100 species of hoverfly at Garnwen

Garnwen, Maesteg     (SS8392)

The Garnwen 1km square is the first square where I have recorded 100 species of hoverfly in the Llynfi Valley. The area itself comprises of a forestry edge walking/driving track between commercialised pine forestry and upland moorland bog and cattle fields 200mts above sea-level. The track sides are rich in a diversity of flora from spring through to summer and this has allowed me to survey it throughout the hoverfly season lasting from March to October.

From the graph you can see recording begins in week 11 (March 12-18), when small numbers start to increase rapidly after week 19 (May 07-13) and peaking at week 21 (May 21-27). There is then a bit of a lull in species numbers between broods until week 28 (Jul 09-15) and from there on stay pretty constant and high until the last recording week which is week 39 (Sep 24-30). After this date all flowers have faded and then it becomes extremely hard to locate and further species.

Spring   (Mar – May)

Main feeding flowers – Blackthorn, Dandelion, Grasses, Meadow Buttercup and Sallow

Specialist species of the season - Cheilosia albipila, Cheilosia chrysocoma, Cheilosia grossa, Cheilosia lasiopa, Cheilosia ranunculi, Chrysotoxum arcuatum, Melangyna lasiophthalma, Parasyrphus malinellus, Parasyrphus punctulatus, Pipizella viduata.

Summer   (Jun – Aug)

Main feeding flowers – Bramble, Creeping Thistle, Hogweed, Slender Thistle, Tormentil

Specialist species of the season – Criorhina berberina, Criorhina floccosa, Chrysotoxum cautum, Didea fasciata, Eriozona syrphoides, Eristalis rupium, Eupeodes lapponicus, Sericomyia lappona, Parasyrphus vittiger, Volucella zonaria.

Autumn   (Sep – Oct)

Main feeding flowers – Angelica, Common Fleabane, Heather, Hemp Agrimony, Japanese Knotweed.

 Specialist species of the season – Baccha elongata, Eupeodes corollae, Eupeodes luniger, Helophilus hybridus, Melangyna umbellatarum, Scaeva pyrastri, Scaeva selenitica, Sericomyia silentis, Xylota jakutorum, Xanthandrus comtus.

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