The inhibitory potential of primary and secondary reproductives was studied using half-orphaned colonies of Kalotermes flavicollis. Both primary and secondary reproductives (neotenics) were equally effective in inhibiting the development of replacement reproductives. Single females totally inhibited the development of female secondary reproductives but did not affect the development of male secondary reproductives. Single males had neither a stimulatory nor inhibitory effect on the development of secondary reproductives. The inhibitory ability of pairs of primary reproductives shortly after dealation and at the stage of incipient colony formation (couple with the first batch of eggs) was also examined. While pairs of freshly dealated reproductives were not able to inhibit the development of neotenics, pairs of primary reproductives that had their first batch of eggs, fully inhibited the development of neotenics.
The effect of removing the functional pair of Kalotermes flavicollis from an experimental colony for 12, 24 or 48 h and the repeated removal for a particular number of hours per day (2, 4, 6, 12, 18, 20, and 22 h) was studied. An absence of the functional pair for 12 h had no affect on the development of new neotenics, whereas 24-h absence induced the development of new neotenics in 5 out of 12 experimental groups. A 48-h absence induced development of new neotenics in all 12 experimental groups. Pseudergates and nymphs can be orphaned for up to 12 h a day without being stimulated to differentiate, after which the number of new neotenics increased gradually with the time for which the reproductive pair was absent. This suggests that the inhibitory process is continuous and cumulative. Both sexes showed similar sensitivity to the absence of reproductives. The study also tested, by exchanging pseudergates between groups with functional pairs and orphaned groups, whether pseudergates in experimental groups actively spread inhibitory factors; however, this was not proven. Only pseudergates and nymphs that were in direct contact with the functional pair were inhibited.