Phaonia subventa (#976)

This is a new fly for the garden, from the genus Phaonia. These are medium-sized flies with a yellow abdomen, black body and bulge in the fore edge of the wing. They can be seen from early Spring through to November, with their larvae overwintering in rotting vegetation. Identification at species level is based on details of bristles on the legs and thorax, but I believe this one is P. subventa.

More Leaf Mines

Here are a couple more leaf mines, this time both are from flies. Phytomyza angelicastri is a leaf-miner found on wild angelica and also, as in this case, on Ground Elder. This is the first mine I’ve noticed here on Ground Elder, and is a new species for the garden. The similar-looking mine (but more “random” in direction) on Aquilegia (Columbine) is from Phytomyza minuscula. Many of these miners are very specific which leaves they will go for.

Twin-spot Centurion

This red and metallic-green Centurion fly got trapped inside the house. Called the Twin-Spot Centurion (Sargus bipunctatus) because if the two white spots on the front of its face, it is a late-flying member of this fly family, typically seen sunbathing on vegetation from September through to November.

Locust Blow Fly (Stomorhina lunata,903)

I photographed this fly feeding on mint flowers in the garden. With the yellow/black bands on the abdomen and boldly striped thorax, I believe it is Locust Blow Fly (Stomorhina lunata). This species is a visitor from the continent, where it is a predator of the egg pods of locusts (but ,they think, it doesn’t predate any UK grasshopper species). Not sure about its status in Gloucestershire, but although once rare in UK this fly has been turning up more frequently in recent years.

Four-barred Major (Oxycera rara, #884)

Looking superficially like a squat, little hoverfly, this male soldier fly is new for the garden. It is supposed to be found in damp places and near ponds, so it’s fitting that I rescued it from the paddling pool, where it was probably trying to cool off.

St Marks Fly

St Marks Fly (Bibio marci), sometimes called Hawthorn Fly, appears around St Mark’s Day (25th April) most years, and can be seen through to June. With its smoky grey wings, this is a female. These flies often appear in large numbers, especially around woodland edges, but only get them occasionally in the garden.

Dagger Fly: Empis opaca (#794)

This is my first “dagger fly” found in the garden; so-named because of its long beak. These come for nectar, as in this case on the flowers of a bramble, but are also predators. Courtship consists of the males offering prey to females, with the most favoured prey getting the girl. There are a few species, but this one with it’s reddish coloured legs (including the thighs) is I believe one of the commoner ones.

#794 Empis opaca

#794 Empis opaca

Bee Fly / Bombylius major

A proper Spring day brought our more insects, including this Dark-edged Bee Fly that was sunbathing on the fence, just next to the insect hotel. These flies are parasites of solitary bees, laying their eggs in the nests pf solitary mining and mason bees. They appear in the spring at the same time as the first mining bees. Usually bee flies are quite difficult to photograph as they fly really fast, but it was still quite cold at lunchtime when I saw this one, so it did not seem too bothered by me getting up close with my phone to get a photo.

#443 Dark-edged Bee Fly (Bombylius major)

#443 Dark-edged Bee Fly (Bombylius major)

Asian Fruit Flies

These tiny fruit flies appeared on a coconut shell I hung out for the birds. When I was a kid we sometimes put these out for the blue tits, but it seems “Generation Alpha” garden birds prefer sunflower hearts and fat balls, as the coconut is not getting much interest. Anyhow checking the flies, they are Spotted Wing Drosophila (Drosophila melanogaster), which is an Asian species that was first recording only in UK in 2012. These are not becoming (yet another) imported garden pest as these fruit flies do not just go for rotten or blemished fruit, but the female cuts into health fruit to lay its eggs, with the larvae then eating the fruit from the inside. The flies go for cultivated soft fruits, but can also be found in wild hedgerow blackberries and sloes. I tend to think that my fruit flies probably came from the coconut itself, but maybe not and they are from an established wild population.

#713 Spotted Wing Drosophila (Drosophila melanogaster)

#713 Spotted Wing Drosophila (Drosophila melanogaster)

Spider & Fly

I’d never realised how bristly flies can be. This black and orange Tachina fera caught sunning itself on the wall has some impressive bristles. This Tachanid fly is a parasitoid, it’s larvae eating moth caterpillars from the inside. I suppose the bristles are sensory organs, maybe to give some early warning if a spider is coming up close behind? The spider here is a new genus for the garden, Tetragnatha, but as quite often with spiders it’s hard to get down to an individual species as there are very similar species, which all vary considerably in colour. These are orb-weaver spiders that often stretch out lengthwise, with their long legs in front, to hide on plant stems.

Band-Eyed Brown Horsefly - Tabanus bromius (#654)

I risked life and limb hanging out of my upstairs window to snap this blood-sucking horsefly that landed on the outside of the glass. It is a Band-Eyed Brown Horsefly (Tabanus bromius), in this case a female with its rather amazingly patterned eyes. You have to wonder if this banding on the eye serves any purpose, or is just decorative. It’s the female horseflies that bite, in order to get blood. Usually they go for cows or horses, but sometimes also people. Band-eyed Brown Horsefly is common in the southern part of UK, but rarely found North of the Midlands.

Semaphore Fly - Poecilobothrus nobilitatus

This fly is easily recognised by its wings which are smoky black from about half way, with (in the male) distinctive white tips. They are usually found close to water, where they feed by catching small freshwater crustaceans and mosquito larvae from the surface. They have a complex courtship dance involving the male waving his wings at the female (hence the “semaphore” name) and then hovering in front of her, before embarking on an aerial display flight.

Weekend Finds

This weekend there were a few new bugs about. This rather fine leaf mine on a Nasturtium leaf is from the larva of a fly, probably Pea Leaf-miner, Chromatomyia horticola (#616), though there is another species with an identical mine. Chromatomyia horticola mines leaves of different plants, which include Sow Thistle and Garden Peas, both of which I find in the garden with similar narrow white mines.

The smart-looking black & grey fly appears to be Anthomyia procellaris (#617), due to the placement of the block spots. It is not an uncommon fly, often found sunbathing - in this case on my potato plants. Its larval life-cycle is not really known.

The moth trap was fairly quiet on Sunday morning, with this rather burgundy-tinted Middle-barred Minor (Oligia fasciuncula, #615) the only new species caught. On Saturday night I noted several insects flying around the light turned which I thought were stripey micro moths, but it turns out hey were my fist species of caddisfly, the aptly named Long-horned Caddisfly (Mystacides longicornis, #618). Caddisflies are usually associated with water, where their larvae live in a case made from bits of sand and gravel. My garden is quite far from any stream, so either these insects roam further than you might expect, or maybe they are from one of my small garden ponds.

Flies in the Afternoon

Even when there’s not much to look at in the garden, there are always flies. Aside from the house flies, these are two of the commoner ones, the Common Greenbottle (Lucilia sericata) and the Common Flesh Fly (Sarcophaga carnaria). As the name indicates, the larvae of flesh flies mostly live on dead animals, while the green-bottle is less fussy and will also go for faeces and rotting fruit.

For both groups, identification at a species level is difficult and requires a microscope, as there are a few very similar species. However for the greenbottle this one has the right pattern of hairs on its thorax for Lucilia sericata, which is also the commonest species of greenbottle fly. Although both are flies, and their larvae feed on similar things, their lifecycles are quite different. The greenbottle lays eggs which then hatch into larvae; but the flesh fly is ovoviviparous, the eggs developing in the uterus of the female before they are deposited as larvae on a suitable food source.