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Falling-letter weevil

by Rowan Hooper

Japanese name: Otoshibumi

Scientific name: Apoderus jekeli

Description: These are odd-looking, but I think quite charismatic little beetles, with elongated heads and powerful limbs, especially the forelimbs. They have straight antennae, which place them among the primitive weevils; they grow to about 6 mm in length. The Japanese name translates as “falling-letter” weevil, and I’m not sure where that name comes from, but another common name for them is leaf-rolling beetle. Their stretched appearance is accentuated by the long and narrow thorax, which is the source of another common name: Snout beetle. This elongated snout is one of the defining characteristics of all weevils. The head, thorax and the limbs of Falling-letter weevils are all glossy black, and the wing cases are nutty brown with dimples. There are thousands of similar species.

Where to find them: In forests, parks and gardens all over Japan, from Hokkaido to Okinawa. Look especially on sweet chestnuts for these particular beetles. This family of beetles is especially common in East Asia.

Food: The fresh, tasty leaves of various tree species. The larvae munch their way through leaves of the tree they hatch on, and continue eating until they are big enough to pupate. The adult beetles survive mainly on the food reserves they managed to put away when they were larvae.

Special features: These beetles are called leaf-rollers because the females lay their eggs on leaves and then roll them up to form protective cases for the larvae. Each egg develops safely in its leaf-roll, and when they hatch, the grubs have a meal immediately available. They are voracious little insects, and sometimes become agricultural pests that may damage trees and bushes in forests and parks. The care the female takes over selecting a “nursery leaf” for each egg is one reason these weevils are so successful. The most vulnerable stages in their life — as an egg and as a soft juicy grub — are spent tucked inside a rolled-up leaf. Then, when the insects pupate and start to explore the world outside the leaf, they are protected by their hard beetley shells.

PHOTO COURTESY OF BIO-IMAGE NET