and by forward body thrusts of the larva which forced the slit open and allowed it to escape. We crushed in distilled water 30 cysts of H. iri Mathews found in association with creeping...

The embryos of red-eyed treefrogs, Agalychnis callidryas, use vibrations transmitted through their arboreal egg clutch to cue escape hatching behavior when attacked by egg-eating snakes. Hatching early increases the risk of predation in the water, so embryos should avoid it unless they are in danger. We exposed egg clutches to intermittent vibrations with different combinations of vibration dur...

Reacting to a threat before physical contact, e.g., induced by air- or water-borne substances, appears to be an elegant way of defense. The reaction may be behavioral, developmental, morphological, or physiological, and it can involve a shift in niche or life history. Hatching from eggs is a shift in niche and in life history. From niche shift and life history models, one would predict that the...