Males of a species of bird known as the marsh harrier have been known to look and behavior like females. Whereas some birds of prey take pride in their masculine characteristics, these birds have no shame in "dressing" in drag. They engage in this behavior in order to fool other males, as to avoid potential conflicts. Surprisingly, these she-males can still successful mate with females and are able to establish territories despite their misleading appearance. "Permanent female mimicry" has been determined to occur in forty percent of all sexually mature male marsh harriers. These lifelong female behaviors and attributes have also been found in other species, particularly ones where males encounter numerous fights with other males, such as in fish, insects and reptiles.
Audrey Sternalski, a researcher at the Instituto de Investigación en Recursos Cinegéticos in Spain, and her colleges François Mougeot and Vincent Bretagnolle, conducted an experiment in order to test their theory that this adaptive behavior of female mimicry could be a ‘permanent non-aggressive pact” that has been made between males. During different stages of their breeding cycle, they set up plastic decoys to each bird group that represented three different bird types; males, females, and she-males. The researchers found that males were aggressive to the male decoys, but seemed more tolerant of the she-male decoys. She-male birds were tolerant of both she-male and male decoys, yet were observed to be aggressive towards the female decoys. Sternalski attributed this behavior to the fact that the she-males mimicking female behavior by defending breeding resources.
Randolph Krohmer, an associate professor of biology at Saint Xavier University, studied this female mimicry phenomenon in red-sided garter snakes, which do not physically look like females, but release pheromones that usually secreted by females. He found that during courtship, these species of snakes form mating balls that contain about 50 males and only one actual female. Since snakes can detect odors with their tongues, they often “taste” the scent that the she-males give off and spend time trying to court them. The she-males use this opportunity to their advantage and score the girl. I guess snakes really are sneaky! Opposed to the marsh harrier, only about ten percent of the population of these snakes are females and seems to remain constant over the years according to Krohmer. If this trait were as advantageous as it seems, wouldn’t we expect to see this percentage to increase? Perhaps only more time will tell.
http://news.discovery.com/animals/she-male-birds-raptors-111109.html
Posted by Sara Corey (7)
I wonder if the males that posses this female mimicry are smaller males that would not succeed in mating if they had to go against males in comoetetion. Is there any study that measure the sizes of males and she- males and compares their size and fitness? This mimicry must help them succeed in mating and reproducing or else it would not be passed down to future generation.I wonder how many different species posses the ability of female mimicry? Very interesting subject, I never knew this happened in nature.
ReplyDeletePosted by Noelle Kellicker
Hi Sara,
ReplyDeleteThis is so interesting. I wonder how many times the marsh harrier tries to copulate with the she males? And wouldn't the males know that when they are copulating, it is actually with another male, which in turn should cause the male bird to attack the she males since male birds are aggressive. And if this does happen why is this behavior not selected against? I guess the advantage of fooling males and holding on to resources are greater than the costs.
Posted by Whitney Huynh
I’m confused as to why the she-males would be aggressive towards the female decoys. You stated that they do so in order to defend breeding resources. How exactly would they be defending breeding resources if they are aggressive to the females? What happens when a male attempts to mate with a she-male? Would he realize he is being tricked and attack the she-male?
ReplyDeletePosted by James Lin
It's one thing to look and act like a female as a male, but I would like to know more about these garter snakes. Do all male garter snakes have the ability to release female-like pheromones in the air? And I wonder if they can switch back and forth between releasing normal male scents and also more female-like ones, that is really cool.
ReplyDeletePosted by Jacob Lafauce
I had heard of males posing as females in the animal kingdom, but I didn't know it was so wide-spread. I had seen videos of male fish who pose as females during courtship in order to gain a reproductive advantage, as they are usually smaller or older and can't actively compete with other males. It's interesting to see this tactic is also employed in both birds and snakes. I wonder how many other Ru Paul animals are out there. I did see a few grammatical errors in the blog, but nothing detrimental to the flow of the entry.
ReplyDeletePosted by Austin Gray
As amusing as it is to consider the Rocky Horror Picture Show playing out in nature, it is in fact quite fascinating to consider. Sexual expression is such an important aspect to species survival, behaving in such a way is both innovative and an evolutionary benefit. It harkens back to other species' sexual acts, such as Bonobos' utilizing sex as a form of diplomacy, or even flat-worm penis fencing. It is both highly amusing and interesting.
ReplyDeletePosted by Jacob Lane
Its pretty interesting that males are able to "dress in drag" as you put it in order to get a mate. You might not be able to answer this, but do you know if there is anything about a she-male that would cause a female to select it, such as coloration or something? Or is it purely because she males are able to distract the other males so "real" males don't get to mate?
ReplyDeletePosted by Janelle Hayes
This is pretty interesting. How intense are the conflicts between males? I would think that to evolve this cross dressing behavior it would have to be pretty brutal. As a side note this sort of reminds me of the parthenogenic lizard. Do you think that males of this species will eventually be entirely phased out?
ReplyDeletePosted by Michael Thomas
Great post. This behavior is very interesting. It makes a lot of sense and it is a great form of mimicry for the males. I wonder if the males were prompted to fight, would they be able to fight as well as the full male marsh harriers. Also, I wonder if the mimicry changes the hormone levels inside the male, to maybe have lest testosterone. I wonder how much success this behavior actually brings them, and although they get mates I wonder if it affects their success with mates at all.
ReplyDeletePosted by Abbie Saranteas
You all raise very good points and questions here. Before reading this article, I had no idea that these behaviors had evolved in animals. In regards to your questions Whitney, since the males are generally aggressive towards other males, the advantage of being able to fool males in order to possibly avoid a formerly guaranteed conflict is definitely an advantage to she-males. You are right, since the benefits outweigh the costs, this behavior is favored in this and other species. Jacob Lafauce, in regards to the garter snakes, I believe that only some have this ability, since if all of them had it, some snakes would not be able to use this advantage over others. The males who do contain the female pheromones possess the male pheromones as well, which is fascinating! Evolution is such an interesting and innovative process, I am interested to see what the future of it entails!
ReplyDeletePosted by Sara Corey
This is really neat. This article reminded me about sneaker males in the animal kingdom. It's known that in alot of animal species a small percentage of males (ususally the strongest) possess most of the females in a species. This then leaves very few females available for other males to mate with. So what the sneaker males will do instead of rather challenge the bigger male. They'll take females from him by going on his territory and fertilizing females before he does. So it didn't surprise me that males in this species of birds would take on female qualities to avoid conflicts which would probably happen against bigger stronger males.
ReplyDeletePosted by: Andrew Ryan