Thursday, 24 September 2009

Now you see me, now you don't

I was walking home through the University woodland area in the afternoon when a large flying insect called my attention, a moth with bright pink hindwings and an erratic flight. It took a while to settle, and it did so on a tree trunk. When I got close I could not see it. I had spotted it when it had landed, so I took a few shots of the trunk, where was it? Can you see it?

and then I saw it. Thanks to it hindwings being slightly exposed.

It was a Red Underwing (Catocala nupta), a large noctuid which flies in August and September, and whose caterpillars feed on poplar and willow. It seems to be a rare species in the North, but it seems to be expanding in range. In the  NBN gateway it does not even appear in Hull.

Friday, 18 September 2009

Recording a nature diary electronically

I moved to writing my nature diary on the computer a year ago. I started using Evernote, for a series of reasons (a recent entry above). It is free, accessible from many platforms and it also has the ability to synchronise notes and you always have an updated back-up copy on the web. Importantly, it is fully searchable and you can put photos or websites in it, in this respect it is quite flexible. The main problem with it, for the use I give it, is that I cannot export the notes in other format than text, and even then, the note creation date does not appear in the text file. I have partially avoided this by writing the date on each note, but is a bit of an extra effort. I also would like it to have a system in which I can do a search for a species and then be able to export the search as a tab-delimited text which I can import into Excel, say, in order to submit my records to various recording societies. Also, I wish I could draw on the notes! I love the feeling when going through my old notebooks looking for something (when did I see the first butterfly this year?) that is missing in the electronic form, devoid of little drawings and sketches - a bird carrying a stick, a sunbathing butterfly, a bee - which give it personality and conveys a sense of the moment. I'd love to hear if anybody records electronically and what software they use.

A sketch on a sunbathing Red Admiral on a fig leaf (14th September 2006).

Thursday, 17 September 2009

Oak Gall Wasps

I went for a walk the other day to the local Wildlife Garden. I was taking photos of autumn berries and when I went to see how the acorns were doing I couldn't find a single intact one. The handful of oaks in the hedge were covered in all sorts of galls on leaves, stems, buds and acorns. Some galls are quite attractive, others just plain bizarre. These galls are produced by the larvae of tiny gallwasps (Cynipidae). These wasps are one of the few a very group of organisms (with waterfleas, rotifers and aphids) that alternate in their mode or reproduction between a sexual phase (with male and females, usually in spring) and an asexual phase (females which reproduce parthenogenetically usually in the summer). Both reproductive phases often happen in the same oak species, but in some cases they occur in two different ones. The gall is a response of the tree tissues to the presence of the wasp larvae and the shape of the gall differs depending of the species of wasp. The gall offers protection and food to the growing larvae, which after pupation, emerge as adults through a hole. There are over 30 gall wasp species in britain in the common oak alone. Despite their tiny size, gallwasps have their own parasitoid species, also wasps!
 All the galls in the photos are produced by the summer, asexual generation on the pendunculate, or common oak, Quercus robur.
Marble Galls, produced by the larvae of Andricus kollari. The exit hole is visible in the middle. The sexual generation uses the Turkey Oak, Q. cerris. This wasp species was introduced in the 19th century and is now widespread.
Knopper Galls on acorns. Produced by Andricus quercuscalicis. Adults emerge in spring to produce the new sexual generation on catkins of Q. cerris (a non-native oak). They first appeared in the UK in 1960 and they are now widespread. I think the little wasp at the left of the centre of the photo is the gall wasp.

Common Spangle Galls produced by Neuroterus quercusbaccarum. The sexual generation forms Currant Galls in young leaves and catkins.
Silk Button Spangle Galls produced by Neuroterus numismalis. The sexual generation causes minute galls on leaves in spring.
Artichoke Galls produced by Andricus fecundator which lays eggs on terminal or leaf buds.

Monday, 14 September 2009

A Poplar Hawkmoth story

One night of early July, a large female hawkmoth heavily laden with eggs got in our laboratory through an open window, attracted by lights. Before she died, she laid her eggs on the window glass.
 It was lucky somebody noticed the dead moth and eggs and kept an eye on them. Tiny pale green caterpillars with disproportionately large heads, started to emerge on the 27th of July, and proceeded to eat their egg shells.
After a quick internet search we identified the hawkmoth as a Poplar Hawkmoth, Laothoe populi, one of the commonest in the UK. After bringing in some poplar branches, the caterpillars started munching away and growing, and growing. After four weeks they were full size, beautiful velvety green caterpillars with yellow and red markings.
Nineteen of them have now pupated and I'll keep you posted when/if they emerge some time next May.

Wednesday, 9 September 2009

Life and Death

A butterfly day: Small Tortoiseshells, Red Admirals and Painted Ladies sunbathing in the morning and gorging on the buddleia blooms; Speckled Wood in their never ending spiral flights. Same old same old. I witnessed more dramatic things though. A Small Tortoiseshell left the spot on the ground where it was sunbathing and flew straight onto the middle of a large garden spider web. The spider quickly grabbed it from below, while the butterfly frantically fluttered trying to get away. The fight continued for a minute or so, then the butterfly started to flutter more and more slowly until it gave up. I didn't have my camera with me (I though I did but it was only the case, doh!) so I returned later and tried to find it. Here it is, the full spider holding onto its neat small tortoiseshell meal or the remains of it.
As I was leaving the spider, two common blues, a female with a male closely following her, fluttered by my head. I watched. They looked like they wanted to settle, flying low amongst the bushes, and after a bit they did, on some marjoram. They rapidly took positions facing away from each other, closed their wings and mated.

Sunday, 6 September 2009

A terrifying ladybird tale (part II)

I had completely forgotten I had put the parasitised ladybird (see previous post) on a plastic container to see if the parasite wasp emerged and to be able to take some photos. I checked regularly the first few days and nothing happened. Today, sixteen days later, I came across the container and there was a tiny wasp, flying about! The ladybird was still alive and it could now move its front and middle legs. I managed some shots of the pair together.
The wasp returned to the ladybird again and again, inspecting it with its antennae. I released the wasp in the garden and it settled nearby so I could take one final shot before it flew away.