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Stick insect advice: Make like a tree and leaf


A fossil of the ancient insect Cretophasmomima melanogramma, left, and the modern leaf-shaped plant organ Membranifolia admirabilis.
(Oivier Bethoux (left photo), Frederic Jacques (right photo))

By Monte Morin
March 19, 2014, 6:59 p.m.

With their extraordinary ability to mimic twigs and leaves, stick insects are among nature's most renowned masters of disguise.

But it's not just predators they've managed to avoid. Sneaky phasmatodae, or "ghost" insects, have also flummoxed scientists by leaving behind precious few fossil clues concerning their unique evolution.

But on Wednesday, researchers from China, France and Germany announced the discovery of a long-extinct species that lived around Inner Mongolia roughly 126 million years ago.

The insect, dubbed Cretophasmomima melanogramma, was described in the journal PLOS One [ http://www.latimes.com/science/sciencenow/%20http:/dx.plos.org/10.1371/journal.pone.0091290 ] and would have existed during the time of the dinosaurs. Long and narrow, the bug probably used its wings as a leaf-like cloak to fool birds and rat-like mammals, according to researchers.

Lead study author Maomin Wang, a researcher at Capital Normal University in Beijing, wrote that the insect lived within the famous Cretaceous Jehol biota [ http://www.latimes.com/science/sciencenow/la-sci-sn-animal-pompeii-china-fossils-volacnoes-20140204,0,1152707.story ] -- making it almost 77 million years older than what was previously believed to be the earliest stick insect.

Wang and colleagues uncovered three fossils of the insect -- one female and two male -- and wrote that their wings appeared to have dark, parallel lines. When folded back, the wings would have assumed a "tongue-like" shape that covered the insect's abdomen.

Researchers argue that the wings resembled a leaf-shaped plant organ called Membranifolia admirabilis. Although fossils of the plant organ have been found in the same region of northern China, it is unclear exactly what type of plant they belonged to.

The authors wrote that since today's stick insects mimic the same plants they eat, they believe this was probably the case in the Jehol biota. (To watch some videos about modern stick insects, click here [ http://www.bbc.co.uk/nature/life/Phasmatodea ].)

Researchers noted that the three specimens each measured roughly 2 inches long, with the female being slightly larger than the males. In modern species, the difference in length between males and females, or what's called sexual size dimorphism, is more pronounced.

"This new record suggests that leaf mimicry predated the appearance of twig and bark mimicry in Phasmatodeans," the authors wrote. "Additionally, it complements our growing knowledge of the early attempts of insects to mimic plant parts."

Copyright © 2014, Los Angeles Times

http://www.latimes.com/science/sciencenow/la-sci-sn-fossils-of-early-plantmimicking-insect-found-20140319,0,4881131.story [no comments yet]


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Scientist finds 19 new species of speedy, clever praying mantises

By Amina Khan
This post has been updated, as indicated below.
March 19, 2014, 6:50 a.m.

Welcome to the fold! An entomologist trekking through Amazonian rain forest and sifting through musty museums has discovered 19 new species of praying mantis in Central and South America. The findings, published in the journal ZooKeys, nearly triple the number of known bark mantis species and reveal the diversity of this charismatic insect group.

These insects aren’t your typical praying mantises, said entomologist Gavin Svenson, curator of invertebrate zoology at the Cleveland Museum of Natural History. The archetypal praying mantis is a fresh, new-leaf green with a tubular body and is seen as an ambush hunter. Not so with the bark mantises, which have brownish, mottled backs and flat bodies that allow them to lie flat against the bark of a tree and hide from predators.

Unlike your garden-variety praying mantis, these bark mantises don’t just sit quietly and wait for unsuspecting prey to come their way -- they’re speedy critters that can quickly chase down a fly or a cricket for a quick snack. They also actively evade their enemies, scurrying around to the other side of a tree if they see someone coming, just as neurotic neighborhood squirrels do. As a last-ditch effort to avoid getting eaten, they even jump to the ground and fall into the dead leaf litter and play dead.

“For an insect, that’s pretty complicated,” Svenson said of the behavior. “I don’t think most people would think an insect would play dead. You can literally find this thing in the leaf litter and poke it and it’ll just lay there.”

But Svenson said that there was relatively little research on the praying mantis, in spite of its high profile compared to other bugs. So he visited countries in South America, North America and Europe to search for mantis species. Some he found while looking though old samples that were close to a century old, that had never been labeled or properly categorized. Others he had to go searching through the jungle to locate. He brought back hundreds of specimens.

[Updated, 6:48 a.m., March 19: Each search came with its challenges. The museum search was painstaking and time-consuming; many samples had been collected decades ago, dropped off at the museum and long forgotten. Looking through them was like sifting through a giant, scientific rummage sale.

"It’s easy to miss stuff," Svenson said. "You’re searching through specimen archives that have been there for a long, long time. You don’t know exactly what you’re going to find."]

In the jungle, these clever insects were fairly skilled at eluding capture. In one instance, Svenson had to poke a branch at an insect entrenched in a tree for three hours in the middle of the night before he could coax it down and nab it.

“Who knows? I probably missed the 20th new species because they’re so difficult to catch sometimes,” Svenson said.

Is there a chance that species discovered in the museum collections may no longer exist in the wild? It’s possible that some have gone extinct or are highly threatened, Svenson said, pointing out that some of the forests where old museum specimens were caught may have been replaced by urban development.

“It has a lot of implications in conservation,” he added.

The new finds bear some colorful names. One insect, named Liturgusa algorei after former Vice President Al Gore to honor his environmental activism, was caught in thick rain forest in northern Peru. So was another named Liturgusa krattorum, after Martin and Chris Kratt of the PBS children’s television show "Wild Kratts," which teaches kids about animal biology. Another, named Liturgusa fossetti, is named after the late explorer James Stephen Fossett. Another named Liturgusa bororum is named after the Bora people, who live in parts of the Amazon Basin. Svenson even got to name two species, Liturgusa tessae and Liturgusa zoae, after his daughters Tessa and Zoey.

Copyright © 2014, Los Angeles Times

http://www.latimes.com/science/sciencenow/la-sci-sn-praying-mantis-19-new-species-bark-20140318,0,4869953.story [with comments]


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