Sugar concentration influences decision making in <i>Apis mellifera</i> L. workers during early-stage honey storage behaviour

Abstract

Decision making in honeybees is based on information which is acquired and processed in order to make choices between two or more alternatives. These choices lead to the expression of optimal behaviour strategies such as floral constancy. Optimal foraging strategies such as floral constancy improve a colony's chances of survival, however to our knowledge, there has been no research on decision making based on optimal storage strategies. Here we show, using diagnostic radioentomology, that decision making in storer bees is influenced by nectar sugar concentrations and that, within 48 hours of collection, honeybees workers store carbohydrates in groups of cells with similar sugar concentrations in a nonrandom way. This behaviour, as evidenced by patchy spatial cell distributions, would help to hasten the ripening process by reducing the distance between cells of similar sugar concentrations. Thus, colonies which exhibit optimal storage strategies such as these would have an evolutionary advantage and improve colony survival expectations over less efficient colonies and it should be plausible to select colonies that exhibit these preferred traits.

No spatial patterns for early nectar storage in honey bee colonies

“…Moreover, clustering of cells with similar concentrations occurred only occasionally, thereby indicating that workers do not follow a consistent rule for spatial nectar storage at this stage of honey production. Our conclusions differ from those of Greco et al (2013) who suggested occurrence of clusters of cells containing similar content in smaller colony units and after a shorter storage period. This shows that honey ripening processes need to be considered under various conditions to provide a more general understanding of the storage behaviour of honeybees.…”

“…During this time, the hives were kept in a cool room at 14 °C to prevent overheating of the closed compartment. Apart from colony size, hive type and experiment duration, the same experimental and feeding conditions as in Greco et al (2013) were used.…”

“…We used 9 small hives (Miniplus (R)) filled with ~4,000 workers each (compared to 1,000 in Greco et al 2013). Such size corresponds to experimental unit able to express all normal behaviours of a full sized colony (Seeley 1995, Jeanson et al, 2007.…”

“…In support of this hypothesis, clustering of cells with content of similar concentration was shown within the first 48h of access to a sugar solution (Greco et al 2013). By building on their methods and by using less restrictive experimental conditions (reflecting a biologically more relevant situation), we aimed at consolidating and generalising these findings.…”

“…Its ontogenesis is described as the result of a self-organized process based on simple decision rules (Camazine 1990, 1991, Johnson 2009, Montovan et al 2013) probably leading to reduced energy expenditure (shorter transport times and distances) and hence to task optimization (Dreller and Tarpy 2000, Schmickl and Crailsheim 2004, Hepburn et al 2014. A spatial pattern in the early carbohydrate storage could restrict the tasks necessary for honey ripening to distinct areas of the comb and thus contribute to reduced energy consumption (Greco et al 2013). Such tasks include active evaporation of cell content by food processors (Park 1925(Park , 1927(Park , 1928(Park , 1933(Park , 1949, or ventilation which has been proposed as a mechanism to regulate atmosphere humidity of honey stores to favour passive evaporation (Reinhardt 1939, Human et al 2006).…”