abstract the effect of different larval density of chilo suppressalis walker was evaluated through 2006-2008 on rice infestation in controlled condition of the cages. the results indicated that there were significant effects between dead hearts, white heads and crop yield. the highest dead hearts and white heads were related to the treatment of 32 larvae per m2 and the lowest ones were obtained...

striped rice stem borer, chilo suppressalis (lepidoptera: pyralidae) is one of the major pests in north part of iran which causes serious damage. the last larval instar overwinters in the stem of weeds around the fields. regarding the importance of weeds as overwintering habitat, population density of larvae was studied in three areas; low-, mid-, and up-lands of mazandaran province and also on...

aim: this study investigates the intraspecific competition, for food and density amongst larvae of anopheles stephensi (main malaria vector in south iran). material & methods: the effects of 4 selected food quantities (1x,2x,4x,6x) and 5 larval densities (0.1 to 3 larva/cm2) were tested individually or in combination on 7 biological indexes of the vector and the results were statistically ...

searching efficiency (a') (attack rate) and handling time are two major components of natural enemies’ functional response and are usually used to evaluate their effectiveness. the age-specific searching efficiency of aphidoletes aphidimyza (rondani) was studied during its larval stage. the experiment was conducted in terms of age-specific functional response to the varying density (5, 1...

the diamondback moth, plutella xylostella (linnaeus, 1758) (lep.: plutellidae) is the most destructive insect pest of crucifer plants throughout the world. in order to study its seasonal population fluctuation, sampling was conducted in the cauliflower fields of south of tehran from late may until october 2011. one hectare cauliflower field in the middle of a large field was randomly selected i...

Sleep has many important biological functions, but how sleep is regulated remains poorly understood. In humans, social isolation and other stressors early in life can disrupt adult sleep. In fruit flies housed at different population densities during early adulthood, social enrichment was shown to increase subsequent sleep, but it is unknown if population density during early development can al...

The application of high-resolution genetic data has revealed that oceanographic connectivity in marine species with planktonic larvae can be surprisingly limited, even in the absence of major barriers to dispersal. Australia's southern coast represents a particularly interesting system for studying planktonic larval dispersal, as the hydrodynamic regime of the wide continental shelf has potenti...

Aedes albopictus, a species known to transmit dengue and chikungunya viruses, is primarily a container-inhabiting mosquito. The potential for pathogen transmission by Ae. albopictus has increased our need to understand its ecology and population dynamics. Two parameters that we know little about are the impact of direct density-dependence and delayed density-dependence in the larval stage. The ...

Observations by Dobzhansky's group in the 1940s suggesting that the presence of recessive genotypes could account for lower larval developmental rates in Drosophila melanogaster were not confirmed at the time and all subsequent investigations on this subject focused on the analysis of ecological models based on competition among pre-adult individuals. However, a paper published in this journal ...

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...