Female Infidelity in Birds
Dateline: 12/31/98
Imagine this: you've successfully raised two kids with your mate when one day... your mate decides to become polygamous. He or she decides to copulate with people outside the partnership and produces other offspring. In addition, you're expected to raise the other offspring! Sounds preposterous--not if you're a bird, specifically the Jacana jacana, commonly known as wattled jacanas.
Wattled jacanas are unique because females typically have a harem of males. Not only that but the males perform all caretaker responsibilities for the young. The females don't possess the genetic programming for care-taking. Since the females have numerous partners, the males often end up raising young that are not their own. Talk about dedicated parenting!
Scientists have long pondered this behavior. In an effort to understand cuckoldry and sex-role reversal, scientists at the University of Buffalo recently published the results of a six year study of the jacana mating behavior.
Among the findings:
Males care for young that are definitely not sired by them. Using DNA fingerprinting, the researchers found that on average, approximately 40 percent of the young were sired by another male.
In such an intensely competitive environment for females by males, some males do not receive the opportunity to copulate. Thus, from a "selfish gene" perspective, it is better to copulate and possibly raise other males' young than to not copulate at all.
On the flip side, the scientists did find that in rare cases, when no other males were available in the harem, the young were all sired by the care-taking male.
The researchers were surprised by the results. It has long been believed that males would only participate in the care-taking process when there was absolute certainty that the offspring were genetically from the male. Since the females don't have the genetic programming for caring for the young, the males must take care of the mixed parentage young in order for the species to survive.
Scientists noted that males of other species often don't know about cuckoldry since females typically tend to be secretive in this regard. The jacanas are different because copulations are typically boisterous and in front of the other male.
What do you think? Do the advantages of this type of mating outweigh the disadvantages? From an evolutionary standpoint, is this an efficient method for insuring the survival of the species? If so, why is this method not as pervasive as it could be? Come over to the Biology Forum and share your thoughts, opinions, and feelings.
Learn more about this study:
- Single-Parent Bird Dads Suffer Female Infidelity Science Daily
