Tuesday 5 November 2019

WEE SNOUT LION: CURCULIONIDAE

Wee Eocene Snout Weevil / Photo: Jim Barkley
A lovely fossil Snout Weevil, family Curculionidae, from the Green River Formation of Western Colorado, USA.

This fellow is from the collection of the deeply awesome Jim Barkley. He gets credit for the lovely photography, too, which shows the exquisite detail on this specimen.

Fossil weevil specimens can be found in the Eocene Green River Formation that outcrops in Wyoming, Colorado and Utah. The Formation is famous for its diverse faunal and floral assemblage of fossils and its fish in particular.

The site boasts beautifully preserved fossil stromatolites, plants, invertebrates and vertebrates. Specimens include reptiles, a broad selection of mammals and, surprise, even primates!

Weevils are herbivorous beetles. They're what your Mamma would call, "good little eaters." And there are plenty of them. The Curculionidae is the family of the "true" weevils and is one of the largest animal families. We likely still haven't met them all. A family reunion would include 6,800 genera and 83,000 species at last count. But don't place your final catering order just yet. If we include all the closely related weevil-type beetles in the superfamily Curculionoidea, we'd have to include an additional ten families. Quadruple that catering menu.

Weevils look like little tiny anteaters with a long 'snout' or rostrum, at the front of their head. Some of the members of this family have rather poor reputations as they make a living by damaging plants of interest to us humans.

Topping the hugely unpopular list is the boll weevil, Anthonomus grandis, a native of Mexico (until it's US invasion in 1892) and famous destroyer of cotton crops.

The Ips genus, feeding on Ponderosa pine, introduces a fungus to the tree. The fungus blocks resin canals, which leaves the weevil free to eat. Resin would normally wash the insects out; it is a defence mechanism. The fungus often kills the tree, and groups of dead trees are a focus for forest fires. In this way the insect is indirectly responsible for serious fires. The maize weevil, Sitophilus zeamais, is a major pest. It attacks both standing crops and stored cereal products, including wheat, rice, sorghum, oats, barley, rye, buckwheat, peas, and cottonseed.