Monday, 28 April 2008

Cuckoo Bumblebee

Last year I found a few specimens of Bombus bohemicus, which is parasitic on Bombus lucorum. Today I noticed the head of a bumblebee poking out from some grass:

After a few minutes' observation it was clear that I had another Bombus bohemicus in front of me, so they clearly managed to find a lucorum nest last year.

The main identification feature is the yellow tail band which almost mirrors the curved golden band on the thorax. Another give-away is the total lack of pollen baskets on the legs.

These cuckoo bumblebees find a nest where the host queen has already laid eggs and then a fight to the death ensues. The cuckoo females then lay their eggs in the host nest. The host workers hatch out and then proceed to feed the young of the cuckoo bees for the duration of the season.

I find this total destruction of the host to be a rather dramatic form of parasitisation, since the parasitised nest will not produce any hosts for the following year. Strictly, these cuckoo bees are kleptoparasites, since they don't live off the body of the host: they 'merely' steal the pollen that would have been used to feed the host larvae.

Status of Bombus bohemicus in Ireland: threatened.

Thursday, 24 April 2008


A few warm days and suddenly everything bursts forth: bees and hoverflies can be seen and heard as they go about their business of gathering pollen or hunting for nesting places.

I spotted this Common Carder Bumblebee - Bombus pascuorum - on Dandelion. I watched her nectaring for a little while and when I got back to the computer I saw that her pollen basket was empty and looked to be in pristine condition. I'd like to think this was her maiden flight, and she was nectaring for energy before commencing her season's work filling those baskets.
The 22-spot ladybird - Psyllobora (Thea) vigintiduopunctata - is a little unusual in that they are herbivores. Well, that's how they're classified, but since they only eat mildews on dead or dying leaves, I rather think they are fungivores. These are quite tricky to find as they are usually deep in vegetation and are only around 3mm long. This one was on my car.

Monday, 21 April 2008

School survey

I was out at a local school today, carrying out a biodiversity survey. One of the lads shouted "Hoverfly". I raced over and immediately knew it was new to me. I couldn't identify it in the field, but once I got back to the books it came out quite easily as Eupodes latifasciatus...a new species to me.

So thanks, boys (I told you there's something new every day).

Imagine first hoverfly of the year, and it's a new one for my list.

Tuesday, 15 April 2008

April Sun

Another small mystery resolved. Some Barbula sp. mosses are very difficult to tell apart unless you have setae to look at, and these can appear irregularly or not at all. This one has yellow setae, and is hence Barbula convoluta. The confusion species (which I also have locally) is Barbula unguiculata, which has red setae. The tumbled specimen at the rear is Bryum capillare. Again.

Things are moving along quite quickly, now. Viola riviniana is out. You can just see the notched, pale, spur at the rear.

The 'Yellow Brain Fungus' - Tremella mesenterica is associated with Gorse. Or rather, it isn't. It is parasitic on another crusting fungus that grows on Gorse - Peniophora incarnata.

Leaf miners will soon be in evidence: this is one from last year. It belongs to the micromoth Stigmella aurella, and is always found on Bramble. I like to look at the path of the mine and try to work out the strategy the larvae use to decide how to turn at leaf edges and veins.

I could happily have made a mystery out of this one: the leaves of Greater Stitchwort.

Just for the record, first Swallow of the summer was 4th April, and first Bombus terrestris queen was 12th April.

Friday, 4 April 2008

Moss life-cycle

I have been trying to decipher the life-cycle of mosses, and believe I now have it worked out. For so-called 'primitive plants', mosses have a complex life-cycle.

We'll start with the sexual generation, with male antheridia and female archegonia, which are usually - but not always - borne on separate plants. The following shot shows the cone-shaped antheridia of Polytrichum commune.

These produce the male gametes which swim (through water, hence the need for humidity around mosses) towards the female archegonia, which are tiny pockets on the stem of the female plant:
Fertilisation takes place, resulting in the sporophyte, or asexual spore-bearing generation, which grows as a parasite on the female shoot. So although the sporophyte - which consists of the seta (capsule-bearing 'stem') and the capsule (spore-bearing container) - appears to be part of the female plant, it is only 50% hers.

This shot shows the immature sporophytes of Polytrichum commune.

And these are the mature sporophytes with open capsules:

Thursday, 3 April 2008

Species list

Over the last 5 years I have been building a cumulative species list for my surrounding area:

One reason for moving to the blog format was the assumption that the 1300 or so species on the list would be my 'core' species, and I thought I wouldn't add too many more new ones this year. Not so: I already have 5 new species for 2008 - 1 fungus, 1 micromoth and 3 macromoths. None are rare, so I suspect the list will keep growing as I look harder.

I'll have a think about bringing the species list to this blog in some way or other.

Meanwhile, here are two of the new species:

First, the micromoth (about 1 cm. long), which flew into the study and onto my computer monitor. Hofmannophila pseudospretella - The Brown House Moth (which I rather think is the one that eats holes in clothes):

And a (very poor) shot of the Water Carpet - Lampropteryx suffumata, which came to light at my rear kitchen window. Some wildlife photographers will tell you that flash doesn't scare insects. They are wrong: this one flew immediately after this first sighting shot.

Late update: first Swallow of the year seen flying alongside the road this morning.

White, white, white

The locations of the very first flowers of each species to open are remarkably consistent from year to year. Some will no doubt be influenced by a favourable location, but others are genetically governed, I'm sure. This is the first of the Wood Sorrel - one of the plants locally referenced as 'Shamrock':

Wood Anemone has been out for perhaps a few days. This blossom is already turning:

The last white for today is Barren Strawberry, again in its preferred early location: a south-facing hedgerow bank.

But we also have a hint of Blue: down by the river Deele the Bluebells are all but open.

Opposite-leaved Golden Saxifrage has been out for a while, now, making the ditch bottoms a rich golden-green: