Monday 20 August 2012

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.


Monday 13 August 2012

Sunny August

In this shot I tried to show the extensive Fuchsia hedging that paints much of western Ireland red at the moment, but the very bright sunshine made a decent shot very tricky.


Fuchsia hedging at Mongorrey

Note the very straight road stretching all the way westwards to the horizon. I had always thought that these long straight roads must be Roman roads, but the Romans never got this far, and the roads are known as 'Famine roads'.

The white umbellifer plants at the front of the shot are Angelica.

Many of the wasps that can be seen slowly crawling over umbellifers at the moment are males:

Male Vespula rufa
Vespula rufa can be identified by a combination of features including the red areas on the abdomen, facial markings and stripes on the thorax.

This Chloromyia formosa soldier fly was happily nectaring on the Angelica......

Chloromyia formosa soldier fly
until a Tenthredo sp. sawfly decided it would make a good meal and jumped on it:

Chloromyia formosa escaping from a Tenthredo sp. sawfly
Even at 1/120th of a second, the fly is just a blur.

It's not only the flowers of Angelica that attract insects: leaf-miners are also present. Phytomyza angelicastri is one of two species that I find locally:

Phytomyza angelicastri on Angelica

The Hawthorn parasite Taphrina crataegi clearly has some special habitat requirements. This is the only tree that I have found to be infected on my patch:
Taphrina crataegi on Hawthorn

I have also found it in one location in Northern Ireland, and in each case the tree overhangs lying water, but I know of many Hawthorns in similar situations that are unaffected, so it must be something more subtle.

As I was searching along a verge, a shadow passed over me and I looked up expecting to see a bird, but it turned out to be a huge Common Hawker dragonfly which was hunting along the same verge. I followed it for a while and it eventually rested on a Willow, so I managed to squeeze in a few distant shots:

Common Hawker dragonfly
And nearby I saw a Common Darter landing on a grass stem. She tolerated me for quite a while before flying off:

Common Darter dragonfly (female)
Slender St. John's Wort is my favourite flower, so I made an artistic crop of this pair:
Slender St. John's Wort








Tuesday 7 August 2012

Wildlife on earth

I can't help but notice that NASA are now looking for wildlife on Mars. I'll stick to my Donegal Hedgerow for now.

The weather has been dull with frequent heavy showers for a few days, but today we had blue bits in the sky and everything suddenly went crazy. At one point I had three species of butterfly in view, including three Small Tortoiseshells nectaring on the much-maligned Ragwort:

Small Tortoiseshell on Ragwort

These specimens were very fresh and will be the offspring of the overwintering generation that emerged in March this year.

I also saw my first specimen of Meadow Brown for the year, although it's fairly obvious that this specimen has been around for a few days:

Meadow Brown and Herb Robert
I cropped that shot to include a Herb Robert flower because it is such an important part of this hedgerow, flowering all year round.

Evacanthus interruptus is a very easily recognised leafhopper:

Evacanthus interruptus
It's never very numerous, and there are some years when I don't see it at all.

Plant galls are made when an insect (or fungus) modifies a plant's growth patterns for its own benefit. These are the galls of Eriophyes inangulis on Alder:

Leaf galls of Eriophyes inangulis on Alder
Notice that the galls are positioned precisely on the intersection of midrib and side vein. New to my species list.

On a nearby Alder, all the galls were of the closely-related Eriophyes laevis, which is the species I find much more often:

Eriophyes laevis on Alder
In this species the galls are randomly positioned, and are clearly different in structure from the previous species.

There are two distinct forms of the Riband Wave moth. All of my local specimens are of the form f.remutata, where the darker central wing band is missing. This form seems to be the norm in more northern areas.

Riband Wave moth

The Devilsbit Scabious is just starting to flower, which tells me that the season is well advanced. Many of the leaves are marked with the parasitic fungus Ramularia succisae:

Ramularia succisae on Devilsbit Scabious

The hedgerows of western Ireland are bright red at the moment with the wild (but introduced) Fuchsia species Fuchsia magellanica. On very rare occasions we find the absolutely beautiful pale variety, Fuchsia magellanica var. Alba:

Fuchsia magellanica var. Alba
I took some cuttings earlier this year, and they have just started to flower. Absolutely gorgeous.

Wednesday 1 August 2012

Seeds and moths

Seeds are the primary propagation method for many species of plants, and any species has a better chance of survival if its progeny can be distributed as widely as possible. Some seeds, e.g. Sycamore, Thistle and Dandelion, can fly. Others, such as Cleavers, Burdock or Herb Benedict have seeds which are furnished with hooks so that they can hitch a ride to their eventual germination spot. Other plants, however, have seeds which are distributed in more bizarre fashion.

The seeds of Meadowsweet are arranged in tightly coiled balls:

Meadowsweet seeds
When the seeds are mature, they drop off and bounce and roll away to their eventual destination.

The champions of subterfuge, though, are the seeds of Cow Parsley (and other Umbellifers, such as Hogweed). These resemble beetles:

Seeds of Cow Parsley
Notice that the similarity extends to antennae and even to 'eyes'.

When a fast-flying insect-eating bird spots these seeds, it is very easy to mistake them for a beetle at the top of a plant. As a result, many of these seeds are picked up and carried for some distance before the bird has noticed that its juicy beetle dinner is, in fact, a seed. If you're an insectivore, the last thing you want to eat is a seed, so these are very quickly dropped to germinate, but not before they have been carried some distance from the parent plant. Plants 1: Birds 0.

Moth identification continues to vex me, but I do think I'm beginning to make some headway.

This is the second specimen of Dotted Clay that I have seen:

Dotted Clay moth
These have a fairly short season, and the first one I saw was on 1st August 2009: exactly 3 years ago to the day. Dotted Clay uses a wide range of herbaceous foodplants, preferring Nettle and (in winter) Willows and other trees.

As usual, this Pug took a little time to identify:

Double-striped Pug
Larvae of the Double-striped Pug can be found on almost any flower. (Pug larvae tend to eat flowers, rather than leaves).