SOLDIER PRODUCTION AND MAINTENANCE OF SOLDIER PROPORTIONS IN L A B O R A T O R Y EXPERIMENTAL GROUPS OF COPTOTERMES FORiVlOSANOS SHIRAKI

Exper imenta l groups of 100 percent pseudergates of Coptotermes formosanus Shiraki were set up in the labora tory and a l lawed to di f ferent ia te for e i the r 4, 8 or 12 weeks. The average percentage of pseudergates d i f ferent ia t ing into presold iers and soldiers at these t ime intervals was 3.8, 14.2, and 21.9 percent , respectively. Dif ferent ia t ion to the soldier caste was affected b o t h by ini t ia l group size and colony origin. Groups initially composed of 100 pseudergates produced a significantly smal le r p r o p o r t i o n of soldiers t han did groups of 300, 500, or 1000. Recently collected field colonies produced soldiers at s ignif icantly h igher ra tes t han one wh ich had been m a i n t a i n e d in the l abora tory for 8 years. The n u m b e r of soldiers p roduced was highly cor re la ted xvith t he to ta l numbe r of all individuals at 4, 8, and 12 weeks, xvhich indicates a precise physiological mechan i sm for regulat ing soldier propor t ions . Exper imenta l groups ~vere also set up w i th " n o r m a l " (24 percent) , "below n o r m a l ", and " above n o r m a l " init ial p ropor t ions of soldiers wi th pseudergates . '~Nhen soldiers were present in " b e l o w n o r m a l " p ropor t ions they inhib i ted the presold ier product ion , so tha t presold ier development gradually declined as the ini t ial soldier-pseudergate ra t io approached the norm. This species can to lera te and will m a i n t a i n an exceptionally h igh p ropor t ion of soldiers (ca. 38 percent) wh ich is far above the a s sumed " no rma l ~ propor t ion . Many, bu t not all, of the excess soldiers xvere p robab ly e l imina ted by cannibal ism. Groups severely over loaded w i th soldiers succumbed to microbia l c o n t a m i n a t i o n af ter the excess soldiers s tarved to death. From these resul ts I conclude t ha t colonies of C. formosanus do m a i n t a i n numerically cons tan t p ropor t ions of soldiers wi th in b r o a d limits. Thus, colonies m i g h t be cont rol led by chemical ly inducing the p roduc t ion of superf luous soldiers. Successful control would requi re the p ropor t ion of soldiers be so great t ha t the pseuderga tes could not