New Horizons in Insect Science Towards Sustainable Pest Management

47

Impact of Adult Size and Sib,

Conspecific, and Random

Mating in Trichopria Sp.

on Progeny Production 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_5, © 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 gregarious endo-pupal parasitoid, Trichopria sp. (Hymenoptera:

Diapriidae) was evaluated for progeny production and sex ratio as influ-

enced by adult size and sib, conspecific and random mating. Trichopria

sp. is a parasitoid of the tachinid fly, Exorista bombycis (Louis), which

causes a reduction of 10–20 % in silkworm ( Bombyx mori L) cocoon

yield in south India. Two-day-old virgin females and unmated males of

Trichopria sp. were categorized into big and small and were allowed to

mate in the following manner: (1) big female × big male, (2) big female ×

small male, (3) small female × big male, and (4) small female × small

male. With regard to sib, conspecific, and random mating, the following

mating combinations were set up: (1) mating among the progeny of the

same mother (sib mating), (2) mating between the female progeny of one

mother (A) and male progeny of another mother (B) (♀A × ♂B) and vice

versa (♀B × ♂A), and (3) mating between the progenies of several moth-

ers (random mating). Observations were made on the number of pupae

parasitized, parasitoid developmental duration, progeny production, and

sex ratio. Both big and small females of Trichopria sp. produced signifi-

cantly more progenies when they mated with big males. Random mated

females produced significantly higher progenies than those from sib and

conspecific mating.

Keywords

Trichopria sp · Parasitoid size · Progeny production · Mating

Introduction

Use of parasitoids in pest management programs

is bound to pay rich dividends in the long run as

these agents can perpetuate under natural condi-

tions with concomitant suppression in the pest