Effects of tannic acid on hatching of Heterodera glycines eggs were determined in vitro using three batches of eggs obtained from greenhouse cultures in Florida or from naturally infested field soil in Minnesota. A quadratic model fits the percentage egg hatch. Hatch increased with increasing tannic acid concentrations from 0 to about 39 mg/liter, then declined with further increases in concent...

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 revealed unexpec...

Egg hatching of winter-collected Ochlerotatus albifasciatus was studied for six months. Batches of eggs were divided into two groups, one of them was stored in the laboratory at 23 degrees C and 12:12 photoperiod, and the other in the field under dead leaves. Every month, from July to December, eggs from the two groups were flooded under both laboratory and field conditions. Unhatched eggs were...

Among many altricial bird species, nestlings within a brood do not hatch simultaneously but over a period of several days (e.g. Clark & Wilson 1981, Ricklefs 1993, Stoleson & Beissinger 1995). Hatching asynchrony is mainly determined by incubation beginning before clutch completion, resulting in first-laid eggs hatching earlier than last-laid eggs (Lack 1968, O’Connor 1984) and consequent size ...

Disinfection by ozonation of sea-water may reduce the risk of transmission of nodavirus, a major fish pathogen, via Atlantic halibut Hippoglossus hippoglossus eggs. In the present study, eggs at 4 d prior to hatching were exposed to nodavirus and then to ozonated sea-water using different concentrations (0.3 to 10 mg l-1) and exposure times (0.5 to 10 min). None of the larvae from virus-exposed...

Abstract:  The optimum dose of UV irradiation to produce gynogenesis rainbow trout, Oncorhynchus mykiss with emphasis of Hertwing effect and photoreactivation (PR) was investigated. For this purpose, the sperm of rainbow trout were inadiated with UV at 2010±200 µw.cm-2 intensity in different alternatives of 0, 1, 3, 5, 8, 10, 15, 20, 25, 35 and 45 minutes and allowed to ferti...

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...

The responses of eggs in diapause and the infective stage of the nematode, Strelkovimermis spiculatus, to larvae of its host, Culex pipiens pipiens, were investigated in the laboratory. The results indicated that the presence of the host induced the egg hatching. The hatching rate increased when larger numbers of host larvae were present. Second instar mosquito larvae induced significantly high...