Evidence of trapline foraging in honeybees

Abstract

Central-place foragers exploiting floral resources often use multidestination routes (traplines) to maximise their foraging efficiency. Recent studies on bumblebees have showed how solitary foragers can learn traplines, minimising travel costs between multiple replenishing feeding locations. Here we demonstrate a similar routing strategy in the honeybee (Apis mellifera), a major pollinator known to recruit nestmates to discovered food resources. Individual honeybees trained to collect sucrose solution from four artificial flowers arranged within 10 m of the hive location developed repeatable visitation sequences both in the laboratory and in the field. A 10-fold increase of between-flower distances considerably intensified this routing behaviour, with bees establishing more stable and more efficient routes at larger spatial scales. In these advanced social insects, trapline foraging may complement cooperative foraging for exploiting food resources near the hive (where dance recruitment is not used) or when resources are not large enough to sustain multiple foragers at once.

Analysing plant–pollinator interactions with spatial movement networks

“…Experiments 3, 5, and 6 (Fig. c,d,e) were completed in outdoor open fields at a small spatial scale for experiment 5 and large spatial scales for experiments 3 and 6 (Lihoreau et al ., ; Buatois & Lihoreau, ). Details about the spatial arrangement of flowers, the number of bees tested, and the numbers of foraging bouts per bee are given in Fig.…”

“…Three datasets were obtained on the bumblebee Bombus terrestris (experiment 1: Lihoreau et al ., ; experiment 2: Lihoreau et al ., ; experiment 3: Lihoreau et al ., ). The three other datasets were obtained on the honeybee Apis mellifera (experiments 4–6: Buatois & Lihoreau, ).…”

“…In these conditions, foragers of many bee species tend to develop stable foraging routes that they follow for several hours or days (e.g. Euglossine bees : Janzen 1971;bumblebees: Heinrich, 1976; honeybees: Buatois & Lihoreau, 2016). These routes are sometimes called traplines in analogy to the fixed circuits that trappers follow when examining a number of traps distributed widely in space (Thomson et al 1997).…”

Inter-individual variability in the foraging behaviour of traplining bumblebees

“…In nature, bees often develop stable foraging routes (sometimes called traplines in analogy to trappers checking their traps along fixed routes 28 ) to exploit multiple feeding locations from their central nest 29, 30 . Manipulative experiments on bumblebees 31, 32 and honey bees 33 foraging for sucrose solution in simple arrays of artificial flowers (equivalent to natural flower patches) show how foragers often find the shortest possible route to visit all flowers once and return to the nest using an iterative improvement strategy based on learning and memory that is different from just linking nearest neighbour locations 31, 34 .…”

“…Thus far empirical research on trapline foraging has been aimed at describing this behaviour at the species level, using relatively small sample sizes (four to seven individuals per experiment), without characterising variation among individuals 31–33, 35–38 . In principle however, some level of variation in the foraging behaviour of the workers of a colony could improve the colony foraging efficiency 39 .…”