Bark Beetle Predator ‘new’ to the north-west 

January 17th 2019

This small but distinctive beetle was found by Gwen Richards in her house at Torbreck on 23rd November 2018. After being photographed it was released.  It was about 6mm long, with four bright orange blotches on its otherwise black elytra. The markings resembled those of the burying beetles Nicrophorus spp., but these are very much larger and have truncate elytra (chopped off at the back end).

The clubbed antennae suggested that it might be a member of a large, ragbag, group of beetles formerly known as the Clavicornia (club-horned).  My first resort with a beetle new to me is a book with beautiful illustrations of over 1000 species, A Field Guide in Colour to Beetles (Harde, K.W. and Hammond, P.M., 1984).  A quick flip through sections containing beetles with clubbed antennae took me to Glischrochilus quadripunctatus, a member of the Nitidulidae or Sap Beetles, which looked a good match. 

However, the text revealed that there were several species of Glischrochilus ‘in central and northern Europe’. So, further ferreting ensued, this time in the ‘beetle bible’ A Practical Handbook of British Beetles (Joy, N.H.,1933).  This has a key to and line drawings of the three species found in the British Isles. This and a trawl through some superb photographs on-line clinched the identification.

G. quadripunctatus, the Bark Beetle Predator, is found between March and November ‘in the passages of bark beetles’ or ‘at escaping sap’, suggesting a carnivorous diet as a larva, perhaps more sugar-rich as an adult.  It has been found in scattered localities throughout England, Wales and Scotland, but previous records from the Highlands are centred on Inverness and the area to its south.  There is one record on the north coast, but this appears to be the first from the north-west.  A variety of conifers were planted on the croft ground surrounding Gwen’s house, some now ailing or dead, and this is probably where it originated.

Ian M. Evans

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