A population of Acrobeloides nanus in Australia is described and illustrated, based on light and scanning electron microscopy. Embryogenesis from egg laying to hatching is followed over a wide range of temperatures. At 15 C, hatching occurs in about 125 hours and at 35 and 37.5 C after about 40 hours. At 40 C, egg development ceases early in cleavage. The capacity of A. nanus to develop over su...

The purpose of the present study is to get a better knowledge of the Malagasy indigenous race of hen through its egg physical characteristics and its laying performance in order to promote villager poultry production. This study was undertaken within a local family farm, of the rural Township of Ambalamahasoa, Haute Matsiatra Region, Madagascar, with 25 hens and 4 roosters in age to reproduce. ...

1. We tested experimentally the e€ects of exposure to high ambient temperatures, for periods of 1±9 days, on the viability of eggs of the green-rumped parrotlet. 2. The hatchability of 534 newly laid parrotlet eggs declined after exposure of 3 or more days. 3. The probability of hatching was not signi®cantly a€ected by the duration or proportion of time exposed to temperatures below physiologic...

1. The loosening of the egg capsule plug prior to escape of the veligers is shown to be chemically mediated in Nassarius obsoletus and N. trivittatus. 2. The hatching substance is not produced continuously during development, but rather in a short pulse beginning just prior to hatching and ending within 4 hours of escaping from the capsule, for N. obsoletus. 3. The hatching substance produced b...

The aim of the performed investigations was to compare eggs of Japanese quail layers of different weights with regard to their shape, selected traits of the content following various times of their storage as well as the results of hatchability and body weight of one-day old chicks. Hatching eggs were divided into four groups: group S – up to 10.50 g, group M – from 10.51 to 11.50 g, group L – ...

Female polymorphism is observed in various animal species, but is particularly common in damselflies. The maintenance of this polymorphism has traditionally been explained from frequency and density dependent sexual conflict, however, the role of abiotic factors has recently attracted more interest. Here, the role of ambient temperature in shaping life-history was investigated for the three fem...

Incubation starts during egg laying for many bird species and causes developmental asynchrony within clutches. Faster development of late-laid eggs can help reduce developmental differences and synchronize hatching, which is important for precocial species whose young must leave the nest soon after hatching. In this study, we examined the effect of egg laying sequence on length of the incubatio...

This study was conducted to observe egg and larvae morphological development of carp to obtain basic data for resource conservation and taxonomic research. Brood carp used in the research (total length 67.3-75.5 cm, average 71.0±3.45 cm) were bred in a circular rearing aquarium (600×300×100 cm) using a running water system from January to July, 2015. Breeding water temperature was maintained at...

Climate change is expected to affect fish populations worldwide through a number of mechanisms. To help understand consistent, failed Lake Erie yellow perch (Perca flavescens) year-classes following warm winters during 1975–2010, we used a combined laboratory-experimental and population-modeling approach. We hypothesized that climate change would negatively affect yellow perch by 1) increasing ...

In birds, egg size aff ects chick growth and survival and it is an important component of reproductive success. Th e shiny cowbird Molothrus bonariensis is an extreme generalist brood parasite that uses hosts with a wide range of body masses. Survival of cowbird chicks decreases with host body mass, as competition for food with nestmates is more intense in large than in small hosts. We studied ...