DEMOGRAPHY OF THE WORKER CASTE OF LEPTOTHORAX-ALLARDYCEI (HYMENOPTERA, FORMICIDAE)

The demography of workers of Leptothorax allardycei was studied by mar king and monitoring individuals within colonies maintained in the labo ratory. The maximum lifespan for a worker in this study was 300 d, wit h an average life expectancy, at eclosion, of 145 d. The workers showe d a type I survival curve. Life expectancy declined slowly until an ag e of almost-equal-to 100 d, after which there was a marked decrease in the rate of change of life expectancy. The probability of survival de creased exponentially with age. Workers that eclosed in the field, and were, therefore, of unknown age, survived longer than predicted on th e basis of the survival of ants of known age. This is probably because workers collected in nature are, on average, substantially younger th an L. allardycei workers in the laboratory. This is almost certainly b ecause older workers, who forage for the colony, are at a great risk o f predation.