Combat traits usually get most of the attention from researchers, because they are thought to have arisen due to intense male-male competition for access to females. Large, elaborate weapons become the focus of sexual selection studies because the connection is obvious. Collared lizards (Crotaphytus collaris), for example, have bite force correlated with head width, and it positively predicts the number of offspring produced in a breeding season, suggesting sexual selection on head morphology and the role of attacking traits.
But maybe defense wins sex games too. Sexual selection in the Forked Fungus Beetle (Bolitotherus cornutus) favors larger body and horn size, and a new study investigates the relationship between these traits and the beetles' grip strength, which is crucial for the male to hold on to the female and shield her from other males in an elaborate courtship ritual. But it also highlights defensive traits - by having a strong grip, males can keep females busy for hours. And hours. And hours. And that blocks out other males from getting involved during mating season.
The grip strength trial. (A) The male grips the dowel rod in a similar fashion to how males grip females during courtship and guarding in the wild. (B) The same male at maximum resistance just before releasing the dowel rod. doi:10.1371/journal.pone.0042738.g002
During the courtship ritual, male beetles grab onto the female and they hold on - that would seem to favor males with a stronger grip. The authors of a study tested the grip strength of 84 beetles, both male and female, by tying a piece of thread around the beetles' bodies, allowing them to wrap their legs around a small rod, and then pulling the beetle vertically until they released the rod.
The larger attacking male uses his clypeal horns in an attempt to dislodge the smaller male. The smaller male was previously courting the female and during the combat grips her with all six legs. The video has been sped up to 5x actual speed. Credit: doi:10.1371/journal.pone.0042738
The researchers found that grip strength grip strength was repeatable, consistent and differed between the sexes. It was very consistent for each individual, males overall have a stronger grip, and they believe that this sexual dimorphism appears to result from a complex relationship between body size and leg length. Their results, they write, suggest that there is a suite of traits that influence grip performance and therefore might affect sexual selection.
Citation: Benowitz KM, Brodie ED III, Formica VA, 'Morphological Correlates of a Combat Performance Trait in the Forked Fungus Beetle, Bolitotherus cornutus', PLoS ONE 7(8): e42738. doi:10.1371/journal.pone.0042738
- PHYSICAL SCIENCES
- EARTH SCIENCES
- LIFE SCIENCES
- SOCIAL SCIENCES
Subscribe to the newsletter
Stay in touch with the scientific world!
Know Science And Want To Write?
- No, Earth's Magnetic Field Is Not About To Flip
- Supersymmetry Is About To Be Discovered, Kane Says
- 140 dead in Paris. Distance from South Korea to New York shrinks by 5,000 miles.
- "Imaginary Bullshit Planet" Nibiru - Lens Flares, Sun Mirages, Hoaxes & Just Plain Silly
- Study Shows Men Attracted to Transgender Women are NOT Gay. DUH!
- New Open-access Data On Paleofloods
- Anomaly! - A Different Particle Physics Book
- "For all folks who regularly read this column:I have just come across this:Physicists Are Desperate..."
- "When it really comes down to it Robert, we either make it as a civilization or don't. We either..."
- "Erinaceus Europaeus,I'm am conflicted about thoughts such as: while this extreme social event can't..."
- "Thank you for giving us a clearer understanding on where we stand with a magnetic field flip.Alex..."
- "Golbeki Temple in turkey.... we're all outta africa with some variations, eh?..."
- Cookin’ Your Bird, The Science Way
- Should the new hep C drugs be used sooner?
- Bilingual patients have better cognitive function post-stroke
- Caveat Comestor: New Yorker Cites ACSH On Cranberry Scare Of ’59
- Does Holiday Feasting Affect Obesity Rates?
- Apple Pie, Mashed Potatoes and Natural Formaldehyde
- Breast MRI after mammography may identify additional aggressive cancers
- Breast cancer clinic attributes increased uptake of double mastectomies to Angelina Jolie effect
- Exploring the physics of a chocolate fountain
- Researchers urge caution in prescribing commonly used drug to treat ADHD
- Stretch the new flex for programmable rubber keyboard