Survivorship, cannibalism, body weight loss, necrophagy, and entombment in laboratory groups of the formosan subterranean termite, Coptotermes formosanus under starvation (Isoptera: Rhinotermitidae)

The effects of starvation on mortality, cannibalism, caste-specific cannibalism, and body weight loss were investigated in laboratory groups of the Formosan subterranean termite, Coptotermes formosanus Shiraki. Groups of50 termites (80% workers and 20% soldiers) were tested under starvation or with access to a filter paper food source. At the end of a 40-d test, starved and fed groups showed a mortality of 90.5% and 23.2%, respectively. The cannibalism rate was about 62.0% when starved and 23.0% when food was provided. Starved groups lost about 7.7% of body weight and fed groups lost 2.3%. Termite mortality was mainly a result of starvation-induced cannibalism during the first 30 d, but some termites died solely from starvation after 30 d. Caste-specific cannibalism was observed between 1 to 20 d when starvingworkers preferred to eat more soldiers (36.0%) than workers (16.0%), and resulted in a solider/worker ratio of 3.0% at 40 d. Our data indicate a refined surviving starvation strategy in this termite species. Under starvation conditions, workers may first rely on their own metabolic stores in addition to occasional non-caste-specific cannibalism. If the starvation continues, workers begin to eat more soldiers to mitigate the trophic burden soldiers place on them. Such practice stops when the soldier/worker ratio declines to some point to maintain a proportional caste composition. Our tests on necrophagy and entombment indicate that starving workers not only cannibalized live nestmates but also termite carcasses. Workers with or without food had a similar propensity to burying carcasses.