Wednesday, 7 July 2010

Bullhead bonanza (or not, as it turns out)

My biology class at school was always a little dull. We never really went on field trips, unless it was for a vitally important piece of coursework of course, but generally found ourselves stuck inside a large beige laboratory. So imagine my surprise when my younger sister bursts in exclaiming that her class had been out stream dipping on a stream I had never heard of, and that most importantly, they had caught some bullheads, miller’s thumbs, Cottus gobio, whatever you want to call them. This is our only freshwater sculpin, (a cottid as was pointed out earlier today by an anonymous reader) and it was not a species I had seen before. I set off the next day armed with a net, buckets and a friend to help catch them.

It took us a few minutes to find where they were hiding, and after a while we had our first bullhead. Admittedly, it was only about 10mm long, but still, it was a bullhead. More searching revealed a couple of juveniles, around 40mm long. But then we stumbled along a dead individual. And another. And then another. This was strange. Bullheads are long lived for small fish, and the chances of seeing these dead specimens all dying from old age was disproven due to the huge variation in size, from babies right up to huge 120mm adult males. By the end of the day, we had caught 6 bullheads of a range of sizes and seen others alive (plus a few young 3-spined sticklebacks and an adult female), but seen more dead ones in a state of decay. We found no dead sticklebacks, which is odd, and anyone thinking that my sisters class from the other day were to blame, they can’t have been because we went quite far upstream to catch ours whereas they went downstream.

We also found a putrid dead badger upstream with a huge pile of maggots on top. I chose not to tell my sister this...

I went down there again today briefly just to get some photos, and saw four dead specimens, and 3 live, one of which was certainly the large adult we caught last time. Does anyone have any ideas what could have caused this?

Tuesday, 6 July 2010

What A "Bee" That Was

A lot has been said about the decline of our bumblebees in the last few years, but fortunately my garden at home still has large numbers of bees visiting which come and go as the flowers on different plants open and mature. Anyway, earlier today I decided to finally begin the long process of teaching myself to identify the bees in the garden. I, like many people, will know that there are a large range of both social and solitary bees which make their way into British gardens each year, and many of them, being constantly on the move in a manner somewhat akin to a clockwork toy, are tricky to narrow down to species level without a close up photograph.

There are 6 main species of British bumblebee (this name specifically refers to members of the genus Bombus) and 95% of sightings of furry bees will be these. Other furry bees include mason (Osmia), miners (Andrena) and hairy footed flower bees (Anthophora), as well as less common Bombus. Many others still look more like honey bees, or, like the white faced bee, something totally different.




(Anthophora)






Bombus terrestris is the most common species, the typical big bee with a pale tip to the abdomen and two bold yellow bands, one at the top of the abdomen, the other on the thorax. Queens are large, prompting the, frankly stunning, headline “bees as big as mice!” to be plastered everywhere. On a bizarre side note, this was one of my favourite random phrases to throw around in conversation last spring. And on another side note, typing said phrase into google has the CFZ news blog as its third link. I suppose we must be doing something right!




















If you live up north, you are more likely to have B. lucorum as your main large bumble bee, though it is common in the south as well. It is similar to B. terrestris, but the yellow bands are paler and the tip of the abdomen is a crisp white. Like B. terrestris, they have short tongues, and sometimes cheat flowers out of nectar by biting through the side of long flowers to steal their food directly. They are declining slightly in abundance, but are faring better than many species.

Bombus horturum is another common bumblebee. Smaller than the above species, and with a longer tongue, B. horturum lives in small colonies in many different habitats, but in summer is often the most common species found in woodlands. Getting a close photograph of its head shows that the workers of this species have a longer head than relatives, but observation should show the extra yellow band on the thorax and the slimmer build over both B. lucorum and B. terrestris.

Ginger fuzzy bees can belong to a number of species, but the most common is Bombus pascuorum. Small and with a medium length tongue, B. pascuorum can be distinguished simply from similar solitary bees by its round compound eyes, which are much taller and slimmer in Anthophora. There are reports of this species being aggressive if disturbed when nesting or feeding, but casual observation should not cause it to attack.







(Anthophora)



By far the most easily recognised bee is Bombus lapidaries. It’s simple colour scheme, with a jet black body and red abdomen tip, renders it easy to identity in the field. Their short tongues mean that they need a landing platform on the flowers they land on, so they have a slim build to reduce weight and to make it easier for them to successfully land on a flower. They are doing well for themselves at the moment, spreading northwards at a strong pace. They are now common in Aberdeen, whereas 50 years ago they were extremely rare.

The final of the Big 6, as they are so called, is Bombus pratorum. The smallest of the 6, and with a short tongue, they are generally found on daisy-like plants with big easy landing pads and very short flowers. Though one of the most variable bee species, the abdomen tip is almost always brown, orange or pink, or any shade in-between. The colour tip of B. lapidaries is much more pronounced, but both the colour of the tip and diminutive size differentiates B. pratorum from the other species. A yellow bar on the thorax is generally present, but its extent (from a full thick band, to a couple of hairs) varies. The yellow bar on the abdomen may be full, broken, or non-existent. The photographs show an individual which lacks this yellow bar.

So there you have it, a quick guide to the 6 most commonly found bumblebee species in Britain. I would recommend looking at some photos of each species on the internet to get a better feel for what they look like. But, next time you are out in the garden, don’t just take the bumblebees for granted, do them the honour of studying them closely to see what they really are!

I must apologise quickly for both the quality of the photographs and the identifications, the lens I was using was rubbish, but any mistakes in the identification of the bees are totally my fault!