Download - NERC Open Research Archive - Natural Environment ...

LITERATURE AND REFERENCES
SOURCES OF INFORMATION
Dragonflies by Corbet, Longfield and Moore (1960),
and A biology of dragonflies by Corbet (1962)
provide a thorough introduction to the subject, and
review the older literature in detail. Dragonflies by
Miller (1987) brings the subject up-to-date, as well
as providing illustrated keys for identification. The
dragonflies of Great Britain and Ireland by Hammond
(2nd edition, revised R Merritt 1983) also has keys
and large illustrations. The colour photographs in A
complete guide to British dragonflies by McGeeney
(1986) are useful adjuncts to his keys and
descriptions.
The dragonflies of Europe by Askew (1988) is an
essential reference work for those studying
dragonflies on the continent of Europe. However, it
is a large book, and some may find A field guide to
the dragonflies of Europe and North Africa by
Aguilar, Dommanget and Prechac (English edition
1986) or Dragonflies and damselflies of Britain and
northern Europe by Gibbons (1986) more portable.
Each of the available guides has its merits and its
drawbacks, and each will appeal to some readers.
A tabular review of identification guides is provided
by Jones (1987).
The British Dragonfly Society produces its own
Journal, with two issues each year. Its articles are
full of interest to those concerned primarily with
British and Irish species. It includes book reviews.
On the world scale, the Societas Internationalis
Odonatologica (SIO) produces Odonatologica four
times a year, as well as Notulae Odonatologicae for
shorter articles. Odonatologica provides a
comprehensive abstracting service, as well as
containing a large proportion of the papers on
dragonflies which are published.
LARVAL IDENTIFICATION
The identification of larvae and exuviae to species is
becoming increasingly important in the context of
Odonata monitoring. The papers by Gardner (1954,
1955) were reprinted in Corbet et al. (1960), and
again in Hammond (1977, 1983). Hammond's work
was intended to be accompanied by a second
volume, to be written by Gardner, dealing in detail
with larvae, but unfortunately Gardner's untimely
death prevented this.
These same keys provided the basis for others, such
as those in Miller (1987), and the keys in Askew
(1988) also rely heavily on Gardner for British and
Irish species. The keys by Carchini (1983) to the
132
larvae of Italian Odonata (written in English and well
illustrated) introduce a few new identification
features, and are differently structured, so provide
some alternative. However, there remain several
difficulties in determining larvae and exuviae to
species. In particular, it should be noted that all
keys so far published are intended for use with fmal
instar larvae, and that they will be correspondingly
less reliable if applied to earlier stages. Almost all
key features are readily seen on exuviae. Many of
the characters used in the key are far easier to
interpret if reference material is available, so it is
worthwhile collecting a range of exuviae before
attempting to use the keys.
Identifications based on the number of labial setae
are not always reliable: in particular, the separation
of Lestes dryas from L. sponsa, and of Ischnura
pumilio from I. elegans by means of counting the
setae on the prementum and the labial palps is not
infallible. Female Lestes larvae are more reliably
separable in late instars by the size and proportions
of the genitalia. In I. elegans, the spines on the lateral
ridges of abdominal segments 7 and 8 are stouter
than those on the ventral surface; there is no such
size difference in I. pumflio. There appears at
present to be no reliable means of separating
Coenagrion puella and C. pulchellum as larvae. The
separation of Sympetrum sanguineum and S.
striolatum/nigrescens, based on the relative length of
the lateral spine on abdominal segment 9, can
cause difficulties for inexperienced observers. A
solution to such problems is to take a few larvae
home and breed them out. Some useful information
on this subject is given by Butler (1985).
REFERENCES USED IN THIS ATLAS
The information contained in the individual species
accounts is based on the work of numerous authors,
as well as on unpublished information. It would be
impractical to include references for every
statement. Therefore, if a statement is derived from
the following works, or from papers referred to in
their bibliographies, it is not usually given a
separate reference.
World distribution
General biology
Conservation status in Europe
Adult population densities
Askew (1988)
Corbet, Longfield &
Moore (1960)
Corbet (1962)
Maibach & Meier (1987)
van Tol & Verdonk (1988)
Moore (1964, 1991c)
The references which are given below are to be
found in the text of this Atlas and draw attention to
some (but only some) recent studies.