Knapweed and Hoverflies

The knapweed is in flower in my meadow and there are hoverflies everywhere!

According to Plantlife, Knapweed (Centauria nigra) is one of our toughest meadow plants and a firm favourite of our pollinating insects, being a source of good quality nectar. As well as supporting our bee, butterflies and beetles, its seeds provide food for many birds. One of the reasons I now have a growing population of Goldfinches (although the teasels probably play an important role too!)

My meadow is still a bit too fertile and in places these plants grow almost to my shoulder, so the insects are easy to spot. Such diversity, but my garden seems to be very popular with hoverflies this year (probably due to the high number of aphids as well as a good flower diversity throughout the year).

Narcissus bulb fly, possibly Merodon equestris

Drone Fly, possibly Eristalis tenax or Eristalis pertinax

There are around 270 species recorded in Britain, with numbers boosted by migratory populations. They are good pollinators and their larvae are important predators. Over one third of hoverfly species eat plant lice and aphids, while others, known as rat tailed maggots, live in dirty, stagnant water eating the decaying matter (such as the Drone Fly above). Larvae of the Narcissus bulb fly feed on the daffodil, tulip and lily bulbs alongside others that live on decaying wood.

There's a really good selection of images on the Naturespot website

Marmalade hoverfly, Episyrphus balteatus

Male and female hoverflies are often similar in size, colour and markings, and some species are very difficult to differentiate without dissection. There were several similar in weight to the Marmalade hoverfly but difficult to photograph.
Their markings are intended to deter predators, by colour or mimicry but there's no evidence that it is successful (except perhaps with humans).

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This one appears to be a parasitic wasp wandering amongst the stems - a species of Ichneumon? I know very little about these and research will have to wait for another day.  But I have been listening to a wonderful podcast series about 'Ologies' and a recent one was 'Spheksology (WASPS) with Eric Eaton'

Other insects spotted included bumblebees, honeybees, beetles, and flies, but my favourite to watch is one of the leafcutter bees (Megachile)

And finally, I learned that there is a species of aphid specific to the knapweed - Uroleucon jaceae. They were neatly spaced up the stem for several days and every so often it was like a ripple ran through them. Then one day, they had gone - hopefully to feed one of my garden birds?

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