UC San Diego

Bees abound in tropical environments, and the communication of valuable resource locations among nestmates allows them to exploit the diversity of food sources found in this complex environment. Rainforest canopies are a sensory melee of light patterns, odors, colors, and obstacles. How bees have evolved to not only navigate but also to communicate specific pathways through this storm of sensory information is still under investigation. The true marvel of this system is not just the ability of foragers to successfully pilot through the environment, but their apparent ability to extract and then encode salient navigational information and transmit it to nestmates. Honeybees are known to use a functionally referential communication system whereby environmental information is encoded and then transmitted to a conspecific receiver for decoding. The transformation of sensory information into a communicable signal is most likely a complex cognitive task, yet the evolution of this behavior in bees remains relatively unexplored. Stingless bees (Melipona spp.) are an excellent group for studying both navigation and communication : the group consists of numerous and diverse species, foraging strategies, and communication techniques (Roubik, 2006). In comparison, bumblebees (Bombini) have a simpler communication system but also share the same navigational needs during foraging as stingless bees (Meliponini) and honey bees (Apini; Michener, 2000). We examined the visual navigation abilities of one species of bumblebee (Bombus impatiens), and one species of stingless bee (Melipona panamica). We found that B. impatiens is able to information from the spatial density of the visual environment to gauge distance traveled, an ability that honeybees to not appear to possess (Si et al., 2003). We then found that the stingless bee M. panamica can use optic flow (the movement of images as they pass across the retina) to gauge not only distance traveled, but also height above the ground. We proceeded to manipulate the visual environment experienced by foraging M. panamica such that their vision -based odometers registered a much larger distance than that which the bees actually flew. We found that this information was then communicated to naïve bees inside the nest, which then flew greatly exaggerated distances in search of food. This result supports the hypothesis that M. panamica is referentially communicating inside the nest