Sperm Production Is Reduced after a Heatwave at the Pupal Stage in the Males of the Parasitoid Wasp Microplitis rufiventris Kok (Hymenoptera; Braconidae)

Understanding reproduction is essential for controlling pests and supporting beneficial insects. Among the many factors allowing optimal reproduction, sperm availability is key to sex ratio control in hymenopteran parasitoids since males are haploid and only females come from fertilization. Microplitis rufiventris (Hymenoptera; Braconidae) is a solitary endoparasitoid of some noctuids. This insect could be used for the control of the cotton leafworm Spodoptera littoralis. Under controlled conditions, sperm quantity was measured in virgin males at 1, 5, 10, and 15 days; it increases in adult males until the fifth day. Sperm stock of control males increased from 2500 at one day to 6700 at 15 days. With the control climatic condition being 25 °C, we tested the effects of a time-limited increase of temperature that can be found in Egypt (36 and 40 °C) during one day at the early pupal stage. Emerging males had 1500 and 420 sperm at 36 and 40 °C, respectively; both lived shorter than the control. The sperm potential of males is dependent on both age and temperature during the early pupal stage. It could have dramatic consequences on the sex ratio of M. rufiventris in natural and controlled populations.

First record of Microplitis rufiventris Kokujev, 1914 (Braconidae: Microgastrinae) from Iran

Occurrence of the genus Microplitis Forster (Braconidae, Microgastrinae) was surveyed in the Northern part of Iran. The specimens were collected using Malaise traps during 2010–2011. Two species, Microplitis rufiventris Kokujev, 1914 and M. ochraceus Szepligeti, 1896 were collected and identified of which the first species is newly recorded from Iran. Diagnostic characters and geographical distribution of the species are briefly discussed.