THE COURTSHIP CALL OF CHRYSOPA DOWN ESI BANKS 
(NEUROPTERA: CHRYSOPIDAE): 
ITS EVOLUTIONARY SIGNIFICANCE* 
By Charles S. Henry 
Biological Sciences Group, Box U-43 
University of Connecticut 
Storrs, CT 06268 
Introduction 
Tauber and Tauber (1977a) suggest that the conifer-associated 
green lacewing Chrysopa downesi Banks evolved sympatrically in 
northeastern North America from its holarctic sibling C. carnea 
Stephens. The proposed mechanism of speciation follows the gen¬ 
eral theoretical model of Maynard Smith (1966) and specifically 
involves simple allelic changes at three loci, one controlling body 
color and two altering the insect’s response to photoperiod (Tauber 
and Tauber, 1977b). Gene substitution at the first locus initially 
induced divergence in habitat association, while later substitutions 
at the other loci produced complete reproductive isolation of the 
two populations by causing each to breed at a slightly (but suffi¬ 
ciently) different time of year (Tauber and Tauber, 1976). 
An alternative explanation of C. downesi's origin from C. carnea 
is proposed which invokes the concept of allopatric speciation 
(Mayr, 1963): two portions of a previously contiguous C. carnea 
population became physically isolated from one another for a 
period of time, perhaps by glaciation events; subsequently, removal 
or disappearance of the geographic or climatic barrier re-established 
contact between the two populations, but intervening, independent 
evolutionary changes prevented much or any gene flow (Hendrick¬ 
son, 1978). Tauber and Tauber (1978) argue that allopatric or geo¬ 
graphical speciation is a less parsimonious explanation of the 
existing data than the sympatric model, although they admit that 
their evidence does not truly discriminate between the two hypo¬ 
theses. However, my studies of courtship and mating behavior in the 
two lacewing species indicate that, in this case, a traditional allopat¬ 
ric model may in fact be preferable to the more intriguing sympatric 
one. 
*Manuscripl received by the editor February 20, 1980 
291 
