What is it?
Whilst most of the leeches you will encounter in the UK are a natural part of your ponds' ecosystem and doing no harm to other wildlife, since 2020 we've been receiving unusual reports of leech predation on amphibians from a small number of quite widely spaced locations in Southern England. In each case there were reports of leeches apparently feeding on common toads (Bufo bufo) and common frogs (Rana temporaria). Affected toads had leeches attached to their eyes, throat and axillae; the frogs seem less affected on their face, but are targeted across their flanks and underside. There have also been reports of newts being affected in a similar way.
Rather puzzled by these unusual reports of leech predation, our volunteers at the Hampshire and Isle of Wight ARG (HIWARG) reported these cases via the Garden Wildlife Health (GWH) portal for their input. The wildlife vets at GWH were collaborating with the Natural History Museum and Buglife who made tentative suggestions regarding the species involved based on morphological similarities; however, in order to confirm the identity of the leech species in each incident, molecular methods are required and are in progress.
To date, there are very few records, but last year HIWARG volunteers reported leech predation on amphibians across the eastern half of the Isle of Wight and they are continuing their investigations there this year. Whether this is a new occurrence, or if recent reports reflect increased awareness, is so far unknown.
How can you help?
The power of the volunteer ARG network is many eyes on the ground - boosted by all our lovely garden pond owners. So please do keep a look out, and if you spot something similar contact us at This email address is being protected from spambots. You need JavaScript enabled to view it. or contact the Garden Wildlife Health Project directly. If possible, take photos and contact them regarding potential submission of a fresh leech sample.
Amphibian recovery - we have had some volunteers take the toads in and carefully help restore them to full health! So there is hope, but its painstaking work!!
Now published!
We are delighted to be able to rpeort that this ground breaking work is now published in The Herpetological Journal and can be downloaded here
Citation:
Seilern-Macpherson, K., Lawson, B., Macadam, C.R., West, P., Reed, N., Gibson, L., Świątek, P., Gajda, Ł., Cunningham, A.A., Heaver, J. and Julian, A.M., (2024) Predation of anurans in southern England by Batracobdella algira, a leech previously unknown in the UK, Herpetological Journal, Volume 34 (October 2024), 221–227, https://doi.org/10.33256/34.4.221227
