Trapline foraging by bumble bees: V. Effects of experience and priority on competitive performance

Abstract

Animals collecting resources that are fixed in space but replenish over time, such as floral nectar and pollen, often establish small foraging areas to which they return faithfully. Some repeatedly visit a set of patches in a significantly predictable sequence (socalled ''trapline foraging''), which may allow them to focus on more profitable patches in their foraging areas. The functional significance of trapline foraging itself, however, has not been empirically demonstrated, especially in competitive situations. We conducted laboratory experiments with artificial flowers to test whether and how accumulated foraging experience in bumble bees affects their movement patterns and foraging performance in the presence of competition. Experienced bees with prior access to flowers achieved higher rates of nectar intake than did later arrivals because they traveled faster between flowers and returned to flowers at more regular intervals. These behavioral skills improved foraging performance in competitive situations in 2 ways: nectar that accumulated in flowers could be harvested before its replenishment rate slowed down, and nectar could be taken before the arrival of a competitor. In each foraging trip, however, bees traveled more slowly as they followed more repeatable routes. Despite this trade-off between speed and accuracy in traplining, bees constantly upgraded both skills as they gained experience from trip to trip. This upgrading still occurred in the absence of a competitor. Foraging area fidelity thus allowed bumble bees to establish long-term spatial memory required for fast movements and accurate traplining and, in turn, increased their foraging performance in competition with less experienced individuals.

Bumblebee flight performance in cluttered environments: effects of obstacle orientation, body size and acceleration

“…While we do not believe that experience is likely to confound our results concerning body size, as the average size of bumblebee workers typically does not change over time (Couvillon et al, 2010) (so bees of different sizes should not differ systematically in age and experience level), this study cannot directly address the importance of learning for flight performance in cluttered environments. However, previous work clearly shows that on a larger spatial scale, bumblebees optimize flight routes (Lihoreau et al, 2012) and increase flight speed (Ohashi et al, 2008) with experience. Likewise, age may have important effects on flight performance (Vance et al, 2009), either through physiological changes or through the accumulation of morphological damage (Cartar, 1992).…”

Recursive movement patterns: review and synthesis across species

“…These include noting regular appearances of individuals at fixed resource sites v www.esajournals.org (Janzen 1971) or the drawing of schematic flight maps tracing bee pathways (Heinrich 1976, Thomson et al 1982. The use of more rigorous quantitative statistical tools to identify traplining behavior only began in the last two decades (e.g., Thomson et al 1997, Ohashi et al 2007, Ohashi et al 2008.…”

“…These benefits were shown to apply for animals foraging alone as well as for animals foraging in competitive environments (Ohashi and Thomson 2005). Furthermore, traplining foraging has been shown to improve foraging performance by improving the forager's experience, thus increasing its competitive advantage over random foragers (Ohashi et al 2008), as well as to increase the forager's ability to detect and adjust to changes in the environment such as fluctuation in competition intensity (Ohashi et al 2013).…”

“…To summarize, the main driver of recursive movement in traplining is the rate of resource recovery (Possingham 1989, Ohashi et al 2008, Ohashi and Thomson 2009)-the time required for the resource to recover following local exploitation-which has direct implications on resource availability, profitability and on the forager's competitive capabilities.…”

Ants and Ant Scent Reduce Bumblebee Pollination of Artificial Flowers

“…When predators are present, pollinators may switch to visiting less rewarding flow-ers, or they may avoid flowers altogether, potentially reducing the amount of pollen donated or received by a flower and thus decreasing plant fitness (Gonçalves-Souza 2008;Ings and Chittka 2009). Similarly, competition for floral rewards with other flower visitors may cause behavioral changes in pollinators (Maloof and Inouye 2000;Ohashi et al 2008). Previous research has shown that bees may spend less time visiting flowers depleted of rewards (Thomson 1986) and may avoid flowers bearing scent marks that indicate recent visits by other individuals of the same or different bee species, as these flowers are likely to be depleted (Stout and Goulson 2002).…”