Costs of parasitism are commonly measured by comparing the performance of infected groups of individuals to that of uninfected control groups. This measure potentially underestimates the cost of parasitism because it ignores indirect costs, which may result from the modification of the competitiveness of the hosts by the parasite. In this context, we used the host-parasite system consisting of ...

1. Previous studies have demonstrated that phenotypic traits of plants have the potential to affect interactions between herbivores and their natural enemies. Consequently, the impact of natural enemies on herbivore vital rates and population dynamics may vary among plant species. This study was designed to investigate the potential for density-dependent parasitism of an aphid herbivore feeding...

The population dynamics of major brassica pests and occurrence of their natural enemies were monitored weekly for a period of 9 months on cabbage (var. Copenhagen Market) at a research station plot (no pesticides applied) and a farmer’s field (weekly application of Permethrin 10 EC or Dimethoate 40 EC) in Central Kenya. Pest infestations occurred within 14 days after the seedlings were transpla...

Parasitism is widely viewed as the primary cost of sociality and a constraint on group size, yet studies report varied associations between group size and parasitism. Using the largest database of its kind, we performed a meta-analysis of 69 studies of the relationship between group size and parasite risk, as measured by parasitism and immune defenses. We predicted a positive correlation betwee...

Agricultural intensification is linked to reduced species richness and may limit the effectiveness of predators in agricultural systems. We studied the abundance, diversity, and species composition of wood-nesting ants and frequency of parasitism of poneromorph ants in coffee agroeco systems and a forest fragment in Chiapas, Mexico. In three farms differing in shade management and in a nearby ...

Three laboratory experiments were conducted to evaluate the side-effects of four common herbicides used to control weeds associated with local crops on egg of the parasitoid Trichogramma evanescens. These herbicides are Glyphosate 48%SL, Bromoxynil 24%EC, Thiobencarb 50% and Clodinafop-propargyl 15%WP. The biological aspects such% parasitism, % adult emergence, sex ratio, developmental period a...

The metaphor of parasites or parasitism has dominated literary critical discourse since the 1970s, prominent examples being Michel Serres in France and J. Hillis Miller in America. In their writings the relationship between text and paratext, literature and criticism, is often likened to that between host and parasite, and can be therefore deconstructed. Their writings, along with those by Derr...

Abstract Background Changes in wild animal gut microbiotas may influence host health and fitness. While many studies have shown correlations between microbiota structure external factors, few demonstrate causal links environmental variables shifts. Here, we use a fully factorial experiment to test the effects of elevated ambient temperature natural nest parasitism by flies ( Protocalliphora sia...

Related host species often demonstrate differences in prevalence and/or intensity of infection by particular parasite species, as well as different levels of resistance to those parasites. The mechanisms underlying this interspecific variation in parasitism and resistance expression are not well understood. Surprisingly, few researchers have assessed relations between actual levels of parasitis...

Many songbird species have experienced significant population declines, partly because of brood parasitism by the Brown-headed Cowbird (Molothrus ater), which is positively associated with increasing landscape forest cover in the midwestern United States. However, cowbirds are also experiencing long-term population declines, which should reduce parasitism pressure and thus increase productivity...