Data from: Are all forms of defense lost on islands? Persistence of an indirect defensive trait in six island colonists from New Zealand

The loss of defense hypothesis posits that island colonizers experience a release from predation on the mainland and subsequently lose their defensive adaptations. However, while support for the hypothesis from direct defensive traits is abundant, far less is known about indirect defensive traits. Leaf domatia are cave-like structures produced on the underside of leaves that facilitate an indirect defensive interaction with predaceous and microbivorous mites. I tested the loss of defense hypothesis in six domatia-bearing taxa inhabiting New Zealand and its offshore islands. No support for the loss of defense hypothesis was found. Changes in domatia investment were instead associated with changes in leaf size – a trait that has been repeatedly observed to undergo rapid evolution on islands. Overall results suggest that not all types of defense are lost on islands.