A Preliminary Investigation of the Interactions between the Brood Parasite Chalcoela iphitalis and Its Polistine Wasp Hosts.

Scott Nacko,Gregg Henderson

doi:10.3390/insects8030089

Abstract

The life history of Chalcoela iphitalis—a common brood parasite of social wasps—has been described in previous literature, but critical information regarding oviposition behavior and possible differential host parasitism remain cryptic. Here we report on infestation levels of this moth in field populations of paper wasps in Polistes and Mischocyttarus, as well as the oviposition behavior of the moths under a laboratory setting. We found evidence for differential parasitism between paper wasp genera in the field, with almost 50% nest infestation in P. bellicosus and no occurrences of moth infestation in M. mexicanus. Laboratory results revealed that oviposition occurs only at night and is stimulated by contact with the wasp nest or adult wasps. In this setting, eggs were laid largely on the substrate above or adjacent to the host nest, but not on the nest itself.

Highlights

The nests of eusocial paper wasps often support a diverse array of insect parasites and symbionts [1]
We examined the behavior of both host and parasite in the laboratory, as well as the occurrence of C. iphitalis in field populations of Polistine wasps in southern Louisiana
Mischocyttarus mexicanus had no observed cases of infestation out of 37 total nests which reached the pupal stage

Summary

Introduction

The nests of eusocial paper wasps often support a diverse array of insect parasites and symbionts [1]. Understanding these insects with which paper wasps have co-evolved can help us understand the paper wasp ecology. The sooty-winged Chalcoela moth, Chalcoela iphitalis (Walker), is a brood parasite in the family Crambidae [2] which attacks Polistine wasps, including at least ten species of Polistes and one species of Mischocyttarus in the US and Central America [3]. Moth larvae feed on pupal or pre-pupal wasps before spinning silken cocoons containing layers of air pockets within wasp brood cells.

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