Effects of parasitoid fecundity and host resistance on indirect interactions among hosts sharing a parasitoid

Abstract

We examine the effects of fecundity-limited attack rates and resistance of hosts to parasitism on the dynamics of two-host-one-parasitoid systems. We focus primarily on the situation where one parasitoid species attacks two host species that differ in their suitability for parasitism. While all eggs allocated to suitable hosts develop into adult parasitoids, some of the eggs allocated to marginal host do not develop. Marginal hosts can therefore act as a sink for parasitoid eggs. Three-species coexistence is favoured by low levels of parasitoid fecundity and by low levels of suitability of the marginal host. Our model also produces an indirect (+, )) interaction in which the suitable host can benefit from the presence of the marginal host, but the marginal host suffers from the presence of the suitable host. The mechanism driving the indirect (+, )) interaction is egg limitation of parasitoids incurred by allocating eggs to marginal hosts.

Multifaceted determinants of host specificity in an aphid parasitoid

“…Two of these, A. nerii and A. craccivora, are poor hosts physiologically, so time spent handling and oviposition within these hosts wastes time as well as eggs (Heimpel et al 2003). The other, S. graminum, is more physiologically suitable, but increased handling time may still decrease fitness under conditions of time limitation.…”

“…Described as the preference-performance hypothesis in phytophagous insects by Jaenike (1978), host preference in parasitoids tends to correlate with fitness gained from the host (van Alphen and Vet 1986;Driessen et al 1991;Kraaijeveld et al 1995;Chau and Mackauer 2001), although very low-quality hosts may also be accepted (Janssen 1989;Heimpel et al 2003). In addition, host defensive behaviors can limit the ability of parasitoids to utilize even highly preferred hosts (Gross 1993; but see De Farias and Hopper 1999).…”

Indirect interaction between butterfly species mediated by a shared pupal parasitoid

“…The rate of predation or parasitism experienced by a species depends not only on its own susceptibility and density, but also on the availability and relative suitability of other species that share the same enemies. One prey species may draw enemies away from another (as in Settle and Wilson 1990;Heimpel et al 2003;Cronin 2007), or the combined density of several prey species can either increase or decrease the chance of predation of all individuals (Abrams et al 1998;Morris et al 2004;Tack et al 2011). Over time, the population size of an enemy will depend on the use of combined prey species, and changes in enemy population size may affect each prey species differently.…”

Asymmetric indirect interactions mediated by a shared parasitoid: connecting species traits and local distribution patterns for two chrysomelid beetles

“…It is becoming increasingly clear that polyphagous parasitoids may have important consequences for the community structure of insect herbivores by mediating negative (Doutt and Nakata 1973;Settle and Wilson 1990;Holt and Lawton 1993;Mu¨ller and Godfray 1997;Hassell 1997, 1999;van Nouhuys and Hanski 2000;Morris et al 2004;Luhring et al 2004) or positive (Hoogendoorn and Heimpel 2002;Heimpel et al 2003;Teder and Tammaru 2003) indirect interactions among hosts. For a recent theoretical overview, see Brassil and Abrams (2004), and for examples in other systems, see Schmidt and Whelan (1998), Chaneton and Bonsall (2000) and Hamba¨ck and Beckerman (2003).…”

“…(2) source-sink dynamics, where one host species may reduce attack rates on another species by being a sink for the parasitoid and thereby reduce parasitoid densities (Heimpel et al 2003); or (3) frequency-dependent parasitism, where parasitization rates on rare species are reduced by the presence of a common species (Teder and Tammaru 2003).…”