Worcestershire Record No. 17 November 2004 p. 31-34

John Partridge

There can be few of us who haven’t looked at shieldbugs, admired them, and wondered how easy it would be to put a name to them. The publication in 2003 of Shieldbugs of Surrey made easily available the means to identify all of the shieldbugs which can be found in Worcestershire, as well as some related species, and I thought that it would be useful to have a look at the records that we already hold, and where the gaps are that could be filled.

When I looked at the printout-out of a couple of species, I was surprised by how late the records started, considering that some of the larger species are both attractive and easily identifiable. The earliest records that we hold at WBRC are from Fred Fincher, starting from 1947, there is a surge from Owen Wilson in 1976/77, some from C W Plant in 1984, with Don Goddard and John Meiklejohn coming into the picture at about the same time, and then Kevin McGee in more recent years, with a few other records from other recorders.

The previous reference book was Land and Water Bugs of the British Isles (Southwood and Leston, 1959), long out of print, and expensive if you can find it, although it is now available as a CD-Rom version. The preface to this refers to the Entomologists’ Monthly Magazine and to The Entomologist, so presumably some keys or identification guides had been available earlier.

Shieldbugs of Surrey also contains some references to older county lists, and I was fortunate to find that Harry Green had copies of the relevant publications. Table 1 lists the species for which we hold records, the number of records of each species, and whether the species occurs in the 1945 and 1955 county lists. The main conclusion that can be drawn is that Worcestershire was under-recorded in 1945, with species missing that were present in both Herefordshire and Warwickshire (the reverse also applies), but that things were better by 1955. There is no indication of the recorder(s) who produced these older lists.

Species which appear to have moved in since these dates are Aelia acuminata, Bishop’s Mitre, which is unlikely to escape notice with its unusual shape, Coreus marginatus which also could hardly have been overlooked and Rhopalus subrufus – fairly conspicuous, although perhaps not so easily identifiable. In Surrey Aelia acuminata ‘… was considered rare in the early days of the present survey…. None of our recorders noted it before 1988…’ and Coreus marginatus appears to have increased its distribution considerably’.

Two species are found in the county lists, but not in the WBRC list – Dicranocephalus medius, which can be found on Wood Spurge, and Sehirus biguttatus, which occurs on Cow-wheat. Both are Notable B species, and not particularly conspicuous, and it is possible that the early records refers to only one specimen of each, but hopefully this will provoke some of us into looking for them.

The distribution maps are on a separate page, producing a file of about 500 kB, which may take some time to download. They cover all the species in the new book which have been recorded in Worcestershire. There is insufficient coverage of even the most well-recorded species to indicate any more than where recorders have been, and it would be impossible to draw any valid conclusions from this data, except that, as with so many other groups, we could do with more records.

Table 1

Map showing the number of records per tetrad