May 2017

Why the long face?

This unusual weevil was sent to the museum for identification. There are tens of thousands of different kinds, but fortunately this is one of the more distinctive species.

Answer

Elephant weevils have distinctive long straight snouts, rugose wing cases and wide flappy feet. Their unusual appearance has a unique appeal, but producers in the wine and grape industry are not so impressed. There are more species of weevils named than any other known group of animals. Numbers are staggering, with an estimated 62000 species in 5800 genera worldwide. And there are suggestions that up to another 140000 species await formal description. That is a lot of weevils!

Despite their enormous diversity, weevils share some distinctive characteristics that usually make them easily recognisable. Most significant are the generally elongated ‘snout’ called a rostrum, and the angular, elbow-shaped antennae set at the end. Following that basic theme, the subtle variations between species are nearly limitless.

There are weevils boring into rotten logs, browsing foliage and hiding under bark. Few plants are without some sort of weevil. And of course weevils are lurking among the stored dry products in our pantries, where some species are tiny enough to develop inside wheat grains. Weevils have travelled the world using humans as their unwilling agents, adding protein (and perhaps flavour) to the hard tack ship’s biscuits.

It’s small wonder that identifications of individual species of weevils can be extremely problematic. It may require the expertise of someone who specialises in the study of Coleoptera (beetles), and more specifically Curculionoidea (weevils).

However, within that extraordinarily diverse group of insects, there are a few common weevils that stand out from the rest. A specimen recently forwarded to the museum was easily identified as an Elephant Weevil (Orthorhinus cylindrirostris). Distinguishing features of this well-known species include the very long rostrum and extremely large, flappy feet.

This is a very widespread weevil, extending from Queensland to Tasmania and South Australia. Wine growers are no fans of the Elephant Weevil. The wood-boring larvae are known to cause damage to grape vines.

At around 2 cm, the Elephant Weevil is a moderately large species. But compared to the largest Australian species, the 6 cm Giant Pine Weevil, it is the lesser of the two weevils.

Queensland Museum's Find out about... is proudly supported by the Thyne Reid Foundation and the Tim Fairfax Family Foundation.