IT鈥橲 an unusual living arrangement: a massive black ant shares its nest with a much smaller brown ant.
Most social insects don鈥檛 tolerate strangers. But the 15-millimetre-long Platythyrea conradti, which lives in the forests of Ivory Coast, builds nests inside holes in trees that it shares with the 2.5-millimetre-long Strumigenys maynei.
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鈥淭his is a remarkable and rare example of cooperation between two ant species that share little in common,鈥� says Thomas Parmentier, an evolutionary biologist at the Catholic University of Leuven (KUL) in Belgium. 鈥淥ne is large and the other minuscule, they belong to unrelated genera and have markedly different behaviour.鈥�
Parasitic species often sneak into nests by producing odours that match those of the nest builders. But Parmentier and colleagues have shown that both species have unique odours. Despite this, the species almost never attack each other (Behavioral Ecology and Sociobiology, ).
Why they live together isn鈥檛 clear. But a clue could be in their behaviour: the small ants are highly aggressive, attacking and repelling any invaders, while the large ants avoid direct confrontations. It may be that the larger ants lack a soldier caste and the smaller ants have effectively taken on this role. In return they get a home and food in the shape of other small creatures found inside the nest.
This article appeared in print under the headline 鈥淕ulliver ants live happily among the Lilliputians鈥�