Relationships between Body Size and Parasitic Fitness and Offspring Performance of Sclerodermus pupariae Yang et Yao (Hymenoptera: Bethylidae).

Shangkun Gao,Yanlong Tang,Xiaoyi Wang,Yanlong Zhang,Ke Wei,Zhongqi Yang,Raul Narciso Carvalho Guedes

doi:10.1371/journal.pone.0156831

Shangkun Gao, Yanlong Tang + Show 5 more

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https://doi.org/10.1371/journal.pone.0156831

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Abstract

The relationship between body size and fitness in parasitoid wasps has several effects on parasitic ability, reproductive behavior in female wasps, and progeny fitness. Female wasps with various body sizes were obtained by mass–rearing a gregarious ectoparasitoid, Sclerodermus pupariae, which is one of the excellent parasites to control the larvae and pupae of Buprestidae and Cerambycidae. We investigated the effects of body size of adult females introduced on Thyestilla gebleri (Coleoptera: Cerambycidae) larvae on their paralysis time, pre–oviposition period, oviposition period and fecundity, and the related fitness of their offspring. Results showed that small female wasps needed more time to paralyze a host and had a higher mortality rate than large female wasps. More offspring were produced by large female wasps than by small female wasps, and the percentage and body size of female offspring was not affected by maternal body size. The duration of the egg stage was not affected by foundress size, nor was that of the pupal stage, but the duration of the larval stage and generation time of small female wasps was longer than that of large females. Our findings suggest that the parasitic fitness and offspring performance are affected by maternal size, and there is need to choose reasonable body size of female wasps, to optimally utilize mass rearing and to control target pests with the lowest mortality cost.

Highlights

Body size is one of main determinants of history strategies in various animals, such as trophic niche parttioning in the rhinolophid bat species [1], life–history trade–offs in a marine fish [2], predatory strategies of spiders [3], the distrbution of caddisworms[4], warm–up rates and body temperatures in bees [5].In insects, body size is found to be positively correlated with fitness of their life–history traits [6]
The different numbers of female parasitoids were presented with a larval of T. gebleri, their female offspring with various body size were selected for the experiments
In the studies of congeneric S. guani, when it was reared on Tenebrio molitor Linnaeus, Ptilineurus marmoratus Reitter and Saperda populnea (Linnaeus), the optimal parasitoid–host ratios were 2:1, 4:3 and 1:5, respectively [42,43,44]

Summary

Introduction

Body size is one of main determinants of history strategies in various animals, such as trophic niche parttioning in the rhinolophid bat species [1], life–history trade–offs in a marine fish [2], predatory strategies of spiders [3], the distrbution of caddisworms[4], warm–up rates and body temperatures in bees [5]. Body size is found to be positively correlated with fitness of their life–history traits [6]. Body size is often considered as one of the most prominent fitness functions for examining resource allocation and predicting clutch size and progeny sex allocation [11,12,13]. The optimal phenotype in most organisms is determined by a trade–off in life–history traits [14]. As one of phenotypes exhibited in parasitoids, body size maybe based on a trade–off between self–development and functional constraints

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