common names/systematics

[Pierre Zagatti]

Maybe a lot of science after that discussion about common names
that seems a little bit wordy for non-english speaking entomologists....

In theory (!) there is a good system to recognize species or subspecies
among contiguous populations. Look at the single mate recognition systems
(smrs of Patterson) in both populations. They may be secondary sexual characters,

behaviors or androconia and Bernardi (among others) has shown that
in really contiguous or overlapping populations, these systems evolved in a way
to produce strong isolating barriers, whereas these barriers may not exist in
geographically
isolated populations. If these barriers exist, the two populations should belong
to
different species.
Frequently, species A won't mate with species B in contiguous populations
although
forced matings (artificial pairing with hand in the case of leps) will produce
quasi-fertile
offspring. On the other hand, species A will mate with (geographically isolated)
species
C without 'help', resulting in sterile mating.

Now practically, the main problem is to identify these smrs. In moths, the sex
pheromone
is a good approach, but immediate conclusions may be hazardous: if we consider 2
groups
of day-flying moths, the burnet (genus Zygaena - Zygaenidae) and clearwing moths
(Sesiidae),
they have developed totally different smrs.
The absolute isolation in Zygaena is induced by sex pheromone. Once the male has
been
stimulated by his female pheromone, he will try to copulate with everything
showing a
strong red contrast (including your red pencil cap or a female of a different
species
you viciously placed here).
In Sesiidae the isolation is essentially visual. A few molecules of sex pheromone
may
attract many different species but mating will occur only by visual
identification of the
partner.
Such difference between two families with similar biology is probably related to
different
strategies to avoid predation: Mullerian mimicry in burnets (i.e. species mimic
each other)
and wasp mimicry in Sesiids.

--
Pierre ZAGATTI
INRA Unite de Phytopharmacie et Mediateurs Chimiques
78026 Versailles Cedex
FRANCE
Tel: (33) 1 30 83 31 18
e-mail zagatti at versailles.inra.fr
http://www.jouy.inra.fr/papillon/