Does mother really know best? Oviposition preference reduces reproductive performance in the generalist parasitoid Aphidius ervi

Abstract

The reproductive success of female parasitoids is dependent on their ability to accurately assess the suitability of a host for larval development. For generalist parasitoids, which utilize a broad range of species and instars as hosts, a set of assessment criteria determines whether a host is accepted or rejected. The suitability of a host, however, can only be imperfectly assessed by the female parasitoid, which can result in the selection of lesser quality hosts for oviposition. In this study we explored the disparity between host quality and host preference using the generalist koinobiotic parasitoid Aphidius ervi Haliday (Hymenoptera: Aphidiidae) and the host Aulacorthum solani (Harris) (Homoptera: Aphididae), the foxglove aphid. The second instar hosts produced the highest level of reproductive success, while third and fourth instars resulted in a substantially reduced reproductive performance. When given a choice of host instars, parasitoids preferred the older hosts for oviposition disregarding their reduced suitability for larval development. Results are discussed in context of mechanisms involved in A. ervi host selection and biases in the criteria used to assess hosts that may arise when parasitoids transfer host species between generations.

Parasitism of the soybean aphid,Aphis glycinesbyBinodoxys communis: the role of aphid defensive behaviour and parasitoid reproductive performance

“…In no-choice assays, B. communis did not refrain from attacking larger or older aphid stages or aphids that exhibited stronger defenses. This could reflect either a low response threshold of B. communis for oviposition (Mackauer et al, 1996) or acceptance decisions resulting from its lack of previous experience (Henry et al, 2005). Binodoxys communis females encountered and probed larger aphid stages at a lower frequency and with many probing attempts unsuccessful.…”

“…Various relationships exist between parasitoid development time and host age at oviposition (Hopper, 1986;Colinet et al, 2005), with positive associations being occasionally reported (Vinson, 1972;Lawrence et al, 1976). Rapid parasitoid development in 1st instar A. glycines shows that these hosts provide minimum required nutrient levels for B. communis (Henry et al, 2005) although parasitoids emerging from young hosts may be smaller. The gradual increase in development time on later A. glycines stages may reflect changes in nutritional value of the host, increased aphid resistance and competition of parasitoid larvae with the developing host embryos (Walker & Hoy, 2003;Colinet et al, 2005) or increased time necessary for development of a larger parasitoid.…”

“…Sequeira & Mackauer, 1992a;Colinet et al, 2005;Henry et al, 2005). Many parasitoids preferentially attack certain sizes, ages or stages of a given host species (Mackauer, 1973;Hopper & King, 1984;Liu et al, 1984;Wang & Liu, 2002;Lin & Ives, 2003).…”

Comparative Evaluation of Spinosad and Phloxine B as Toxicants in Protein Baits for Suppression of Three Fruit Fly (Diptera: Tephritidae) Species

“…Both physiological and morphological changes in the host are related to development at a particular age, which varies and results in variation in its acceptability to the parasitoid and its suitability for the progeny of the parasitoid (Henry et al, 2005) Food quality is one of the most important factors, as pupae of different ages may not have the same nutritional quality. During the pupal development internal tissues undergo histolysis, histogenesis and differentiation to form adult internal organs and sclerotized appendages.…”

Qualidade de diferentes espécies de pulgões como hospedeiros do parasitóide Lysiphlebus testaceipes (Cresson) (Hymenoptera: Braconidae, Aphidiinae)

“…Geralmente, os parasitóides avaliam o tamanho como um indicador da qualidade do hospedeiro (Henry et al 2005), mas isso normalmente ocorre de forma mais clara com os parasitóides idiobiontes, os quais se desenvolvem em hospedeiros que não se alimentam durante o parasitismo (Li & Mills 2004). Entretanto essa característica pode não ser necessariamente verdadeira para os parasitóides cenobiontes, como L. testaceipes, cujas larvas se desenvolvem enquanto os hospedeiros ainda se alimentam e crescem (Sequeira & Mackauer 1994, Chau & Mackauer 2001.…”