Update: June 17, 2008

BATS AND TOADS AND ROACHES, OH MY!! By Pam Eastlick

By Pam Eastlick for THE DEEP on line

Welcome to The Deep science and technology column where we cover topics from the deep sea to deep space and beyond.

Greetings everyone, I thought that today we'd delve into the wild and wonderful world of animals. We share the planet with some strange creatures and some of them, quite frankly we could do without. So join me as we learn a little about some scientific news about animals.

THE ROARING BAT

Researchers studying echolocation behavior in bats have discovered that the diminutive flying mammals emit exceptionally loud sounds -- louder than any known flying animals. European scientists studied 11 species of insect-eating tropical bats from Panama and discovered that these bats emit exceptionally loud sounds exceeding 140 dB (at 10 cm from the bat's mouth), which is the highest level reported so far for any animal in air. For comparison, the level at a loud rock concert is 115-120 dB and the loudest ever recorded for a lion's roar was 114 dB. The threshold of pain for humans is around 120 dB. The researchers used microphone arrays and photographic methods to reconstruct flight paths of the bats in the field when these nocturnal hunters find and capture their insect prey in air using their sonar system. Bats emit their echolocation calls at ultrasonic frequencies, which means that humans can't hear them.

The high frequencies are necessary to get echoes from small insects, but the drawback of high frequencies is that they don't travel very far. So the bats have to make them REALLY loud. Fruit bats don't echolocate at all because fruit doesn't fly around like insects and our local bats are among the few comparatively silent bat species. You have to wonder if all that ultrasonic noise would give you a headache even if you couldn't hear it.

HE SCRATCHED YOU????

Biologists at Harvard University have determined that some African frogs carry concealed weapons. When they are threatened, the frogs in these species puncture their own skin with sharp bones in their toes and use the bones as claws that are capable of wounding predators.

"It's surprising enough to find a frog with claws," says David Blackburn, a doctoral student in Harvard's Department of Biology. "The fact that those claws work by cutting through the skin of the frogs' feet is even more astonishing. These are the only vertebrate claws known to pierce their way to functionality. Most vertebrates do a much better job of keeping their skeletons inside". Blackburn first became aware of the clawed frogs while conducting fieldwork in the central African nation of Cameroon. When he picked up one of the hulking fist-sized frogs, it flailed its hind legs violently, scratching him and drawing blood.

Back in the U.S., Blackburn examined museum specimens of 63 African frog species. He found that in 11 species, the bones at the ends of the toes were pointed and hooked, with smaller, free-floating bones at their tips. Eventually he determined that these small nodules at the tips of the frogs' feet were connected to the rest of the toe by a collagen-rich sheath. "These nodules are also closely connected to the surrounding skin by dense networks of collagen," Blackburn says. "It appears they hold the skin in place relative to these claw-like bones, such that when the frog flexes a certain muscle in the foot, the sharp bone separates from the nodule and bursts through the skin."

This claw-like structure is not a claw, though: It's pure bone, free of the keratin sheath that normally surrounds vertebrate claws. And unlike a claw that retracts into a specialized structure in an animal's foot, as in cats, the site where the frogs' foot bones emerge appears to be covered with ordinary skin. ,br> Blackburn plans to study live specimens of the African frogs to determine whether retraction of the foot bones back into the body is an active or a passive process, and how the damaged skin regenerates after the claws are deployed. "We suspect, since the frog does suffer a fairly traumatic wound, that they probably use these claws infrequently, and only when threatened," Blackburn says.

UNDER THE ICE

A team of Penn State scientists has discovered a new ultra-small species of bacteria that has survived for more than 120,000 years within the ice of a Greenland glacier at a depth of nearly two miles. The microorganism's ability to persist in this low-temperature, high-pressure, reduced-oxygen, and nutrient-poor habitat makes it particularly useful for studying how life, in general, can survive in a variety of extreme environments on Earth and possibly elsewhere in the solar system. This new species is among the ubiquitous, yet mysterious, ultra-small bacteria, which are so tiny that the cells are able to pass through microbiological filters. In fact, some species have been found living in the ultra-purified water used for dialysis. The ultra-small size of the new species could be one explanation for why it was able to survive for so long in the Greenland glacier. Called Chryseobacterium greenlandensis, the species is related genetically to bacteria found in fish, marine mud, and the roots of some plants. The organism is one of only about 10 scientifically described new species originating from polar ice and glaciers.

A living organism that's been at the bottom of a glacier for 120,000 years. We may think we know our planet, but we have only just begun to explore! Many of us like to think of ourselves as animal lovers, but there are a few animals that very few people profess to love and our last stories are about a few of them. Probably the single most hated insect here on Guam (and quite possibly the entire world) is the cockroach and scientists have come up with a wonderful new cockroach killer.

GOOD RIDDANCE!

One dose of a new insecticide can kill three generations of cockroaches as they feed off of each other and transfer the poison, according to Purdue University entomologists who tested the effectiveness of a specific gel bait. It's the first time that scientists have shown that a pest control bait can remain effective when it's transferred twice after the first killing dose. Passing the insecticide from one cockroach to the next is called horizontal transfer.
These findings are exciting because as we well know cockroaches are difficult to control because they multiply so rapidly. It's difficult rid areas of the insects because cockroaches come out at night and live in inaccessible places. They invade places where they easily can find plenty of food and water. In addition, cockroaches are attracted to where other cockroaches are by chemical compounds called pheromones that the cockroaches excrete.

In their laboratory study, the scientists used German cockroaches, the most common household species in the United States, to test a DuPont product with the active ingredient indoxacarb.

In the first transfer of the insecticide from a dying adult to the youngest stage nymphs, an average of 76 percent of the cockroaches also succumbed to the insecticide contained in the dying cockroaches. In the third stage of transfer, or tertiary kill, an average of 81 percent of the adult male cockroaches that ate the dead nymphs' bodies also died. Both statistics were taken 72 hours after the insects were exposed to a cockroach dead from indoxacarb. Adult German cockroaches are a shiny orangey tan and about half an inch long. The youngest nymphs, as used in this study, are called first instars and are one to five days old. Nymphs go through five stages on their way to adulthood. We do have German cockroaches here, but the ones I really hate are the big black ones that are big enough to carry off small puppies. I sure hope this new insecticide works against them too!

KEEP THEM FROM BITING A naturally-occurring compound made from pine oil that seems to keep mosquitoes from biting and repels two kinds of ticks has been found by Agricultural Research Service (ARS) scientists. A patent has been issued for the compound, isolongifolenone, and partners are being sought to bring this technology to commercial production. In laboratory tests, ARS chemists discovered that the naturally occurring compound deters the biting of mosquitoes more effectively than the widely used synthetic chemical repellent DEET. The compound also repelled two kinds of ticks as effectively as DEET. Insect repellents are used widely to prevent bites from mosquitoes, sand flies, ticks and other arthropods. For the most part, people apply repellents just to avoid discomfort, but there is a more serious side to the use of these products. Human diseases caused by blood-feeding ticks and mosquitoes represent a serious threat to public health worldwide. Malaria is the chief threat, killing approximately two million people per year and threatening billions. Other diseases include dengue fever, chikungunya, Lyme disease and typhus. Some segments of the public perceive efficient synthetic active ingredients as somehow more dangerous than botanical compounds, giving additional importance to the discovery of plant-based isolongifolenone. The researchers also developed an easy and efficient method to prepare this repellent. Many natural-product chemicals isolated from plants and essential oils have proven to have repellent effects. Most often, such compounds never attain commercial development and their use is limited or impractical because they are expensive and not available in pure and large quantities. In contrast, this newly-discovered repellent can be prepared inexpensively from pine oil feedstock in ton quantities for large-scale commercial applications, giving it a significant advantage over many of the other natural-product repellent chemicals. New techniques to fight both cockroaches and mosquitoes. Makes my day! And to make your day, cruise on over to the Deep Website at www.thedeepradioshow.com to learn more about these and many other topics. Enjoy!