Assisted hatching (AH), which is known to improve the hatching potential of mammalian embryos, has been used to increase the pregnancy rate in in vitro fertilization cycles. However, the effect of AH on a trypsin-like protease, which is known to be associated with the hatching process, has not been studied. In this study, we evaluate whether the intactness of zona pellucida affects the secretio...

Embryonic development of the common chameleon, Chamaeleo chamaeleon, was monitored from oviposition to hatching at a field site in southwestern Spain and in the laboratory under five experimental temperature regimes. Embryos were diapausing gastrulae at the time of oviposition; developmental arrest in the field continued as cold torpor during winter. Postarrest development in the field commence...

AssTr•cT.--Marked asynchronous hatching was observed in Tree Swallows (Iridoprocne bicolor), apparently because incubation started before the full clutch was laid. Asynchronous hatching resulted in pronounced size differences of nestlings. Immediately after hatching, the first-hatched nestling was, on average, 94% heavier than the last-hatched. Clearly, a weight hierarchy was established, with ...

Attaining endothermic homeothermy occurs at different times post-hatching in birds and is associated with maturation of metabolic and aerobic capacity. Simultaneous measurements at the organism, organ and cellular levels during the transition to endothermy reveal means by which this change in phenotype occurs. We examined development of endothermy in precocial Pekin ducks ( ITALIC! Anas platyrh...

In the presence of potato plants cv. Golden Wonder, Globodera pallida exhibited delayed in-soil hatch compared to that of G. rostochiensis, with significantly fewer G. pallida second-stage juvenile nematodes hatching in the first two weeks, though the difference disappeared after four weeks. Inoculation of potato plants with arbuscular mycorrhizal fungi eliminated this delay in G. pallida hatch...

This study examined whether polyandrous female Chinook salmon Oncorhynchus tshawytscha obtain benefits compared with monandrous females through an increase in hatching success. Both of the alternative reproductive tactics present in male O. tshawytscha (large hooknoses and small, precocious jacks) were used, such that eggs were either fertilized by a single male (from each tactic) or multiple m...

The barnacle life cycle has two key stages at which eicosanoids are believed to be involved in cellular communication pathways, namely the hatching of nauplii and the settlement of cypris larvae. Barnacle egg-hatching activity has previously been reported to reside in a variety of eicosanoids, including 8-hydroxyeicosapentaenoic acid and a number of tri-hydroxylated polyunsaturated fatty acid d...

A major life stage transition in birds and other oviparous sauropsids is the hatching of the cleidoic egg. Not unlike amphibian metamorphosis, hatching in these species can be regarded as a transition from a relatively well-protected "aqueous" environment to a more hazardous and terrestrial life outside the egg, a transition in which thyroid hormones (THs) (often in concert with glucocorticoids...

This study was undertaken to determine the effects of storage period and egg weight of hatching eggs of Japanese quails on fertility, hatchability results. Eggs were obtained 150 females quails, all at 15 weeks of age. A total of 1942 hatching eggs were separated into 3 groups as light-weight (9.50-10.50 g), medium-weight (10.5111.50 g), and heavy-weight (11.51-12.50 g). Based on storage period...

Phenology is increasingly recognized as an important factor structuring communities because it determines when and at what life stage organisms interact. Previous work indicates that changes in first or mean timing of a phenological event can affect populations and communities, but little is known about the consequences of changes in the distribution (e.g., synchrony) of a phenological event. W...