Abstract:
Some parasites of social insects are able to exploit the exchange of food between
nestmates via trophallaxis, because they are chemically disguised as nestmates.
However, a few parasites succeed in trophallactic solicitation although they are
attacked by workers. The underlying mechanisms are not well understood. The
small hive beetle (=SHB), Aethina tumida, is such a parasite of honey bee, Apis
mellifera, colonies and is able to induce trophallaxis. Here, we investigate
whether SHB trophallactic solicitation is innate and affected by sex and experience.
We quantified characteristics of the trophallactic solicitation in SHBs from
laboratory-reared individuals that were either bee-na€ıve or had 5 days experience.
The data clearly show that SHB trophallactic solicitation is innate and further
suggest that it can be influenced by both experience and sex. Inexperienced
SHB males begged more often than any of the other groups had longer breaks
than their experienced counterparts and a longer soliciting duration than both
experienced SHB males and females, suggesting that they start rather slowly and
gain more from experience. Successful experienced females and males were not
significantly different from each other in relation to successful trophallactic
interactions, but had a significantly shorter soliciting duration compared to all
other groups, except successful inexperienced females. Trophallactic solicitation
success, feeding duration and begging duration were not significantly affected by
either SHB sex or experience, supporting the notion that these behaviors are
important for survival in host colonies. Overall, success seems to be governed by
quality rather than quantity of interactions, thereby probably limiting both SHB
energy investment and chance of injury (<1%). Trophallactic solicitation by
SHBs is a singular example for an alternative strategy to exploit insect societies
without requiring chemical disguise. Hit-and-run trophallaxis is an attractive
test system to get an insight into trophallaxis in the social insects.
