1. Most trophic interaction theory assumes that all predators are an abstract form of risk to which prey respond in a quantitatively similar manner. This conceptualization can be problematic because recent empirical work demonstrates that variation in the responses of prey to different predators can play a key role in structuring communities and regulating ecosystem function. 2. Predator identi...

Previously, we have show that the co-evolution of patch selection strategies of hosts and parasitoids in heterogeneous environments can lead to contrary habitat choices in which the hosts preferentially select patches that the parasitoids avoid. Since this work did not include the variable parasitoid sex ratios that have been found in field and laboratory systems with contrary choices, we exten...

Microplitis mediator (Haliday) is a solitary endoparasitoid of larvae of the cotton bollworm, Helicoverpa armigera (Hübner) and the oriental armyworm, Mythimna = Leucania separata (Walker). The preference and suitability of different instars of M. separata for M. mediator were determined under laboratory conditions at a constant temperature of 26 ± 1 C, 65 ± 5% RH and L14:D10 photoperiod. The s...

Laboratory experiments were conducted to examine selection by Cotesia plutellae between host larvae feeding on two plant species: Chinese cabbage, Brassica campestris ssp. pekinensis and common cabbage, Brassica oleracea var. capitata. When C. plutellae wasps were provided with equal numbers of Plutella xylostella larvae on both species of plants in one arena, the parasitoid parasitised 4-15 fo...

Plant infestation, stem borer density, parasitism, and parasitoid abundance were assessed during two years in two host plants, Zea mays (L.) (Cyperales: Poaceae) and Sorghum bicolor (L.) (Cyperales: Poaceae), in cultivated habitats. The four major host plants (Cyperus spp., Panicum spp., Pennisetum spp., and Sorghum spp.) found in natural habitats were also assessed, and both the cultivated and...

Observed changes in mean temperature and increased frequency of extreme climate events have already impacted the distributions and phenologies of various organisms, including insects. Although some research has examined how parasitoids will respond to colder temperatures or experimental warming, we know relatively little about how increased variation in temperature and humidity could affect int...

This study investigated the temporal patterns of parasitoid attack and diversity within and among years and the potential ecological factors inßuencing the incidence of parasitism experienced by the larvae of a bivoltine moth, Psilocorsis quercicella Clemens. To do this, Þeldcollected larvae were reared throughout both generations during 1995Ð1997 in eastern Missouri. Annual variation inpercent...

Antagonistic relationships between parasitoids and their insect hosts involve multiple traits and are shaped by their ecological and evolutionary context. The parasitoid wasp Cotesia melitaearum and its host butterfly Melitaea cinxia occur in several locations around the Baltic sea, with differences in landscape structure, population sizes and the histories of the populations. We compared the v...

Parasitoid-induced mortality of house fly, Musca domestica L., pupae and parasitoid progeny emergence by four species of pteromalid parasitoids, Muscidifurax raptor Girault & Sanders, M.zaraptor Kogan & Legner, Spalangia cameroni Perkins and S.endius Walker, were determined for a 24 h exposure period using parasitoid: host ratios ranging from 1:2 to 1:50. When the number of parasitoids was held...

introduction: parasitoid wasp, trichogramma brassicae (bezdenko) (hym.: trichogrammatidae) has excellent position in mass production technology, scope of application, wide geographical distribution and unmatched talent to adapt to different climatic conditions that can be easily reared on mediterranean flour moth (mfm), ephestia kuehniella zeller (lep.: pyralidae). the parasitoid use is in orde...