1981] Howard, Mallette, Haverty, & Smythe — Reticulitermes 85 
ings contained protozoa typical of both parents, we also infer that 
the larvae engage in proctodeal feeding with both parents. We do 
not know whether such mixed-species pairing occurs in the field. 
The main flight periods of R. flavipes and R. virginicus are 
separated by about one month (late February to early April for R. 
flavipes and mid-April to mid-May for R. virginicus). But unpub- 
lished records from the Forestry Sciences Laboratory in Gulfport, 
Mississippi, indicate that R. flavipes, at least, may have flights every 
month of the year, rendering it at least theoretically possible for 
interspecific pairing to occur. 
Despite the success of incipient colonies in the laboratory, their 
intrinsically slow growth rates raise serious questions regarding the 
importance of such pairs as a major means of population expansion. 
As noted in the introduction, our field studies (Howard and 
Haverty, 1980) sugget that R. flavipes frequently undergoes popula- 
tion expansion by colony fission with subsequent production of 
multiple neotenic reproductives. Since such new colonies pre- 
sumably consist of several thousand individuals, their ability to 
survive should be markedly greater than that of dealate headed 
incipient colonies. It is, of course, possible that dealate individuals 
or pairs could be adopted by an established colony, but we know of 
no data to support such a position. 
Clearly, considerably more work should be done to verify the 
findings of these studies. The success of intraspecific matings is not 
in question. The confounding results of the interspecific matings 
demand further cytological and experimental evaluation. The 
mechanisms of reproductive isolation should be clarified as well as 
the integrity of these two sympatric species. 
Summary 
Incipient colony foundation in the laboratory by dealates of 
Reticulitermes flavipes (Kollar) and R. virginicus (Banks) was used 
to examine several possible reproductive strategies available to these 
sympatric subterranean termite species. Successful colony forma- 
tion and progeny production occurred with pairings of R. flavipes 
males + R. flavipes females (from either spring or fall flights), R. 
virginicus males + R. virginicus females, R. virginicus males + R. 
flavipes females, and R. virginicus females + R. virginicus females. 
Few progeny resulted from pairing R. flavipes males + R. virginicus 
