High Heath

The Green-veined White butterfly has two generations per year. Unusually, the two generations are quite close, with some slight degree of overlap. Summer generation specimens are more strongly marked, with the black markings being darker and sharper than those of the spring generation.

 This pristine specimen is a female:

Female Green-veined White, summer generation

Given the lateness of the year, this is a rather early specimen for the second generation.

I have found the same, strange, earliness in the bumblebees this year. Queens emerged rather late, and nests were subsequently late, with workers not appearing until a few weeks ago. There is usually quite a delay until the new queens and males are ejected, but I have been seeing new queens and males for a couple of weeks now: much earlier than usual. It seems that some species are actually accelerating this year, despite the slow start, and are now ahead of normal schedule, rather than maintaining the 'lateness'.

Male bumblebees are ejected from the nest to fend for themselves, mainly because they do no work and would be an overhead on the nest. They are quite easy to identify, both in behaviour and appearance: they tend to crawl slowly over flowerheads in contrast with the workers which gather pollen almost frantically. They are also rounder, more colourful and have longer hair, giving them a 'fuzzy' appearance:

Male Bumblebee on Common Catsear

Any bumblebee with yellow hair on its face is likely to be a male, although not all males show this feature:

Male Bumblebee showing yellow hairs on the face

It isn't possible to identify these males to species without internal examination, but given the location, I'd go for Bombus lucorum s-s.

The hoverfly Helophilus pendulus is very numerous at the moment, with sightings on every excursion and location.

The hoverfly Helophilus pendulus

But I still examine every specimen, since I know that the much more local Helophilus hybridus can occasionally be found:

The hoverfly Helophilus hybridus

These rarely fly more than a few hundred metres from the boggy areas that contain Bulrush - the foodplant of their larvae. Identification relies on the differences between the markings on the abdomen. I might see only one or two of these each year.

The hoverfly Platycheirus scutatus was split into 4 species quite recently. Irish specimens appear to be the original Platycheirus scutatus s-s.

Platycheirus scutatus, female

Platycheirus scutatus, female

The larvae of these feed on aphids on low-growing vegetation.

Digger wasps can often be mistaken for hoverflies due to the oval yellow markings on the abdomen, the large head and the apparently short antennae: all features of hoverflies. These are predators on hoverflies, killing them and taking them back to the nest to feed their larvae:

Ectemnius continuus

Their appearance enables them to mix with hoverflies and approach them without disturbing them: I have often seen hoverflies and Ectemnius wasps feeding on the same flowerheads.

Hoverflies mimic the colour patterns of wasps and bees with greater or lesser accuracy. This enables them to inherit the protection that the colour patterns give to bees and wasps: birds know to avoid yellow and black -  nature's danger signal. So Ectemnius wasps are imitating hoverflies that are imitating wasps.

Staying with mimicry, Volucella bombylans is a hoverfly that mimics bumblebees (and lays its eggs in bumblebee nests):

The bumblebee-mimicking hoverfly Volucella bombylans

Volucella bombylans comes in at least three colour versions, each mimicking different bumblebees. I would dearly like to know if the different versions choose appropriate bumblebee hosts to rear their young.

Sawflies are very difficult to identify to species without a specimen, a microscope and a key. I have recently obtained a copy of the (55 year-old!) key and have identified this specimen as Tenthredo mesomelas:

The sawfly Tenthredo mesomelas

In an effort to understand these adults and larvae, I am participating in an online effort to gather together images of both adults and larvae of all sawfly species together for the first time.

When I was down taking photographs of orchids (see here), this micromoth flew over my head and landed on the Luzula upside-down, as so often happens.

The micromoth Glyphipterix thrassonella

The larvae of Glyphipterix thrassonella feed on Juncus rushes, which were in profusion. This is the first time I have seen this species since 2005.

Meadowsweet must be a very nutritious plant: there are many miners, micromoths and fungi which use it as a host. This is the fungal rust Triphragmium ulmariae, which is specific to Meadowsweet:

Triphragmium ulmariae on Meadowsweet

Note that the fungus has distorted the stem of the plant in order to maximise its surface area and therefore increase its chance of spore-dispersal.

And this is the mine of  Agromyza filipendulae on the same plant:

Unusually-shaped mine of Agromyza filipendulae on Meadowsweet

Note that this particular mine is atypical: it should have continued spreading to the left, but for some reason it has turned back at the fourth vein. Perhaps it was parasitised.

Serendipity

My photography sessions are dominated mostly by the weather, and even when the weather is half-reasonable I can still struggle to get half a dozen decent shots. Sometimes, however, everything clicks and I manage to get a good range of illustrative images.

Scaeva pyrastri is a hoverfly that can be readily identified by the abdominal markings: they are paler than most species and the inner part of the curve is further forward than the outer part. In this shot, you can also see the hairy eyes, which separate it from other similar species.

Scaeva pyrastri hoverfly

Scaeva pyrastri is thought to be immigrant from mainland Europe, and I know that there has been a mass migration of moths to Ireland in the past couple of days, so this hoverfly has almost certainly flown from France to breed here. (The brown hoverfly at top left is Eristalis pertinax).

Eristalis intricarius is one of our best bumblebee-mimicking hoverflies:

The bumblebee mimicking hoverfly Eristalis intricarius

That yellow/orange 'band' is very convincing in life, but when you see it close-up, it's clearly just a scutellum with longer than usual hairs.

And just as I was standing up from taking that shot, I saw the very bumblebee that it is mimicking:

Bombus lucorum (agg) (right) and Bombus pascuorum (left, both workers)

That's a nice shot of two of my 6 local bumblebee species.

Helophilus pendulus is perhaps the most common single species of hoverfly on the patch at the moment. I know that there are a few related (but rarer) species that might be around, so I examine each specimen very carefully just in case. Today I got that 'eureka' moment as I found this male Helophilus hybridus:

Helophilus hybridus (male)

Helophilus hybridus larvae are associated with black mud where Bulrush is present, and the adults don't disperse very far. There is a stand of Bulrush about 300m. from where this shot was taken.

Here's an archive shot of Helophilus pendulus for comparison:

Helophilus pendulus (archive)

Notice that the yellow abdominal markings are quite different, and the rear legs are yellow only at the 'knee' in hybridus, but the yellow is extensive on pendulus.

The larvae of some fly and micromoth species feed on the seeds of composite flowers such as Knapweed. The seeds are an excellent food source, and the larvae can feed inside the undeveloped seedheads in relative safety.

Notice the word 'relative'; some parasitic wasps are aware that there are larvae inside the flowerhead, and at the appropriate time (now) we can see the Ichneumonids searching the unopened flowerheads. When a larva is detected, the ovipositor is deployed and we see the drilling operation that takes place:

Ichneumonid ovipositing in larvae inside the Knapweed flowerhead

The eggs are deposited inside the body of the hidden larva and will remain there until the larva has reached full size. At this time (or soon after the larva has pupated) the ichneumonid egg hatches out and the ichneumonid larva eats the host before pupating inside the husk. This egg-laying process can be seen in perhaps three days per year.

Here's an unusual shot of the process from the rear:

Ichneumonid ovipositing

A few days ago, I showed a picture of a very atypical Square-spot Rustic. Here's one that looks as if it has read the book and followed the rules:

Square-spot Rustic

Here's a link to the original post, for comparison.

One of those days

Some days are just simply better than others.

Helophilus pendulus (to the lower left, below) is a very common hoverfly that has similar but scarcer relatives, so I always examine each specimen in the hope that it might be one of the scarcer ones.

Today I noticed that one of the many specimens was slightly different , especially in the amount of yellow on the abdomen. I managed one poor shot before it zoomed off to another area:
The photograph is just enough to identify it as Helophilus hybridus, which requires black, boggy soil for its larvae. The habitat matches precisely, so that's one new species for today.

There is a stand of young Alder trees just opposite where we usually park the car, and this unusual mine caught my eye:
The mine is unusual in that the larva starts off at the midrib, makes one anticlockwise circuit between two veins and ends up back at the midrib. Then it appears to disappear. In fact, the larva is now tunnelling along the inside of the midrib and will appear a few veins closer to the petiole and will then cut an oval piece of leaf which it takes to the ground and will then roll up and pupate inside it. This extremely sophisticated beast is the micromoth Heliozela resplendella, and is new species #2 for today.

New species #3 is the moth The Magpie. Notice the 'The'. For some unknown reason, about 60 of our moths have 'The' as the first part of their name. I suppose it happened as part of the original naming process and someone's list was kept differently and the names got stuck. Nice beast, anyway:

And the fourth and final new species for today is the Centre-barred Sallow, which is one of the few insects that is dependant on the Ash tree:

I would have been happy to call a halt on the page at this point, but I got a couple of other shots that are worth showing.

This Eristalis nemorum hoverfly insisted on trying to mate with a worker Bombus pascuorum bumblebee:
It made numerous slow approaches from above, each time forcing the bumblebee to move to another flowerhead. Eventually the bee gave up and flew away over the hedge, after which the hoverfly tried to approach a number of other bees and hoverflies.

Alder is host to a large number of insects and fungi, which is testament to its nutritional qualities as well as its obvious lack of protective toxins.

Taphrina alni is a rather scarce fungus which attacks the fruiting cones and forces them to produce these large, red tongue-like growths:
These growths (strictly-speaking, galls) are part Alder and part Taphrina, much in the manner of lichens, and their only purpose is to produce fungal spores.

The closer you look, the more complex it gets.

Four new species in one day.