Functional response and egg distribution among hosts by Pseudapanteles dignus, a larval endoparasitoid of Tuta absoluta

Abstract

The functional response of a biocontrol agent has been classically pointed out as a quantitative evaluation criterion to understand its killing capacity to an arthropod pest. In this paper, we revisited the functional response of the internal larval parasitoid Pseudapanteles dignus (Muesebeck) (Hymenoptera: Braconidae), a candidate for biocontrol of the South American tomato leafminer, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), measured as the daily egg oviposition of single parasitoid females at increasing densities of T. absoluta larvae through dissection of hosts. The functional response curve of the number of parasitized hosts was fitted out taking into account the number of eggs laid and their distribution among hosts at each T. absoluta larval density. The data also allowed us to discuss the self-superparasitism strategy of this parasitoid as an adaptive trait. Pseudapanteles dignus showed a sigmoid shape functional response and a contagious distribution of eggs among hosts, favouring self-superparasitism and laying a similar number of eggs in each superparasitized host at each T. absoluta density. This research is firstly intended to ascertain about the oviposition behaviour of P. dignus and additionally to provide information on its reproduction to be applied in mass rearing procedures and augmentative releases against T. absoluta.