I took this photo of a butterfly last year in the Walter Sisulu Gardens in Roodepoort. Nothing too special about it, I thought. Just one of the hundred-odd butterfly LBJ’s (little blue jobs). But it wasn’t quite like any of the commoner blues, so when I submitted the photo to the ADU for adding into the LepiMap butterfly atlas, in the collector’s id field I just put “some blue” and waited for the experts to get to something a bit more specific.
Sure enough it was a lifer for me in the form of a twin-spot blue (Lepidochrysops plebeia plebeia). It was my first sighting of a member of the genus Lepidochrysops, commonly known as ant blues because of their fascinating life cycle.
Twin-spot blues start their lives like most butterflies, when the female lays her eggs on Lantana rugosa, which is one of the seven indigenous species of lantana. (Did you know there were indigenous lantanas? Me neither). The small white caterpillars start off true to type by feeding on the lantana flowers. But after the third instar they drop to the ground and emit a chemical which imitates the brood pheromone of the ant species Camponotus niveosetus. (See glossary at the end of this article). This soon attracts the ants, which take the caterpillar down into their nest’s brood chamber, where it grows fat by eating the ant larvae. The chemical signal it emits is obviously very powerful, because if the nest is disturbed, the ants will save the butterfly larvae first. Eventually the larva pupates in the ant nest, before emerging as a mature butterfly. It then emits a chemical which repels the ants, and escapes through the tunnels of the ants nest with wings folded. On emerging, it climbs up a convenient plant stem, deploys its wings, and flies off to start the cycle all over again.
So watch out, hey. One day some cute little species of butterfly might just identify the burgeoning human population as a great potential ecological niche.
PHEROMONE: A substance emitted by a member of a species which is intended to alter the behaviour of other members of that species, to the benefit of the species.
ALLOMONE: A chemical substance produced and released by an individual of one species that affects the behaviour of a member of another species to the benefit of the originator but not the receiver. The chemical released by the twin-spot blue larva is an allomone.
KAIROMONE: A chemical substance emitted by an organism and detected by another of a different species which gains advantage from this. Some chemicals can act as a pheromone by, for example, attracting a potential mate, whilst at the same time acting as a kairomone if they are also detected by a predator.
SYNOMONE: A chemical substance produced by an individual of one species that benefits both the producer and the recipient which is of a different species
Submitted By: Roger Mayes