Black Snail Beetle - Silpha atrata


Black Snail Beetle - Silpha atrata

5th October Today was a lovely sunny day and so we went to the beach and had a little walk along Barry Island Beach. The place was packed, and everyone had a dog. Then we figured it out, this was the first weekend of October and so out of season and dogs were allowed once more to run and play on the sand. Heading back to the car we spotted Black Snail Beetle, Silpha atrata scuttling across the path to the safety of the grass. I didn’t have the camera with me and so a few quick snaps with the iPhone was all I could manage, so the photos here are not top drawer. I’ve never knowingly seen one before, but it’s been a great exercise to finding out about it’s rather gruesome eating habits. 
It’s not a large beetle varying in size between 10-15mm. Many black in colour, it can vary from entirely black to almost completely red. The head and mandibles seem to stick out from beyond the main body and this is an adaption to its method of predation. You wouldn’t be surprised to learn from its common name the main prey are snails. In order to feed the S. atrata climbs onto the shell of the snail and bites it behind the head. The snail  then withdraws into the safety of it’s shell and secretes defensive mucus. However the snail is not safe as S. atrata has a strategy which involves then applying a salivary secretion which dissolves both the mucus and the snail tissue. When ready S. atrata then enters the shell and begins feeding on the snail. 


Although I’ve not noticed S. atrata it is common and found throughout the UK as far north as Orkney. But normally I leave beetles alone as they can be difficult to identify. However, I’l certainly look closer now I know what its looks like. Typical habitat includes deciduous woodland borders but also parkland, gardens, damp grassland, peat bogs and coastal dunes - almost everywhere it seems. The Black Snail Beetle is mainly nocturnal and probably the main reason I may not seen it before. It can live for a number of years.

ReferencesNational Biodiversity Network. Silpha atrata. https://species.nbnatlas.org/species/NBNSYS0000023050. Accessed 20.10.2019.

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