Venom is beneficial but not essential for development and survival of Nasonia |
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| Authors: | ELLEN O MARTINSON JOHN H WERREN |
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| Affiliation: | 1. Biology Department, University of Rochester, Rochester, New York, U.S.A.Current address: Entomology Department, University of Georgia, 120 Cedar St Athens, GA 30602, U.S.A.;2. Biology Department, University of Rochester, Rochester, New York, U.S.A. |
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| Abstract: | 1. Parasitoid wasps sting and inject venom into arthropod hosts, which alters host metabolism and development while keeping the host alive for several days, presumably to induce benefits for the parasitoid young. 2. This study investigates the consequences of host envenomation on development and fitness of wasp larvae in the ectoparasitoid Nasonia vitripennis, by comparing wasps reared on live unstung, previously stung, and cold‐killed hosts. Developmental arrest and suppression of host response to larvae are major venom effects that occur in both stung and cold‐killed hosts, but not in unstung hosts, whereas cold‐killed hosts lack venom effects that require a living host. Thus, cold‐killed hosts mimic some of the effects of venom, but not others. 3. Eggs placed on live unstung hosts have significantly higher mortality during development; however, successfully developing wasps from these hosts have similar lifetime fecundity to that of wasps from cold‐killed or stung hosts. Therefore, although venom is beneficial, it is not required for wasp survival. 4. While wasps developing on both cold‐killed and stung hosts have similar fitness levels, rearing multiple generations on cold‐killed hosts results in significant fitness reductions of wasps. 5. It is concluded that the largest benefits of venom are induction of host developmental arrest and suppression of host response to larva (e.g. immune responses), although more subtle benefits may accrue across generations or under stressful conditions. |
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| Keywords: | Developmental arrest ectoparasitoid Nasonia venom |
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