Social Parasitism in Ants

The Behavioural Ecology of 15

Social Parasitism in Ants

Robin J. Stuart

Citrus Research and Education Center, Institute of Food and Agricultural

Sciences, University of Florida, 700 Experiment Station Road,

Lake Alfred, FL 33850, USA

Introduction

I shall next bring forward a scene still more astonishing, which at first,

perhaps you will be disposed to regard as a mere illusion of a lively

imagination. What will you say when I tell you that certain ants are affirmed

to sally forth from their nests on predatory expeditions, for the singular

purpose of procuring slaves to employ in their domestic business....

(Kirby and Spence, 1859, p. 328)

it is possible that pupae originally stored as food might become developed;

and the ants thus unintentionally reared would then follow their proper

instincts, and do what work they could. If their presence proved useful to

the species which had seized them – if it were more advantageous to this

species to capture workers than to procreate them – the habit of collecting

pupae originally for food might by natural selection be strengthened and

rendered permanent for the very different purpose of raising slaves....

(Darwin, 1859, pp. 341–342)

Social parasitism refers to the coexistence of two species of animals in

which one is parasitic on the society of the other (Wilson, 1971, 1975a).

In social parasitism, the parasite or parasite society exploits the labour

performed by a host society, often through social interactions. In this form

of parasitism, it is the altruistic or selfless behaviour of the hosts that

would normally be directed towards other members of their society, i.e.

their relatives, that is diverted by the parasite to its own advantage and to

the detriment of the hosts. Brood parasitism in birds is a familiar example

of social parasitism (Rothstein and Robinson, 1998), but it is among the

social insects in general and ants in particular where we find the greatest

abundance and diversity of socially parasitic relationships. Indeed, over

200 cases of interspecific symbiosis have been documented among the

CABInternational2002.The Behavioural Ecology of Parasites
(eds E.E. Lewis, J.F. Campbell and M.V.K. Sukhdeo) 315