Natural enemies such as predators and parasites are known to shape intraspecific variability of behaviour and personality in natural populations, yet several key questions remain: (i) What is the relative importance of predation vs. parasitism in shaping intraspecific variation of behaviour across generations? (ii) What are the contributions of genetic and plastic effects to this behavioural di...

The corn leafhopper Dalbulus maidis (DeLong) (Hemiptera: Cicadellidae), transmits three important plant pathogens that adversely affect crop and ranges from the USA to Argentina. vector has a rich natural enemy complex generates high levels of parasitism, but its populations are persistent prevalent. We characterized oviposition sites D. on young plants in order verify hypothesis an strategy fo...

Until recently, analyses of gender-dependent differences in viability selection and the ontogeny of sexual size dimorphism have been plagued by difficulties in determining the sex of nestling birds on the basis of morphology. Recently, this problem was overcome using molecular sex identification to report for the first time body-size-mediated antagonistic selection on the viability of male and ...

1. Sex-biased mortality in adult vertebrates is often attributed to lower immunocompetence and higher parasite susceptibility of males. Although sex-specific mortality has also been reported during growth, the importance of sex-specific immunocompetence and parasite susceptibility in explaining male-biased mortality remains ambiguous in growing individuals because of potentially confounding sou...

this study was conducted to evaluate the age-specific functional response of psyllaephagus zdeneki noyes & fallahzadeh (hymenoptera: encyrtidae) at different nymph densities of olive psyllid, euphyllura pakistanica loginova (hemiptera: psyllidae). due to parasitoid behaviour of feeding and parasitizing the host, both traits were separately explored on a daily functional response. results of...

1. In a population of American coots ( Fulica americana ) breeding in central British Columbia, Canada, some females pursued a reproductive strategy that combined nesting with laying parasitic eggs in the nests of conspecifics. To understand why only one quarter of the nesting females laid parasitically, I examined social and ecological factors that could potentially constrain nesting females f...