The Essex Naturalist
11
Returning to Surrey, for just a moment, one can deduce from an analysis of
the species recorded that several of those absent are not likely to be found and it
may thus be taken, at least in very broad terms, that Surrey is a well-recorded
county. Thus, any comparison with the county may be of interest. South Essex-
has 39 species recorded since 1979 - fourteen less than Surrey (though ranking
third, nevertheless). This is particularly interesting since I personally worked in
South Essex for much of the survey period and, as perhaps may be expected from
the co-ordinator of the Recording Scheme, was actively engaged in Neuroptera
field-work during that time. I regard the vice-county as moderately to very well-
covered. For the last seven years of the survey that generated the "league table",
I lived at my present address in Hertfordshire. A new county! An active field-
worker! Yes - I regard Hertfordshire also as being quite well-covered, though
perhaps less so than South Essex. Hertfordshire has 41 species in the post-1979
period and so may be broadly said to be similar to Essex. Why then does Surrey
have so many more species and, of greater importance perhaps to the Essex Field
Club, what is "wrong" with Essex?
The answer to this question is far from clear. Thermophilic species, which one
may expect to be more evident further south, are few in the Neuroptera. In any
case, recent work on the aculeate Hymenoptera (Plant & Harvey, 1997) has
clearly demonstrated the value of the Eocene and Recent sand and gravel based
habitats in the region of Grays-Thurrock to thermophilic species and it may be
concluded that any thermophilic Neuroptera may also find this region
acceptable. Atmospheric and other forms of pollution are on the decrease and
are unlikely to have a more profound effect on the Essex fauna than on that in
Surrey. The lack of suitable habitat could also be considered but is unlikely to be
the real reason if one considers the preferred requirements of the species
concerned (Table 3).
One could, of course, look at the data in Table 2 a different way and consider
that whilst Essex has only 39 species presently recorded, it only ever had forty,
and so we have only apparently lost one! Surrey, on the other hand, may have
more species, but has evidently lost twelve over the years since the last century.
On that basis, Surrey has evidently more to worry about than Essex!
Table 3: Species recorded since 1979 in Surrey but not yet recorded in Essex with
their preferred habitats
RAPHIDIOPTERA
Atlantoraphidia maculicollis - Pine trees, including conifer plantations
NEUROPTERA
Sisyra dalii — Rock strewn, fast-flowing rivers
Sisyra terminalis - Rivers
Coniopteryx lentiae - Unknown - possibly broad-leaved woodland