Behavior of Japanese subterranean termite, Reticulitermes speratus in Sapporo, Hokkaido, under low-temperature conditions. 3. Comparison of the mortality and survival ratio of dark-brown ants, Lasius japonicus under winter conditions

Abstract

Petri dishes with humidified vermiculite containing Japanese subterranean termites, Reticulitermes speratus, or dark brown ants, Lasius japonicus, were kept at room conditions without heating for four winter months in Sapporo City, and mortalities of both species were monitored. Accumulated mortalities of the ants increased by 50.4% followed by 37.6% for termites with food and 26.2% for termites without food by the end of experiment (mixed conditions: non-aggregated and aggregated). The mortality in the aggregated conditions of termites without food was only 3.7%, and none of the ants died (0 mortality; all survived). In contrast, 37.6% of termites with food died as did 84% of the ants in the non-aggregated conditions. Aggregation thus seems to be an important behavior for both species in cold seasons.