Acorn weevil (Curculio glandium)
|Size||Length: 4-8 mm (2)|
Common and widespread (3).
The most striking feature of the acorn weevil is its elongated snout, known as a 'rostrum', which is longer in females than males (2). Adults have a brownish and patterned body (1). The larvae are short, and cylindrical in shape, and move by means of ridges on the underside of the body (2).
Found mainly in southern and central parts of Europe, becoming increasingly rare further north (2). In the UK, the acorn weevil has a wide distribution in the south (1).
This species is found on oak trees (2).
Adults feed on oak (1). The females lay their eggs in acorns; the long rostrum is used to bore through the thick wall of the nut (3) with jaws located at the tip of the rostrum. When it has almost reached the centre of the nut, the egg is inserted in the hole, which subsequently heals up (4). The larvae develop inside the acorns, burrowing out when they are fully-grown in order to pupate in the soil, leaving a small hole in the wall of the acorn (2).
This species is not threatened at present.
For more on weevils see: Weevils by M.G Morris. (Richmond Publishing Co, Slough).
For more on invertebrates and their conservation see Buglife, the Invertebrate Conservation Trust at:
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- Larvae: stage in an animal's lifecycle after it hatches from the egg. Larvae are typically very different in appearance to adults; they are able to feed and move around but usually are unable to reproduce.
- Pupate: the process of forming a pupa, the stage in an insect's development, when huge changes occur that reorganise the larval form into the adult form. In butterflies the pupa is also called a chrysalis.
- National Biodiversity Network Species Dictionary (Jan 2003): http://www.nhm.ac.uk/nbn/
- Harde, K. W. (2000) A field guide in colour to beetles. Silverdale Books, Leicester.
- Morris, M.G. (1991) Weevils. Richmond Publishing Co, Slough.
- Joy, N. H. (1949) British beetles: their homes and habits. Frederick Warne & Co Ltd., London.