Wednesday 4 January 2023

Wildlife Review 2022 - Flies

It was a relatively poor year for Diptera with 126 species recorded compared with 140 in 2021, although the total does include 10 new species. The Recording Area audit (including hoverflies, covered tomorrow) currently holds records for 702 species.

Similar to other groups, the dry conditions throughout the year affected the life-cycle of many species. For example, various craneflies and the nationally scarce Ornate Brigadier, that require moist soil conditions, were not recorded this year. 

Several flies are winter active, the bluebottle Calliphora vicina and Yellow Dung-fly Scathaphaga stercoraria could be seen on sunny days in January, but a Downland Bibio B. anglicus on 20th, an exceptionally early date for this spring flying species, it was also a new species for the Recording Area. Other Bibio flies appeared on schedule with Bibio johannis on 17 Mar, Bibio lanigerus on 24th and the larger, more familiar St. Mark's Fly Bibio marci on 24 Apr, numbers of which, although up, remain a fraction of what they once were.

Calliphora vicina - Alan Keatley

The first cranefly of the year was Limonia nubeculosa on 10 Feb, but only another seven cranefly species, and the phantom cranefly Ptychoptera contaminata, were identified during the year including Tipula lunata on 18 Apr, although common and widespread, a new species for the Warren.  

Tipula lunata - Alan Keatley

On 23 Mar a Yellow-faced Blowfly, or more dramatically the Fly-of-the-dead Cynomya mortuorum was found nectaring on a sallow on Warren Point. A new species for the Recording Area and just the second South Devon (VC3) record. It is so named because the maggots fed on dead animals and was previously considered very useful in the field of forensic science.

Yellow-faced Blowfly Cynomya mortuorum - Alan Keatley

A migrant Locust Blowfly Stomorhina lunata found on 14 Jul, continued a run of sightings in recent years. 

Locust Blowfly Stomorhina lunata - Alan Keatley

Empid or Dagger Flies are typically found in spring nectaring on dandelions and umbellifers. Four species were recorded this year with Empis tessellata from 22 Apr, Empis stercorea and E. trigamma from 19 May and Empis livida from 8 Jun.

Empis stercorea - Alan Keatley

Several Thick-headed Flies (Conopids), parasites of bees and wasps, were found including a new species for the Recording Area, a Plain-winged Spring Bee-grabber Myopa testacea on 24 Apr. Others weren't active until July with Ferruginous Bee-grabber Sicus ferrugineus from 5th, Four-banded Bee-grabber Conops quadrifasciatus from 10th, and Waisted Bee-grabber Physocephala rufipes from 14th.

Waisted Bee-grabber Physocephala rufipes - Alan Keatley

The second site record of Small Bee-grabber Thecophora atra was seen on 13 Aug and the second site record of Ivy Waspgrabber Leopoldius signatus on 15 Sep, with several others before the end of the month.

Small Bee-grabber Thecophora atra - Alan Keatley

Robberflies (Asilidae) are predatory hunters active from spring into autumn. Five species were recorded this year, Dune Robberfly Philonicus albiceps from 30 Apr, Fan-bristled Robberfly Dysmachus trigonus from 7 May, and Kite-tailed Robberfly Tolmerus atricapillus from 12 May; these three are mainly ground hunters. 

Kite-tailed Robberfly Tolmerus atricapillus - Alan Keatley

Preferring to hunt from vegetation; Striped-legged Robberfly Dioctria baumhaueri from 19 May and Common Red-legged Robberfly D. rufipes were seen from 22 May. A frequent prey item of Dune Robberfly, Coastal Silver-stiletto Acrosathe annulata were on the sand dunes, also from 30 Apr.

Striped-legged Robberfly Dioctria baumhaueri - Alan Keatley

Two species of Snipefly (Rhagionidae) were found this year, the first on 5 May, the common and widespread Downlooker Snipefly Rhagio scolopaceus was new for the Recording Area. The other, Small Fleck-winged Snipefly Rhagio lineola was on the wing from 20 Jun. 

Downlooker Snipefly Rhagio scolopaceus - Alan Keatley

Despite the absence of the Ornate Brigadier, six Soldierfly (Stratiomyidae) species was a good return with Green Gem Mircochrysa flavicorni from 7 May, Broad Centurion Chloromyla formosa from 27 May, Flecked Snout Nemotelus notatus and Dark-winged Black Pachygaster atra from 1 Jul, Twin-spot Centurion Sargus bipunctatus from 17 Sep and a Bright Four-spined Legionnaire Chorisops nagatomii on 6 Oct. 

Flecked Snout Nemotelus notatus - Alan Keatley

The first Dark-edged Bee-fly Bombylius major were on the wing on 2 Apr, with a few more sightings around woodland edges this year.

Dark-edged Bee-fly Bombylius major - Alan Keatley

A wide variety of flies are parasitoids or parasites on other insect groups, these were represented by the flesh flies (Sarcophagidae), Thelaira nigripes (moths) on 12 May, Tessellated Satellite-fly Miltogramma germarilaying eggs in solitary bee nests from 16 Jul, and Dark-palped Shadow Fly Senotainia conica observed entering nests of Spiny Digger Wasps, to lay eggs on captured flies, from 11 Aug.

Dark-palped Shadow Fly Senotainia conica - Alan Keatley

The Sciomyzid Common Buff Snail-killer Tetanceri ferriginea was frequently noted from 26 May with Tachinids emerging later in the year including Dexiosoma caninum (beetles) and Eriothrix rufomaculata (moths) on the hunt from 21 Jul, and a female of the nationally scarce Ectophasia crassipennis (bugs) seen on 22 Sep, the second site record for a species which was first recorded in the UK in 2019

Ectophasia crassipennis - Kevin Rylands

The heaviest fly in Europe, the Dark Giant Horsefly Tabanus sudeticus was recorded on 8 Jun, but whilst a relief to some, the lack of biting cleg records this year is of concern. Records from the Muscid family this year included one of the orange species Phaonia subventa on 25 Mar, the greenbottle Lucilia sericata from 14 Jul, and again late and in low numbers, Noon Fly Mesembrina meridiana from 11 Oct.

Dark Giant Horsefly Tabanus sudeticus - David Flack

Several families have patterned or pictured wings, which are often used in elaborate courtship rituals. The following species were recorded this year, Oxtongue Tephritid Tephritis vespertina from 12 May, Small Semaphore Fly Rivellia syngenesiae from 22 May, Burdock Fly Terellia tussilaginis from 1 Jul, a Looped Flutterfly Palloptera muliebris on 29 Sep, Opomyza germinationis on 10 Oct, Geomyza tripunctata on 25th and Geomyza subnigra, the final new species of the year, on 31 Oct.

Looped Flutterfly Palloptera muliebris - Alan Keatley

Those species that are gall causers or leaf miners make up the bulk of records, including some of the above groups. Despite over 40 species being recorded it was a poor year with many food plants shrivelling their leaves or dropping their flowers early due to the drought. 

Three new galls were however discovered in the Recording Area, Resseliella betulicola, a birch leaf gall midge on 13 May, Germander Speedwell Gall Midge Jaapiella veronicae on 1 Jun, and Wild Carrot Gall Midge Kiefferia pericarpilcola on 23 Jul.

Galls of Wild Carrot Gall Midge Kiefferia pericarpilcola - Alan Keatley

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