In the last issue of the White Admiral (55, Summer 2003, pp. 34 and 45) I asked if anyone could identify an organism that I described. Not surprisingly, perhaps, I got no response, for it turned out to be a rather strange insect with a peculiar life cycle.
Its identity was eventually tracked down, via Google and a bit of serendipity. Searching for references to the ladybird, Stethorus, I found a site at the Canterbury Christ Church University College website concerned mainly with biological control which listed papers on ‘soft scale’ by Dr D. J. Ponsonby. This sounded very like my query and he kindly had a look at the photograph and description and confirmed that it was a soft scale insect, possibly of the genus Coccus. To identify it more precisely will need to help of an expert and more specimens. Unfortunately the Suffolk Naturalists’ Society does not have a recorder for the Hemiptera.
The insect is a member of the sub-order Homoptera, part of the Hemiptera (Dolling, 1991). The complexity of this group that contains many insects with bizarre life cycles and life forms makes the study of mammals and birds look like child’s play and it was no surprise to learn that some people elect to work only with a single group such as the Coccoidae. This contains some of the most highly modified forms, some scarcely recognisable as insects. The adult females are not segmented and often lack legs and therefore cannot move. Only the first instar larvae, called crawlers, have well developed legs and can disperse to new sites. Like aphids, members of a related group, soft scales feed on phloem and produce copious amounts of honeydew. The males, where they occur, often resemble small flies have no mouthparts and have very short lives.
It will be interesting to find out more about the soft scale on gorse but try not to become addicted to this fascinating group.
Reference
Dolling, W. R. (1991) The Hemiptera. Natural History Museum Publication, Oxford University Press.
e-mail: e_j_m_kirby@btinternet.com
© 2003 Suffolk Naturalists' Society