Worcestershire Record No. 19 November 2005 p. 4


Mike Averill

This summer was generally warm and dry and gave good opportunities for observing insects. The months from April to September all had below average rainfall with long periods of sunny weather. Dragonflies particularly are seen to be more active in such conditions. The first herald of dragonfly activity was very early with the first sightings of Large Red Damselfly Pyrrhosoma nymphula on the 14th of April.

Concerns about low numbers of emerging Club-tailed Dragonfly Gomphus vulgatissimus at Bewdley on the River Severn over the last four years, led to simultaneous surveys on the Severn, Wye and Avon to see if anything unusual was happening on the Severn. The results were very close showing that although the Bewdley numbers were similar to the Wye, they were somewhat lower than the Avon. There is still the question as to why the Bewdley emergences are only a quarter of what they used to be in previous years. The Bewdley survey will continue next year to monitor the situation. The full results of these surveys are planned to be published in a later issue of Darter.

A long sunny summer nowadays means that there is always the prospect of immigrant dragonflies, usually darters, however this was not the case in Worcestershire on 2005 where no Red-veined Darters Sympetrum fonscolombii were reported. After the arrival in neighbouring counties of the Small Red-eyed Damselfly Erythromma viridulum, searches were made but none were found in Worcestershire. It is just a matter of time and once again it will be worth looking next year at lakes with associated Water Milfoil, Hornwort and other similar water weeds.

One vagrant that was seen again and only for the second time in the county, was the Lesser Emperor Anax parthenope. This insect was briefly seen at Pirton on the 23rd of June and it was part of an influx spreading from South Wales, to Devon, Buckinghamshire and later even to Yorkshire and Gloucestershire. These large insects may only be briefly seen at sites as they move around the country and so it is always worth taking a second look at any emperors that are seen. The key points to notice as the male insect flies away from the observer is the block of blue on the upper abdomen, which stands out against the remainder of the abdomen which appears dark off-brown coloured. The eyes appear green and the wings may be suffused with a brownish tinge.

The Common Hawker Aeshna juncea is, despite its name, not that common in Worcestershire, but an ovipositing female was seen at Bishop’s Wood Educational Centre on the 2nd September.

Last year there was much excitement about the sudden explosion of records of the Scarce Chaser Libellula fulva on the River Avon. This year it was with interest that those sites were revisited, but the general impression was that although they were seen in all the same locations again, they were less numerous and there was no range expansion. It remains to be seen if this new colony is to be short lived or not.

The mild weather lasted well in to the autumn and Common Darters Sympetrum striolatum were seen up to mid November when the first cold snap of the year began to bite.

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