Hazel
Pot Beetle Cryptocephalus
coryli  |
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| Click here for larger Cryptocephalus coryli images | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Many years
ago, the Hazel Pot Beetle was a widespread species across
the southern counties of England, but it declined greatly
during the last century and is now one of the UK's most
rarest insects. Since 1970 it has been found at only
three single sites - in Berkshire, Lincolnshire and
Surrey (Ref: Natural
England) It is now
classed as an RDB1 species (Species which have shown a
rapid continuous decline over the last twenty years, and
now exist in 5 or fewer 10km squares of the national
grid) The female is shown in the accompanying photographs (the male has a black thorax) The lower left photograph, shows the female in the process of covering the egg with droppings before release. |
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| This beetle has been the subject of a successful reintroduction programme at two Lincolnshire sites, where both larvae and adults were released. After some information requests, it is believed that no such reintroduction programme has taken place in Nottinghamshire. It now seems that this species has remained overlooked at Sherwood Forest for around 70 years, as the last records I can trace date back to 1938. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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| It's decline
is thought possibly to coincide with the reduction in
coppicing. Sherwood Forest was once regarded as being
good for C. coryli by collectors in the early
1900's, when over a dozen specimens would be taken on
each visit to this locality the beetles being beaten or
picked from young Birches and Oaks during June. In the
south, it occurs on hazel along woodland edges, rides and
hedgerows, but in the north prefers a heathland habitat
with Birch scrub or young trees. C. coryli is one of the largest Cryptocephalus beetles in the UK. Females can reach lengths of 8mm, with the males reaching 6mm. The adult beetles emerge from mid-May to mid-June and has an unusual life cycle. The female covers it's eggs with droppings to protect them, and feeds it's larvae with leaves cut and dropped from the foodplant (usually Birch) The larvae remain in their protective cases throughout their life, increasing the size of it's case as it grows. The larval stage usually lasts one or two years. |
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