Environmentally cued hatching allows embryos to escape dangers and exploit new opportunities. Such adaptive responses require a flexibly regulated hatching mechanism sufficiently fast to meet relevant challenges. Anurans show widespread, diverse cued hatching responses, but their described hatching mechanisms are slow, and regulation of timing is unknown. Arboreal embryos of red-eyed treefrogs,...

In the present study, the effect of successive milt collection was investigated on spermatological parameters and reproduction successes of wild and cultured endangered caspian brown trout. The milt collection was done 3 times with two weeks intervals. After milt collection, amount of milt was allocated for milt quality evaluation and reminders used for fertilization. According to results, in w...

Leatherback turtles have an average global hatching success rate of ~50%, lower than other marine turtle species. Embryonic death has been linked to environmental factors such as precipitation and temperature, although, there is still a lot of variability that remains to be explained. We examined how nesting season, the time of nesting each season, the relative position of each clutch laid by e...

Breeding mistiming is increasingly frequent in several ecosystems in the face of current climate change. Species belonging to higher trophic levels must employ mechanisms to reduce it. One of these mechanisms is hatching asynchrony, with the eggs in a clutch hatching over a period of several days. Some authors have suggested it to be adaptive when food is unpredictable. However, these birds can...

It has been demonstrated previously that removal of acellular debris from the preimplantation mouse embryo is beneficial for subsequent development to the hatched blastocyst stage. We have studied the impact of cellular fragmentation induced in the mouse embryo during the late pronuclei and 8-cell stages on the hatching frequency and total cell number at the blastocyst stage. At the late pronuc...

In temperate regions, the seasonal dynamics of Aedes aegypti (L.) (Diptera: Culicidae) is mainly influenced by temperature. It is assumed that, during the winter season, the population remains as eggs and that the development and population growth of surviving eggs begin during the following spring. The aim of the current study was to assess the temporal dynamics of egg hatching of Ae. aegypti ...

The aim of the present study was to determine whether the size of the zona pellucida (ZP) thinning area by laser-assisted hatching affected the potential development of vitrified-warmed embryos. A total of 196 vitrified-warmed cleavage-stage embryos (from 49 patients, four sister embryos per patient) were used in the study, i.e., four sister embryos from each patient were randomly assigned to f...

Most animals begin life in eggs, protected and constrained by a capsule, shell, or other barrier. As embryos develop, their needs and abilities change, altering the costs and benefits of encapsulation, and the risks and opportunities of the outside world. When the cost/benefit ratio is better outside the egg, animals should hatch. Adaptive timing of hatching evolves in this context. However, ma...

This study reports that common carp (Cyprinus carpio) embryos were successfully frozen and preserved by vitrification. The modified Haga solution was tested by using two different cryoprotectants and three different concentrations at 4°C to obtain appropriate vitrified solutions ((dimethylsulfoxide 5, 10, 15% (DMSO) and glycerol 5, 10, 15% (gly)) in the study.  The hatching rates of embryos exp...

Maternally derived yolk androgens affect many aspects of phenotypic development. To explore this phenomenon I injected clutches of American kestrels (Falco sparverius) with one of three different dosages of testosterone + androstenedione or with vehicle. Morphological measurements taken from nestlings 26 days after hatching showed no significant treatment effect. In 2007, nestlings with more yo...