We studied the reproductive biology of a box-nesting population of Tree Swallows Tachycineta bicolor in southeastern Wisconsin, USA. We were interested particularly in the relationship between laying order and hatching order and the extent to which each was a predictor of nestling body mass. We found that laying order was a significant predictor of hatching order. Laying and hatching order were...

culture filtrates (cf) of two species of the nematophagous fungi, arthrobotrys oligospora and arthrobotrys conoidesat three concentrations (25%, 50% and 100%) of stock, were tested on the mortality of second stage juveniles (j2) and egg hatching rate of meloidogyne incognita and meloidogyne javanica. results showed that the percent juvenile mortality was directly proportional to concentration o...

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...

Embryos attached to the female crab Sesarma haematocheir hatch synchronously within 1 h. Hatching is also synchronized near the time of the expected nocturnal high tide. These events are governed by a single circatidal clock (or pacemaker) in the female crab. The present study examined the role of the optic peduncle of the eyestalk on hatching and hatching synchrony. Surgery was performed eithe...

the main objective of this study was to elucidate the effect of short- term exposure of japanese quail eggs to acute high incubation temperature on embryonic development and on the ability of post- hatched chicks to cope with subsequent heat stress conditions during the growing period. a total of 998 japanese quail eggs were divided into two groups, the first group (470 eggs) was maintained at ...

The behaviour of the cow blastocyst in vitro was studied by time-lapse cinematography and analysed by morphometry. Three types of behaviour were observed: continuous expansion followed by hatching; discontinuous expansion interrupted by few contractions and followed by hatching; discontinuous expansion interrupted by several rapid contractions without hatching. This demonstrated that the pulsat...

Increased variance in the reproductive success of males relative to females favors mothers that optimally allocate sons and daughters to maximize their fitness return. In altricial songbirds, one influence on the fitness prospects of offspring arises through the order in which nestlings hatch from their eggs, which affects individual mass and size before nest leaving. In house wrens (Troglodyte...