Perennial Indeterminate Colony Cycle in a Primitively Eusocial Wasp

Chandrashekara, K and Bhagavan, Seetha and Chandran, Swarnalatha and Nair, Padmini and Gadagkar, Raghavendra (1990) Perennial Indeterminate Colony Cycle in a Primitively Eusocial Wasp. In: Social Insects and the Environment: 11th International Congress of IUSSI, August, 1990, Bangalore, India, p. 81.

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Abstract

The colony cycle of primitively eusocial wasps consists of three phases: the pre-emergence phase, the post-emergence phase and the declining phase. Most species of wasps in temperate regions follow a seasonai colony cycle. Being initiated synchronously in Spring by overwintered females, colonies grow through summer and are abandoned in Fall, after producing reproductives. Females produced in Fall mate and overwinter while the remaining individuals, including the males, die. In the tropics, however, colonies are aseasonal and may be initiated throughout the year. Colony cycles in most species, either temperate or tropical, may thus be termed determinate since they are abandoned after a fixed time after initiation. Ropalidia marginata follows a colony cycle which often encompasses multiple repeats of a typical determinate colony cycle. We therefore call it an indeterminate colony cycle. A major portion of the brood and cells are destroyed and a large fraction of adults leave the nest during the declining phase of each unit of the colony cycle but a small number of females may stay back on the nest and begin a new unit of the cycle. This leads to two interesting questions: why is there a decline if the colony is to continue? and why is the decline not complete as in the determinate colony cycle. We propose two alternate hypotheses.One is that the colony cycle is a response to predation by Vespa tropica. It may be adaptive to issue 'swarms' of dispersing wasps periodically to found new nests, before all is lost to the predator. This hypothesis predicts that queen replacements need not necessarily coincide with the beginning of every unit of the colony cycle. The second hypothesis is that the queen produces reproductives and dies at the end of each unit of the colony cycles. One of her daughters may however stay on and use her natal nest to produce her brood. This hypothesis predicts that queen replacements should necessarily coincide with the beginning of every unit of the colony cycle. Our present results are incapable of distinguishing between these hypotheses. In some colonies queen replacements always coincide with new units of the colony cycle but in others, this is not so. Further studies of such perennial indeterminate colony cycles are bound to be rewarding.

Item Type:	Conference Paper
Publisher:	Oxford and IBH
Additional Information:	Copyright of this article belongs to Oxford and IBH.
Department/Centre:	Division of Biological Sciences > Centre for Ecological Sciences
Date Deposited:	04 Apr 2007
Last Modified:	19 Sep 2010 04:34
URI:	http://eprints.iisc.ac.in/id/eprint/9473

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