Temperature Influences the Handling Efficiency of an Aphid Parasitoid Through Body Size-Mediated Effects

Abstract

It is well known that increasing the ambient temperature increases the metabolic rate and consequently, the foraging rate of most insects. However, temperature experienced during the immature stages of insects affects their adult size (an inverse relationship). Because body size is generally correlated to foraging success, we hypothesized that temperature indirectly influences the foraging efficiency of adult insects through developmental effects. We first investigated the role of parasitoid: host body size ratio on the handling time of Aphidius colemani (Viereck) (Hymenoptera: Braconidae), then tested the prediction that increasing temperature during immature development increases the handling time of adults. As expected, parasitoids took longer to handle large aphids than small aphids. However, large parasitoids did not have shorter handling times than small parasitoids except when attacking large (adult) aphids. Developmental temperature had the predicted effect on parasitoids: Individuals reared at 25°C were smaller than those insects reared at 15°C. Parasitoids reared at 15°C had similar short handling times for both first instar and adult aphids, whereas parasitoids reared at 25°C took longer to handle adult aphids than first instar aphids. The size-mediated effect of temperature through development on parasitoid efficiency was opposite to the more familiar direct effect of temperature through metabolic rate. We conclude that the net effect of temperature on foraging insects will depend on its relative influence on immature and adult stages.

Temperature influences host instar selection in an aphid parasitoid: support for the relative fitness rule

“…A high developmental temperature would thus affect the parasitism rate of parasitoids not only through changes in host instar acceptance, but also through changes in their ability to parasitize large aphids. Similarly, Wu et al (2011) showed with Aphidius colemani attacking the green peach aphid Myzus persicae that large parasitoids reared at a cold temperature have similar handling times for both small and large aphids, whereas small A. colemani reared at a high temperature take longer to parasitize large aphids than small aphids.…”

“…Similarly, Wu et al . () showed with Aphidius colemani attacking the green peach aphid Myzus persicae that large parasitoids reared at a cold temperature have similar handling times for both small and large aphids, whereas small A. colemani reared at a high temperature take longer to parasitize large aphids than small aphids.…”

“…Parasitoids of different size can be produced at different developmental temperatures (Colinet, Boivin & Hance, 2007;Wu et al, 2011). The temperaturesize rule (Atkinson, 1994;Angilletta, Steury & Sears, 2004) states that ectotherms generally grow larger at lower temperature.…”

Elevated Temperature and Drought Interact to Reduce Parasitoid Effectiveness in Suppressing Hosts

“…As an illustration, elevated temperature significantly reduced adult parasitoid longevity by about 51% in our laboratory experiment. This could be attributed to an increase in metabolic rate [52], which is likely to mediate many of the biotic impacts of climate change globally [53]. Alternatively, higher temperatures or increased metabolic rates could simply influence the way parasitoids invest their energy.…”

MalagasyConostigmus(Hymenoptera: Ceraphronoidea) and the secret of scutes

“…Similar intraspecific variability is common among microhymenoptera and can be stimulated by alternative host species with different nutritional quality (Nalepa & Grisell, 1993; Medal & Smith, 2015) gregariousness with variable brood sizes (Harvey et al, 1998), and climatic differences, such as temperature (Wu et al, 2011). Ceraphronoids are parasitoids on insect parasitoid and predator larvae (Haviland, 1920; Withycombe, 1924; Kamal, 1939) and have a broad host range (Gilkeson, McLean & Dessart, 1993; Sullivan & Völkl, 1999).…”