Household maintenance

Today was spent in a very hot sand quarry in Suffolk. One of the highlights of the quarry was the very large number of solitary wasps, nesting on areas of flat compacted sand. This species, Cerceris arenaria, was amongst the most frequent. I spent a little bit of time trying to get some shots of the wasps, but the hot weather made them very fast-moving! This was my best effort and shows a female digging out sand from in front of her nest hole, which can be seen on the left. The reproductive biology of this species is fraught with danger, as the following extract from the BWARS website illustrates...

Nests are deep burrows dug in the soil, from which side-tunnels radiate leading to cells at depths of 20-25 cm. In sandy areas, dense aggregations containing thousands of nests may form. Each cell is provisioned with 3-14 prey, the number depending on prey size and sex of offspring. A colony of 1000 nests must cull around 100,000 weevils each year. Paralysed weevils are carried in flight, and are probably stored temporarily somewhere in the burrow until enough have been accumulated to fill a cell. The prey are then moved into a cell and an egg laid on one of them. Nests are left open and unoccupied through most of the day, and nest-less 'searcher' females often usurp them. Some searchers, on entering a nest, immediately close it at the entrance with a plug of soil: when the owner returns, she tries to dig through the closure, but sometimes fails to do so. The old owner then becomes a searcher, and has to find another female's nest to usurp, or occasionally that of a different species, such as the bee Dasypoda hirtipes. Some 10-15% of nests are usurped each day, each nest being sequentially occupied by many different females. Usurpers are not always successful, however, and may be evicted or killed by the owner.