Spatial distribution, size and density of nests of Myrmicaria opaciventrisEmery (Formicidae, Myrmicinae)

We recorded over the course of one year the location of nests of Myrmicaria opaciventris on five sites in the region surrounding Yaounde (Cameroon). O n these sites, the colonies are polydomous and polygynous. The size of the largest colony, which was made up of 27 nests, was evaluated at 216,575 +/- 24,750 individuals of which 147,230 +/- 15,336 were workers. The nests are interconnected by trails that the workers dig during the rainy season. The y consist of trenches that are slowly closed to form tunnels. Thanks to the se tunnels, the workers are sheltered from their predators when going from one nest to another. They also have easy access to food sources far from th e nests. We noted a seasonal variation in the location of the nests. It con sists of a kind of budding. Depending on the case, the initial nest might s urvive or end up by being abandoned during the main rainy season or early i n the dry season. The spatial distribution of the nests in the field is, in general, random and the density is lower during the dry season (from 6.2 t o 26.4 nests/ha) than during the rainy season (from 12.1 to 50 nests/ha).