Introduction
 In
Britain just over 40 species of Odonata (Dragonflies and Damselflies)
have been recorded almost three-quarters of these can be found in Cheshire
and Lancashire, although not all breed and some have been only recorded
as migrants. The term dragonfly is used widely to describe the order.
Damselflies and dragonflies can be easily separated down to order level.
Damselflies are slimmer and rest with their wings along their bodies.
Their large eyes are widely separated. Dragonflies rest with their wings
at right angles to their bodies and large eyes that usually meet. For
full descriptions see one of the books listed in the bibliography section.
When to Look
Most species of dragonfly and damselfly are on the wing, i.e. in their
adult form, between May and October, although the period from mid-June
to late August is perhaps the best time to undertake survey work. It should
however be noted that some species only fly in the early part of the season,
so survey work for them should be concentrated in May and June. The underwater
nymph stage of the life cycle can be found all year round, although they
are not as easy to identify as the adult stage.
Life Cycle
Larval Stage
All dragonflies spend the first part of their lives underwater. Depending
upon species this may last from a single season, through to four or five
years for the larger species such as the Golden-ringed Dragonfly. especially
in cooler waters. The larva continue to grow and do not have a pupal stage
as butterflies and moths do. When fully grown they climb out of the water
on a suitable piece of vegetation and split their final larval skin (the
exuvia).
Emergence Stage
As mentioned above, once the larva is ready to emerge it leaves the water
by climbing a reed stem or other suitable piece of vegetation, splits
it larval skin and climbs out. This stage can take an hour before the
adult is eventually free of the exuvia. The exuvia can be collected as
confirmation of successful breeding - they can also be identified down
to species level. The emerged insect may then take several hours before
it is ready to make its maiden flight.
Teneral Stage
This term is used to describe the newly emerged dragonflies. Their colours
are not fully developed and their wings appear very shiny or milky and
even more fragile than normal, they are easily damaged at this stage they
should not be handled and are difficult to identify. The maiden flight
is away from the water and can vary from just a few metres in the case
of damselflies and to over several kilometres in the case of the larger
hawkers. The insect spends several days or weeks away from water maturing
during which time it acquires adult colours and perfects its flying and
hunting skills. At the end of this period it will return to a water body
and search for a mate.
Mature Adult Stage
This is the stage at which the majority of recording is undertaken. The
males are more brightly coloured and therefore more likely to be seen.
The males patrol over their chosen stretch of water, defending it against
others of the same species and waiting for a suitable mate. Once a female
enters a male's territory she is seized and the copulation process begins,
this may last from just a few seconds to several hours depending upon
species. The male clasps the female behind her neck and then she curls
her abdomen up towards his auxiliary genitalia located between his 2nd
and 3rd segments, where the male has earlier transferred his sperm to.
This is known as the "wheel" or "heart position" and
is illustrated in the various guides in the bibliography section. The
dragonflies usually rest in this position or may fly around for periods.
Once copulation is complete the female begins ovipositing. In some species
the female is suspended by the male, in others he may fly around her to
ensure that no other male mates with her. Eggs are laid directly into
the water, on to vegetation or earth in or next to water - the location
depending upon the species.
Recording Methods
The easiest way to record Odonata is to visit suitable habitat and observe
adults as they patrol over their territories searching for a mate or looking
for food. It is possible to find dragonflies, especially the Aeshna, away
from water, when they have recently emerged and are looking for food.
Woodland rides and hedgerows were there are plenty of flies are often
popular. The activity and number of individuals should be recorded, e.g.
was mating, ovipositing or tandem flying noted? For confirmation of breeding
it is necessary to record either the larval stage (nymphs) or exuvia in
or around a pond.
Ideal Conditions for Recording
- Visits should commence after 10.45 and finish before 15.45.
- The weather conditions must satisfy minimum requirements:
- The temperature must be above 13°C
- If the temperature is between 13°C and 17°C there must be
at least 60% sunshine
- If the temperature is over 17°C, then it can be either sunny
or cloudy.
Netting, Photographing and Collecting Specimens
Netting
In some instances it may be necessary to net a damselfly to confirm the
identity, especially when just starting to learn the differences, but
with field experience the need to net becomes less. Netting should be
carried out carefully; in fact some of the larger species are virtually
impossible to net. As dragonflies have a delicate balancing mechanism
between the head and the thorax, this can be damaged by sudden impact
with a net.
Photographing
A good close-up photograph / slide can be useful for identification purposes,
providing the diagnostic features are clearly visible. A 35mm camera with
a close-up lens is necessary obtain a good shot. The subject should be
approached slowly, without casting a shadow; compound eyes of dragonflies
give them almost 360° vision.
Collecting
This is not necessary. If you should come across a new species for the
county, take a description and try to have an independent observer confirm
your record - take a photo if possible.
Useful Books
- Brooks S and Lewington R (1998) Field Guide to the Dragonflies and
Damselflies of Great Britain and Ireland. British Wildlife Publishing.
- D'aguilar, J., Dommanget, J.L. and Prechac, R (1986) A Field Guide
to the Dragonflies of Britain, Europe and North Africa. Harper Collins
- Gabb, R. and Kitching, D. (1992) The Dragonflies and Damselflies of
Cheshire. Liverpool Museum.
- Hammond C.O. (1983) The Dragonflies of Great Britain and Ireland.
Harley Book
- Hill, P.M. and Twist,C. ( 1996) Butterflies and Dragonflies - A Site
Guide, Arelequin
- McGeeney A. ( 1986) A Complete Guide to British Dragonflies Jonathan
Cape.
- Powell, D. (1999) A Guide to the Dragonflies of Great Britain. Arelequin
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