Showing posts with label Curculio. Show all posts
Showing posts with label Curculio. Show all posts

Thursday, October 15, 2009

Nut Weevil -- Curculio sp.



Acorn weevil meets leafhopper (9/11/09).


These robust-bodied, long-snouted weevils are fairly easy to identify to the genus level (Curculio), but a species ID is more difficult, though I think these are Curculio proboscideus. If so, several different species of oaks are their host plants.

A female has a longer rostrum (snout, beak) than a male, longer than her body. (Total length including rostrum is around half an inch.) The apex of the female's rostrum includes cutting apparatus that allows the drilling of a deep hole in a nut or acorn; eggs are then laid in the hole. Various species specialize in the nuts or acorns of particular species.


Shorter rostrum indicates this is probably a male.


Each female lays about 25 eggs which hatch in about one week. Larvae feed 6 to 10 weeks then chew their way out of fallen nuts and enter the ground where they spend the winter and spring. Larvae pupate in late spring and early summer. Adults begin to appear about the first of August.  There was an approximately 10 day period in mid-September when these weevils were numerous under our porch light.





An extremely long rostrum indicates this is almost certainly a female (9/16/09).




.
Share/Bookmark