The density of females of Palmistichus elaeisis Delvare and LaSalle (Hymenoptera: Eulophidae) affects their reproductive performance on pupae of Bombyx mori L. (Lepidoptera: Bombycidae)

Teresinha V. Zanuncio,Patrik L. Pastori,Fabricio F. Pereira,José C. Zanuncio,José E. Serrão,Dirceu Pratissoli

doi:10.1590/s0001-37652010000200008

Abstract

Palmistichus elaeisis Delvare and LaSalle (Hymenoptera: Eulophidae) is a gregarious and polyphagous parasitoid mainly of Lepidoptera pupae. The objective of this paper as to study the developent of parasitoid on Bombyx mori L. (Lepidoptera: Bombycidae) pupae exposed to one, nine, 18, 27, 36, 45 or 54 female P. elaeisis, respectively. The females of the parasitoid remained in contact with pupae for 24 hours in glass tubes (14.0 x 2.2 cm), packed in a climatic chamber regulated at 25 +/- 2 degrees C, 70 +/- 10% relative humidity and photo phase of 12 hours. With the exception of density 1:1 (72.72%), in other densities parasitism was 100%. Adults of P. elaeisis did not emerge from pupae at densities of 1:1 and 9:1, but 100.0% of parasitoid emergence was observed at the density of 45:1 and 54.54% at 54:1. The duration of the life cycle of this parasitoid ranged from 20 to 28 days. P. elaeisis produced 49 to 589 descendants per pupa of B. mori. The sex ratio of P. elaeisis ranged from 0.93 +/- 0.01 to 0.97 +/- 0.01 without differences with 18, 27, 36, 45 and 54 females/host. This parasitoid should be reared with the density of 45 females per pupa of B. mori.

Highlights

The family Eulophidae comprises 297 genera and 4.472 species worldwide
The density of females of P. elaeisis affected their percentage of parasitism and the number of specimens of this parasitoid that emerged per pupa of B. mori
No specimens of P. elaeisis emerged from pupae of B. mori at the densities of 1:1 and 9:1, but those of 45:1 and 54:1 had 100.00% and 54.54% of pupae with parasitoid emergence, respectively (P = 0.0055) (Fig. 1)

Summary

Introduction

The family Eulophidae comprises 297 genera and 4.472 species worldwide. They are end or ectoparasitoids; idiobionts or koinobionts; solitary or gregarious; primary or secondary parasitoids; specialists or generalists (Noyes 2003, Pereira et al 2008b). Palmistichus elaeisis Delvare and LaSalle (Hymenoptera: Eulophidae) is a gregarious endoparasitoid mainly of Lepidoptera pupae This species was recorded in Brazil in Eupseudosoma involuta (Sepp) (Lepidoptera: Noctuidae) and Euselasia eucerus Hewitson (Lepidoptera: Riodinidae) (Delvare and LaSalle 1993), Sabulodes sp. The mass rearing represents an important stage of control programs (Parra et al 2002, Pastori et al 2008, Pereira et al 2009), and the nutritional quality, size, age, mechanical resistance and capacity of immunological response of parasitoids should be considered to select alternative hosts (Godfray 1994). The low cost to rear this alternative host indicates that it could be used to mass rear the parasitoid P. elaeisis for biological control programs (Zanuncio et al 2008)

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Conclusion