This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: The genital structures of male hawkmoths are lifesavers. By rubbing specialized scales on their genitals against parts of their abdomen, the nocturnal insects emit ultrasonic sounds that can potentially scramble the acoustic signals that bats use to hunt.
These predator and defense systems have been locked in an evolutionary arms race for millions of years. Whenever one adapts, the other must respond. But questions remain about how often these defenses evolved independently and why different hawkmoth species developed different ways of producing ultrasound.
Getting to the bottom of this involved a lot of moths. Masonick at the University of Florida and colleagues tested hawkmoths' responses to recordings of attacking bats and gentle handling designed to simulate being caught by a predator. And they recorded any ultrasound the insects produced.
Next, the research team performed detailed analyses of male genital structures from 124 species. They wanted to understand how the different sound-producing mechanisms worked and how they had evolved. To trace the history of these defenses, they also examined the evolutionary relationships between 310 hawkmoth species.
The scientists discovered how many times nature has come up with different solutions to the same problem, as they report in a paper published in Proceedings of the Royal Society B. The anti-bat sound responses may have evolved independently up to seven times over roughly the past 30 million years. "Phylogenetic analyses reveal that stridulatory responses to bat echolocation evolved independently multiple times among hawkmoths within the past approximately 30 million years," wrote the scientists.
However, the moths didn't all develop the same solution. The researchers identified three distinct mechanisms for producing ultrasound. Each involved rubbing specialized genital scales against a different structure on the abdomen: other scales, tiny spines or small bumps called nodules.
Extract — continue reading at the source.
