Oldest Known Insect Camouflage Dates Back 110 Million Years

U.S.-Spanish scientists have found evidence of what they say is the oldest known camouflaging behavior in insects.

This is an artist’s reconstruction of H. diogenesi (J. A. Peñas)

A paper published in the Proceedings of the National Academy of Sciences reports the discovery of a fossil of a new insect larva species with specialized pack of plant remains.

The 4-mm-long fossil is a predatory larva of the order Neuroptera. It is covered by a tangle of plant filaments that it collected with its jaws to form a defensive shield and camouflage itself. This survival strategy, sometimes called the trash carrying, is observed in current species to render them nearly undetectable to predators and prey. It was found in a piece of amber unearthed in 2008 in the El Soplao outcrop in Cantabria, Spain, the Mesozoic’s richest and largest amber site in Europe.

Related to current green lacewings, the fossil represents a new genus and species designated Hallucinochrysa diogenesi.

“The name alludes to its ‘mind-blowing appearance and its resemblance to Diogenes syndrome, a human behavioral disorder characterized by compulsive hoarding of trash,” the scientists said.

The study identified the filamentous plant remains composing the larval trash packet as trichomes, or plant hairs with diverse shapes and functions. The trichomes are thought to belong to a specific group of ancient ferns.

Today green lacewing larvae harvest plant materials or even detritus and arthropod remains and carry them on their backs, nestled among small tubercles with hairs. On the contrary, Hallucinochrysa diogenesi possessed a bizarre characteristic: it possessed extremely elongate tubercles, with hairs that had trumpet-shaped endings acting as anchoring points. All this structure, completely unknown until now, formed a dorsal basket that retained the trash and prevented it from sliding when the insect moved.

Green lacewing larva with its dense trash packet composed of fern trichomes from the Early Cretaceous of Spain. The inset shows a close-up of plant hairs, scale bar is 0.5 mm (Ricardo Pérez-de la Fuente et al)

Hallucinochrysa diogenesi demonstrates that camouflage strategy and its necessary morphological adaptations appeared early and was well developed during the era of the dinosaurs. In the case of green lacewings, this complex behavior has been around for at least 110 million years. This is significant for evolutionary studies pertaining to animal behavior and the adaptative strategies of organisms throughout Earth’s history.”

_______

Bibliographic information: Ricardo Pérez-de la Fuente et al. Early evolution and ecology of camouflage in insects. PNAS, published online before print December 12, 2012; doi: 10.1073/pnas.1213775110