Friday, 3 July 2015

A just emerged Elephant Hawkmoth

In the early morning, we found this Elephant Hawkmoth, Deilephila elpenor, in the garden, on the base of the iron leg of a chimenea. It took us a bit to realise that it was fresh, just emerged from its pupal skin, wings still floppy. We moved it to a cat-safe location higher up on bushes, where she positioned herself again facing up, wings folded over her back as they filled up.
 Elephant Hawkmoth caterpillars feed on Rosebay Willowherb, Bedstraws and Fuschias. There is a fuschia overhanging our garden and many cleavers. It was nice to realise that this moth's amazing caterpillar, which gives its common name to the moth, grew somewhere in the garden, and pupated nearby on the soil.
 When I came back from work, in the evening, she was still hanging there, her wings hardened and opened (below). Hopefully she'll fly away tonight.

Thursday, 2 July 2015

A Southern Hawker

As I was about to leave the park this morning on my way to work I checked around an area of trees for Speckled Woods. Instead, I noticed a large dragonfly flying about and landing on a horse chestnut branch. I approached and searched for it. I had clearly seen where it had landed, but it took me a while to find it again. There! hanging from a leaf was a hawker. It rested, about 4 m high at an angle away from the sun, so it wasn't a great spot for photos, but after a while I managed this shot showing its features. As I checked the photo tonight thinking it's a bit early for Migrant Hawkers, I was pleasantly surprised to find that it was an immature Southern Hawker, which I have never seen in the area. Southern Hawkers breed in small ponds or canals, and often in garden ponds. After the adult dragonflies emerge from their native ponds, they spend about month away from water while they mature. Then they will find ponds where to breed. They like to feed on woodland glades, often away from their breeding ponds.

Semaphore flies

After a wildlife-packed June with the 30 days wild challenge, I felt like I needed a new focus and I decided to carry on a wildlife challenge by blogging/tweeting about an invertebrate I've seen that day for July. Yesterday, while walking by the local park pond I saw a Speckled Wood. The butterfly flew away, but it made me notice the flies dancing on the Colt's Foot leaves: they were Semaphore Flies, Poecilobothrus nobilitatus, a whole swarm of them signalling to each other. Although small, this species is very easy to identify by their smoky wings with a white tip. They are very active in July on muddy puddles and ponds.

Thursday, 25 June 2015

A garden stretch spider!

It has been so pleasant today, warm and still, with high clouds. I had planned to do a little evening gardening and I was about to start trimming the olive tree when I noticed a busy spider web spinning. Wait, a stretch spider, Tetragnatha, a new spider for the garden! I rushed back home to fetch the camera and took some photos. I think it is a female, possibly adult. Her yellow abdominal stripe glowing with the flash. I couldn't bring myself to capture it for ID as I would have surely destroyed her web and spoiled her night hunt, so I might do tomorrow. I will update the post if I find out what species she is.

Wednesday, 24 June 2015

The patrolling Red Admiral

Since the beginning of June, Red Admirals have been well established, having returned from the Mediterranean in their one way spring migration. Females should be mating and looking for sunny nettle patches in which to lay their eggs. Males should be looking for receptive females to mate with. They will produce one or more broods in the summer. As temperatures drop in the autumn, butterflies will prepared themselves for the autumn migration and then they become very apparent in gardens, where they feed on buddleia and other nectar rich flowers. Male and female have the same wing colour pattern. If you have a good view of the abdomen when the butterfly is resting with its wings open,  a swollen abdomen will allow you to identify a female, but otherwise it might be easier to tell them apart by their behaviour in early summer.
  Last week, in the afternoon, I have flushed a Red Admiral from the same sunny spot on a grassy area amongst trees, where they were sitting day after day, exactly where I often found them last year. This afternoon was unusually warm and, as I left work, a Red Admiral sat on a low hedge on a wooded glade teeming with nettles in our university campus (above). It would sit and then fly up patrolling around the trees and chasing passing bumblebees in a similar way a Speckled Wood male would do, and then return to the same perch. I had never noticed this behaviour in the Red Admiral, but it appears that I had observed a male, and that red Admiral males actually defend territories. It might seem hard to believe that beautiful, fluttery butterflies actually engage in any kind of aggressive interaction. Indeed, butterflies have no offensive weapons other than their wings, and, butterfly contests, even when they are defending a territory are often perceived as chases instead of aggressive interactions. However, there is now abundant research showing territorial behaviour in a number of butterfly species. The important point is not the presence of an actual fight but the outcome: as a result of the behaviour the owner remains in the territory and the intruder flies away.    Royce Bitzer and Kenneth Shaw carried out research on the territorial behaviour of the Red Admiral on the Iowa University campus. They captured and marked individual Red Admirals with different spots of paint and observed their behaviour once released. They found that Red Admirals spend the morning feeding, but each evening males establish temporary territories for a couple of hours before roosting. Males spent most of their time perched, but occasionally patrolled their territory boundaries. They were not seen feeding. Birds or other butterfly species were chased in a linear way, but male intruders are chased upwards in a spiral. In Red Admiral chases, the owner often retains ownership and the intruder flies away. Good territories are likely to be an area containing resting spots from where passing females can be easily detected, usually with linear features (e.g. a pavement or a few trees in a line). The maintenance of these temporary territories could allow better access to receptive females moving into their roost, as mating is thought to happen in the roosting sites in trees.
A particularly bright red and intact individual, maybe the result of a first local brood?
Two days later a much more faded individual with tattered wings, on the same favoured spot on the grass.

More information
Red Admiral and Painted Lady Research Site. Here.

Bitzer, R. J., & Shaw, K. C. (1979). Territorial Behavior of the Red Admiral, Vanessa atalanta (L.)(Lepidoptera: Nymphalidae). Journal of Research on the Lepidoptera, 18(1), 36-49. here.