Dominance hierarchy In the
P. occidentalis species, a social
dominance hierarchy exists. The queens are at the top and produce the
brood and the workers right below them build the nests. Smaller wasps are higher up in social hierarchy. These smaller wasps seem to have more social interaction, which influences a division of labor and of
age polytheism. Age polytheism is the system that wasps perform different tasks as they age. In
P. occidentals, it refers to the age at which the wasps begin work outside of the nest. The larger wasps are sped up in this process and they work outside of the nest long before the smaller wasps take on these outside tasks. This implies that the larger wasps are removed from the direct
reproduction tasks, while the smaller wasps are kept in the nest to be a part of reproduction. Smaller bodied wasps pass through age polytheism and are kept in the nest longer because they seem to have a higher social position in the colony, while the larger bodied wasps are viewed as
subordinates.
Division of labor and cooperation When building the nest, discrete division of labor occurs in the larger colonies and a more fluctuating division happens in smaller colonies. For larger colonies, all workers have a designated job. While each worker does its own job, it cooperates to form a cohesive, productive, and efficient unit. The jobs are water
foragers, wood-pulp foragers, and builders. Water foragers gather water droplets from surrounding
crops and give them to the pulp foragers and the builders. Wood-pulp foragers gather wood pulp from nearby
fiber sources. Using the water received from the water foragers, the pulp foragers give the moist pulp to the builders. Builders receive the water and then the pulp. They use the water to moisten the pulp, and then they work this new mixture into the nest to create a stronger wall for the combs and the envelopes. After receiving the wood pulp from the pulp foragers, a builder divides that amount among other builders until she has the proper amount of wood-pulp she can work with. Also, in higher-populated colonies, the cost is minimized in time delay because so many wasps are doing the jobs and rotating in foraging and supplying the builders. This saves
energy and
time because each forager is making fewer trips to gather resources. Because the foragers take fewer trips outside of the nest, the
risk of
predation in larger colonies is reduced. In a small colony, the workers are more likely to rotate roles. This causes more expended energy and more time delays due to the workers’ constant need to make trips outside of the nest to gather resources. These costs affect the nest building.
Communication Odors P. occidentalis wasps have a way of indirectly communicating to each other in terms of information sources. As opposed to movement and verbal communication, they secrete specific odors depending on their food source. In various studies, information concerning where to forage was communicated through odors to newcomers from those that knew where the prey was due to experience. While this is not recruitment, because it is not intentional communication, newcomers are able to figure out where to find food sources due to information extracted from experienced foragers.
Biting P. occidentalis engages in social
biting to maintain worker productivity. This communication (a worker biting another worker) has been shown to regulate work among the foragers. Because foragers are bitten more often than nonforagers, the
intent is clear. The bitten wasp, soon after it is bitten, leaves the nest, implying that the bite was effective. Because the worker caste is self-organizing, jobs will not get done if individuals do not do their assigned tasks. Therefore, a
reminder comes in the form of these bites.
Alarm recruitment P. occidentalis also has a way of communicating if a potential
predator is in the nest. If the nest is rattled or threatened,
alarm recruitment occurs through
venom and venom-bearing structures in body. The alarm recruitment causes all adult wasps to move out of the nest to the outside to block the entrance and the nest from destruction and intruders. Although the wasps’
wings buzz for under a second when this threat occurs, the recruitment has nothing to do with the wing buzzing. The emergence from the nest is definitely by means of communication because a brief lag occurs between the jarring of the nest to when the wasps all emerge at one. This means that there was some initiating cue. Like the information gained for foraging by odors, during a potential predator threat, alarmed wasps cover the outside of the nest and drag the tip of their
gasters, which evokes an odor. This specific odor lets others know that a threat to the colony exists. ==Kin selection==