A subject that is not often discussed outside of grad student circles, but the pressure to develop many different skills at once, and execute them at a consistently high level, makes academic research a much less glamorous gig than watching Neil Tyson or Bill Nye may suggest.
Another gap in the fossil record has been filled, and it’s a sexy one. A pair of froghoppers, tiny insects that jump around on plants and make weird spit bubbles to protect their young, were not only caught but fossilized in the act of copulation 165 million years ago. That means this rock porn was created 100 million years before the dinosaurs went extinct.
These ancestors to modern froghoppers, if sex was enjoyable for both of them, died happily in a rain of volcanic ash.
The fossil was found in northeastern China, where a treasure trove of fossils is still being explored and many recent discoveries have made it clear that birds did not evolve feathers on their own but have inherited them from their feathered dinosaur ancestors. (As an aside, in addition to dino feathers, we’re also beginning to find evidence about what color they might have been). Not only is this the oldest example of fossilized insect sex known to date, it also represents a previously undescribed species – although given the sparse nature of the fossil record, it is not at all unusual for paleontologists to find new species.
The researchers, who recently published their finding in PLoS Biology, concluded that the rare fossil suggests that a belly-to-belly mating position (or side-by-side, which can’t be ruled out) and symmetrical genitalia have not changed much in the froghopper lineage since the Middle Jurassic (you can insert your own Kama Sutra joke here…or not). It also supports previous suggestions that asymmetric insect genitalia have evolved multiple times independently, presumably as an adaptation to different sexual positions. For example, when insects have evolved behaviors leading them to always approach mates from one side, their genital structure tends to become asymmetric to the point where other sexual positions just won’t work. But in the case of froghopper sex, it seems they’ve heeded the advice that I assume everyone’s crazy uncle has given them at some point: “if it ain’t broke, don’t fix it.”
Every animal needs energy to live, and they usually get it by ingesting other living things. We’ve all seen videos of predators hunting down and killing their favorite prey, or docile herbivores munching on grass, leaves, or berries. But one group of animals has evolved a strategy to harness energy that’s a bit more complex and far more clever than simply finding something and eating it. Sacoglossan sea slugs are close relatives of the more colorful and better-known group of slugs called nudibranchs.
Nudibranchs are carnivorous – they prey on sponges, cnidarians, bryozoans, and even cannibalize other members of their own species. Sacoglossans, on the other hand, are more like their hippie vegan cousins. They feed on green algae using a specialized tooth-like feeding structure common to all snails and slugs called a radula. A sacoglossan sea slug uses its radula to pierce cell walls, allowing it to suck out all those sweet, sweet algal juices.
Close up view of functional chloroplasts in the tissues of Elysia crispata.
Photo courtesy of Patrick J. Krug.
Okay, so some sea slugs are vegan, but what’s so clever about that? Continue reading
Evolution Happens 