Unexpected pollinators

One of my spurge plants is in full bloom now. Spurges have complex flowers with exposed nectaries, which are available to insects lacking a long tongue, although they appear not to be very appealing to bees and butterflies. They attract bluebottles, hoverflies, ladybirds and wasps. Later in the season they will be taken over by ants, which will defend them aggressively from competitors. In the last few days, dozens of 7 spot ladybirds have been enjoying this early nectar, in the company of bluebottles and hoverflies. They pay back the plant by acting as its pollinators. Some of the ladybirds were covered in pollen and the one on top seems to be pushing up the plant pistil, so the anatomy of the plant is right for ladybirds to act as pollinators

This 7 spot ladybird, from 2/04/11 was laden with spurge pollen

Bluebottle enjoying the nectar

More 7 spots on the flowers, and possibly a harlequin

A little hoverfly, Meliscaeva auricollis

The CSI Blowfly

At this time of the year, when there has been a few frosts and the sun is weak, the most likely insect you are likely to see on the wing are bluebottles. I found this one yesterday enjoying the sun in my conservatory. It is the urban blowfly, Calliphora vicina, a very cold tolerant species which is the most common buebottle in the UK.
  Calliphora vicina is one of the most important species in forensic entomology, especially in investigating human remains. Different fly species arrive at a body at different stages of decomposition and they will lay their eggs on it. Blowflies can smell rotting flesh from large distances and are one of the earliest finding a body. They have a very fast life cycle, and they can produce up to five generations a year, depending on the temperature.

(Figure from Amendt, Krettek & Zehner 2004)

The female lays batches of 150-200 eggs in open wounds, rotten meat, or bodies. These eggs can hatch almost immediately after being laid, but they can take up to 9 days to hatch at 5 oC. The maggost will start feeding immediately. As the duration of each of the three larval stages depend on the temperature and is known in great detail, the age of the oldest maggots together with the average arrival time of the species allows to estimate the post mortem interval and approximate time of death.

Bluebottles will enter houses and lay batches of eggs in exposed meat either cooked or raw, and their attraction to rubbish makes them very abundant in cities. Bluebottles have an important ecological role as carcass decomposers...

... but they are also pollinators of several plants with exposed nectaries, such as ivy, spurges (Euphorbia) and plants from the carrot family. Some companies have even used bluebottles for greenhouse pollination of various crops as they fly at lower temperatures than bees. They also act as dispersers of fungal spores, and some fungi, like Stinkhorns (Phallus impudicus) have specific adaptations to attract blowflies, releasing chemicals that smell like rotting meat. The flies feed on the surface on the fungus and the spores attach to the fly, which can disperse them.
 Next time you are annoyed when a bluebottle enters your house, you might want to give a thought to how useful these flies are.

More information
Amendt, J., Krettek, R., & Zehner, R. (2004). Forensic entomology. Naturwissenschaften, 91 (2), 51-65 DOI: 10.1007/s00114-003-0493-5

Donovan, S., Hall, M., Turner, B., & Moncrieff, C. (2006). Larval growth rates of the blowfly, Calliphora vicina, over a range of temperatures. Medical and Veterinary Entomology, 20 (1), 106-114 DOI: 10.1111/j.1365-2915.2006.00600.x

November bug magnets

I went for a walk this afternoon to re-acquaint myself with my clean and repaired camera. After spending almost three weeks camera-less, it was great to have it back. I just walked back to the spot where a few days ago I spotted the B. hypnorum and waited around the sweet smelling Mahonia bushes trying to spot more bumblebees. There were flies (Bluebottles and a smaller species) and wasps around, but my patience finally paid when I saw the distinctive large and dark shaped of a bumblebee amongst the flowers. Not a B. hypnorum, but a worker B. terrestris, stayed just for a few shots (top).

 The second bug magnet today was Ivy. There were dozens of male wasps feeding on Ivy flowers on the wildlife garden. Their large antenna reminded me of mountain Ibex males. I am not very good identifying wasps, although in a post in WAB today somebody pointed at a very informative webpage to identify them. I will update the post if I manage to get an ID. Around the ivy there were also feeding Bluebottles and a parasitoid wasp.
 The third bug magnet was a non-native bush related to the Ivy, the Fatsia japonica. Here the ubiquitous bluebottles were the only insects around.

Ten bluebottles sitting on the wall

Posts in BugBlog are necessarily becoming spaced out now. Although we have not had a frost yet, days are colder and darker heralding the arrival of winter, and insects are becoming scarcer by the day. Sunny today, there were still some bugs around. There were several active spider species: Garden spiders, Mouse spider, Linyphia triangularis, Amaurobius and Zygiella. The garden spider female above hangs her web every day just outside the kitchen window. I liked the effect of the ripe cotoneaster berries in the background.

We came across this colourful Birch Bug, Elasmostethus intersinctus, while gardening. I identified it using the site British Bugs A great resource on hemipterans.
Greeting me early in the morning this bunch of bluebottles sunbathing on a fence. There were more than ten, but they reminded me of the song...

A harvestman, Opilio canestrini with legs outstretched on the wall.

Honeybees were the first active bees of the year and by the look of it, they are going to be the last ones too. A few are feeding on the Fuschia in the last few days. 

The positive aspect of the relative scarcity of bug activity in the garden is that I can actually do some gardening without having to rush every two minutes to the house to fetch the camera!

A glimpse of Spring

We've had a wonderful sunny start of March. Mornings are still frosty, but - compared to the past three long, cold, cloudy and gloomy months - spring seems to be on its way. The first Grape Hyacinths (Muscari racemosum) of the year have opened, joining Snowdrops, Crocuses and Primroses. Today I've been tidying up in the garden. There have been many plant casualties of this unusually cold winter, but the survivors have started to grow, buds are thickening and leaves slowly unfurling.

A Wolf Spider (above) walked on a white wall and settled on an Ivy leaf to sunbathe.
 The pair of 7-spotted ladybirds, of which I wrote before, are still nestled together amongst the spiky leaves of the monkey puzzle tree. They have been there since early November. In contrast, I have seen active ladybirds in more sunny positions in the garden, enjoying the sunshine and hiding again afterwards.

A 7 spot ladybird enjoying the sun

A Bluebottle feeding on an Ivy leaf

Unidentified fly

Signs of spring

Once the Chistmas holidays are gone, no matter how cold or gloomy it is out there, it feels so different. The long darkening days of the Autumn are finally gone, and daylight seem to tangibly increase day by day. Sunny, crisp, cold days are a bonus. But is not only the light - or is not only me who feels it - buds are fattening, catkins unfurling and the woodland floor flowers are hurrying up before tree leaves shade the ground. Birds have noticed the longer daylight hours and are singing and pairing. The last day of January and I have already heard wrens, dunnocks, woodpigeons, greenfinches, goldfinches, collared doves, robins and song thrushes singing. It's not only me, is not wistful thinking. There are sings of the new spring already coming.

 Ok, this is BugBlog, where are they? It feels a bit lonely in the sole company of occasional bluebottle or cloud of winter gnats. I am hopeful and keep watch. Any day now, and this means, possible during February, a butterfly, a red admiral, or a small tortoiseshell, will wake up from hibernation and will make my day...