|The wool-carder bee Anthidium manicatum|
In Britain, A. manicatum is only locally common in the south, especially SE England, and becomes scarcer as you look further north. Until 1993 it was scarce even in the SE, after which it began to expand its range (Edwards, 1997) and become common is some southern locations. This suggests that temperature is a key factor in its distribution and to me indicates that this is one of many invertebrate species expanding it range as a result of climate change. Its common name of 'wool-carder' referes to its habit of shaving the hairs from downy plant leaves (such as Stachys) in order to line its nest - possibly a behavioural adaptation to provide insulation due to a requirement for high temperatures.
Considering the colour pattern, this specimen (like those in continental Europe) clearly seem to display wasp-mimicry, while typical British specimens do not, or at least only weakly. This would be a clear defensive adaptation, so why do British specimens tend not to show it? One possibility is that the relatively dark colouration permits more rapid warming when basking - certainly this individual was also vibrating its wings at intervals, a typical insect behaviour used to warm the flight muscles. If, further south in Europe, this aid to warming is outweighed by the benefits from defensive mimicry, then the clearer stripes might be an advantage. This leads me to consider three possibilities:
1. This is an aberrant individual with no further significance.
2. It is a vagrant continental individual.
3. It is a British individual and increased temperatures are selecting for stronger stripes.
Of these, #3 is the most interesting but also the most speculative and there is no way of knowing from a single sighting. However, I intend to watch closely - males are highly territorial (and may kill other bees) so might use the garden regularly - and would be interested to hear from anyone else who has seen a specimen like this in Britain.
|Anthidium manicatum basking on common bird's-foot trefoil Lotus corniculatus|
Baldock, D.W. (2008). Bees of Surrey. Surrey Wildlife Trust, Woking.
Edwards, R. (ed.) (1997). Provisional Atlas of the Aculeate Hymenoptera of Britain and Ireland. Part 1. BWARS/BRC, Huntingdon.