Tree Weta

Explanation: On a road trip from Wellington to Rotorua, North Island, New Zealand, my host, Dr. Stephen Pawson, had us explore a nighttime woodland at Pureora Forest Park. There, among the calling Morepork owls and various invertebrates, we spotted several tree wetas clinging to the branches and bark of their namesake plants.

Note the characteristically
enormous length of the
antennae!

Wetas are largely nocturnal. They feed on other insects and vegetation ... and they get large, up to nearly 3 inches (7 cm) long. They are endemic to (found only in) New Zealand.

Tree wetas form harems, where males will mate with groups of females in tree cavities and will defend their harems (Kelly 2006).

Tree wetas are in a different taxonomic family than their cousins, the cave wetas, that we encountered in a previous EPOW episode.

Tree wetas can make for a unique pet, but they do need special care and are better left in their native forest environment.

Wetas can be susceptible to predation by introduced, invasive species, but may be capable of rebounding once the invaders are removed.

In one study (Rufaut and Gibbs 2003), a population of Wellingon tree wetas on the Chetwode Islands in Pelorus Sound was studied before and after eradication of invasive Polynesian rats and introduced South Island wekas (a large terrestrial bird of New Zealand but not native to the islands under study). The tree wetas were not observed to increase in population size, but they did become more active and formed larger groups in tree cavities (galleries).

The photo above is likely of a male, and the photo below is likely of a female.

Information:
Kelly, C.D. 2006. Movement patterns and gallery use by the sexually dimorphic Wellington tree weta. New Zealand Journal of Ecology 30(2):273-278.
Rufaut, C.G., and G.W. Gibbs. 2003. Response of a tree weta population (Hemideina crassidens) after eradication of the Polynesian rat from a New Zealand island. Restoration Ecology 11(1):13-19.

EPOW - Ecology Picture of the Week