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.

Accelerating towards the solstice

99.9% of the bumblebees seen any year will be female; either queens or workers. The much rarer males or drones are generally brighter, with much wider yellow bands and a yellow tuft of hairs on the head. This is a male Bombus lucorum (or more probably Bombus cryptarum, which seems to be my local form of the Bombus lucorum complex):

Crab Spiders don't make webs, but instead lurk on leaves and stems of plants, poised to leap out on unsuspecting prey. This Xysticus cristatus wasn't particularly well camouflaged (which is probably why I saw it so readily):

Small Copper butterflies are always scarce. Since they feed on Sorrel - which is very common -there must be some other environmental factor which governs their development.

The Tenthredo sp. sawflies are just starting to make an appearance. Aggressive predators as adults (although vegetarians as larvae), they will have a field day on the larger umbellifers when they start to flower next month.

More moths continue to come to light. This is a new species for me: the Map-winged Swift - Hepialus fusconebulosa.

And this is the Beautiful Golden Y - Autographa pulchrina:

This last shot isn't so much about the aphid and her young, it's more about the amazing look of the leaf of Cocksfoot grass:

Hot Spot

I went to a spot that's usually very good at this time of year (south-west facing vertical banking below a hawthorn hedge) . It proved to be a good choice.

As soon as I saw this little (12mm) hoverfly, I knew she was new to me. She appears to be a female Melangyna, and a couple of microscopic features suggest Melangyna lasiopthalma. Since this would be a first Irish record, I need to go back and get some more solid evidence.

This Small Tortoiseshell was basking and feeding on the Lesser Celandines. It seems in pretty good condition, considering it has overwintered in those freezing conditions:

Common Fumitory - Fumaria officinalis - adds a splash of pink to the predominantly yellow verge:

A couple of weeks ago, I mentioned the tight threads that pull the Coltsfoot head into a downward-facing position. Here's a shot that shows the process:

Primroses were visible in a more sheltered part of the bank:

The queen bumblebees are getting very heavy already, and this B. cryptarum was clumsily crashing from flower to flower. Some appeared unable to fly at all and simply crawled from one flower to the next. I presume her nest is within walking distance!

The fungal rusts don't waste any time. The leaves are quite fresh and already the yellow spots of Uromyces dactylidis are clearly visible on Celandine leaves:

Yet another new member of the Orthosia family, the Clouded Drab - Orthosia incerta - came to light last night. Guess which pollen it eats....

Definite signs of spring

I was out looking for hoverflies - unsuccessfully, as it turned out - when this queen Bumblebee flew over my head and immediately started to rummage in the hedge base, looking for a nesting site:


I rattled off a few shots and a closer look reveals her to be a queen Bombus cryptarum - a recent segregate from Bombus lucorum. The notch in the yellow collar is the clue:

I have been watching the parasitic bumblebee Bombus bohemicus over the last couple of years. This is known to be a parasite of Bombus lucorum, but I wonder if it's also a parasite of Bombus cryptarum, which appears to be the dominant white-tailed species in this location.

Mimicry and more

Here's a close-up of the Bumblebee Bombus cryptarum:


Bombus lucorum was recently split into 3 species: Bombus lucorum, Bombus cryptarum and Bombus magnus. Bombus cryptarum was added to the Irish list in 2006, and consistent sampling has shown that my local population contains this species. I recently posted about the Cuckoo Bumblebee Bombus bohemicus, which was known to be parasitic on B. lucorum sensu lato, but I don't know if it also parasitises B. cryptarum or if I also have B. lucorum s-s, which I rather suspect. Work to be done, here.

The best diagnostic feature of B. cryptarum is the black notch in the forward yellow band, just in front of the wing joint:

Just as the parasite B. bohemicus is a lucorum lookalike, we also have the hoverfly Eristalis intricarius:



Note the distinctive Eristalis loop in the wing vein.

There are two main reasons for the mimicry. In the case of parasitic species like the Cuckoo Bumblebee, it may need to be able to get into the nest undetected, so it looks rather like the host. In the case of the hoverfly, it can either be to get into the nest undetected, or to fool predators into thinking that it is a Bumblebee, and can sting. Eristalis intricarius larvae live in the bottom of ditches, so they are applying the mimicry to avoid being eaten by birds.

Eristalis intricarius is known to be widespread, but in low numbers, and of the 50 or so specimens I have found over the past four years, they can all be pinned down to two separate patches of ditch, each no more than 10 metres long. So there is something that controls their distribution very tightly. To make things even more confusing, the two ditches (roughly 1.5 km apart) could hardly be less similar:

One runs North-South, the other East-West. One is at the edge of cattle pasture; the other, the fringe of a bog. One is fringed by Meadowsweet, the other Soft Rush. Just about the only thing in common is some Hawthorn and some Gorse and Bramble. Interesting......