If it be true, as we cannot doubt, that social insects have developed from solitary ancestors, there is reason to believe that communistic societies were originally monogamous, that is to say established by a single female. That is what we see normally with the wasps and the bees of our country, with Vespa and most of the Polistes and some of the Polybias of tropical regions. It is the same with the termites, where one rarely finds several royal couples in a nest. This is the belief of Buttel-Reepen, of Lameere, and also mine, as well as of Von Ihering and his son Rodolph's, supporting the idea that polygamy is a primitive character of communistic societies, that it originated in an epoch of perennial summer in which the social life developed under the influence of the warm climate, that it persists to-day in regions which have preserved that climate, while it has given place to monogamy in localities where the climate has become colder.
These biologists apply this thesis to the consideration that in our country insect colonies are all monogamous, but, on the contrary, very often polygamous in tropical regions. But from the fact that we find several queens in one society we cannot conclude that this has a polygamous foundation. In reality climatic influences act on the constitution and the duration of communistic groups in the measure in which they favor the provisioning of the nest. When they permit a continuous and more or less abundant harvest the society can become perennial, and one can conceive that then the young queens can remain in the nest with its founder until the period of swarming. When, on the contrary, the harvest is limited to a single season this perennial form cannot become possible except with those species (termites and trae bees) which store up sufficient reserve food for hard times ; otherwise the colony dissolves when food begins to be scarce. Thus a favorable climate may produce a perennial colony, and this favors in its turn the association of females, but these possibilities are not always realized and their realization depends on the habits of the species, as is shown by the true wasps, or Vespid, which in all countries form annual monogamous societies. Therefore, to know whether polygamous societies are established by several queens we must know about their beginnings, and so far this has been so only with Belonogaster junceus.
But it appears from the observations of Roubaud that the colonies of this very primitive social wasp are ordinarily monogamous at the time of their fecundation. "Customarily," says the author, "it is an isolated female which lays the first base for the nest, but very often, also, two or more females associate together to found a new nest."
We know that ants* nests very often contain several queens, but it is probable that they were established by a single queen. I have told before how Jacob Huber was able to follow the establishment of a colony of fungus-cultivating ants from the original queen, and on the other hand Bondroit had the good fortune to find a nest of Lasius in which the queen was still alone with a small number of larvae coming from her first eggs. It will be interesting to know whether or not the formicaries of Lasius and those of Atta, which cultivate fungi, usually contain several queens at the period of their complete development.