Oviposition behaviour of mated or unmated Cleruchoides noackae (Hymenoptera: Mymaridae).

Luciane Katarine Becchi,José Eduardo Serrão,Gabriella Ferreira De Camargo,José Cola Zanuncio,Carolina Jorge,Carlos Frederico Wilcken,Leonardo Rodrigues Barbosa,Marcus Alvarenga Soares

doi:10.1371/journal.pone.0239285

Abstract

Cleruchoides noackae (Hymenoptera: Mymaridae), native to Australia, is the most promising biological control agent for Thaumastocoris peregrinus (Hemiptera: Thaumastocoridae), an exotic Eucalyptus spp. pest in Brazil. The aim of this study was to determine the courtship behaviour, mating and oviposition of unmated or mated C. noackae females parasitizing T. peregrinus eggs utilizing the same rearing system used in biological control programmes in Brazil. The mating behaviour of eleven C. noackae unmated couples was observed and the time taken for males and females to find each other in polystyrene vials and the duration and number of copulations were recorded. Ten unmated or mated females were placed individually in vials with 10 T. peregrinus eggs each, and oviposition behaviour, percentage of eggs inserted and parasitized, viability and sex ratio of emerged C. noackae were recorded. This species lacked defined courtship behaviour and mated in less than an hour after adults' emergence. The time spent finding the first host, evaluating and inserting the ovipositor was similar for mated and unmated C. noackae females, as well as the frequency of inserted and parasitized eggs and their viability. Mated females took less time to find other host eggs and the sex ratio is female-biased. Occurrence of arrhenotokous parthenogenesis was confirmed. The ability of C. noackae to mate and lay eggs in less than one hour and parasitism of T. peregrinus eggs by females can improve the parasitoid mass rearing and biological control of T. peregrinus.

Highlights

Australian exotic pest insects have damaged forest plantations in several countries around the world, especially those of the genus Eucalyptus (Myrtaceae) [1,2,3]
The aim of this study was to evaluate, in laboratory conditions, the courtship, mating and oviposition behaviour of unmated or mated C. noackae females on T. peregrinus eggs, in the same vials used for parasitoid mass rearing in Brazil
Thaumastocoris peregrinus eggs were obtained from LCBPF breeding stocks, with previous field collection done in eucalyptus plantations infested by the pest in the state of Minas Gerais, Brazil

Summary

Introduction

Australian exotic pest insects have damaged forest plantations in several countries around the world, especially those of the genus Eucalyptus (Myrtaceae) [1,2,3]. The bronze bug, Thaumastocoris peregrinus Carpintero & Dellape, 2006 (Hemiptera: Thaumastocoridae), detected in Brazil in 2008 in the states of São Paulo and Rio Grande do Sul, has spread rapidly throughout the country [4,5,6]. This invasive insect pest has a gregarious and sucking habit, lays eggs in clusters and it has caused intense defoliation in eucalyptus trees [3, 7, 8]. The egg parasitoid Cleruchoides noackae Lin & Huber, 2007 (Hymenoptera: Mymaridae), the main biological control agent of the bronze bug [13, 20, 21], was introduced to Brazil in 2012 to promote classical biological control of this pest [6]

Objectives

Methods

Results

Discussion

Conclusion