Lesser Emperors at Wentwood reservoir in July 2023: the first breeding records for the county

by Steve Preddy (photograph by Lee Gregory)

As part of their work with Newport City Council, Lucy Arnold-Matthews and Ollie Jenkins-Boobyer spent the early part of summer 2023 carrying out a review of sites of nature conservation importance. On a visit to Wentwood reservoir, they were impressed by the numbers of dragonflies present, and invited me to accompany them on a repeat visit on 7 July to compile a more complete species list. The reservoir is slowly filling again after being drained a few years ago, and as a result is a sizeable body of quite shallow water, with much surrounding vegetation. As we approached the water, it was obvious that there were very large numbers of dragonflies present again. Particularly noticeable were the numbers of Emperor Dragonfly (Anax imperator), with at least 20 along the western side of the reservoir alone. I mentioned Lesser Emperor (A. parthenope) to Lucy and Ollie, as I was aware that this was a potential colonist of the county.

After exploring both the west and east sides of the reservoir, we started to head back along the southern side of the resrvoir to our starting point, when a male Lesser Emperor stopped us in our tracks. We saw it briefly, and then it (or another male) appeared, this time copulating with a female; these then flew off, and a male appeared again. We temporarily doubted exactly how many we’d seen, but we spread out along the base of the dam wall and all three individuals (the copulating pair and the original male) gave repeat viewings over the next half an hour or so. The female was seen to oviposit.

I spread the word, and Lee and Cath Gregory visited later that day and also saw one or more of the dragonflies in a similar area; one of Lee’s photos accompanies this article. All three individuals were identified by the combination of mid-green eyes, a dark purplish-brown thorax without any green markings, bright pale blue on two to three basal segments of the abdomen and the remainder of the abdomen dark brownish-grey. No variation was noted between the males; the colours of the female’s thorax and abdomen were a more washed-out greyish-brown rather than the more intense dark colour shown by the males.

A Lesser Emperor at Wentwood reservoir in July 2023, photographed by Lee Gregory
A Lesser Emperor at Wentwood reservoir in July 2023, photographed by Lee Gregory

With the establishment of populations at Slimbridge in Gloucestershire, at Chew Valley Lake near Bristol, and on the Somerset Levels, and three individual males in Monmouthshire previously (at Lamby Lake and Ynys-y-Fro reservoirs), it was only a matter of time before we had our first breeding record here. Note that Lesser Emperor spends two years in the larval stage, so a little patience may be needed before we find out if the species has become an established feature of the county’s dragonfly fauna.

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