Bombus hypnorum here to stay

Coming out of work I see the first Bombus hypnorum of the year: a dying, squished female, possibly a queen. B. hypnorum, or the tree bumblebee is a newcomer in the UK. It appears to have arrived on its own steam, possibly an inseminated queen crossed the channel around the turn of the century. The first specimen was collected in the New Forest in July 2001. In mainland Europe it is a species closely associated to human habitats. It is a species quite easy to identify due to its striking coloration: ginger thorax and black abdomen with a white tail. It is a good size bumblebee, similar to B. terrestris.
 In July 2005 I reported the first B. hypnorum in Hull and I have recorded it every year since. In the UK B. hypnorum has expanded steadily through most of England - click here for the 2009 records - and it appears that its status as a British bumblebee is consolidated.
 It nests in trees, often in nest-boxes and also in roofs and while foraging, it has a preference for high flowers. The bumblebee is found from March until September. These are the flowers I have observed it foraging:
March: Mahonia
April: Cherry
May: Rowan, Comfrey, Cotoneaster horizontalis
June: Bramble, Deutzia, Cotoneaster, Comfrey, Angelica, Hebe, Snowberry bush
July: Teasel, Cotoneaster, Lavender, Hebe
August: Snowberry bush, Buddleia
September: Ceanothus

The first recorded B. hypnorum in Hull

The entrance to a B. hypnorum nest in a nest box. Flies appear to be always at the entrance.

BWARS gallery page for B. hypnorum here. You can also send your records to BWARS.

First B. hypnorum record by Dave Goulson and Paul Williams here.

At close range

If a neighbour had casually seen me on my garden this morning, he or she could have rightly thought either that I was out of my mind or that I was practicing some tai-chi. But no, in one of the few sunny spells we had on an otherwise windy, cold morning, an Anthophora plumipes male stopped to sunbathe for a bit longer than usual. It is the longest time I have seen one of these fast high-pitched buzzing bees sitting still. The spot was quite near to the wall where I photographed the male in yesterday's post, possibly the same individual, but the background was much more interesting and I wanted to get a closer picture. Unfortunately, a barrier of lavenders, plum branches and primroses separated me from my subject, so I had to stretch and contort, while supporting myself with one hand on the mud, moving very slowly to take this photo one-handed. I just cannot hold it for a future post, as it is since now my favourite A. plumipes male photo. After a few minutes, the male started looking around nervously, flicking his antennae and, having warmed up, flew away.

Anthophora plumipes is back!

Yesterday it was the equinox, so it is finally spring. We had a sunny mild day today and from first thing in the morning we've had a couple of Anthophora plumipes males patrolling in the garden. I saw the first male of the year on the 17th of March, but it was too fleeting a sight and he did not stop. Today I managed a few shots during the few seconds one of the males Anthophora stopped to rest on a wall. You can see their forward-pointing middle legs, with the plumes of hairs that give them their name. These bees - as honey bees and bumblebees - are extremely endothermic, that is, they are able to increase their body temperature with respect to their environment and this allows them high activity levels at temperatures where other insects just sunbathe to increase their body temperature. Experiments by Graham Stone and colleagues have studied the ability of A. plumipes to increase their internal temperature. Accordingly, at the 8 degrees in which bees were active this morning, their body temperature is likely to have been around 28oC. The males patrolled constantly in a route around the garden and occasionally stopped to feed in some small Daffodils and Primroses. Males always emerge first from the nest where they were born, followed by the females. This is so because in the long tunnels where females nest, they lay fertilised eggs first (which will become females) and the last ones unfertilised (which will become males) and the bees emerge in reverse order of laying as the last eggs laid are closer to the opening.

The stone dwellers

When repotting a Rosemary I disturbed this Brown Centipede (Lithobius forficatus) which had taken residence at the bottom of the pot. It obviously was taken aback and sat still on the ground for a few moments so I went to grab the camera. Centipedes lose moisture from their bodies quite fast, as they lack an impermeable layer in their integument, so they live in moist environments and are most active at night. For this reason, when exposed from their hiding places under stones, logs (or pots!) Brown Centipedes tend to run away from the light as fast as they can and scuttle under the nearest dark crevice. These common centipedes are carnivorous or detritivorous, feeding on springtails, aphids, flies, spiders, mites, millipedes and molluscs which they immobilise with a venom they inject through fang-like apendages located at the sides of their head.

A close up of the Brown Centipede showing its fattened head with eyes made of a cluster of simple eyes (ocelli), the side of their fangs under its head and their long mobile antenna.

I found this cluster of eggs under a pot last May and a Lithobius next to them. Unfortunately, the little information on eggs I found describes that they lay eggs singly and bury them. I counted 42 eggs here.

Although quick, the Brown centipede is a small animal, up to 3 cm in length, and due to its habits, hard to watch. In contrast the longest centipede can reach over 30 cm. Watch a video of this giant centipede, Scolopendra gigantea, moulting and searching for prey in this post of The Bug Whisperer.

Dronefly portrait

I photographed this female dronefly, Eristalis tenax, sunbathing on the Phlomis bush. I like the soft green of the leaves and I played with the depth of field to make the background blurry. If you download the large version of the photo you can see yellow pollen on the fly's legs and some has transferred to the leaves. The only flowers nearby were a few crocuses, so I guess the dronefly had been feeding on them before.