[6] Coxella weevils are also regularly found on Chatham Island lancewood (Pseudopanax chathamicum), on which they seem to shelter but only intermittently eat.

[3] Adult weevils are gregarious, and congregate in reasonable numbers on coxella flower heads on warm, humid nights.

[6] This species is only found on the two small predator-free islands of Mangere and Rangatira; it may exist on other smaller rock stacks that have coxella.

[4] Its host plant, A. dieffenbachii, is similarly rare, mostly found on Mangere, though some exists on Rangatira, and those parts of Pitt and main Chatham Island where livestock have not eaten it.

[5] Because it has such a small range and is dependent on a single host plant species, H. spinipennis is classified as Nationally Vulnerable by the Department of Conservation.