to compare the reproductive performance of the wild and cultured stocks of beluga, huso huso males, some spermatological parameters were measured including: sperm motility, sperm density, spermatocrit and also fertilization rate, hatching rate and larval growth and survival rates. the semen samples were sampled from 11 wild spawners and 12 cultured brooders. a half of each semen sample was allo...

Entomological studies to determine the effect of the physical characteristics of mosquito larval breeding water bodies and reservoir water level changes on the occurrence of Anopheles mosquito larvae were conducted in two villages at Koka reservoir in central Ethiopia between August and December 2007. Of the two study villages, Ejersa is located close to the reservoir, and Kuma is 5 km away fro...

Large body size confers a reproductive advantage to adults of the wood-boring beetle Phoracantha semipunctata (F.) (Cerambycidae: Cerambycinae: Phoracanthini). Larvae of this species feed subcortically in stressed and dying eucalypt trees and logs. We evaluated the influence of the larval environment on larval performance and adult body size by manipulating the post-felling age of host logs (fr...

Introduction: Density is one of the critical factors in echinoderm larvae for aquaculture purposes. Echinoplutei are very sensitive to overcrowding. High culture density can lead problems with bacteria or protozoa, decreasing survival and generating abnormal morphotypes. Objective: To evaluate effect on larval growth sea urchin Arbacia dufresnii. Methods: Two days after fertilization A. dufresn...

Many species of reef fishes form large spawning aggregations that are highly predictable in space and time. Prior research has suggested that aggregating fish derive fitness benefits not just from mating at high density but, also, from oceanographic features of the spatial locations where aggregations occur. Using a probabilistic biophysical model of larval dispersal coupled to a fine resolutio...

Genetic trade-offs such as between generalist-specialist strategies can be masked by changes in compensatory processes involving energy allocation and acquisition which regulation depends on the state of the individual and its ecological surroundings. Failure to account for such state dependence may thus lead to misconceptions about the trade-off structure and nature of constraints governing re...

Different standing water bodies act as breeding grounds of mosquitoes, thus responsible for the spread of diseases. A survey was conducted to study the population dynamics of mosquito larvae in three village ponds of Ludhiana district (Punjab), India. For this purpose water samples were collected at monthly intervals from July 2011 to June 2012 and larval density (LD/L) and larval density index...

When larvae of the tenebrionid beetle, Zophobas rugipes, were allowed to disperse among 26 equivalent chambers in a circular dispersarium, distribution patterns were found to be a function of larval weight and number of larvae in the apparatus (N). Small larvae (x wt 250 mg) were significantly aggregated while large mature larvae (, 1000 mg) were highly overdispersed. Medium larvae were interme...

Parthenogenesis, a natural form of asexual reproduction produced from unfertilized eggs, occurs in many insects in Hemiptera and Hymenoptera, but very rarely in Lepidoptera. The current study aimed to test the larval density dependent occurrence of parthenogenesis in potato tuber moth, Phthorimaea operculella (Zeller; Lepidoptera: Gelechiidae) under laboratory conditions. More than 10% of femal...

The distribution and abundance of mosquito larvae in a freshwater marsh were determined during a low water period in the late summer. Culex tarsalis larval abundance was significantly associated with the percent cover by Typha spp. root masses and Typha spp. stem density in 1-m2 quadrants. Larval mosquito abundance was not significantly related to bulrush (Scirpus californicus) stem density, po...