Foxhill Farm: around the big pond

A lovely, sunny day, so I decided it was time to pay another visit to Foxhill Farm, this time concentrating on the new lake. I got off to a bad start as I have mislaid my pond-dipping net, but I went ahead anyway.


There is a broad margin of vegetation around the pond and it was supporting large numbers of insects. Every thistle and sow thistle was covered in flies - but they were overwhelmingly of one species: Eriothrix rufomaculata. This is one of the first species a would-be Tachinid enthusiast will encounter, the size if a rather large house fly and with its rust-red abdominal flanks it is instantly recognisable. (In truth there are a couple of other species broadly similar but they are much less common.)

Eriothrix rufomaculata is abundant during the summer months

The Tachinidae are flies with parasitic larvae which are in fact usually parasitoids, i.e. their attack leads to the death of the 'host'. In the case of E. rufomaculata the host is usually a caterpillar of a crambid moth, a tiger moth, a lappet moth or one of the ermine moths.


Clumps of Scentless Mayweed, Tripleurospermum inodorum, were particularly favoured by the Eriothrix.

Scentless Mayweed formed large clumps on the land surrounding the

pond. Foxhill Farm, 12 July, 2020

This extremely common weed of disturbed or waste ground flourishes perhaps because it is unpalatable to livestock. Apparently its sap contains an anti-viral agent that inhibits the growth of polio and herpes viruses. The flowers are too tatty to give it garden merit, but that doesn't bother insects.

Scentless Mayweed has rather tatty flowers but are much visited by

small flies.

I was pleased to note that Purple Loosestrife, Lythrum salicaria,  had gained a foothold. It is certainly less common than a century ago  but is still frequent beside suitable bodies of water.

The Purple Loosestrife belongs to the Lythraceae family.

Foxhill Farm, 12 July, 2020

Oddly enough Dotted Loosestrife, Lysimachia punctata, was also growing at the pond side. It is not at all related to Purple Loosestrife and is a garden perennial which has become well established in many locations. Unlike the  native Yellow Loosestrife, Lysimachia vulgaris, its leaves are stalked, i.e. with petioles.




The Yellow Loosestrife is a member of the Primrose family, Primulaceae.

Foxhill Farm, 12 July, 2020

Oddly enough, the walk to and from the pond took me through a hayfield overwhelmingly consisting of Rye Grass, Lolium perenne or a closely related taxon bred for the grazing.

It was predictably poor in insects but yielded many spiders, largely of the Money Spider family, Linyphiidae. These are a microscope job and will be dealt with when time allows.(In fact they turned out to be largely Erigone atra.)


This pond will ultimately become important for wildlife but was only constructed a couple of years ago. We must be patient