Economics of comb wax salvage by the red dwarf honeybee, Apis florea

Abstract

Colonies of Apis florea, which only abscond a short distance, usually return to salvage old nest wax; but, those colonies, and all other honeybee species which go considerably further, do not. Wax salvage would clearly be counter-productive unless the energy input/energy yield threshold was a profitable one. There are two possible trade-offs in this scenario, the trade-off between the energy expended to recover the wax (recovering hypothesis) as against that of replacing the wax by new secretion (replacing hypothesis). In order to compare the two hypotheses, the fuel costs involved in salvaging wax on one return trip, the average flower handling time, flight time and relative values for substituting the salvaged wax with nectar were calculated. Moreover, the energy value of the wax was determined. Net energy gains for salvaged wax were calculated. The energy value of the salvaged wax was 42.7 J/mg, thus too high to be the limiting factor since salvaging costs are only 642.76 mJ/mg (recovering hypothesis). The recovery costs (642.76 mJ/mg) only fall below the replacement costs for absconding distance below 115 m thus supporting the replacing hypothesis. This energetic trade-off between replacing and recycling plus the small absconding range of A. florea might explain why A. florea is probably the only honeybee species known to salvage wax and it parsimoniously explains the underlying reasons why A. florea only salvages wax from the old nest if the new nesting site is less than 100–200 m away—energetically, it pays off to recycle. Electronic supplementary material The online version of this article (doi:10.1007/s00360-010- 0530-6) contains supplementary material, which is available to authorized users.