Wildlife at the North Elmham Cathedral Meadows

Mayflies

Species recorded since April 2018: 10.

Coverage: poor: mayflies are attracted to light and are often recorded (here) as by-catch when moth-trapping. More intense light-trapping would certainly increase the number of records and the number of species recorded. There are a few day-time records but more intense survey-work would no doubt uncover more records. Identification confidence is moderate: some species are relatively easy to identify but others are trickier and the only comprehensive identification guide available is not as helpful as it should be.

Mayflies are attractive and fascinating insects that don’t get the attention they deserve. They are unusual among insects in that once they moult after they have attained adulthood. The first adult stage is known as “sub-imago” (and in many cases these can be recognised by their smoky-grey wings, duller colours and shorter tails) and then after their moult they are known as “imago” (the two stages are also known as duns and spinners, particularly by anglers). When mayflies reach adulthood their lives are nearly over with many species not usually surviving more than a few hours.

All photos below are of insects found at the Cathedral Meadows.

BAETIDAE

Pale Watery Baetis fuscatus

A common species locally but only the yellow-eyed males are straightforward to identify.

male sub-imago and male imago Pale Wateries Baetis fuscatus, 15th September 2019

probable female Pale Watery Baetis fuscatus (sub-imago in first photo then after moult to imago in second photo), 28th August 2018

Small Spurwing Centroptilum luteolum

A small species that often comes to light locally.

male Small Spurwing Centroptilum luteolum (sub-imago in first photo then after moult to imago in second photo), 7th August 2020

female Small Spurwing Centroptilum luteolum (sub-imago in first photo then after moult to imago in second photo), 7th August 2020

Pond Olive Cloeon dipterum

A very common species locally.

female Pond Olive Cloeon dipterum (sub-imago in first photo then after moult to imago in second photo), 12th August 2018

Lake Olive Cloeon simile

Difficult to separate from the next species and past records are best regarded as tentative and in need of confirmation.

probable female imago Lake Olive Cloeon simile, 7th July 2019

Pale Evening Dun Procloeon bifidum

Difficult to separate from the previous species and past records are best regarded as tentative and in need of confirmation.

probable male Pale Evening Dun Procloeon bifidum (sub-imago in first photo then after moult to imago in second photo), 7th August 2020

probable female Pale Evening Dun Procloeon bifidum (sub-imago in upper photo then after moult to imago in lower photo), 25th May 2019

CAENIDAE

The common name Angler’s Curse is applied to any of a number of very similar species in the genus Caenis, at least two of which are likely to be common at the meadows. So far most of those that have been identified have proved to be Caenis horaria but these are probably the hardest of all the local mayflies to identify. They are very small, readily come to light at night but are very short-lived (as adults) and can be expected to be dead by the end of the night.

Caenis horaria

The species of Angler's Curse identified the most at the Cathedral Meadows so far.

Angler’s Curse Caenia horaria, 2nd June 2021

Caenis luctuosa

The species of Angler's Curse identified the most at the Cathedral Meadows so far.

Angler’s Curse Caenia luctuosa, 2nd June 2021

EPHEMERIDAE

These relatively large mayflies are the species most likely to be encountered during the day.

Green DrakeEphemera danica

On warm summer evenings they can sometimes be seen swarming along the bottom of the Cathedral Meadows or especially along the more open parts of the railway engaging in their fascinating display flight.

Green Drake Ephemera danica, 25th May 2018

Drake Mackerel MayflyEphemera vulgata

This relative of the Green Drake is commoner along some river valleys in Norfolk but isn’t usually found so easily in the Wensum (or Yare) Valleys. Nevertheless a displaying swarm of at least 20-25 were seen along the railway and East Field in late spring 2021 (and a few records of smaller numbers over the following days).

Drake Mackerel Mayfly Ephemera vulgata, 31st May 2021

EPHEMERELLIDAE

Blue-winged OliveSerratella ignita

One of the commonest mayflies locally.

male Blue-winged Olive Serratella ignita (sub-imago in first photo then after moult to imago in second photo), 15th September 2019

female imago Blue-winged Olive Serratella ignita, 18th July 2020