Above, the real deal; below, the clay models used to test predators’ reactions to local and foreign frog markings.
Sometimes, you have to make a thousand frogs from modelling clay to make your point.
A single species of poison dart frog sports ten completely different coloration patterns, depending on where they live. Are these color divisions being encouraged by the birds that prey on them?, wondered evolutionary biologist Mathieu Chouteau from the University of Montreal. To find out, he set out 1800 clay frogs, made by himself and his (saintly!) girlfriend, in the Peruvian forest.
What’s the News: Among the many creepy denizens of Australia—such as the red back spider, seen here hauling a lizard into its nest, and the saltwater crocodile, which kills with its distinctive “death roll”—the assassin bug is right at home. With its erratic, long-legged walk, it stalks along spiders’ webs, caressing its prey with its antennae and then stabbing them with its beak. Now, scientists who spy on these spider-eaters report that the bugs have yet another charming behavior in their toolkit: using the breeze as cover when they go in for the kill.
It’s common wisdom that the big cats, like so many animals, evolved their particular look to blend into the background and skulk around undetected. But just how much are a cat’s spots or stripes fine-tuned to its habitat? To find out, William Allen and colleagues dug into the markings in detail for a study in Proceedings of the Royal Society B and found that their specificity is even more connected to the species’ home and lifestyle than scientists ever knew.
The Allen team studied 35 different species of big cats, looking at their markings next to their habitat, history, and hunting patterns.
Dark-colored coats, which are common to leopards and jaguars but unknown to cheetahs, were tied to species that may roam both day and night and that occupy a wide variety of habitats. Solid-colored coats were linked to cats that are active during the day, usually walk on the ground and that live in open habitats, such as in deserts or on the plains. Stripes, on the other hand, remain somewhat of a mystery. “There aren’t enough species of stripy cat to reliably make associations between stripes and potential drivers of stripyness,” Allen explained. [Discovery News]