Pemphigus spyrothecae

Description

Pemphigus spyrothecae, or the poplar spiral gall aphid, is a social insect which exhibits apparent altruistic behaviors. The aphids form galls and act as colony defenders, at times sacrificing their own lives to do so. It has been shown that colony defense is more likely in habitats that are difficult to obtain and can hold a large number of individuals. These gall locations are crucial because plants have a short window in which a gall can be produced. Thus, it is important for there to be a defense system that enables the aphids to retain their galls. The need for defense arises when the gall is opened up to allow winged aphid migrants to leave and to release any waste. The process of repairing the holes can take up to 10 days; during this time, the gall is susceptible to intruding predators.