Friday 28 December 2018

2018 Wildlife Review: Flies

Nearly 580 true flies (Diptera) have been found within the Dawlish Warren Recording Area, but as proved this year there are still many more overlooked species to be found.

Spring saw three new species Bibio lanigerus, a St. Marks Fly, nectaring on Gorse blossom, Celery Fly Euleria heraclei a picture-winged fly with mines recorded in Hogweed later in the year, and at the end of May Empis stercorea, a brightly coloured Dagger Fly.

 Empis stercorea - Alan Keatley

In July a further three new species were found; the Band-eyed Brown Horsefly Tabanus bromius and two tachinid flies, Dexiosoma caninum and Thelaira nigripes.

The last two new species of the year were found and identified in September. One the aptly named Ivy Waspgrabber Leopoldius signatus can be readily identified, the other was a green bottle, Lucilia caesar, a common blowfly but difficult to identify without close examination. 

Although not new for the Warren, the continued presence of the nationally scarce soldier fly Ornate Brigadier Odontomyia ornata was good news but conversely there was no sign of the very rare and threatened cranefly, Geranomyia bezzii. Much of the habitat for this species was lost during the beach recharge, hopefully searches next year will be more successful.

More familiar species recorded included several Dark-edged Beefly Bombylius major in Spring, with the soldier fly Broad Centurion Chloromya formosa and the craneflies - Tipula fascipennis and Tipula lateralis present in good numbers. Also out in numbers the dune specialists Coastal Silver-stilleto Acrosathe annulata and Dune Robberfly Philonicus albiceps.  Later in Autumn both Noon Fly Mesembrina meridiana and Yellow Dung Fly Scathophaga stercoraria were numerous on flowering Ivy, providing a useful food source for migrant warblers.

Coastal Silver-stiletto - Alan Kealtley

As with other group migrants do occur, the pick of which was the third site record of Locust Blowfly Stomorhina lunata. This is a rare visitor from North Africa, and its appearance coincided with a large influx of migrant hoverflies.

The first hoverfly of the year was Striped-eyed Dronefly Eristalis tenax fresh out of hibernation on 17th February, but the exceptionally cold weather of over the next few weeks curtailed activity until Mid March. By then Marmalade Hoverfly Episyrphus balteatus had started to appear on flowering sallows and were joined by a new site record the Great Spring Cheilosia Cheilosia grossa.

Cheilosia grossa - Alan Keatley

By the start of April there were plenty of Tapered Dronefly Eristalis pertinax on the wing with several Furry Dronefly E. intricaria - a bumblebee mimic. The common Tiger Hoverfly Helophilus pendulus appeared at the end of April and remained in good numbers until mid October.

Other Spring species recorded included Bumblebee Hoverfly Volucella bombylans, Common Dainty Hoverfly Baccha elongata, Humming Syrphus Syrphus ribesii, Superb Ant-hill Hoverfly Xanthogramma pedissequumThick-legged Hoverfly Syritta pipiens and Epistrophe eligans, a new site record.

Large numbers of Long Hoverfly Sphaerophia scripta were on the wing in mid Summer, many of which were migrants, Other arrivals included Eupeodes luniger, Migrant Hoverfly E. corollae, Pied Hoverfly Scaeva pyrastri and more Marmalade Hoverfly.

As Summer progressed numerous Hogweed Cheilosia Cheilosia illustrata were feeding in the meadows with Large Tiger Hoverfly Helophilus trivittatus and Marsh Tiger Hoverfly H. hybridus, also present another overlooked new species for the Recording Area, Small Spotty-eyed Dronefly Eristalinus sepulchralis. In the more sheltered areas Batman Hoverfly Myrathropa florea and the territorial Large Pied Hoverfly Volucella pellucens were regularly recorded but there were only a few Hornet Hoverfly V. zonaria sightings.

Eristalinus sepulchralis - Alan Keatley

Late Summer and into Autumn saw both Striped-faced Dronefly Eristalis nemorum and Striped-winged Dronefly E. horticola on the wing, with Dasysyrphus albostriatus a further new species for the site.

With warm weather conditions continuing until end of October there were still several migrant species to be seen, joining the resident Dronefly species on late flowering Ivy.

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