The larvae will then develop and feed inside the stems of the host plants.

It is hypothesized that these flightless insects disperse from one island to another by rafting on their host plants.

This could be facilitated by the wood-boring life-style of the eggs and larvae, as well as the air cavity under the fused elytra that help adults to float.

This suggests that the eggs and larvae are the primary dispersive stages in Pachyrhynchus.

[1][3] Other research has shown that the eggs can survive digestion in certain birds, such as Hypsipetes leucocephalus and Turdus chrysolaus, which may be another explanation for the genus' successful dispersal.