Wilder Blean's invertebrate sorting volunteers

19th March 2026

If someone comes to Tyland Barn over the winter months they have a good chance of seeing several hardened Trust volunteers staring down microscopes looking at insects collected from West Blean & Thornden Woods. The aim is to separate the insects into various Orders (beetles, flies, moths etc) with these being sent to subject-matter experts, and to monitor changes in the insect population from 2021, including release of the European bison in 2022.

It all started when Kent Wildlife Trust asked for volunteers back in 2021 and, following a day’s training led by the head of Bedfordshire, Cambridgeshire & Northamptonshire Wildlife Trust, we were let loose on the samples. These were collected using a type of insect trap known as a flight intercept trap, with around seventy pots collected throughout the summer months from fifteen locations in the woods.

What have we found?

In terms of volume of numbers, the biggest factor so far appears to be the weather as the year-on-year change is quite variable, with 2021 and 2025 being the better years as regards the number of insects recorded. Before the Bison bridges have been built (two were built in 2025 with two more due to be completed in 2026/2027) only one of the trap locations was in the Bison enclosure so we haven’t been able to see any significant impact of the Bison to date, although we are hoping to see an increase in insect numbers in both numbers and diversity of species in the future due to the role of bison as ecosystem engineers, changing the vegetation and improving the habitat for other species. A section of the Kent Wildlife Trust website summarises the findings from 2021-2024.

In terms of individual specimens, the most interesting was initially a few male glow-worms (roughly one a year). Despite the name glow-worms are beetles, and the males of the more common of the two UK species fly but do not glow. These then look for the flightless females who glow on the ground. As the traps are located above ground it is unlikely we will capture any females.

Aenigmatias lubbocki

In 2025 however, another interesting specimen was found. One of the volunteers queried something small remaining at the bottom of the pot, and it turned out to be a member of the true flies, the Diptera, but unlike any we had seen before.

Experts at the Natural History Museum in London identified it as a female Aenigmatias lubbocki ((PDF) British Phoridae - introduction to genera). These are unusual as the females do not have wings and are carried by the male who has extra long legs to do so. We have since found the male in the same pot!

Blean invertebrate sorting volunteers ©️ Faye Hanscombe

If reading this blog post interested you and you would like to help... Kent Wildlife Trust is currently looking for UKBMS butterfly survey volunteers! Butterfly transect surveys are an extremely important method of robustly measuring changes in butterfly populations. Some of the existing transects have been carried out for many years, giving a fantastic amount of data on how our management of our reserves is helping butterflies.