March 2005. The bug is sometimes seen in dense clusters on plants. What is the purpose of the aggregations?

This bug looks like a species of Leptocoris (Rhopalidae). There are a few species in Australia. In some species there is an aggregation pheromone and, together with the attractive scent of the host fruit, they bring the bugs together.

The preferred host is said to be seeds of the plant family Sapindaceae. In northern Australia, they feed on fallen seeds in large numbers, but only occasionally are seen on taller plants, and then only in small numbers. Some bugs will occur in large clusters. If they are not feeding, then they are probably in a sexual diapause – a relatively inactive period during which the reproductive organs are completing their development. It would be interesting to know if the bugs are actively feeding in these clusters, what parts of the plants they are on and if they are also present on the ground.