Rate, amount, and distribution pattern of alimentary fluid transfer via trophallaxis in three species of termites (Isoptera : Rhinotermitidae, Termopsidae)

Trophallaxis, defined as the direct transfer of alimentary liquids, includi ng suspended particulates and derivatives, from one nestmate to another via regurgitation or anal feeding, is important in the nutritional dynamics an d communication of many social insects. Trophallaxis is a mechanism for the transfer of nutrients, symbionts, pheromones, and information within socia l insect colonies. We used the radioactive tracer cobalt-60, combined with the vital dye Nile Blue A, in a standard diet to investigate the rate, amou nt, and distribution pattern of alimentary liquids in the termites Reticuli termes flavipes (Kollar) (Isoptera: Rhinotermitidae), R. virginicus (Banks) , and Zootermopsis nevadensis subsp. nevadensis (Haverty & Thorne) (Termops idae). The technique did not affect termite survivorship and enabled determ ination of the rate and quantity of material transferred from identifiable, marked "donor" individuals to "recipients." This method of tracing trophal lactic transfer of alimentary fluid would be an appropriate standardized te chnique facilitating comparison of data among researchers. Transfer of a de tectable amount of alimentary fluid in R. flavipes, R. virginicus, and Z. n . subsp. nevadensis occurred within 6-12 h after introduction of potential donors to potential recipient termites. The amount of isotope transferred f rom the donor to the recipient group varied, but generally ranged fr om 5 t o 30% of the isotope initially acquired Ly the donor. Transfer of isotope i nitially was to a few members of the recipient group; isotope acquired by t hose recipients was distributed subsequently among the other termites. Diff erences in patterns of trophallaxis between Isoptera and Hymenoptera are di scussed.