Response to variance in nectar concentration by honey bees, Apis mellifera

Date of Award




Degree Name

Doctor of Philosophy (Ph.D.)

First Committee Member

Keith D. Waddington, Committee Chair


I examined the effects of flower color and different nectar concentrations on honey bee choice behavior to develop a protocol to determine honey bee response to variance in nectar concentration. Some birds, fish, mammals, and invertebrates adjust their response to variance when their energy budgets are altered. Theory proposes that this behavioral shift maximizes their probability of survival. But, honey bees differ from these other animals and thus respond differently to variance. Honey bees have a eusocial organization with hundreds or thousands of foraging workers in the nest, pounds of stored honey in the nest, and a foraging recruitment system.I determined the preferences of individual bees given binary choices between blue and yellow artificial flowers dispensing one $\mu$L of 10%, 20%, or 30% wt./wt. sucrose solutions. Bees had a slight preference for blue flowers that was exhibited most strongly when differences between rewards offered by the flowers of the two colors was smallest. But overall, 21 of 25 bees tested preferentially visited higher sucrose concentrations over lower ones.To test for response to variance, I gave individual bees binary choices between variable and constant sucrose concentration rewards delivered in blue and yellow artificial flowers. Amount of colony honey stores was varied but had no effect on bee response to variance. Nine of the bees tested from colonies with low amounts of honey preferred constant flowers, two were indifferent, and nine preferred variable flowers. Nine of the bees tested from colonies with high amounts of stored honey preferred constant flowers, five were indifferent, and six preferred variable flowers.Energy profits offered by the variable and constant flowers in these experiments were within 0.02 Joules/second of one another. In this study there was no confound between profitability and variance. On a proximate level, this accounts for lack of honey bee consensus on a strategy with respect to variance. But, an ultimate explanation is that having hundreds of foragers, that make hundreds of flower visits per day causes honey bee colonies not to be strongly affected by variance: they acquire the mean of resources available in the environment, regardless of the variance.


Biology, Ecology; Biology, Entomology

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