plant quality in herbivores’ diet may affect the performance of both herbivore and its parasitoids. in the present research, parasitism capacity of diadegma semiclausum (hellen) on plutella xylostella (l.) reared on different genetically manipulated brassica plants including the canola’s progenitor (brassica rapa l.), two cultivated canola cultivars (cultivar-opera and cultivar-rgs003), one hyb...

Holcopasites ruthae Cooper is a cleptoparasite of Calliopsis pugionis Cockerell. At five sites, parasitism rate of host cells varied from 0 to over 30%, with an overall parasitism rate of 6.6% when data from all sites were combined. Significant influences on parasitism rate included site, nest density, and date of excavation, and density had a significant interaction with date. Together these f...

1. Testosterone (T) co-ordinates the seasonal and sex-specific expression of numerous physiological, behavioural and morphological traits that contribute to male reproductive success. However, increased susceptibility to parasitism has been proposed as a potential cost of elevated plasma T. 2. During the spring breeding season, male striped plateau lizards Sceloporus virgatus harbour significan...

tlsb-1%Males are often the 'sicker' sex with male biased parasitism found in a taxonomically diverse range of species. There is considerable interest in the processes that could underlie the evolution of sex-biased parasitism. Mating system differences along with differences in lifespan may play a key role. We examine whether these factors are likely to lead to male-biased parasitism through na...

Although there is growing evidence that males tend to suffer higher levels of parasitism than females, the implications of this for the population dynamics of the host population are not yet understood. Here we build on an established 'two-sex' model and investigate how increased susceptibility to infection in males affects the dynamics, under different mating systems. We investigate the effect...

Although there is growing evidence that males tend to suffer higher levels of parasitism than females, the implications of this for the population dynamics of the host population are not yet understood. Here we build on an established ‘two-sex’ model and investigate how increased susceptibility to infection in males affects the dynamics, under different mating systems. We investigate the effect...

The restrictive assumptions associated with purely genetic and purely ecological mechanisms suggest that neither of the two forces, in isolation, can offer a general explanation for the evolutionary maintenance of sex. Consequently, attention has turned to pluralistic models (i.e. models that apply both ecological and genetic mechanisms). Existing research has shown that combining mutation accu...

Parasitism of mammals is ubiquitous, but the processes driving parasite aggregation on hosts are poorly understood, as each system seems to show unique correlations between parasitism and host traits such as sex, age, size and body mass. Genetic diversity is also posited to influence susceptibility to parasitism, and provides a quantifiable measure of an intrinsic unchanging host property, but ...

Females of brood parasitic shiny cowbirds, Molothrus bonariensis, search and prospect host nests, synchronizing parasitism with laying. This behavior is sex-specific, as females perform this task without male's assistance. Host nests must be removed from the female’s memory "library" after being parasitized, to avoid repeated parasitism, or when they become unavailable because predation. Thus, ...