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  • Acorn Weevil - (Conotrachelus posticatus)

    Acorn Weevil - (Conotrachelus posticatus)

    This nut-loving insect is an efficient user of acorns: first as food, then as a nursery.


    Picture of Acorn Weevil


    Staff Writer (10/20/2014): Like all weevils, Acorn Weevils have a long snout reminiscent of an elephant's trunk. This snout is a hollow tube and is used, like a drinking straw, to suck juices out of plant matter. Adults pierce the soft tissue of a young acorn, the seed of oak trees, while they are growing. They drink from the acorn and create a puncture that is wide and deep enough to house an egg. Females will lay a fertilized egg inside this hole and plug it up with a pile of their own feces.

    After some time the acorn hardens and turns brown, ready for germination. It will fall off the branch onto the ground below. Soon after, a newly hatched weevil larva (grub) will squeeze itself through the small hole created by its parent, slowly forcing its chubby body out of the acorn nut. Once free, the grub will start burrowing into the dirt to remain hidden from predators while it develops into an adult.

    Acorn Weevils can damage an acorn crop if a tree is infested. This would result in fewer new oak trees in that area. The larvae are a protein-packed food source for many other insects, as well as spiders and small animals. Adult Acorn Weevils are hunted by a variety of Weevil Wasps and will eventually become live meals for hatching wasp larvae.

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    Details of the:
    Acorn Weevil


    Category: Beetle
    Common name: Acorn Weevil
    Scientific Name: Conotrachelus posticatus
    Other Names: Nut Weevil

    Taxonomy:
      Kingdom: Animalia
       Phylum: Arthropoda
        Class: Insecta
         Order: Coleoptera
          Family: Curculionidae
           Genus: Conotrachelus
            Species: posticatus

    Size (Adult, Length): 4mm to 10mm (0.16in to 0.39in)

    Identifying Colors: brown, black

    Additional Descriptors: snout, trunk, nose, hairy, fuzzy, flying


    North American Reach (Though Not Limited To*): Alabama; Alaska; Arizona; Arkansas; California; Colorado; Connecticut; Delaware; Florida; Georgia; Hawaii; Idaho; Illinois; Indiana; Iowa; Kansas; Kentucky; Louisiana; Maine; Maryland; Massachusetts; Michigan; Minnesota; Mississippi; Missouri; Montana; Nebraska; Nevada; New Hampshire; New Jersey; New Mexico; New York; North Carolina; North Dakota; Ohio; Oklahoma; Oregon; Pennsylvania; Rhode Island; South Carolina; South Dakota; Tennessee; Texas; Utah; Vermont; Virginia; Washington; West Virginia; Wisconsin; Wyoming; Alberta; British Columbia; Manitoba; New Brunswick; Newfoundland and Labrador; Nova Scotia; Ontario; Prince Edward Island; Quebec; Saskatchewan; Mexico


    * Keep in mind that an insect's reach is not limited by lines on a map and therefore may appear in areas/regions/states beyond those listed above.