Abstract
This laboratory study investigated whether the larval-pupal parasitoid Oomyzus sokolowskii females adjust their brood size and sex ratio in response to body size and stage of Plutella xylostella larval hosts, as well as to their own body size and the order of oviposition. These factors were analyzed using multiple regression with simultaneous entry of them and their two-way interactions. Parasitoids brood size tended to increase with host body size at parasitism when the 4th instar larval host was attacked, but did not change when the 2nd and 3rd instar larvae were attacked. Parasitoids did not vary in brood size according to their body size, but decreased with their bouts of oviposition on a linear trend from 10 offspring adults emerged per host in the first bout of oviposition down to eight in the third. Parasitoid offspring sex ratio did not change with host instar, host body weight, wasp body size, and oviposition bout. Proportions of male offspring per brood were from 11% to 13% from attacking the 2nd to 4th instar larvae and from 13% to 16% across three successive bouts of oviposition, with a large variation for smaller host larvae and wasps. When fewer than 12 offspring were emerged from a host, one male was most frequently produced; when more than 12 offspring were emerged, two or more males were produced. Our study suggests that O. sokolowskii females may optimize their clutch size in response to body size of mature P. xylostella larvae, and their sex allocation in response to clutch size.
Highlights
Parasitoids make oviposition decisions depending on a variety of factors, including the quality of hosts and characteristics of ovipositing wasps (Charnov et al, 1981; Van Alphen & Visser, 1990; Godfray, 1994; Ellers & Jervis, 2003)
Brood size did not change with ovipositing wasp hind tibia length (HTL) (Fig. 1D), but varied with the temporal sequence of oviposition, decreasing on a linear trend over increasing bouts of oviposition from 10 offspring adults emerged per host in the first oviposition bout down to 8 in the third (Fig. 1E)
We showed that O. sokolowskii offspring brood size tended to increase with body size of P. xylostella 4th instar larvae, but did not change with that of the 2nd and 3rd instar larvae
Summary
Parasitoids make oviposition decisions depending on a variety of factors, including the quality of hosts and characteristics of ovipositing wasps (Charnov et al, 1981; Van Alphen & Visser, 1990; Godfray, 1994; Ellers & Jervis, 2003). The wasp size is frequently considered to be the main target for selection (Godfray, 1994; Ode & Strand, 1995; Bezemer, Harvey & Mills, 2005) It can affect fitness by influencing searching efficiency, longevity, or egg supplies (Mayhew & Heitmans, 2000; Milonas, 2005; Jervis, Ellers & Harvey, 2008; Kasamatsu & Abe, 2015). Parasitoids may integrate the information provided by a variety of cues about hosts and themselves to make oviposition decisions
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
