Acorn Weevil (Conotrachelus posticatus)
Detailing the physical features, habits, territorial reach and other identifying qualities of the Acorn Weevil.
Updated: 1/30/2018; Authored By Staff Writer; Content ©www.InsectIdentification.org
The nut-loving Acorn Weevil efficiently uses acorns that it collects: as larvae, acorns are food, and as adults, acorns are a secret nursery.
Acorn Weevils have a long snout reminiscent of an elephant's trunk. This unique proboscis makes it easier to identify this type of beetle. This snout has chewing mouth parts at the end. Females lay a fertilized egg into the soft tissue of a young acorn, the seed of oak trees, when they first start growing.
Through summertime, the acorn grows and hardens. Inside the weevil larva feeds on the seed's interior. In early autumn, the acorn falls off the branch onto the ground below. Soon after, the weevil larva (now a curvy, legless grub) chews a small hole into the acorn seed and leaves the acorn in early winter, burrowing into the soil. There it can remain hidden from predators while it develops into an adult. The larvae are a protein-packed food source for many other insects, as well as spiders and small animals.
Acorn Weevils can inhibit oak tree expansion if an area is infested. Their larval diet of acorns can result in fewer new oak trees in that area, however, existing trees are not in any danger. Adult Acorn Weevils are hunted by a variety of Weevil Wasps and can eventually become living meals for hatching wasp larvae.