6.2 Intra-species communication & Foraging in social insects  (Page 3/9)

Furthermore, when it is insufficient, social insects can’t rely exclusively on the information they receive from their nest mates and must employ certain techniques to account for discrepancies. The receivers of communication must also know when to disregard signals or compare multiple sources or sometimes the received information with their own personal knowledge. Different species of insects, based on prior experience at food sources, can choose to disregard certain sensory signals and even interpret them differently when the quality of resource changes. For example, stingless bees will mark food sources with either attractant or repellent chemical signals that can be disregarded if the profitability at a particular resource location changes (Sánchez et al. 2007). Ants cannot rely solely on the tandem run, where they carefully guide a worker to a food source or nest site, and even the highly specialized honeybee waggle dance is not perfectly precise. These methods of communication must be supplemented by additional information such as the carried scent of a particular food resource and forager’s prior experience at a resource location. We will look into exactly how different species of social insects communicate locations of resources, change particular roles, and how they are able to deal with the issues of incomplete or imprecise information when recruiting and foraging.

Reinterpreting multimodal signals by stingless bees&Bumblebees

Stingless bees, which have a simpler communication system than honeybees, use methods of pheromone or scent trails, pilot flights and vibration cues to guide recruits to new resources. Olfaction and the used of attractant and repellent chemicals on food sources is the principle means of forager recruitment (Nieh 2003). Boogert et al. (2005) showed that the stingless bee Trigona corvina was even able to interpret the attractant and repellent signals of different bee species. However, they must be at the resource for these signals to be of any use. To lead them towards the resource from the hive, the guides make quick flights, or pilot runs, through the group of recruits to keep them together and show them the way towards the new resource (Aguilar et al. 2005). When they become lost in transit or they receive incomplete information, they can cope with this by incorporating multimodal signals in decision-making (Kulahci et al. 2008). Kulahci et al. (2008) performed experiments that showed that bumblebees trained on food sources having both visual and olfactory cues were more accurate in their selection of profitable food sources. Stingless bees use pheromone trails close to the food source to aid in final orientation of the new recruit, and it is speculated that spatial information can be communicated within the hive through antennal contact and vibrations (Nieh 2003). Hrncir et al. (2005) also found that specific thoracic vibrations of the stingless bee Melipona seminigra may be a method by which to communicate resource location. They found the intensity of the signal was directly related to the energy output during a foraging run, meaning the weaker the vibration the longer the distance traveled.