Polistes dominula BIO 203
Interactions
Polistes dominula is considered to be eusocial for the large basis of its behaviors. Eusociality in insects in general means they have a higher level of organization within a colony. In P. dominula, the terms of eusociality are met through overlapping generations working together, care for young by other individuals within the colony, and labor allocated to individuals that can't reproduce or are low in the colony hierarchy. (Encyclopedia of Life 2011). The common divisions that can be observed within a colony are a foundress, her co-foundresses, workers, and helpers (Encyclopedia Britannica 2013).
Workers within the colony are responsible for a wide variety of activities. This includes, but is not limited to: foraging for food, protecting and rebuilding damaged parts of the nest, and watching over the young (Encyclopedia Britannica 2013). Colonies of P. dominula are also much more productive because workers emerge early in the spring (Liebert et al. 2006). Helpers also roughly have the same responsibilities, but because they emerge later in the year due to how the reproductive cycle functions, and they also perform these same tasks at a much higher frequency. They are able to accomplish these tasks at a higher frequency because of their generally larger size. The size of helpers can be nearly as large as the queen of a colony. Beyond that, they also turn into the primary providers for the colony as workers start to fight for dominance in preparation for overwintering. Workers will often ask helpers for food, which is fed to them mouth to mouth (Cini and Dapporto 2009).
Queens, on the other hand, are not as vital to the P. dominula nest as one would think. The first queen is the individual who was the foundress of the nest. When they start a nest, it is generally in coordination with co-foundresses, whom then become subordinate workers once a nest is completely established. The foundresses and co-foundresses both will lay eggs to help start the colony (Cini and Dapporto 2009, Gamboa et al. 2004). When a colony becomes large enough, there is a chance that it is led by multiple queens. This is due to the range of populations which P. dominula nests with which is anywhere between a few dozen to hundreds of individuals. If a queen is to either die or never return to the colony, there is a simple way in which the new queen is decided – the dominant co-foundress, who is the most dominant over other co-foundresses and workers will likely become the queen. However, if there are not any co-foundresses left, a worker who lays the most eggs will become the new queen (O’Donnell 1998).
Dominance in the hive has a clear cut way of being decided. Both males and females show dominance by biting, darting, grappling, and mounting. Mounting generally occurs after dominance has been decided and is the final way a wasp lets another individual know who is really in control (Izzo and Tibbetts 2011, Stout 2013). Mounting itself is when the more dominant individual drums their antennae on the other’s head to cause a lowering of the head and antennae as a sign of compliance (Stout 2013). Females often observe these fights for dominance from lekking areas or from nearby in order to determine who is worthy of mating (Izzo and Tibbetts 2011). When females enter the lek, males will flicker their antennae toward females in an attempt to initiate sex (Cappa et al. 2013). Females will then oblige to or reject their advances. Rejection is done through mounting, biting, darting, or even stinging. If that fails and the male mounts anyways, the female will simply move her abdomen to make it impossible for sex to occur (Izzo and Tibbetts 2011).
Behavior within the P. dominula nest changes very drastically throughout the summer until the first few frosts. At the beginning of the summer and colony founding, the nest is still quite dormant due to larvae growing and being tended to by the foundress and co-foundresses. Once the larvae mature enough to become workers, they start taking on their responsibilities as noted above. P. dominula is relatively docile when resources are plentiful, but as September rolls around, prehibernation colonies start to form (Cini and Dapporto 2009). During this time, workers and co-foundresses leave the nest to start their own overwintering colonies. Due to the continuous reduction of resources at this time, P. dominula protects itself and colony at all costs (Cini and Dapporto 2009, Gamboa et al. 2004).
With nests in a constant hustle and bustle, there is a way in which P. dominula is able to recognize intruders. This was figured out by Dani et al. in 1996. They conducted experiments to see if individuals from other nests were able to be recognized based upon secretions that come from the Dufour’s gland. The Dufour’s gland secretes an epicuticular hydrocarbon that is specific to a colony. These hydrocarbons are able to differ by attached functional groups, which include esters, terpenes, ketones, and carboxylic acids. In Dani et al.’s experiment, they removed the epicuticular hydrocarbon from a dead worker that was originally part of the nest and proceeded to see what would happen when they placed the dead worker near the nest. Workers immediately swarmed this now unrecognized individual and attacked it. Dani et al. also collected the secretion from other individuals and covered a member of a different colony with it. This time, the workers accepted it like it was one of their own. Recognition through this way also happens with larvae in order to protect from other species invading and laying eggs within the nest (Dani et al. 1996).
There is one intruder that P. dominula
cannot keep out of the nest, however. This is the parasite Xenos
vesparum (Cappa et al. 2013). X. vesparum castrates
females, which makes them useless to the hive. It further takes
advantage of P. dominula by altering the mind of the wasps it
infects and ensures they stay near the center of the colony for maximum
chance of infection (Cappa et al. 2013).
Beyond X. vesparum, P. dominula interacts with some other organisms as well. As mentioned in the habitat section, this wasp lives near areas of higher human population, which makes their nests perfect areas for birds to build their nests close to (Jacobs 2011). Both birds and P. dominula build nests to protect and raise their young. Birds know the sting of these wasps is very painful, thus know other organisms will avoid wasp nests as much as possible (Earley 2013). Beyond that, how close a bird makes their nest to a wasp nest is dependent upon the relative visibility of the wasp nest. If the wasp nest is very visible, birds can build their nests further away from the wasp nest because other predators will know the wasps are present, but if the wasp nest isn’t overly visible, birds will make their nests closer to the relative area of wasp colonization (Earley 2013). P. dominula wasps are carnivorous as mentioned on the form and function page. The primary organisms they hunt are caterpillars from the order of Lepidoptera. Additionally, P. dominula uses artichokes (Learn more about Artichokes HERE) as a prime hunting ground for ants, flies (Learn more about the Elm Sawfly: Cimbex americana), and smaller bees (Garvey 2013).