THE EFFECT OF PLANTS ON THE HOST RELATIONS OF A SPECIALIST PARASITOID OF HELIOTHIS LARVAE

Abstract

Microplitis croceipes (Cresson), a parasitoid of Heliothis larvae, was reared on 9 host insect/plant combinations. In general, parasitoid survivorship was (1) higher in host larvae that were reared on cotton than in hosts reared on either bean or tomato, (2) higher in H. zea hosts than in H. virescens and (3) higher in a laboratory strain of H. zea than in a wild strain. A series of parasitoid oviposition preference tests showed that wasps laid more eggs in host larvae on cotton plants than on bean and more on bean than on tomato. However, the wasps did not distinquish between H. zea and H. virescens hosts. Wasp oviposition preferences were not conditioned by the host insect/plant combination in which the parasitoid developed. These results indicate that the plant on which host larvae feed is an important factor in determining both the likelihood of parasitoid attack and the probability of successful parasitism. ZUSAMMENFASSUNG Der Einfluss der Pflanze auf die Wirtsbeziehungen eines spezialisierten Parasiten von Heliothis‐Larven. Microplitis croceipes (Cresson), Parasit der Heliothis‐Larven, wurde in 9 Kombinationen von Wirtsinsekt/Wirtspflanze gezüchtet. Im allgemeinen war das Ueberleben der Parasiten (1) besser in Wirtsraupen von Baumwolle als von Bohnen oder Tomaten, (2) besser in H. zea als in H. virescens und (3) besser in laborgezüchteten H. zea als in Raupen aus dem Freiland. Mehrere Versuche über die Eiablagepräferenz der Parasiten zeigten, dass mehr Eier in Raupen von Baumwolle als in Raupen von Bohnen oder gar von Tomaten abgelegt wurden. Die Wespen unterschieden aber nicht zwischen H. zea und H. virescens. Die Eiablagepräferenzen waren unabhängig von den Kombinationen Wirtsinsekt/Wirtspflanze, in denen sich die Parasiten entwickelt hatten. Die Ergebnisse weisen darauf hin, dass die Pflanze, auf der die Wirtsraupe frisst, wichtig ist für die Wahrscheinlichkeit eines Parasitenangriffs und für den Erfolg der Parasitierung.

Learning to discriminate between infochemicals from different plant‐host complexes by the parasitoids Cotesia glomerata and C. rubecula

“…The same is true for C. glomerata for which we studied the effect of both kinds of experience. Potting et al (1997) found no early adult learning (or any learning) in Cotesia flavipes, whereas for the parasitoid species Campoletis sonorensis, and Microplitis croceipes rearing environment did not seem to affect their subsequent responses, but the effect of adult learning was however easily shown (Müller, 1983;McAuslane et al, 1990). Potting et al (1997) found no early adult learning (or any learning) in Cotesia flavipes, whereas for the parasitoid species Campoletis sonorensis, and Microplitis croceipes rearing environment did not seem to affect their subsequent responses, but the effect of adult learning was however easily shown (Müller, 1983;McAuslane et al, 1990).…”

Complex effects of parasitoids on pharmacophagy and diet choice of a polyphagous caterpillar

“…While the influence of plant chemistry is important, studying host plant selection in a multitrophic context captures important direct and indirect effects that can provide increased explanatory power (Price et al 1980;Bernays and Graham 1988;Singer and Stireman 2005;Schmitz 2008). In particular, including natural enemies in the study of herbivore host plant selection has stimulated a body of research investigating how plant chemistry and natural enemies interact to influence host plant choice (Mueller 1983;Dyer 1995;Lill et al 2002;Denno et al 2003;Kursar et al 2006; Barbosa and Caldas 2007;Singer et al 2009). Given the influence of both trophic levels, a necessary goal for host plant selection studies is to elucidate the mechanisms Parasitism by wasps and flies is an important factor determining host plant choice (Karban and English-Loeb 1997;Singer et al 2009).…”

Differential Parasitism of Macrolepidopteran Herbivores on Two Deciduous Tree Species

“…Clearly, these studies were not designed to assess the relative importance of niche-vs. taxon-specific lifestyles of parasitoids but they do provide strong evidence of the importance in host selection of nontaxon related traits, i.e., those associated with plants. In many cases, an herbivore's food plant provides primary host selection cues to which parasitoids and other natural enemies respond (see discussions and references in Price et al 1980, Nordlund et al 1981, Mueller 1983, Bell and Cardé 1984, Barbosa and Saunders 1985, Barbosa and Letourneau 1988, Kester and Barbosa 1992, Barbosa and Benrey 1998, Barbosa and Wratten 1998 and which mediate host finding (Way and Murdie 1965, Obrycki 1986, Andow and Prokrym 1990, Wäckers 1994, Wäckers and Lewis 1994. Thus, by influencing parasitism, herbivore plant hosts can be considered an important dimension of an herbivore's niche (see Ricklefs 1973: 742).…”