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Noonfly Mesembrina meridiana (L.) at Flatford Mill GEN BROAD The large shiny fly with distinctive orange wing bases caught my eye as I strolled past the ivy covered hedge beside the pond at Flatford Mill on 16 October. The sun was shining brightly, reflecting off the wings of dozens of flies, wasps and numerous other flying insects as they made the most of the yellow globes of ivy before the onset of winter. The fly was highly conspicuous, sitting on a glossy, dark green ivy leaf and I was convinced I had never seen one before. Excitedly, I took several photographs thinking this must be a rare and unusual species (see cover). However, when I checked my photograph later for identification, I found the noonfly Mesembrina meridiana to be ‘widespread and common’ (Chinery, 1976). How many times had I walked past this relatively large species, and many other invertebrates, without noticing them? I resolved to take more care with my nature observations. The noonfly, sometimes called the mid-day fly, is presumably so named because of its habit of sunning itself on exposed surfaces such as walls, tree trunks, fences and paths, during the hottest part of the day. At 9–16 mm, the fly is larger than the housefly Musca domestica and can be identified by the bright yellow or orange patches at the wing bases, a pale or gold patch on the face and orange-brown feet. According to E. and H. Drabble (1927), the adults feed on plants with exposed nectaries such as rough chervil Chaerophyllum temulentum, hogweed Heracleum sphondylium and tansy Tanacetum vulgare. The species is on the wing between March and October, usually near to grazing cattle and therefore often in fairly rural areas. This is because the larvae develop in cattle dung and perhaps the dung of other animals. ‘Cow pats’ provide a rich habitat for many invertebrates, particularly flies and coprophagous beetles, which help to convert the dung into humus as part of the pasture nutrient cycle. Suffolk Biological Records Centre has records of this fly from several traditional grazing sites across the county including Somerleyton Marshes, Helmingham Hall park, Bramford meadows, Bromeswell Green, Ickworth Park, Pashford Poors Fen and Redgrave and Lopham Fen. However, the Suffolk records almost certainly reflect the location of the people recording, rather than the distribution of the species, assuming that it is still ‘widespread and common’. References Chinery, M. (1976) A field guide to the insects of Britain and north Europe. Collins, London. Drabble, E. and H. (1927) The syphrid visitors to certain flowers New Phytologist 16: 105-109. G. Broad SBRC, Ipswich Museum, High St, Ipswich, Suffolk IP1 3QH
Trans. Suffolk Nat. Soc. 46 (2010)
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Trans. Suffolk Nat. Soc. 46 (2010)