Intrinsic Inter- and Intraspecific Competition in Parasitoid Wasps

Abstract

Immature development of parasitoid wasps is restricted to resources found in a single host that is often similar in size to the adult parasitoid. When two or more parasitoids of the same or different species attack the same host, there is competition for monopolization of host resources. The success of intrinsic competition differs between parasitoids attacking growing hosts and parasitoids attacking paralyzed hosts. Furthermore, the evolution of gregarious development in parasitoids reflects differences in various developmental and behavioral traits, as these influence antagonistic encounters among immature parasitoids. Fitness-related costs (or benefits) of competition for the winning parasitoid reveal that time lags between successive attacks influence the outcome of competition. Physiological mechanisms used to exclude competitors include physical and biochemical factors that originate with the ovipositing female wasp or her progeny. In a broader multitrophic framework, indirect factors, such as plant quality, may affect parasitoids through effects on immunity and nutrition.

Trichogramma pretiosum (Hymenoptera: Trichogrammatidae) Parasitism of Trichoplusia ni (Lepidoptera: Noctuidae) Eggs Under Different Temperatures

“…The variability in reproductive success may be related to inadequate proportions of female parasitoids per host, which reduced oviposition and toxin injections necessary to reduce the immune response of the host (Andrade et al 2010;Cusumano et al 2010;Harvey et al 2013). In contrast, the parasitism and emergence ratios of P. elaeisis from B. mori pupae were similar with different densities of this parasitoid, suggesting that B. mori did not present nutritional or physiological barriers for the development of P. elaeisis .…”

“…This finding indicates that inadequate proportions of females per host result in reduced oviposition or increased competition and death of immature parasitoids . The density of the parasitoid females per host pupa can reduce fertility and efficiency of mass rearing, primarily due to mortality of immatures within the pupae (Harvey et al 2013) and competition between adults during oviposition .…”

“…The size range of P. elaeisis adults with different densities of parasitoid females can be explained by the limited resources of the host pupa as the number of larvae developing inside the host increases (Tian et al 2008;Harvey et al 2013). A reduced body size may reduce the efficiency of biological control, because body size is positively correlated with indicators of quality of parasitoids such as longevity, fecundity, progeny emerged, and sex ratio .…”

Interference competition in entomopathogenic nematodes: male Steinernema kill members of their own and other species

“…In solitary species of parasitoid insects a host can support only one individual. Most solitary endoparasitoids produce first instars with enlarged mandibles; these larvae move through the host haemocoel and locate competitors which they fight with their mandibles until one of the opponents is killed (Strand, 2002;Harvey et al, 2013).…”

Sex differences in the protection of host immune systems by a polyembryonic parasitoid

“…Endoparasitoids develop in a host haemocoel by consuming haemolymph and later the internal organs, and eventually kill the host [1]. Various physiological interactions and regulations exist between the parasitoid and the host.…”