User:Sean Comeau/sandbox

Pleometrosis

Plectroctena sp. worker ants fighting each other over territory

Pleometrosis is a behavior observed in social insects where colony formation is initiated by multiple queens primarily by the same species of insect. This type of behavior has been mainly studied in ants but also occurs in wasps, bees, and termites. This behavior is of significant interest to scientists particularly in ants and termites because nest formation often happens between queens that are unrelated ruling out the argument of inclusive fitness as the driving force of Pleometrosis.Whereas in other species such as wasps and bees co-founding queens are often related. The majority of species that engage in Pleometrosis after the initial stages of colony formation will reduce their colonies number of queens down to one dominant queen and either kill or push out the supernumeracy queens. However there are some cases where pleometrosis formed colonies keep multiple queens for longer then the early stages of colony growth. Colony Formation can help to speed through the early stages of colony growth by producing a larger worker ant population faster which helps to out compete other colonies in high colony dense areas. However forming colony's with multiple queens can also cause intra-colony competition between the queens possibly lowering the likelihood of survival of a queen in a pleometrosis colony.

Selection Pressures causing Pleometrosis in Ants

The driving selection pressure that causes ant species to form colonies through Pleometrosis is because of inter-colony competition in high density colony areas. When a queens enters an area in which they want to form a colony if there is a finite amount of resources to fuel the colony there is usually intense competition and territoriality for resources between ant colonies. If the queen were to form a colony on her own then she has a low probability of surviving because other colonies may be able to produce workers faster then her or may already be past the early stages of colony formation.Forming the colony on her own could also cause her to have to forage for food to try and rear the amount of offspring she needs to out compete other colonies to survive and this foraging behavior puts her at risk of predators. However if her and multiple queens form a colony through pleometrosis they can produce a larger worker force of ants faster and get to a reproductive stage of colony growth faster thus decreasing the chances of death due to inter-colony competition. It has been observed in ants that form pleometrosis colonies engage in less foraging behavior, thus lowering there chance of predation due to pleometrosis as well. Having multiple queens cuts down on Foraging behavior because each queen uses her own stored energy reserves to feed the brood . By founding the colony pleometrotically ants can form new colonies in high colony density areas and take control of resources in the surrounding area faster. Some Genera of ants such as Azteca use the additional worker ants early in the colonies formation to monopolize and take control of resources in close proximity of the colony thus stopping other con-specific colonies from acquiring those resources. This strategy allows the plemetrolic colonies to monopolize the area and starve out the other competing colonies. The additional worker force in pleometrolic colonies also allows for bigger and more effective brood raids from con-specific colonies which additionally helps to out compete colonies. Overall one of the most key aspects of founding a colony in a high density colony area is being able to produce a worker force quickly and efficiently so as to not be starved out or robbed of brood from other colonies causing starvation. By engaging in pleometrosis it increases a queens chance of survival past the early stages of colony formation due to the increased worker force at disposal to take control of resource in the surrounding area.

Cost/Benefit of Pleometrosis

Ant queen creating hole for colony formation

Pleometrosis is necessary to survive inter-colony competition in high density and resource limited areas but the majority of pleometrosis colonies cut back to one queen before the reproductive stages of colony growth. So this suggests that a queen has a better chance of surviving and reproducing offspring if she forms a colony with other queens even though eventually she may be pushed out or killed by Intra-colony competition. So the risk of being out competed by a con-specific queen within ones own colony must be less then the risk of dieing out due to other insect colonies. So in high density colony areas or resource limited areas where inter colony competition are high, selection for pleometrosis is higher because the chance of survival in a pleometrolic colony is greater due to an increased worker population in the early stages of growth. As the number of queens in a pleometrolic colony increases, the chances of each queen becoming the dominant queen in the colony lowers, but still selection pressures choose pleometrosis over haplometrosis even in larger pleometrophic colonies.Depending on the species of ant and the selection pressures of the colony there are multiple ways a queen can become the one dominant queen in the colony and gain the full benefit of a pleometrophic colony. Based on past research the queens that normally come out as dominant in pleometrolic colonies lay more eggs, have well developed ovaries, and don't engage in foraging behavior. Worker ants even play a role in if a queen will become the dominant in some species by feeding the queen who is the most fertile more then other queens in the nest. Queens will also engage in dominance actions to try and assert dominance over the nest such as brood cannibalism of other queens brood. When the most fertile queen in the nest decides to directly challenge the other queens usually the queen who initiates the challenge is the one who wins and takes control of the colony turning it into a one queen colony. Pleometrosis benefits outweigh the costs for queens which is why it has evolved to occur in high density areas of inter-colony competition regardless of the intra-colony competition it causes for queens.

Colony Foundation by Pleometrosis in Azteca genera ants

Azteca ants form Colonies in the inter nodes of Cecropia trees which are native to mexico and south america. The Tree provides the ants with food and shelter and the ants protect the tree from other insects thus engaging in a mutualistic relationship. Queens form colonies by borrowing into the inter node of the tree and then sealing off the hole they used to get in with parenchyma cells and then begin to lay eggs to produce the first brood. Any queens which decide to engage in pleometrosis can easily see the filled in hole and will chew through it quickly and join the fellow queen in the inter node.Colonies that are formed in these trees try to out compete other colonies by monopolizing the resources of a tree first.By forming a pleometrophic colony in a Cecropia tree the queens can produce workers faster and take control of the resources in the tree first thus out competing other colonies. However depending on the species of Azteca genera the social interactions between queens in a pleometrophic colony are different. In A. xanthacroa which are more aggressive, pleometrophic colonies work together to produce a greater number of workers at the start of colony formation but once the colony breaks out of the inter node of the tree the interactions between the queens change. Once this step occurs queens will try to kill each other to become the dominant queen in the colony and switch the colony to a single queen colony. However in species of A. constructor which are less aggressive, once the worker ants leave the inter node to take control of the tree's resources, multiple queens remain cooperative with each other for sometimes up to a year. Hypothesizes as to why A. constructor colonies engage in cooperative breeding with multiple queens could be due to similarities in A. constructor queens fighting ability's or there inclusive fitness in some colonies of A.constructor. In contrast A. xanthacroa pleometrophic colonies form and change to one queen colonies after the early stages of colony formation. There are also examples of pleometrophic colonies forming with multiple species of Azteca , however when these form the more aggressive species will out compete and kill off the other queens in the colony once the early stages of formation have passed. Mixed species pleometrosis is rare but helps to support the fact that the majority of social insects who form pleometrophic colonies do not base it on kin selection but to be able to out compete other colonies in the early stages of development.

Pleometrosis Assignment Topic

Sources for Article

https://link.springer.com/article/10.1007/s00265-017-2429-7

https://www.nature.com/articles/srep29828

https://www.cabdirect.org/cabdirect/abstract/19941102774

https://link.springer.com/article/10.1007%2FBF00439886

https://www.sciencedirect.com/science/article/pii/S000334720400260X

Ideas for animal behavior assignment

-Nest Usurpation

-Transverse Orientation in moths

-pleometrosis

Article Evaluation

Aestivation

-Some paragraphs are missing citations

- there are areas that are already marked saying that they need citations

- there is basically no information in the section about Aestivation in Fish except for an example of one fish with no describe just a citation

- Seems to have a lot of references in the Reference section but areas within the body of the article need to have the citations placed in them more thoroughly

Week 4 Assignment

- Reconstructed this Sentence from the Aestivation article under the crustacean heading and gave it a proper citation.

Crustacea: An example of a crustacean undergoing aestivation is with the Australian crab Austrothelphusa transversa , which undergoes aestivation underground during the dry season.

Peer Review by Caroline McDonald

This is article is well written and has a good amount of detail. The sub sections that were added make sense and clearly demonstrate why and how pleometrosis works for certain animals. I'm not sure if this kind of information is available but it could be interesting to talk about the modalities of this behaviour in terms of what underlying mechanisms are associated with its formation. There may also be space to go into species-specific pleometrosis and how it differs from species to species and expand on the examples already provided. There are also some citations missing in the body.

The formatting could be adjusted to traditional wiki articles. In order to fully demonstrate this behaviour, it may be beneficial to add some photos or even link a video of Pleometrosis to your article (making sure that there is no copyright).

Finally, you may want to try and relate this behaviour back to Tinbergen's four questions and see why and how this behaviour is beneficial and why it has evolved.

Overall a very good article with substantial information about the topic and why this behaviour has evolved.