New Horizons in Insect Science Towards Sustainable Pest Management

39

Do Size and Age of Female

Trichopria Sp. Influence Longevity,

Reproductive Performance, and Sex

Ratio?

N. Veena and D. Manjunath

A. K. Chakravarthy (ed.), New Horizons in Insect Science: Towards Sustainable Pest Management,
DOI 10.1007/978-81-322-2089-3_4, © Springer India 2015

N. Veena ()
Forest Wood Protection Division, Institute of Wood
Science and Technology, Malleswarm, Bangalore
560003, India
e-mail: [email protected]

D. Manjunath
Department of Studies in Sericulture Science, University
of Mysore, Manasagangotri, Mysore 570006, India
e-mail: [email protected]

Abstract

The present study was conducted to record the effect of female size and

age on the longevity and reproductive performance of Trichopria sp. (Hy-

menoptera: Diapriidae), an endo-pupal, gregarious parasitoid of Exorista

bombycis Louis (Diptera: Tachinidae). Being an endo-larval parasitoid of

the silkworm Bombyx mori L. (Lepidoptera: Bombycidae), E. bombycis

causes a cocoon yield reduction of 10–20 % in south India. Two-day-old

females of the wasp were segregated into big and small based on their size.

The longevity of big and small females was recorded at 24 h intervals by

feeding 30 % honey. The progeny production and sex ratio were assessed by

allowing big and small gravid parasitoid females as well as 1–8 day-old fe-

males of the wasp to parasitize 3 day-old puparia of E. bombycis for 2 days

at a wasp: host ratio of 1:4. Number of host puparia parasitized, parasitoid

developmental duration, progeny production, and sex ratio were recorded.

The longevity of big parasitoid female wasps was significantly longer than

small ones. Similarly, big females of the parasitoid produced significantly

more progenies with higher sex ratio compared to small females. With re-

gard to parasitoid age, young females (1–3 day-old) produced significantly

more progenies in comparison to old ones (7–10 day-old).

Keywords

Female longevity · Parasitoid size · Progeny

Introduction

One of the important components of integrated

pest management is the use of natural enemies

as biocontrol agents. This has many advantages

over the traditional chemical control (Schol-

ler and Flinn 2000 ). The natural enemies are

self-perpetuating, effective on a long term, and