Gallery: Big spiders eating small vertebrates

The comforting notion that an evolutionary hierarchy more or less governs predator-prey relationships – specifically, that vertebrates eat invertebrates, and not the other way around – has been roundly demolished by a team of researchers armed with cameras.

“This is an underappreciated source of mortality among vertebrates,” says evolutionary biologist Daniel Rabosky from the University of Michigan in the US. “A surprising amount of death of small vertebrates in the Amazon is likely due to arthropods such as big spiders and centipedes.”

For some years, Rabosky and colleagues have been venturing into the lowland Amazon rainforest, looking for examples of arthropods – invertebrate animals with exoskeletons – capturing and chowing down on victims with backbones.

A paper published in the journal Amphibian & Reptile Conservation demonstrates that their missions were certainly not in vain.

They report – and show – many incidences of spiders, as well as a few centipedes and in one case a giant water bug, taking vertebrate prey, including frogs, tadpoles, lizards, snakes, and even a small opossum.

“These events offer a snapshot of the many connections that shape food webs, and they provide insights into an important source of vertebrate mortality that appears to be less common outside the tropics,” says co-author Rudolf von May.