292 
Psyche 
[June-September 
Implicit in most models of geographical speciation is the streng¬ 
thening of reproductive isolation between imperfectly isolated pop¬ 
ulations after contact is re-established; in animals, behavioral 
patterns associated with courtship are thought to be particularly 
subject to alteration, since premating barriers are presumed to be 
less wasteful of reproductive effort, gametes, or offspring than those 
that intervene after copulation (Dobzhansky et al., 1977). In lace- 
wings of the genus Chrysopa Leach, I have shown that short- 
distance acoustical communication by substrate transmission of 
abdominal vibration or jerking is a necessary component of success¬ 
ful courtship (Henry, 1979, 1980). A different “calling” pattern char¬ 
acterizes each of the eight sympatric lacewing species that I have 
studied in detail, suggesting that abdominal jerking is or has been 
important to the reproductive isolation of lacewing species in east¬ 
ern North America. This view is strengthened further by the fact 
that the most closely related species, particularly those of the subge¬ 
nus Chrysoperla Steinmann, 1 predictably show the most distinctive 
and elaborate patterns. Since C. carnea and C. downesi are 
members of this latter taxon, the nature of their acoustical signals 
could indicate how they speciated. If their separation occurred 
within a single continguous population by the simple genetic 
changes postulated by Tauber and Tauber, one would predict iden¬ 
tity or at least similarity of calling pattern in both species, since (1) 
barriers to gene flow are presumed complete after the three allelic 
substitutions and (2) even casual attempts at interspecific matings 
are precluded by the Taubers’ model. On the other hand, allopatric 
speciation followed by re-established sympatry should produce 
unmistakably different patterns of abdominal jerking in the two 
species, since different calls would terminate heterosexual interac¬ 
tions between them before copulation could occur. I propose that 
the latter alternative is consistent with the extreme calling differen¬ 
ces that exist between the two siblings. 
Methods and Materials 
Lacewing calls consist of discrete bursts or volleys of abdominal 
strokes (jerks); the call itself is actually a sequence of one or several 
different kinds of volleys repeated in characteristic temporal pat- 
'This taxon has been given full generic status by Y. Semeria (1977). 
