Denizens of the Dark

Denizens of the Dark
Meta merianae

At this time of the year there is always much excitement around the appearance of the first bumblebee or the first butterfly, and why not? It's a signal that the year is advancing and the cold, dark days of winter are behind us. But for every one of these brash, bright daylight show-offs there are many more which shun the light and live in the dark!

Compost bins, for instance, are excellent places for an invertebrate to develop. The decaying material provides ample food as well as giving off heat as it decays. Emptying the office compost bin earlier in the year I came across several species of fly, including one or two moth flies (below) so-named because their wings are covered in scales or flattened hairs giving them the appearance of tiny moths. The larvae of these flies feed on bacteria in decaying material, often around drains and an alternative name for this group is drain flies or sewer gnats.


Whilst not strictly associated with compost, there were several species of spider in the compost bin, including, Meta merianae (top), a species usually associated with dark, damp places such as caves, culverts and cellars. Despite the fact that it was mid-winter all the individuals I came across were adult and this highlights a feature of many invertebrates that live in sheltered habitats - they tend to be much less seasonal than species which occur in less sheltered environments, with adults and young found at all times of the year. 


Even on the bare shingle, an extremely harsh and unforgiving habitat at any time of the year, there is always something to be found.  Checking wheatear nest boxes recently I came upon several species of woodlouse nestled amongst the rocks. Most of these were Philoscia muscorum (the three largest individuals in the image above) a very common species which occurs in a range of habitats. The image also shows a pill woodlouse (the smaller individual at the top, probably Armadillidium vulgare), a species that can role into a ball when disturbed. I also found several  Porcellionides cingendus (below), In the UK this species tends to be concentrated in the south-west, though I find it quite regularly at Rye Harbour, particularly on the poorly vegetated shingle.

RxPorcellionides cingendus 020320

Another beastie I uncovered while checking nestboxes was the tiny rove beetle Drusilla canaliculata (below). Again, this is a very common species in a range of habitats in the UK, and a species I see regularly at Rye Harbour. It is quite distinctive with its red body and black tail end and in common with its much larger relative, Devil's coach horse, it will raise its rear end when threatened as though it is about to sting (though neither species can!). This species is often found near ants nests as the adults prey on ant larvae and pupae.



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