Tuesday, 30 April 2013

The season progresses

It's very interesting that at the very time when I'm photographing queen bumblebees, the EU has been trying to decide whether or not to ban or curb the use of neonicotinoid based insecticides. The most recent vote was indecisive, with UK voting against a ban and Ireland abstaining. But despite those disappointing votes, a two year ban has been implemented. I'd say the trial ban with a review in a couple of years certainly won't further damage the chances of our bees (and hoverflies!) surviving. It will, however, damage the profits of large, wealthy (and hence influential) producers, so I can guess where the pressure is coming from. Sooner or later we will all wake up and realise that we haven't got any food because the pollinators are all dead. 

The fourth of my queen bumblebees of the year is Bombus pascuorum:
Queen Bombus pascuorum - Common Carder Bumblebee
These are among the later of our local bumblebees to emerge, after B. lucorum s.l., B. terrestris and B. pratorum. I rarely see the queens of B. pascuorum, whilst it is relatively common to see the other queens hunting along hedgerows looking for a nesting spot. This is probably due to the fact that B. pascuorum is a surface-nesting species and the queen can therefore choose her nesting-spot relatively quickly.

The s.l. (sensu lato) after Bombus lucorum indicates that this is actually a complex of at least 3 species: B. lucorum, B. magnus and B. cryptarum. These three species are extremely difficult to separate when looking at anything other than queens. It seems that B. cryptarum is an upland, western species, B. magnus appears to prefer heathland and B. lucorum s.s. (sensu stricto) is a lowland species.

The reference is:

Niche differentiation of a cryptic bumblebee complex in the Western Isles of Scotland
JOE WATERS, BEN DARVILL, GILLIAN C. LYE and DAVE GOULSON School of Biological and Environmental Sciences, University of Stirling, Stirling, FK9 4LA, UK

I managed to get a shot of a queen 'lucorum' this morning:

Bombus cryptarum queen nectaring (empty pollen baskets)
My local specimens of the lucorum complex all seem to be B. cryptarum, since they always show the distinctive thin line through the collar as indicated in this close-up:

Bombus cryptarum queen, showing the thin line through the yellow collar
That's how I'm recording them for the moment, anyway.

The 1k challenge is making me look much more closely at almost every specimen I see, and today I thought I  had found a new snail:

Cepaea nemoralis - Dark-lipped Banded Snail
So I keyed it out (height = width, > 8mm., no umbilicus, dark lip round aperture) and it turns out to be a common colour variant of the Dark-lipped Banded Snail - Cepaea nemoralis, which I've had before.

I took a few other shots, including this face shot, which shows the stalked eyes rather well:

Cepaea nemoralis, showing eyes
Preferred habitat is moist vegetation in cooler areas.

Going back to my initial moan about pesticides, I'm pretty sure that politicians are the wrong people to handle environmental issues: they are driven by short-term votes rather than thinking about longer-term issues. Is there some body or mechanism that can act outside government? If not, I fear that our wildlife is doomed to be a perpetually low priority.

Monday, 22 April 2013

A bit warmer

We had a couple of weeks when the wind was blowing from the east, and I agree that it's "fit for neither man nor beast". I reckon nothing happened in wildlife terms during that period, so I'd say we are currently running about 4 weeks behind what I have come to expect on the patch. Now that we have reverted to the prevailing westerlies, we have to dodge the rain showers. Ho hum.

Now that Willow catkins have opened, a few insects have started to pollinate. This hoverfly is Parasyrphus punctulatus:

The hoverfly Parasyrphus punctulatus
Parasyrphus punctulatus is one of the earliest hoverflies to be found, although I rarely find it in large numbers. The main identification features are the semicircular yellow markings on the abdomen, which are strangely described in the standard reference as 'hemispherical'.

I have seen plenty of queen bumblebees searching for a place to nest - both Bombus terrestris and Bombus lucorum - seemingly in larger numbers than I have seen before. Perhaps the searching season has been compressed by the weather. I first found Bombus pratorum - the Early Nesting Bumblebee - in a fairly wild area in 2006, but I have seen several workers appearing on the hedgerow in the last few years: apparently it is becoming increasing urbanised due to the removal or loss of its usual habitat.

I found this queen - one of two queens that I have seen for the first time this year - crawling slowly around, so I suspect she had just emerged, since she is shiny clean.

Queen Bombus pratorum
Bombus pratorum is one of our smaller bumblebees, with queens the size of the workers of larger species and workers not much larger than a pea. Identification of the queen is based on size, the orange/red tail and the two-tone yellow bands on thorax and abdomen. You can see the worker here, and the male here.

A couple of moths came to light. The micros were worn beyond identification, but the March Moth is always very easy to identify due to the very triangular shape of the wings at rest:

March Moth
This is a good 6 weeks later than I normally see.

A few more flowers have opened, the most notable being Common Fumitory:

Common Fumitory
The Fumitory family (which is large and complex) gets its name from the glaucus ('smoky') colour of the leaves.

The 1k square challenge list now sits at 295 species. The list can be seen here.

Sunday, 7 April 2013

Warming up

It was 15C today (that's 59F in old money), so I was quite hopeful that I might find some activity. A loud buzzing led me to a queen Bombus lucorum that was scanning that back wall of a ditch, looking for a nesting spot:

Queen Bombus lucorum searching for a nesting spot
I had already seen a queen B. terrestris earlier in the week, but couldn't get a shot, since they move pretty quickly. I would certainly expect to see B. terrestris a lot earlier than B. lucorum, so this one was a bit of a surprise. I also saw another B. terrestris in my garden late yesterday afternoon, so they're clearly out and about.

Now that I'm doing the 1k square challenge, I'm looking even more closely at everything. I noticed that a specimen of Soft Shield Fern had some brown blotches on the upper surface and suspected that something was going on. I turned the frond over and found the feeding signs and pupal case of the micromoth Psychoides filicivora:

Larval case of Psychoides filicivora (centre)
The larva eats the sori (spore-bearing containers), leaving the distinctive brown blotches (to the right and top of the image) and then makes a shelter (centre) where it pupates. The adult emerges in May. Psychoides filicivora was discovered in Dublin in 1909, and has now spread throughout the island. It is thought to have arrived on ferns brought in from other countries, and has now been found in coastal areas in England and Wales. The literature states that it is known from Soft Shield Fern, Male Fern and Hartstongue Fern, but in Ireland it can also frequently be found on Polypodium. I examined a few fronds and, sure enough, I found this specimen: 
Psychoides filicivora on Polypody
I'll have to inform the references to get them updated.

A couple of flowers have opened in the last week:

Primrose, which is probably 2-3 weeks behind the usual schedule:


And Coltsfoot which is at least a month late in flowering:

Coltsfoot is a little unusual, in that the flowers appear before the leaves. That means that the energy used to produce the flowers comes from last year's growth, and must be stored in the root system. There must be a good reason for that odd behaviour, but I can't immediately think of a beneficial one.

The 1k challenge has now reached 258 species. You can see the list here.

Thursday, 4 April 2013

Season under way

When I woke up this morning and saw the clear blue sky stretched all the way to the horizon, I knew that today was the day for the season to start. I waited until mid-day before I ventured forth, since insects need time to emerge, inflate and dry their wings and have a few test flights before they start nectaring, not to mention a decent temperature to support flight.

The first specimen I saw was a female Eristalis tenax, which was entirely expected (see my earlier post here). She was on a Dandelion, which flowers for 12 months around here:

Female Eristalis tenax on Dandelion
I chose that shot because it shows the very wide dark facial stripe.

I went to a sunny bank where the Celandines are in full bloom and quickly found a male Platycheirus albimanus, also on Dandelion:  

Male Platycheirus albimanus on Dandelion

I noticed that this close-up shot shows one of the conclusive identification features: a clump of thick, dark bristles under the front leg, near the top:
Male Platycheirus albimanus, showing dark tuft of hairs
Although this isn't the earliest I have seen this species (last year I saw it on March 27th), it is a good indicator that we're catching up at last.

Fungal rusts are usually specific to one family of plants, although some are unique to species. This is Puccinia umbilici on Navelwort - Umbilicus rupestris:

The fungal rust Puccinia umbilici on Navelwort
Notice how fresh the Navelwort leaf is: rusts don't waste any time.

I suppose I should clarify my 'specific to one family of plants' statement. Fungal rusts very often have two hosts which are completely unrelated. This odd situation arises because fungi need somewhere to exist when the primary host loses its annual growth (perennial) or dies altogether (annual). So they tend to live on one host in the summer months before transferring to their overwintering host. The most extreme example I know of locally is Puccinia sessilis which spends the summer on members of the Allium family (in my case on Ramsons), but overwinters on Canary Reed-grass, which I don't have locally. The airborne spores must therefore travel many miles to ensure their overwintering survival. The detail is even more complex, since the fungi have different parts of their reproductive cycles on differing hosts. Sometimes I begin to wonder if these travelling rusts are actually an amalgam of two species. The more I study wildlife, the more complex it becomes.

Finally for today, a shot of the fungus Milesina scolopendrii on Hartstongue fern:

Milesina scolopendrii on Hart's-tongue Fern
This one doesn't need an alternate host, since the fern is evergreen, but as an example of perversity, complexity and downright confusion, other members of the Milesina family (which all infect different ferns) rely on Pine trees as an alternate host.