First-instar aphids produced late by the fundatrix ofCeratovacuna nekoashi (Homoptera) defend their closed gall outside

The fundatrix ofCeratovacuna nekoashi attacks an axillary bud ofStyrax japonica to form a “cat's-paw” gall with a number of completely closed subgalls. Larvae produced early by the fundatrix enter subgalls, but late-produced ones cannot because the subgalls close too early. The average number of these “outsiders” produced per gall was 3.81±2.37 (n=26). In spite of their small numbers, outsiders attacked caterpillars placed on the gall. Thus outsiders function to defend their gall against external attacks such as those from lepidopterous predators.