[For explanations and definitions see here. Almost all of the data here is derived from NBN Atlas and the species information from Steven Falk's Flickr and the HRS website]

This is the last of the big months for hoverflies. Many species that peaked in previous months are still busily buzzing around, but the number of species at peak this month is a fair bit lower, at 41. The number reaching 10%opa for the first time is a big fat 0 (although there is one species waiting for September - I'll keep you in suspense!).

August is the best month to see....

...Cheilosia soror (45,-44%)

One of the three Cheilosia with fungus-feeding larvae - subgenus Eucartosyrphus - and the only one with orange antennae. Females of the subgenus are easily identified by the pale tip to the scutellum, so female soror is easy to determine by the combination 'pale-tipped scurellum + orange antennae'. Males are more challenging to identify. Be sure to get the best possible pictures of the eyes (not hairy), bristles on the scutum, the leg and antennae colour. Hairs under the hind femur also help with males.

This is the only Cheilosia that remains above 50%opa in September, and it can be seen on hogweed and later, ivy. Common as far north in England as the Wash, although uncommon in the south west peninsula and Wales. Scattered records as far north as Newcastle. Larvae have apparently been bred from truffles, but other fungi may well be used. Falk's pics

*TOP TARGET*

...Meligramma guttata (76,-100%)

This rare Meligramma has more the appearance of a Melangyna. It is most easily identified from females which have yellow stripes along the side of the scutum (like Sphaerophoria), and two yellow dust spots (often merged into one large spot) on the back of the scutum, in front of the scutellum. Males are harder to identify, but both sexes have particularly small markings on T2, and very little yellow on the hind margins of T4 and 5. The markings are more 'bar-shaped' than triangular, unlike Meligramma trianguliferum.

The species is widespread across Great Britain, but there are hotspots between Nottingham and the Yorkshire Dales, around County Durham and Tyneside, and the central belt of Scotland. Falk's pics

*TOP TARGET*

...Neoascia podagrica (7,-98%)

One of three Neoascia with clouded crosveins in the wing. It can be tentatively distinguished from the other two by not having oblique markings on T2, and not having markings on T4. But the best way to make sure is a clear picture of the underside of the thorax, showing the area in front of the hind coxae: no mean feat in such a small fly.

It is ubiquitous everywhere. The larvae live in wet manure and compost, or around the edge of ponds. The adults can be found with a sweeping net, but they do regularly visit low-growing flowers. Falk's pics

*TOP TARGET*

...Platycheirus peltatus (22,-96%)

As usual with Platycheirus the male front leg is key. Males in the peltatus-group of species are notable for their large paddle-shaped forebasitarsi. peltatus itself is larger than the other two, (amplus and neilseni) with larger markings on T2 A front view of the shape and hair tufts of the*middle* tibia is also valuable in distinguishing these.

Ubiquitous everywhere in Great Britain. Damp grassy areas and hedgrows.

...Sericomyia superbiens (27,-68%)

A hairy bumble-bee mimic, most similar to Mallota cimbiciformis - but the radial wing vein is straight. It is also similar to the oxycanthae form of the Spring-flying Matsumyia berberina, but the wings have a cloud.

Occurs north and west of a straight line from Weymouth to Scarborough, with an outpost in Norfolk. Visits flowers. Larvae are unknown, but probably develop in wet mud.

Also look out for Didea fasciata this month, which is very close to its peak - be sure to get a shot of the pale halteres!

The following species were discussed in July's 'First month you may find', but they peak now:

Triglyphus primus (59,-100%)

The following species were discussed in June's 'First month you may find', but they peak now:

Eristalis rupium (38,-71%)

The following species were discussed in May's 'First month you may find', but they peak now:

Cheilosia impressa (25,-81%)

Other species that peak in August [species in square brackets usually require microscopy to identify]:

Callicera aurata (67,-40%)
[C. carbonaria (79,-100%), C. cynocephala (71,-100%), C. latifrons (43,-100%), C. mutabilis (63,-100%), C. vulpina (47,-93%)
Dasysyrphus albostriatus (20,+53%), D. tricinctus (24,-45%)
Episyrphus balteatus (0,+45%)
Eriozona syrphoides (40,-64%)
Eristalis arbustorum (3,-41%), E. pertinax (1,+57%), E. tenax (1,+91%)
[Eumerus funeralis (34,-96%), E. strigatus (30,-99%)]
Eupeodes latifasciatus (19,-55%), E. luniger (8,0%)
Ferdinandea ruficornis (65,-100%)
Helophilus hybridus (16,-63%), H. trivittatus (17,-18%)
Leucozona glaucia (11,-33%)
Melangyna umbellatarum (35,-61%)
Meliscaeva cinctella (12,-49%)
Myathropa florea (4,+174%)
Paragus albifrons (85,-100%)
Pelecocera caledonica (92,-100%)
Rhingia rostrata (32,+32%)
Scaeva albomaculata (100,-100%), S. selenitica (37,-9%)
Sericomyia silentis (3,-48%)
[Syrphus vitripennis (6,-99%)]
Volucella inanis (18,+309%), V. zonaria (16,+1034%)

Posted on February 8, 2024 09:53 AM by matthewvosper