Researcher discovers the social dynamics of Yellow Jacket wasps

February 19th, 2008 - 1:21 pm ICT by admin  

Washington, Feb 19 (ANI): A researcher from Georgia Institute of Technology has studied the social dynamics of yellow jackets (a type of predatory wasps), which includes multiple sex partners, extreme cooperation and a caste system.
In his laboratory, Michael Goodisman, an assistant professor in the Georgia Institute of Technologys School of Biology, has found out the paternity of wasps to study family dynamics within a colony. Through his experiments he found that even though only one family lives within a colony, each yellow jacket queen mates with several males, creating a complex family tree.
Social insects such as yellow jackets have been described as one of the greatest achievements of evolution because of the incredible cooperative nature of their societies. I wanted to know why the females would risk this cooperative nature by having multiple partners, said Goodisman.
Goodisman wanted to know if yellow jacket workers would kill new queens having a different father or if they were more likely to turn their sister larvae into reproducing queens instead of sterile workers. According to him, turning a worker into a queen simply requires a comb nest with larger holes. The larger holes signal to the workers to feed the developing larvae different food, resulting in queens.
You can actually take developing workers and if theyre young enough, put them into queen cells and they will develop into queens, explained Goodisman.
The researchers tested the paternity of each insect to investigate if any of the males in a colony fathered more queens than workers. After determining the genetic make up of each of the queens male mates, the later determined what proportion of workers and new queens each male mate sired.
DNA fingerprinting results showed that males fathered an equal number of queens and workers in a colony, making Goodisman believe that there is no conflict within a colony because of multiple mating.
Instead of intense competition, yellow jackets seem to exhibit extreme cooperative and helping behaviors, noted Goodisman.
As there was no disadvantage to having mixed families in the colony, he thought there must be a benefit to the colony for each queen having multiple partners.
The researchers found no correlation between the number of mates and the number of worker cells. But, it was found that queens that effectively mated 4 or more times produced significantly more queen cells in the comb than queens that effectively mated fewer than 4 times.
As colonies typically survive only 1 year, so the number of queens produced at the end of the season represents the entire reproductive output of the colony and, by extension, the original queen. Only inseminated queens survive the winter and emerge in the spring. Thus, it was found that the benefit to multiple mating is that the queens colony is more successful.
In his research, Goodisman wanted to investigate how yellow jacket development leads to a caste system with queens, males and workers each with a different role in the colony. The queens mate with males to produce new queens and workers, but dont require a male to produce new males. The female workers maintain and expand the colony, while the new queens and males just hang out and eat until its time to mate.
The division of labor has made these animals so incredibly successful in cooperative behaviors, but workers and queens are genetically the same, explained Goodisman.
Decision-making within a colony also intrigues Goodisman. Different events occur in the colony based on the time of year. For example, the queen constructs a nest and rears the first cohort of workers in the spring. Once the workers mature, they take over the task of colony maintenance and expand the nest by constructing a worker nest throughout the spring and summer. At the end of the summer, the colony begins to produce males and new reproductive queens.
We want to know whos telling the workers to stop making more workers and start making queens, so were studying the life cycle of yellow jacket colonies. Is it an environmental cue or possibly a cue from the queen, explained Goodisman.
Even though some people think that yellow jackets are just a backyard nuisance, there are benefits to having yellow jackets around, contends Goodisman. They kill insects, suppress fly populations and eat roadkill, he says.
And hes quick to point out, Yellow jackets are not here for our pleasure. Theyre reproducing, surviving and doing a great job at it. (ANI)

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