Effects of temperature on the activity of antioxidant enzymes in larvae of Bactrocera dorsalis (Diptera: Tephritidae) parasitized by Diachasmimorpha longicaudata (Hymenoptera: Braconidae): Optimizing the mass rearing of this braconid by varying the temperature

Pumo Cai,Hehe Zhang,Jia Lin,Chuandong Yi,Jiahua Chen,Jianquan Yang,Yong Wang,Huimin Xia,Qinge Ji,Qiwen Zhang

doi:10.14411/eje.2019.001

Abstract

Diachasmimorpha longicaudata is the most widely used endoparasitoid in biocontrol programmes against various species of tephritids and is continuously mass-reared under laboratory conditions at a constant temperature; however, little is known about how varying the temperature might affect the effectiveness of the mass rearing of immature D. longicaudata. This study aimed to determine the optimum temperature for the development of larvae D. longicaudata the larvae of its host, Bactrocera dorsalis. Third-instar B. dorsalis were exposed for 4 h to five pairs of parasitoids, and then they were kept at one of six temperatures ranging from 19°C to 34°C. The activities of three major antioxidant enzymes (CAT, POX, SOD) were individually measured 4, 24, 48 and 72 h after exposure to each of the six temperatures. The results were as follows: for CAT the highest CAT activities were recorded at 25°C (intervals 5-24 h and 25-48 h), at 28°C (interval 0-4 h) and at 31°C (interval 49-72 h), and for POX and SOD identically at 25°C (intervals 0-4 h, 5-24 h) and at 31°C (intervals 25-48 h, 49-72 h), respectively. Subsequently, the effects keeping the parasitized larvae at these different temperatures on the biological attributes of D. longicaudata reared under laboratory conditions were investigated. The percentage of their eggs that hatched, percentage of adults that emerged, pupal weight and longevity were significantly greater than that recorded for the control when the parasitized host larvae were kept at 28°C for 4 h, 25°C for 5 and 48 h and 31°C for 49 and 72 h.

Highlights

The oriental fruit fly Bactrocera dorsalis (Hendel) (Diptera: Tephritidae) is a generalist pest that feeds on more than 270 species of host plants in 46 different families of plants throughout tropical and subtropical Asia (Allwood & Chinajariyawong, 1999; Clarke et al, 2001; Vargas et al, 2007)
The variations in temperature during the course of a day strongly affect the performance of parasitoids reared in a laboratory for long periods (Firake & Khan, 2014)
Determination of the optimal thermal requirement for the development of a parasitoid is a fundamental aspect of biological control programmes against pests and is important for its laboratory production and field release

Summary

Introduction

The oriental fruit fly Bactrocera dorsalis (Hendel) (Diptera: Tephritidae) is a generalist pest that feeds on more than 270 species of host plants in 46 different families of plants throughout tropical and subtropical Asia (Allwood & Chinajariyawong, 1999; Clarke et al, 2001; Vargas et al, 2007). This species is a devastating pest of carambola, peach, jujube, citrus, loquat, guava, lychee, longan and other tropical and subtropical crops, causing significant yield and financial losses in southern China (Ji et al, 2016). Among the fruit fly parasitoids available for augmentative release in Fujian Province of China, D. longicaudata is the most reliable (Cai et al, 2018a)

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