Friday, 20 May 2011

Large Red-eyed Damselflies in Cheshire

May 19, 2011:
Large Red-eyed Damselflies (Erythromma najas) have now emerged here. At this small pool at the north-western limit for the species in Britain, several males could be seen out in the centre of the water where they rested on floating pondweed. As soon as the sun emerged there was frenzied activity as the males defended their territories from intruders. Occasionally also, an ovipositing pair would be ‘buzzed’. When egg-laying in tandem, the female was totally immersed under the surface but protected by an envelope of air around her body. Today all remained at long range and made photography difficult. These are quite fast-flying insects which keep low down close to the water surface but are easily picked out by their striking bright red eyes.

[Male; the female totally immersed when egg-laying]

[Territorial males resting on pondweed]

This same sheltered pool had several other species of Odonata, especially damselflies, and was a haven for other wildlife as well. A group of resting Mallard ducklings added to the idyllic scene.

Monday, 16 May 2011

DRAGONFLY: Banded Demoiselles have emerged at Brockholes Wetlands

May 11, 2011:
Banded Demoiselles (Calopteryx splendens) are now flying here. Several males showing their beautiful metallic-blue colouring were resting in the long grass adjacent to the Meadow Pool reed beds. At this date there was no sign of the females which have browner wings lacking the dark banding and a greener thorax and abdomen.

[Males above, female below]

Thursday, 12 May 2011

PLANT: Fen Violet in central England

May 9, 2011:
Fen Violet (Viola persicifolia Schreb.) is a very scarce plant and in Britain is now only reliably found at a single locality in central England. A visit there this week revealed several hundred plants in full flower.

Much of the success of the plant here is due to conservation work carried out over recent years by a band of dedicated botanists. The locality is a fen meadow which approaches the NVC classification M24 (Molinia caerulea-Cirsium dissectum) and where other interesting plants grow nearby.

[Fen Violet, all above]

[The habitat where Fen Violet occurs; local botanists assessing the population]

Also found here is the related Dog Violet (Viola canina) with which the Fen Violet sometimes hybridises (V. x ritschliana). Dog Violet and the (sterile) hybrid appeared to be scarce here this year although a few plants were found.

[Flower of the hybrid, V. x ritschliana]

Fen Violet is characterised by its broad, very pale blue-white flowers, its greenish coloured spur and narrowly ovate, subcordate leaves. The hybrid approaches Dog Violet in flower characters and Fen Violet in habit. Fen Violet also occurs spasmodically in small numbers at two localities in eastern England and was much more widespread in past centuries before drainage reclamation drastically reduced its habitat.

Good populations are also known in the Burren area of western Ireland where it grows as the lowest zonal layer of violets on the sides of turloughs (small lakes with rapidly changing water levels). There the hybrid grows slightly above the Fen Violet with V. canina forming the uppermost zone. I saw it here in 1989 when all three taxa were locally profuse.