Blaencaerau [SS8694] - 100 species of hoverfly

The Blaencaerau 1km square is the second square in the valley where I have recorded 100 species of hoverfly, following on from Garnwen (SS8392) in 2018. The area comprises of damp grassland and sparse sallow woods on former colliery spoil, surrounded by upland moorland and conifer plantation, with 2 small rivers flowing through the square. The area is 250mts above sea level and is rich in flora from March through to October.

Records begin in week 11 (Mar 12-18), when small numbers increase rapidly from week 20 (May 14-20), peaking in week 24 (Jun 9-15), than after a lull in numbers between broods around week 28 (Jul 7-13). Numbers really pick up with the summer brood and stay high thereafter until week 38 (Sep 17-23) and then drop off rapidly with no new flowers blooming, making it difficult to detect any new species. The last records come from week 40 (Oct 1-6).


Spring   (Mar-May)

Main feeding flowers   -   Dandelion, Dogwood, Hawthorn, Meadow Buttercup, Sallow

Specialist species of the season   -   Anasymia contracta, Cheilosia albipila, Chrysogaster virescens, Criorhina floccosa, Didea fasciata, Eumerus strigatus, Melangyna lasiophthalma, Parhelophilus versicolor, Platycheirus tarsalis, Xanthogramma citrofasciatum.



Summer   (Jun-Aug)

Main feeding flowers    -   Bramble, Creeping Thistle, Fine-leaved Water Droplet, Grasses, Hogweed.

Specialist species of the season   -   Cheilosia carbonaria, Cheilosia longula, Chrysotoxum cautum, Eriozona syrphoides, Megasyrphus erratica, Microdon myrmicae, Parasyrphus lineola, Pipizella viduata, Platycheirus manicatus, Sericomyia lappona.



Autumn   (Sep-Nov)

Main feeding flowers    -   Angelica, Common Fleabane, Common Ragwort, Devilsbit Scabious, Goldenrod.

Specialist species of the season   -   Chrysotoxum arcuatum, Eristalis intricaria, Eristalis rupium, Eupeodes latifasciatus, Ferdinandea cuprea, Rhingia rostrata, Scaeva pyrastri, Scaeva selenitica, Sericomyia silentis, Xanthogramma pedissequum.



*****     Species marked in red are rare for Glamorgan and even Wales in some cases.   *****

Maesteg cemetery Ivy

Being the last fine day for a while I went and checked out the Ivy, but only about 50% had bloomed and combining the time of the year where numbers drop dramatically, I only recorded 12 species. Platycheirus clypeatus was new for the year (number 102), while the most numerous was Eristalis tenax (85). Other records included Rhingia campestris (1), Myathropa florea (1), Volucella pellucens (1) and an Eumerus species that got away which would probably been new for the valley.

No other interesting insects or birds were noted. Surprised there were no Ivy Bees amongst the 30 Honey Bees.

 Syrphus ribesii

Eristalis tenax

The DBS patch still going strong

Re-visited the Devils-bit scabious patch again on Tuesday after work, with hoverfly numbers still high. Saw all the species I saw on Saturday plus further species in Chrysotoxum arcuatum, Eristalis rupium and Helophilus trivittatus. Sericomyia silentis numbers reached double figures also. A single very late Hogweed plant also produced a very late Cheilosia illustrata. Also present were the conopid flies Physocephala rufipes and Sicus ferrugineous.

 Chrysotoxum arcuatum

 Helophilus trivittatus

 Cheilosia illustrata

Physocephala rufipes

Blaencaerau Devils-bit Scabious patch

It's the time of the year when hoverflies start to die off rapidly and are all but gone by early October. But not today due to the cool fine weather I recorded 26 species albeit in mainly small numbers on the DBS patch near the stream coming down through the forestry. Ferdinandea cuprea was new for the year, but more importantly it was my 100th species for the Blaencaerau 1km square, the second square in the valley following in the footsteps of Garnwen in 2018. Eristalis tenax (110) was the most numerous whilst there were good records in the form of Rhingia campestris (14), Rhingia rostrata (1), Eristalis intricaria (2), Sericomyia silentis (9), Volucella bombylans (1 late record) and Volucella pellucens (1 latish record).

I was so busy searching the DBS (possibly a 1000 flower heads) that I didn't see many other insects except 7 species of butterfly headed by Small Copper and a migrant Silver Y moth.

 Part of the Devils-bit Scabious patch, which is about 300mts by 100mts in size.

 Small Copper

 Eristalis horticola

 Eristalis intricaria

 Rhingia campestris

 Sericomyia silentis

 Volucella bombylans - late record

 Volucella pellucens

Ferdinand Cuprea - a species rarely seen, it has a symbiotic relationship with the Goat Moth, its larva live in the wound/sap runs of trees caused by the infestation of Goat Moth larva, which is a species not yet recorded in the valley, so I'll be keeping an eye on the nearby trees next year.

weekly round up

The last week of August was a lame duck for hoverflies with only 49 species recorded during the whole week, whereas I would expect about 60 species. Today was much better up Top Llan though with good numbers of Eristalis tenax (65), Eristalis arbustorum (50) and Eristalis pertinax (45). Eristalis intricaria was my 100th species for the year and good records included Chrysotoxum arcuatum (2), Eristalis rupium (1) and Riponnensia splendens (1). There was also 20 Rhingia campestris which has been rather scarce this year, with 12 on a single Buddleah Bush and the rest on Heather and Black Knapweed.

On the butterfly front Painted Lady continues in good numbers and I also had 2 Wall. A host of other insects were seen with some photographed below. In the week I also came across a passage flock of 200 mixed Hirundines resting on wires and trees up Mynydd Caerau, consisting of mostly House Martin  but a few Swallow and Sand Martin amongst them. Other good birds seen included late Swifts passing through, 3 families of Spotted Flycatcher at breeding sites I found during the summer, also sightings of female Goshawk and Peregrine.

 Painted Lady

 Wall

 Tipula varipennis

 Hirundines

 Eristalis nemorum mating hover display

Rhingia campestris on Buddleah