October 2019

I found a new fly last month.  It was sitting on a wild carrot flower and there was something striking about it that made me get the camera and take some photographs. 

Ectophasia crassipennis

When I opened up the Facebook group to try and identify the fly, there was a picture of an identical fly with the comment ‘This is the 8^th or 9^th record we’ve had this year – mostly from Devon and Cornwall and one from Sussex.  It is new to the UK this year.’  So my fly was only the 9^th or 10^th record for the UK and the second for Sussex.  The fly goes by the name of Ectophasia crassipennis.  It doesn’t have a common name.  Its traditional range has been in southern Europe and the warmer parts of central Europe but it now appears to be expanding its range, or moving its range farther north due to the acceleration of global warming (which is now often called global heating to emphasize just how serious it is).

The fly Ectophasia crassipennis, is a tachinid fly.  This is a large group of flies (about 270 species in the UK) that parasitize other species.  They are parasitoids, rather than parasites – the difference being that parasitoids kill or fatally weaken their hosts whereas parasites take resources from their hosts but don’t kill them (like the stylops I described in a previous Nature Notes).  Some tachinids parasitize butterfly or moth caterpillars, but this species parasitizes hemiptera, for example, shield bugs.  They lay their eggs on the back of the insect where they can’t be reached and when the larvae hatch they burrow into the insect and eat it from the inside.

Tachina grossa

Incidentally, on a recent trip to Braunton Burrows in Devon to survey bumblebees we found another tachinid fly – Tachina grossa – it is the biggest and ugliest fly I have ever seen, as big as a bumblebee and being black and hairy, also resembles one.  That particular fly lays eggs on hairy caterpillars like the oak eggar moth with eventually fatal consequences for the moth.

I seem to have seen more hornets in the garden recently.  Normally we get the occasional one preying on the wasps eating windfall apples, but recently I have regularly seen one hunting round our meadow area.  A week or two back we put out the moth trap to see what late summer species were about.  Imagine my surprise when I looked in the trap the following morning and found more than a dozen hornets in there.  This made emptying the trap a much more hazardous task than usual.  They were all a bit dopey and most flew off as I pulled the egg boxes out.  A couple of them ran out of energy and subsequently died, but judging by the moth wings in the bottom of the trap, none of them had gone hungry during the night.  Seeing so many hornets, as well as the hornet rove beetle I described in last month’s column, suggests that there was a colony nearby, possibly in the wooded area at the bottom of Elm Lane as that is the direction I have seen them fly off in.

European Hornet - Vespa crabro

September 2019

Green Shieldbug nymph

It’s been a busy month in the insect world as you would expect at this time of year and we’ve seen many new species – new as in insects we haven’t seen or noticed before.  The hemiptera have been well represented – this group of insects, as the name suggests have half the wing membranous and the other half hard like a beetle.  Shield bugs are typical hemiptera.  We have seen Hairy Shield-bug, Green shieldbug and a Black-kneed capsid bug.

There have also been a couple of tiny ones that only have latin names so I won’t bore you with those.  I found one hemipteran bug called an Ant Damsel bug which looks like an ant but isn't one that I didn’t know existed until I looked on a Facebook Group to identify the others.

The pond has attracted 5 species of dragonfly, and one or two emperor dragonfly females have been laying lots of eggs in the pond, so that bodes well for future years.  The moth trap has given us at least 3 species that we’ve not seen before as well as a mayfly, an hemipteran bug and two new beetles.

Ant Damsel Bug nymph

Mayfly - Cloeon dipterum

Hairy Shield-bug nymph

The most interesting beetle was called a Hornet Rove Beetle.  Rove beetles are the sort of radical wing of the beetle party and choose not to look like beetles at all.  They don’t bother with wing cases to cover the whole of their abdomen and could easily be mistaken for an earwig.  The wing cases are very short (typically less than a third of the length of the abdomen) so that the wings have to be folded up to fit into the small space.  These obviously take longer to deploy than normal rigid wings which perhaps explains why rove beetles tend to run rather than take flight.  Probably the best known type of rove beetle is called the Devil’s Coach Horse. 

Devil's Coach Horse (Staphylinus olens) in threat pose

This is a fearsome looking insect with powerful mandibles and will raise its tail in a threatening scorpion-like manner should you approach it.  If you ignore the threat it will give you a painful bite and probably emit a foul odour from the white scent glands on its tail.

The Hornet Rove Beetle is a similar looking insect – in fact, I thought it was a devil’s coach horse at first.  It is however much broader and stockier than the devil’s coach horse and used to be very rare, but as hornets are extending their range, so are the hornet rove beetles.  This is because the hornet rove beetle spends most of its time in hornet nests where they feed on the detritus inside the nest and are presumably tolerated by the hornets for providing this clean-up service.  It is a strong flier with a keen sense of smell (which enables it to find hornet’s nests in the first place) and when it runs out of food in the hornet’s nest it can fly considerable distances in search of other insects and invertebrates.  It does this extra-mural foraging at night which explains how it ended up in the moth trap.

And for those who think I don’t get out enough – I found a very interesting fly in Philippa’s garden.  Whatever the bush is called that it was found on, it must be a very good nectar source because it had attracted a large number of flies.  This particular fly is one of the picture-winged flies that often have interesting markings on their wings – in this case the wings were rather plain but it did have rather striking stripy red eyes.  It goes by the catchy name of Physiphora alceae.

Hornet Rove Beetle -  Velleius dilatatus

Picture-winged fly - Physiphora alceae

Black-kneed Apple Capsid - Blepharidopterus angulatus

Miridius quadrivirgatus

Stenodema (Stenodema) laevigata