Influence of Temperature and Photoperiod on the Fecundity of Habrobracon hebetor Say (Hymenoptera: Braconidae) and on the Paralysis of Host Larvae, Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae).

George N Mbata,Sanower Warsi,Mark E Payton

doi:10.3390/insects12080753

George N Mbata, Sanower Warsi + Show 1 more

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https://doi.org/10.3390/insects12080753

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Abstract

Simple SummaryThis study illustrated the role of optimum temperatures of 25 and 30° in maximizing oviposition by the female H. hebetor. The optimum temperatures for paralysis of P. interpunctella larvae by H. hebetor were shown to be 28 and 30 °C at short exposure periods. However, at long exposure periods, the paralysis rates did not differ significantly. Photoperiod had no impact on oviposition or paralysis of P. interpunctella by the wasp.Studies were carried out in the laboratory to understand the optimum environmental conditions at which the ectoparasitoid, Habrobracon hebetor Say (Hymenoptera: Braconidae), can paralyze and lay eggs when reared on the larvae of the stored product pest, Plodia interpunctella Hübner (Lepidoptera: Pyralidae). At the four temperatures investigated (20, 25, 30, and 35 °C), optimum temperatures for oviposition were found to be 25 and 30 °C, while 35 °C was the least favorable temperature. No significant differences were found between the percentages of diapausing and non-diapausing larvae paralyzed by the wasp at the temperatures of 20, 25, 30, 35 °C within 5 days. However, in another experiment that investigated the effect of photoperiods at different temperatures that included 15, 19 and 28 °C, the number of paralyzed larvae was highly reduced at low temperatures (15 °C) but photoperiods had no significant impact on the number of host larvae paralyzed. In addition, observations at short time intervals also showed that lower temperatures slowed down host larvae paralysis. The results suggest that H. hebetor can paralyze host larvae of P. interpunctella more efficiently and deposit more eggs at temperatures within the range of 20–30 °C.

Highlights

Several members of the Pyralidae family of the Lepidoptera constitute worldwide pests of postharvest commodities [1]
The numbers of eggs laid by mated female H. hebetor depended on the host larval type, diapausing or non-diapausing, and temperature, and these two factors significantly interacted with each other (Tables 1 and 2)
The temperatures at which the highest numbers of eggs were laid by female H. hebetor in the current study were 25 and 30 ◦ C

Summary

Introduction

Several members of the Pyralidae family of the Lepidoptera constitute worldwide pests of postharvest commodities [1]. Larvae of these pyralid moths, the Indian meal moth (Plodia interpunctella Hübner), infest raw commodities such as cereals, dried fruits, vegetables, peanuts, and value-added processed food such as wheat flour [2,3,4,5]. The management of pyralid moths in warehouses, food processing plants, and in other storage structures depends on conventional chemical pesticides, some of which have been found to leave harmful residues in food and the environment [8,9,10,11]. Parasitic wasps represent an alternative and environmentally friendly approach in postharvest systems for the management of pest populations because parasitoids are environmentally safe and do not negatively impact humans or beneficial organisms [14]

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