Thursday, 25 June 2015
Wednesday, 24 June 2015
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.
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.
Friday, 19 June 2015
The Batman hoverfly, Myathropa florea on hagwort
Nettle tap moth
A male Bombus lucorum swinging from the flowers.
This is a dronefly, Eristalis pertinax.
There were at least three male longhorn, Nemophora degeerella, moths about. They danced as they flew high up. It looks like quite a challenge to fly with such oversized antennae, which presumably attracts the female's attention. This one rested on nettles for a while.
A female Marmalade fly, Episyrphus balteatus, with extended ovipositor.
And to finish, a Speckled Wood. I rarely see these butterflies nectaring. They have a short tongue and like to lap honeydew on tree tops, but the exposed, flat flowers of the hogweed seem to appeal to them.
Sunday, 14 June 2015
We pushed through nettle beds, brambles and hogweed, waded through muddy puddles, crossed others by walking on logs and did a little millipede collection on the way. The wet weather had also brought some interesting fungi.
Millipedes do often go unnoticed, as they live under the cover of logs, bark and stones, on leaf-litter or in the soil. They have many similar body segments and a pair of legs on each segment. Despite their name, no species reaches 1000 legs. Millipedes have defensive glands and they often open into colour spots on the side of the body called ozadenes. There are about 60 British species of which we found four.
Pterostichus niger ground beetle, centipede, Discus snail under stone.
Tachypodoiulus niger is very easy to identify as it has a black body and white legs. When disturbed it wriggles like a snake. I often find it on dead wood.
In contrast, Cylindroiulus punctatus curls up when disturbed.
Here is once stretched. C. puctatus has a characteristic face mask between its eyes and a clubbed tail end.
In Blaniulus guttulatus the ozadenes are bright red. This species has no eyes and it's thin and tiny
Here are two Blaniulus guttulatus under a stone. They are often found together in large numbers.
A Flat-backed millipede, Polydesmus sp.
The Sycamore embracing a headstone.
A mushroom on yew that looked like mango ice cream.
Lots of Jelly ear fungus.