Marmalade flies everywhere!

Marmalade flies, Episyrphus balteatus, are the most common British hoverfly, and can be seen year round as they are able to overwinter as adults. However, at this time of the year, they are at their most abundant, as I walk around the garden, every flowers seems to have a few males hovering nearby or females feeding on the flowers. These slim, small hoverfly is able to migrate, and this occasionally bumps the numbers of British individuals. They are very distinctive, as the pattern of double black lines in the abdomen is unique to this species. The male above (eyes meet at the top of the head in many male hoverflies), settled briefly on an Agapanthus flower bud, and rubbed its feet together, keeping its wing open for a few seconds.

Marmalade fly ovipositing

Aphids are everywhere now, under tree leaves, on herb stems and on tender bush shoots. But they have many enemies. Amongst them, many hoverfly species are busy egg laying, carefully choosing their oviposition sites to be next to rows of fat aphids. This is my first photo of the year of a Marmalade Fly, Episyrphus balteatus: a female laying on a Wood Avens stem full of aphids. It was the only shot I took before she flew away. Soon their voracious larvae will be munching aphids away.

Buzzing laurustinus

 I planted a laurustinus (Viburnum tinus) bush on a large pot a couple of years ago and placed it opposite the window where we eat, a sheltered patio area. I did not realised at the time what a great location this was and what a fantastic bug magnet this bush is. One of the best features of lauristinus is its long winter flowering season (from October to May). My new vantage point has also revealed that their pollen and nectar rich flowers are often visited by honeybees, hoverflies and droneflies during mild winter days, as you can see in the photos below, all taken a few days ago. Come spring they are also visited by butterflies like the Holly Blue and early bumblebee Bombus pratorum queens. As this hardy bush does not mind shady conditions, their pink-white flowers are a good way of lightening dark corners of the garden.

A poor shot of Episyrphus balteatus

Eristalis sp. Dronefly.

The one on top of the post is possibly Meliscaeva auricollis, thank you Geoff F from WAB for the tentative ID given the difficult angle.

Twelve bugs of Christmas

Today we woke up to a mild, sunny day and I was pleasantly surprised by the diversity of active bugs about. I made a count of species and when I got to twelve I was reminded of the traditional carol and made up a buggy version:

12 ladybirds walking | 11 winter-gnats dancing |10 honeybees buzzing |9 bluebottles basking | 8 leafhoppers leaping | 7 woodlice hiding | 6 hoverflies flying | 5 snails sleeping | 4 spiders weaving | 3 harlequins | 2 drone flies | and a bumblebee on ivy

The honeybees in the local wildlife garden were coming out tripping over each other and ladybirds (7 spots mostly but also harlequins and 22 spots) were awaken by the mild temperature. I counted 5 spider species outside (Tegenaria, Zygiella, Pholcus, Steatoda, Linyphia). The main surprise was the bumblebee worker, extremely fast and active and with pollen baskets full with pollen.

Here is a slideshow of bugs seen and photographed today

A business of hoverflies

A business and a swarm, are the collective terms for flies, in this case, hoverflies. In the last few days, hoverflies, particularly the Marmalade fly, Episyrphus balteatus (above) have descended covering every flower, bush and branch with a stripy fuzziness. The group of Marmalade hoverflies on the flowering teasel above greeted me first thing in the morning. As I have said before, many hoverflies are migrants: numbers are swelled in the summer by migrants from southern Europe. I have taken shots of several species today, including Scaeva pyrastri, which I had only seen once in 2006 before, and now seems to be everywhere.

Syritta pipiens on fennel

Eristalis sp.

Syrphus sp.

Scaeva pyrastri on Knapweed

Myathropa florea on fennel

More information
Stubbs A.E. & Falk, S.J. (2002) British Hoverflies. BENHS.
Hoverfly Recording Scheme.

Hovering high

Today I read a very interesting paper by David Lack (of fame as an ecologist and evolutionary biologist for his bird studies and his books, of which 'The Life of the Robin' is my favourite). He described his observations on a day of October on top of a high Pyrenean pass. In addition to various flock of migrating birds, he accounts in detail how large numbers of butterflies (mainly Red Admirals and Clouded Yellows) and Common Darter dragonflies (Sympetrum striolatum) steadily crossed the pass towards the Spanish side. That birds migrated had already been well established, but insect migration was then a much more recent, still controversial phenomenon.Lack felt provileged to have witnessed such extraordinary phenomenon, and the feeling was probably enhanced by the beauty of the surrounding mountains, at 2227 m altitude. He wrote "Once in a lifetime perhaps, the ecologist is translated back into a naturalist, through chancing on a spectacle which combines grandeur with novelty. Such was our fortune at the Port de Gavarnie on 13 October 1950."

Cirque du Gavarnie (Photo by Marando-fr, Wikipedia Commons)

Lack's was the first account of hoverflies migrating. In his own words:

Not until we had been at the pass for over an hour did we realize that another insect was migrating, so we do not know whether it was passing from the start. This was a hoverfly, the two collected specimens being males of Episyrphus balteatus. All the other individuals looked the same, and we have no reason to think that any other species was present. The syrphid flies, like the dragonflies, flew steadily forward WSW. against the wind, keeping extremely close to the ground, where the wind was, of course, weaker. Very occasionally one settled for a moment, but otherwise they travelled steadily onward. An estimate of numbers was impossible, but at a guess they were at least twenty times, and perhaps a hundred times, as numerous as the dragonflies. They were the most remarkable migrant of all.

Today there were many E. balteatus in the garden. To think that such tiny, flimsy looking hoverfly, is able of such powerflul climbs and long voyages! It is just plainly amazing.

Episyrphus balteatus on Cat's ear (summer 2006)

A close up. Today, on an ice plant.

Reference
Lack and Lack (1951) Migration of insects and birds through a Pyrenean pass. Journal of Animal Ecology 20:63-67.