THE world鈥檚 first farmer bees have been discovered in the Amazon basin. The Schwarzula bees keep a 鈥渉erd鈥� of aphid-like bugs from which they collect wax to repair their nests and a sugary substance to make honey.
Reports a century ago suggested that some species of bees have taken to animal husbandry, but the evidence was sketchy. The Amazonian discovery marks the first time that bees have been observed domesticating another species.
The bees and their herd, a type of soft-scale insect, are so new to science that they have not yet been given species names. The bees are only 4 millimetres long, but their soft-scale insect livestock are about twice that size.
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Uniquely, the two sets of insects live together in cavities made by a single species of wood-chomping caterpillar in the trunks of a particular tree. 鈥淭he soft-scale insects have not been found anywhere else,鈥� says social insect specialist Francis Ratnieks from the University of Sheffield.
The main thing the bees appear to be getting from their herd is wax, Jo茫o Camargo from the University of S茫o Paulo in Brazil will report in a future issue of Biotropica. The bees collect the soft-scale insects鈥� waxy coating, which accumulates on their backs, and use it to reinforce and repair their nest. Making the wax themselves would cost them more energy, says Ratnieks.
The soft-scale insects feed on the tree鈥檚 sap, and in the process produce a sugary substance called honeydew which the bees then collect to make honey. This arrangement is similar to that in many ant species which farm sap-sucking aphids.
Whenever the bees need to build a new nest elsewhere, it seems they transport the wingless insects with them. 鈥淓ven in young nests, we observed many soft-scale insects,鈥� says Camargo. But because the fully grown insects are so much larger than the bees, it鈥檚 probably only the newly hatched larvae that hitch a ride when the bees move.