QUESTIONS AND ANSWERS

Social life from solitary circuits: a new paradigm of caste in social wasps. 
James Hunt, Univ. of Missouri.

Q:  If the larvae are able to refuse giving saliva to adults, why would they give it up at all?  Wouldn't selfish behavior be more beneficial to them?  What is the cost of refusing saliva?

A:  One possible answer addresses a phenomenon that may have played a role at the origin of the behavior. When the going gets tough, the tough eat the babies and then reproduce another day. Therefore larval trophallaxis may have originated, at least in part, as an appeasement to forestall cannibalism. Another possible answer–and one that may be central to maintaining the behavior once it evolved–is colony-level selection. The fitness payoff of a large number of gynes at the end of the season may have selected strongly for life history components, including the saliva trophallaxis behavior, that contribute to that payoff.

Q:  Do G1 and G2 vary in the amount of saliva shared?  Does the amount or frequency of saliva shared affect the amount of food it receives?

A:  These are unanswered questions. Inquiring minds (my own!) would like to know. I’d also like to know if the quality (nutrient content) of the saliva varies among individuals or across the lifetime of single individuals.

Q:  Does the "decision" of a G1 female to become a gyne or worker depend on her socially-influenced nutritional status?  Your model focuses on a developmental nutritional influence on adult caste/behavior.  How might variation in adult nutritional status influence plasticity?

A:  I think that variation in adult nutritional status is precisely what determines the options in the “queen lives” pathway for G1 females. When G1 females emerge in a colony environment with a living queen but few workers, they engage in maternal behaviors alloparentally, but the high costs of foraging (= depleted nourishment) constrain them from ovary development. When G1 females emerge in a colony environment with an established worker force, they forage little. Consequently their ovaries can develop, they may establish “satellite” nests, and there they undertake maternal behaviors parentally. Dominance behaviors might well play a significant role in these plastic options in the G1 pathway, but dominance studies done heretofore have mostly looked at co-foundresses rather than offspring, and of course no previous studies have looked at offspring through G1/G2 lenses. Having mentioned co-foundresses – these, of course, were last season’s G2’s, and dominance interactions among them as foundresses play out in a distribution of nourishment (both received and retained) that is highest in alpha and lowest in omega. The few cite-able studies on intra-colony variation in nourishment are old, and the work very much needs to be repeated as well as expanded.