Cryptocephalus Leaf Beetles in Nottinghamshire
     
Cryptocephalus leaf beetles are amongst some of the most interesting and rarest within the Chrysomelidae group of leaf beetles. Out of 20 species currently on the UK list, at least 14 of these are either Red Data Book listed, or are Nationally notable A or B.

Many species are extremely specific in their habitat preference and they are generally poor colonisers, showing a reluctance to move far enough to colonise new sites. Quite a number of species are in decline.

Their generally small size, coupled with a tendancy to drop to the floor easily when disturbed, renders them difficult to find and they are probably most easily found by sweeping, or through careful searching of suitable foliage by eye (probably the better method for Birch feeding species)

 
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Although Cryptocephalus coryli is a relatively large species and with a deep red colouration on the pronutum and elytra, the Sherwood Forest colony was missed during several surveys for at least 70 years, until it was accidentally rediscovered in 2008.

Like all the other Cryptocephalus species, the female C. coryli produces an egg and holds it between the rear legs, then coats the egg in layers of faeces to produce a 'pot' before dropping them to the floor. C. coryli (more commonly known as the Hazel Pot Beetle) is the most obvious and largest of those species still occuring in Nottinghamshire and the pot size is small in relation to adult size, than those produced by smaller Crytocephalus species.

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The two adjacent photographs show females of C. pusillus (left) and C. coryli (right) in the act of producing the pot by layering faeces over the egg.

Pot construction between the two species varies, with C. pusillus being considerably more articulate in it's pot construction and producing a much larger pot in relation to size. Presumably, the number of eggs a female C. pusillus can lay, is much less than C. coryli.

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The eggs hatch and the larvae make a hole at one end of the 'pot' through which the head and legs can be extended to allow for feeding and movement. The pot continues to protect to the larva throughout it's growth. The larval stage can last two years, with larvae feeding on leaf litter (sometimes specific leaf litter to species) and the larva continually increases the size of the pot during the course of it's development. Pupation takes place within the pot.
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Known UK Cryptocephalus species and their current status

The following species are currently on the UK list. C. aureolus, C. biguttatus, C. bilineatus, C. bipunctatus, C. coryli, C. decemmaculatus, C. exiguus, C. frontalis, C. fulvus, C. hypochaeridis, C. labiatus, C. moraei, C. nitidulus, C. parvulus, C. primarius, C. punctiger, C. pusillus, C. querceti, C. sexpunctatus and C. violaceus.

RDB1 . RDB2 . Na . Nb
C. coryli . C. biguttatus . C. frontalis . C. aureolus
C. exiguus . C. decemmaculatus . C. punctiger . C. bilineatus
C. nitidulus . C. querceti . .. . C. bipunctatus
C. primarius . C. sexpunctatus . .. . C. parvulus
  The table on the left shows the current status of the rarest UK species. Several of those listed as being RDB1 or RDB2 are now restricted to fewer than a handful of sites. It is also possible that Sherwood Forest is the only site in the UK for C. coryli.
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Cryptocephalus beetles in Nottinghamshire

Including historical records, Nottinghamshire has recorded just eight species of Cryptocephalus, most of which were listed by Carr in his book The Invertebrate Fauna of Nottinghamshire published in 1916. These are C. coryli, C. fulvus, C. labiatus, C. nitidulus, C. parvulus, C. pusillus, C. moraei and C. querceti. It should be noted that the occurrence of C. nitidulus in Nottinghamshire, would have been classed as historical, even when Carr published his book in 1916. Cryptocephalus parvulus has only been recorded from one site in the extreme north of Nottinghamshire.

 
Cryptocephalus coryli (Linnaeus, 1758)
Historically recorded from two Nottinghamshire sites - Langford Moor near Newark in 1899 and from Sherwood Forest between 1899 and 1907 (Thornley, Kidson-Taylor, Hardy, Donisthorpe and Bedwell) with records from the late 1930's and 1940. This large Cryptocephalus measures around 8mm and was rediscovered in a small area of Sherwood Forest CP in 2008, which until recently was believed the only site in the UK where it was known to still occur. However, a recent email (Sep 2012) has implied that Cryptocephalus coryli is still being recorded from the North Downs in Surrey, Woolmer Forest in Hampshire and at one Lincolnshire site.
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Cryptocephalus fulvus (Goeze, 1777)
A tiny species, with adults measuring only around 2 - 2.5mm. Known historically from Barrow Hill, Everton in north Nottinghamshire (Chamberlin 1905) Many former pit sites will probably hold this beetle and in recent years we have swept adults from St John's Wort (Hypericum sp) growing at Warsop Main Pit Top, Gedling Pit Top and Bevercotes Pit Wood.
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Cryptocephalus labiatus (Linnaeus, 1761)
Another very small Cryptocephalus, C. labiatus is considerably smaller than the more well known (but much rarer) Cryptocephalus coryli. Recorded historically from near Edwinstowe and at Sherwood Forest, also at Barrow Hills, Everton in north Nottinghamshire and from Langford Moor near Newark. We found C. labiatus to be quite common on Birch scrub and occasionally on Oak in the eastern-most section of Budby South Forest at the end of June 2009 and have since recorded it from Sallow at Warsop Main Pit Top, from Elm at Warsop Wood and both Hazel and Birch at Gamston Wood near Retford.
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Cryptocephalus moraei (Linnaeus, 1758)
A rare species in Nottinghamshire. We currently know of just three locations where this beetle is found, but many of the old pit tops should be capable of holding this species. It is found on St John's Wort (Hypericum) but it took three visits to Gedling Pit Top in late June and July 2010, before we swept this male from a sheltered area there. Regular searches over two years at Warsop Main Pit Top proved unsuccessful until 2011, when adults were discovered in an area that had been previously been regularly searched. Similarly, after spending a fruitless few hours searching for this beetle at Bevercotes Pit Wood in July 2010, we were amazed to find it within five minutes of a search in June 2011, at the same location as that searched in 2010. There are no Sherwood Forest NNR records.
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Cryptocephalus parvulus (Müller, O.F., 1776)
Known from just a single Nottinghamshire site, Cryptocephalus parvulus was recorded by P. Skidmore from King's Wood at Bawtry in 1983. It is not known if it still occurs there and the adults can be found on Birch.
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Cryptocephalus pusillus (Fabricius, 1777)
A small species with adults measuring around 3mm maximum and a variable amount of black on the elytra. We found C. pusillus commonly on Alder, growing at the bottom of a south-facing slope at Warsop Main Pit Top in July 2009. Historically recorded from Sherwood Forest and more recently from Sherwood Heath (Marsh, B. 2003). In June 2011, we found two adults on coppiced Hazel at Gamston Wood near Retford in June 2011.
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Cryptocephalus querceti (Suffrian, 1848)
A very rare Cryptocephalus beetle, having RDB2 status and known from only a handful of UK sites. The adults have a preference for feeding on the epicormic growth on ancient/mature Oaks. The years 1998 and 2010 have provided the only recent records from the Sherwood Forest NNR, until we found C. querceti in 2011 at Clipstone Old Quarter.
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Cryptocephalus coryli at Sherwood Forest    
Cryptocephalus querceti at Sherwood Forest    
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