Is it a flower or what?

August 22nd 2017

On 6th August 2017 Gwen Richards and I were botanising around the old gravel quarry on the top road at Culkein Stoer (NC033326). In one place on the edge there was a small stand of sneezewort Achillea ptarmica, with white and yellow daisy-like heads of flowers and characteristic saw-edged leaves.

Gwen noticed one shoot that looked markedly different, with a crowded terminal rosette of leaves sheltering a dark spongy structure in its centre. This was a communal gall of the midge Rhopalomyia ptarmicae, the spongy tissue of which had housed and fed a number of larvae; these had changed into pupae, from which the adults had already emerged.

Galls are composed of plant tissue fashioned, under the influence of the causers, to provide just the right conditions for the development of their early stages. They are often very specific to one part of a particular host, as in this case. It does make you wonder how the young larvae manage to divert the host into making a home for them rather than heads of flowers.

Ian M. Evans

 

Report a Sighting

Recent Sightings

Manx Shearwater

27 birds off Bay of Clachtoll (DAH) (16/06)

Harbour Porpoise

Mother and calf off Stoer Head Lighthouse (DAH) (15/06)

Small Magpie moth (Anania hortulata)

Single moth in garden, Culkein Drumbeg (DAH). This is only the second ever record of this micro-moth in the West Sutherland recording area, VC108. The first record was on 1st June this year in the garden of the County Moth Recorder in Melvich on the north coast. However, this does make it the first ever record for Assynt. Photo Gallery - Moths. (14/06)

Golden Plover

Eight birds over Clachtoll (DAH) (13/06)

Peregrine

Single bird flying over garden, Ardvar (Beccy Garvey) (12/06)

Small Pearl-bordered Fritillary

Single butterfly, Nedd (Stefan Taylor) (12/06)

Small Pearl-bordered Fritillary

Single butterfly recently emerged at Glen Leraig (AS) (11/06)

Barn Owl

Single bird hunting over croft land, near Stoer primary school (Jane Livingstone) (11/06)

Map