Effect of mound size on intranest thermoregulation in the red wood ants formicarufa and f. Polyctena (hymenoptera, formicidae)

Abstract

Red wood ants are capable of active thermoregulation in the nest, which allows them to achieve a high number of workers and a dominant position in biocenoses. We investigated the features of the spring warm-up and the ability for active thermoregulation of the mounds of the ants Formica polyctena and F. rufa in the vicinity of Kyiv, Ukraine. We have proposed a model of thermoregulation of the mound, which takes into account the heat flow from the sun, heat exchange with air and soil, and endogenous heat generated by the antcolony. The calculation of the model for specific values showed that only F. polyctena mounds with a diameter of more than 0.9 m and F. rufa mounds with a diameter of more than 1.1 m are able to maintain a constant optimum temperature in the nest. Comparison of the calculated data with the measurement results on the studied nests showed that the diameters of the majority of mounds exceeded the critical values for both species indicating the ability of thermo regulation. The possibility of using the model to study the thermoregulation of mound sin different natural areas is discussed.