Maternal Care in the Parasitoid Sclerodermus harmandi (Hymenoptera: Bethylidae)

Zhenjie Hu,Xingli Zhao,Yisong Li,Xiaoxia Liu,Qingwen Zhang,William Hughes

doi:10.1371/journal.pone.0051246

Zhenjie Hu, Xingli Zhao + Show 4 more

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https://doi.org/10.1371/journal.pone.0051246

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Abstract

Guarding behavior is an important activity in sub-social insects, and this behavior is believed to improve the survival of offspring. Sclerodermus harmandi (Hymenoptera: Bethylidae) is one of most powerful epizoic parasitoid wasps, and it parasitizes Monochamus alternatus, a borer of wood and also the primary vector of the pinewood nematode Bursaphelenchus xylophilus. After laying eggs, S. harmandi exhibits sub-social behavior involving the female tending the clutch of eggs until emergence (guarding behavior). In this study, the benefits of this maternal care with regard to improvements in the survival of offspring were examined. During the developmental stages, only offspring in the egg and larval stages were sensitive to guarding behavior. A positive relationship between the survival of the offspring and the duration of guarding was detected with logistic regression analysis. A female replacement experiment demonstrated that multiparous S. harmandi stepmothers showed guarding behavior and that this behavior improved the survival of the immature offspring, whereas nulliparous stepmothers failed to exhibit the guarding behavior. These results indicate that S. harmandi females display maternal care and that this behavior improves the survival of offspring.

Highlights

Maternal care, which is typically defined as any post-ovipositional behavior that promotes the survival, growth, and development of offspring [1], is considered a hallmark of sub-sociality in insects [2,3,4,5]
Maternal care in insects is considered a hallmark of sub-sociality [1,26], and an understanding of the evolution of maternal care offers insight into the origin of eusociality in insects [27,28]
The evolution of maternal care depends on the benefit of care, in terms of offspring survival, as well as the cost of future female fecundity under given ecological conditions

Summary

Introduction

Maternal care, which is typically defined as any post-ovipositional behavior that promotes the survival, growth, and development of offspring [1], is considered a hallmark of sub-sociality in insects [2,3,4,5]. According to the behavioral form, maternal care is classified into three groups [1,6]: behaviors that protect offspring from natural enemies (predators, parasitoids, and microorganisms) [7], behaviors that provide/protect resources needed by the offspring [8], and behaviors that improve resources and/or facilitate resource acquisition (e.g., feeding) by offspring [9]. Among the three behavior forms, predators and parasitoids usually serve as the primary agents that lead to maternal care in insects [10]. Food provision is considered an important form of maternal care [13]. Anisolabis maritime (Dermaptera: Anisolabididae). improves the survival of its nymphs by collecting turtle food pellets even when long distances from the food resource [13]

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