Praying Mantis: Re-Evolution Of Disruptive Camouflage Revealed In Horned Praying Mantises

Praying mantises are iconic insects named after their apparent prayer-like stance. More importantly though, mantises are known for their alien-like heads and camouflage abilities that put them at the top of the insect world. Praying mantises have huge compound eyes mounted on their triangle heads that give them a wide range of vision. This ability paired with their sneak attack hunting strategy makes it almost impossible for crickets, beetles, moths and other insects to escape from the grasp of a mantis' long, slender raptorial front legs.  

To get a better sense of how the horned praying mantis blends in with its surroundings while waiting for the perfect opportunity to capture prey, researchers from the Cleveland Museum of Natural History traced the evolution of its distinctive camouflage, or cryptic, features. In doing so, researchers identified a new genus and new tribe of praying mantises, in addition to discovering that their disruptive camouflage evolved twice within the group, according to a news release. (Scroll to read more...)

"Praying mantises depend on camouflage to avoid predators, but we have known little about the patterns of how body structures contributing to crypsis evolved," Dr. Gavin Svenson, curator of invertebrate zoology at the Cleveland Museum of Natural History and lead author of the study, explained in the release. "We discovered that two mantis lineages evolved structural camouflage millions of years apart in very similar ways. This not only suggests that re-evolution occurred, but demonstrates that the developmental mechanisms controlling cryptic features may be more ancient than the camouflaged mantises themselves."

Camouflage is a widely adapted characteristic of many animals aiming to avoid predation. However, simply matching one's background does not prove to maximize concealment because an animal's outline may still give them away. As a result, some animals use disruptive camouflage, which simply means they adopt differing patterns that break up their appearance and body outline in addition to background matching. This ultimately increases the animal's likely hood of remaining hidden. 

In the recent study, Dr. Svenson and colleagues revealed that the second, more recent, evolution of disruptive camouflage abilities occurred following the re-evolution of a special leg lobe that disguises the body profile and helps praying mantises hide from predators themselves. Their study was recently published in the journal Systematic Entomology.

To do this, researchers used DNA sequence data generated in the Cleveland Museum of Natural History's DNA Laboratory. This allowed them to closely study morphological features and reclassify the species. In total, researchers examined the origins of 16 features that contribute to the camouflage strategies of Central and South American horned praying mantises. These features include an extended head process, or horn, and leafy looking lobes on their legs.

So what did they find? Researchers discovered leafy lobes found on the insect's middle and hind legs evolved during the first origin of the horned mantises. However, 20 million years later a second lineage of praying mantises adopted disruptive camouflage features, which suggests the original leg lobes had re-evolved in the same positions, along with a similar horned head process.

Essentially, the insects were already equipped with the genetic and developmental mechanisms necessary to trigger the second emergence of disruptive camouflage features. This indicates praying mantises most likely have an ability to selectively turn on or off their camouflage abilities in a variety of ways, researchers noted.

Additionally, researchers identified a new genus named Alangularis, which is characterized by a colorful species of praying mantis with unique wing tips that was previously mistaken as a member of another genus. A new tribe, Heterovatini, was also established within the new genus to include two species that appear to be very similar to other praying mantises, but retain no disruptive cryptic features other than the shared leg lobes. (Scroll to read more...)

"Finding that camouflage evolved twice in the horned mantises was surprising," Svenson added. "But even more amazing is how alike the two distantly related camouflaged groups really are and what that means for camouflage evolution in mantises as a whole."

Related Articles 

Evolution: Study Sheds Light On Arms Race Among Venomous Animals

For more great nature science stories and general news, please visit our sister site, Headlines and Global News (HNGN).

-Follow Samantha on Twitter @Sam_Ashley13