Influence of factitious hosts on the morphometry and diversity of endosymbionts of the egg parasitoid Telenomus remus: insights for applied biological control

Abstract

The use of alternative hosts enables the mass creation of parasitoids in an economically viable manner, for examples, Telenomus remus Nixon (Hymenoptera: Platygastridae) created in Corcyra cephalonica Stainton (Lepidoptera: Pyralidae) and Anticarsia gemmatalis Hübner (Lepidoptera: Erebidae). Due to the possible modifications resulting from the parasitoid-host relationship, we characterized the eggs of these hosts and studied the endosymbionts of each T. remus population. Scanning electron microscope images of freshly parasitized Spodoptera frugiperda, A. gemmatalis, and C. cephalonica eggs with T. remus exit orifice were taken. The morphometry of the parasitoids was based on the measurements of wing length and width, and body and tibia lengths. Polymerase chain reactions were performed to detect bacteria of the genera Arsenophonus, Spiroplasma, Rickettsia, Serratia, and Wolbachia. The eggs of the hosts differed in terms of morphological characteristics. T. remus females, when raised in A. gemmatalis eggs, had a longer body length than females raised in other hosts, and T. remus males were larger in all morphometric characters evaluated. Female parasitoids reared in C. cephalonica had body and tibia lengths similar to those in S. frugiperda; however, wing length and width were smaller than those of the other parasitoids. In the three T. remus populations Serratia grimesii were detected, and only in the population raised in C. cephalonica was the Wolbachia endosymbiont found. The results elucidated the understanding of host adaptation dynamics.