After talking in class last night about the evolution of behaviors, I ran across some interesting articles in National Geographic today. I wanted to share a few with you. The article descibes the great bustard “one of the few animals in the world that can stomach certain species of blister beetles (Berberomeloe majalis andPhysomeloe corallifer). The insects produce a potent toxin called cantharidin, which can be exuded as a blood-red goo. Great bustards of both sexes have been observed to eat blister beetles, though usually only one to three beetles at a time. If the birds eat too many, they can become intoxicated and die, as other animals do. However, Juan Carlos Alonso, the study’s project leader and research professor at the National Museum of Natural History in Madrid, said that just the right amount of blister beetles may kill the great bustard’s parasites or at least persuade them to look for a new host.”
The initial article that came across my newsfeed was this – Male Birds Poison Themselves to Appear Sexier—a First. From the article:
Scientists already knew the large birds, which are native to parts of Europe and Asia, snack on toxic insects to clear their guts of certain intestinal parasites, including bacteria, nematodes, and tapeworms.
But the new research, published this week in PLOS ONE, shows that males eat substantially more blister beetles than females, a strategy that makes them appear healthy—and thus sexier—during courtship rituals.
If true, the findings may be the first known case of a male “self-medicating” to attract females, according to the study authors. (Also see “Watching ‘Sexy’ Males Leads to Better Chicks, Study Says.”)
This goes along with the discussion from class about the evolution of behaviors – do the birds KNOW that they are eating poisonous beetles, that will kill their internal parasites? No, how could they know that? It’s scientists who study these birds who know what happens with the bird’s diet. Check out the video from the article:
The article goes on to state:
To look at a male great bustard at the height of his mating pomp, you might think that the female would be attracted to puffed and preened feathers at the front. But just a few seconds of watching the dance reveals that it’s actually what’s going on in the rear that matters.
So what exactly is the female looking for?
“If I can be a bit crude, it’s probably not to see whether the male is well-endowed,” said Daphne Fairbairn, an evolutionary biologist at the University of California, Riverside, who was not involved in the study.
Instead, it’s likely that the female is evaluating the male’s cloaca—an all-purpose hole that serves reproductive, urinary, and intestinal functions—to see if it might give her a sexually transmitted disease. (By the way, this kind of mating is sometimes called a “cloacal kiss,” which is about as lovely as bird sex gets.)
Sexy, right? You thought we were going to discuss sex, and now we’re talking about “all-purpose holes” and STDs!
Following one of the links from the article, “Watching “Sexy” Males Leads to Better Chicks, Study Says.” Watching attractive males strut their stuff makes female birds more fertile and leads to healthier chicks, a new study suggests. Here is a description of that experiment:
For the experiment, the team allowed 90 female Houbara bustards to watch other birds before being artificially inseminated. Of that total, 30 females watched healthy-male displays, 30 watched poor-male displays, and 30 saw nondisplaying females.
Females that had watched the healthier males dance laid eggs containing about twice as much of the growth hormone testosterone as the eggs laid by females that watched inferior dances or no dances at all. Testosterone in both genders is associated with building bone density and muscle mass.
Or this brilliantly titled article, “Flashier Great Tits Produce Stronger Sperm, Bird Study Shows.” The tits in this article are BIRDS! What do you think I’m going to show you? But these articles go on to show you that behaviors are extremely complex, and can be learned or innate. There are advantages to using your energy to put on a great mating ritual – you go on to pass your genes along to your offspring. Maybe you’ll be thinking about biology and the evolution of your own behaviors next Saturday night when you go out with your friends. You may notice elaborate rituals that both males and females go through, trying to meet their potential mates. How much of what you do is your own decision, and how much of it has come from your ancestors? Think about that the next time you see two guys in a fist fight over a girl (AKA every episode of Jerry Springer!)