Diving beetles engage in such exhausting, uncomfortable sex that these insects have actually evolved two different types of females, as well as unusual variations among males, according to a new study.
The find adds to the growing body of evidence that sexual conflict between males and females influences evolution. In many cases, individuals over time develop characteristics that are appealing to the opposite sex.
For diving beetles, however, researchers believe females have tried to avoid the painful sex for so long that some have actually evolved a feature that enables them to spurn most suitors.