Today I visited Maesteg cemetery again to visit the Ivy. But the prize of the day was on the Buddleah Bush at the small gate round the front wall of the cemetery in the car park. Eristalis similis has never been recorded in Wales and is a hard species to identify and therefore probably overlooked by the casual observer. It is the size and shape of the big two Eristalis - pertinax and tenax, with a tapered body closer to pertinax. The diagnostic characters are a combination of 1) dark front and middle tarsus [pale in pertinax], 2) hind tibiae pale at base [all black in tenax], 3) the stigma on the wing is elongated and has a unique shape, [lacking in all the other Eristalis species]. Other features also back up similis and discount other species 4] lacks eye hair stripes of tenax 5] lacks furry appearance of intricaria. 6] the hind femora is grey dusted and dull rather than shining and 7] the sides of the thorax are also dull, shining in other species 8] large robust size rules out everything other than tenax and pertinax.
I sent the photos of the fly to Roger Morris of the Hoverfly Recording Scheme and he and the other experts on his team have all confirmed that it is indeed an Eristalis similis and thanked me for the record. Eristalis similis was only discovered in Great Britain in 1990, up until 2013 there had only been 2 records, but it has been recorded more regularly since then particularly this year, where there has been half a dozen records. So 20 records in total, mainly on the south and east coasts but not in Wales. It is thought to be a migrant, but there is now evidence that it may have established in this country just like my other record first for Wales Eupeodes lapponicus.
Not much is known about its life cycle but on the continent it has a preference for mature deciduous woods. The nearby trees which are Large-leaved Lime are well over 50 years old, so fit the bill well. Hopefully it is a resident rather than a migrant.
It is number 132 for the valley and a welcome addition to the Glamorgan and Wales lists.
I also had some other stuff today, but they seem unimportant right now.
2 comments:
Excellent find well done they are hard to pin down unless you photograph a lot of eristalis
Nice find!
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