Doncaster and Shepherd (1) reported that hatching of eggs of Heterodera rostochienis Woll. was preceded by larval movement, by purposeful and accurate stylet thrusts which cut a slit at the end of the egg shell, and by forward body thrusts of the larva which forced the slit open and allowed it to escape. We crushed in distilled water 30 cysts of H. iri Mathews found in association with creeping...

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 ...

We investigated whether reduced reproductive success of copepods fed with diatoms was related to nutritional imbalances with regard to essential lipids or to the production of inhibitory aldehydes. In 10-d laboratory experiments, feeding, egg production, egg hatching success, and fecal pellet production of Temora longicornis were measured for six different diatom species as well as for a nondia...

The embryos of red-eyed treefrogs, Agalychnis callidryas, use vibrations transmitted through their arboreal egg clutch to cue escape hatching behavior when attacked by egg-eating snakes. Hatching early increases the risk of predation in the water, so embryos should avoid it unless they are in danger. We exposed egg clutches to intermittent vibrations with different combinations of vibration dur...

Reacting to a threat before physical contact, e.g., induced by air- or water-borne substances, appears to be an elegant way of defense. The reaction may be behavioral, developmental, morphological, or physiological, and it can involve a shift in niche or life history. Hatching from eggs is a shift in niche and in life history. From niche shift and life history models, one would predict that the...

Background & Aim: Tetranychus urticae Koch is one of the most important pests of crops, ornamental and greenhouse plants in the world and, can damage to 900 plant species. Resistances to pesticides and acaricides have guided researches to introduce new methods to control T. urticae. Botanical pesticides are an important group of natural productions that are usually safer than ...

In this study the effect of different protein levels on reproductive performance of Channa striatus was conducted. Snakehead juveniles (65.5±0.2 g) were randomly distributed into nine homogenous groups of 75 fish each. Three isocaloric experimental diets differing in protein levels were prepared. The experiment lasted for 8 months and gonadosomatic index, absolute fecundity, egg diameter, numbe...

Climate warming has been suggested to augment the risk of infectious disease outbreaks by extending the seasonal window for parasite growth and by increasing the rate of transmission. Understanding how this occurs in parasite-host systems is important for appreciating long-term and seasonal changes in host exposure to infection and to reduce species extinction caused by diseases. We investigate...

The concentration of heavy metals in the environment is normally low. We here address whether using the development of isolated pond snail Radix auricularia eggs would provide a more sensitive endpoint and whether the gelatinous matrix of the egg mass surrounding the eggs indeed protects the snail embryos. In the present study, artificial removal of the gelatinous matrix of egg masses greatly i...