Aphids Are Sentinels Of Climate Change

Aphids are emerging as sentinels of climate change, researchers at BBSRC-supported Rothamsted Research have shown. One of the UK's most damaging aphids – the peach-potato aphid (Myzus persicae) – has been found to be flying two weeks earlier for every 1°C rise in mean temperature for January and February combined.

This year, the first aphid was caught on 25 April, which is almost four weeks ahead of the 42-year average.

Dr Richard Harrington of the Rothamsted Insect Survey said: "One of the most noticeable consequences of climate change in the UK is the frequency of mild winters. As a direct result of this, aphids seeking new sources of food are appearing significantly earlier in the year and in significantly higher numbers. We have been studying the seasonal biology of aphids for a long time now and we know that populations can continue to grow over the winter and spring provided that conditions are warm enough. After a warm winter, there are much larger numbers flying and they are hence detected much earlier. This means that there are more aphids flying in spring and early summer, when crops are particularly vulnerable to damage."

Scientists at Rothamsted Research have been monitoring the flying form of all aphid species for 42 years. They use a network of 16 suction traps (12 in England and 4 in Scotland), placed at various sites, to collect a representative sample of all flying insects. The long term data on aphids can be used to understand the wider implications of climate change, and also to prepare for the season ahead by determining the need for and timing of aphid control measures (based on preceding winter temperatures).

As well as being important indicators of a changing climate, aphids can cause devastating damage to crops. They extract large amounts of sap, weakening the plant, and also spread plant viruses. In addition, because the sap is very high in sugars the aphids excrete very sticky honeydew, which can encourage the growth of sooty moulds that build up and prevent sunlight from reaching the leaves, causing further weakening.

Professor Nigel Brown, Director of Science and Technology, BBSRC said: "Environmental change is one of the big challenges facing the world today. These long-term data on the seasonal appearance of flying aphids not only show that there are already noticeable changes in the UK climate, but they also provide the knowledge which will help to mitigate the consequences."

This work is reported in BBSRC Business, the quarterly research highlights magazine of BBSRC (the Biotechnology and Biological Sciences Research Council).

SOURCE : Biotechnology and Biological Sciences Research Council

Are Pronghorns Smarter Than Classical European Royalty?

Over the past two decades, John Byers has proven that female pronghorns are smarter than many humans when it comes to mate selection. Rather than going for the male with the biggest body or most impressive horns, female pronghorns expend a ton of energy searching for the most vigor and best stamina; traits that will give their offspring the greatest chance of success.

 An American pronghorn male chases an intruder away from his territory. 

Pronghorns are commonly accepted as the second fastest land animal 

in the world--behind only the cheetah--reaching speeds in excess of 45 miles per hour. 

(Credit: John Byers, Department of Biological Sciences, University of Idaho)

But are they smarter than classical European royalty? When pronghorns select a mate, can they factor in what many historians believe doomed the famous Hapsburg dynasty – inbreeding?

Thanks in part to a four-year, $600,000 grant from the National Science Foundation, Byers will be able to answer that exact question.

“We’ve shown the pronghorns know the benefit of selecting the best males,” said Byers, a professor of biological sciences at the University of Idaho. “Now we’re trying to show whether females can balance the cost benefits of selecting a strong male versus a closely related one. Will they accept mating with a relative if the projected cost of inbreeding is not too high? Or reject the male because the cost is way off the chart? Or will they breed without any regard to genealogy?”

Because Byers has worked with the same pronghorn herds in eastern Montana since the early 1990s, and can identify each pronghorn by sight, he is in a unique position to carry out this study. During that time, he has proven female pronghorns expend 50 percent more energy while searching for the strongest males, and that offspring sired by the chosen few are stronger, have a much higher chance of survival and strike out from their mothers much sooner. Because of this mate testing, nearly all offspring are sired by a small subset of males.

As a result of his research, Byers has a complete pedigree of the entire population. When a fawn is born, genetic testing removes any doubt which male is the father.

When a drought in 2003 killed off most of the males and about 30 percent of the females, Byers knew he was in a unique place to study mate selection based on inbreeding.

“I realized we were going to be in an incredibly interesting position,” he said. “We now know females select males for their vigor with a real benefit in survival for their offspring. But today, about three years after the weather caused a bottleneck in the population, they’re faced with a different set of choices.”

Byers’ research will be two-fold. First, the research team will test the paternity of new fawns, measure their living conditions and monitor their survival rate to see what, if any, negative effects occur in pronghorns from inbreeding. Once that is determined, scientists will study female behavior to see if females avoid closely related males – even the best choices for mates – if the benefits of strong genes are outweighed by the average negative effects of inbreeding.

“I think they’ll be able to discern the best choice,” said Byers. “But only time will tell.”

The results of Byers’ study should help conservationists keep the population of pronghorns – and perhaps many other types of hoofed animals – healthy in the future.

SOURCE : University of Idaho  

Red Flour Beetle's 'Selfish' Gene Sequenced

Tracking the red flour beetle in grain storage facilities could become easier, thanks to research to identify a key gene in this grain-feeding pest.

Determining the genetic code of a key gene could make the red flour beetle (Tribolium castaneum), a major problem.in grain storage facilities, easier to track and may offer new ways to control this pest. (Credit: Photo by Peggy Greb)

Researchers with the Agricultural Research Service (ARS), Purdue University, the Human Genome Sequencing Center at Baylor College of Medicine, Kansas State University, and Exelixis, Inc. in South San Francisco, Calif., have determined the genetic code of the so-called "selfish" gene in the red flour beetle (Tribolium castaneum).

This genetic information may offer a potential tracking tool for facilities where grain is stored. Operators could use the information to determine whether beetles are local or from a distant location--and even to develop a plan to control infestations.

ARS entomologist Richard Beeman and molecular biologist Marcé D. Lorenzen at the agency's Grain Marketing and Production Research Center in Manhattan, Kan., deciphered the genetic code of the "selfish" gene. The research was reported in the Proceedings of the National Academy of Sciences.

The selfish gene is important because red flour beetles that don't inherit it from their mother don't survive. It is called the selfish gene because, whether beneficial or deleterious, it ensures its own perpetuation through the population. These genes are widespread in natural populations of red flour beetles, but are otherwise unknown in the invertebrate world.

According to Beeman, the discovery in red flour beetle may provide a useful vehicle for driving desirable genes into populations, since the gene spreads almost like a disease, and since hitchhiker genes can be attached to it. Malaria researchers think other, similar genes introduced into mosquito populations could reduce the spread of mosquito-borne malaria infections. It may be possible to "attach" another gene to the malaria gene that could negate or minimize its function, thus impeding mosquitoes from spreading the disease.

SOURCE : USDA - Agricultural Research Service

Global Warming's Effects Extend To World's Smallest Butterfly

The latest issue of Conservation Biology examines the viability of the Sinai baton blue and the results of human population pressures. The study predicts that in the absence of global warming, grazing, and plant collection (three activities directly linked to humans) the world's smallest butterfly would persist for at least 200 years.

The population could withstand small increases in grazing intensity that would decrease their climate, but not increases in temperature. As the level of global warming raises its impact, extinction rapidly accelerates. This implies "... that there may be an annual average temperature, specific to each endangered species, above which extinction becomes much more likely," authors Martin Hoyle and Mike James state. There is no such threshold of grazing pressure.

The authors mapped the entire global range of this butterfly and obtained data on the intensity of livestock grazing. The Sinai baton blue is one of only two endemic animals in St. Katherine's Protectorate, one of Egypt's most recently designated protected areas. Based on the authors' model, the effect of global warming on the chance of extinction does not depend on the future level of habitat destruction due to this grazing; the growing number of families that live on the protectorate keep a small herd of goats and sheep that graze on the plants the butterflies thrive on. Global warming is the deadly culprit.

"If the areas of habitat patches individually fall below certain prescribed levels, the butterfly is likely to go extinct,"the authors conclude.

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This study is published in the August issue of Conservation Biology. Media wishing to receive a PDF of this article please contact journalnews@bos.blackwellpublishing.net

Conservation Biology is a top-ranked journal in the fields of Ecology and Environmental Science and has been called, "required reading for ecologists throughout the world." It is published on behalf of the Society for Conservation Biology.

Martin Hoyle is at the School of Biological and Chemical Sciences at the University of Exeter, Hatherly Laboratories. He has performed research on metapopulation dynamics and has been published in numerous journals.

SOURCE : Blackwell Publishing Ltd.

Amber Specimen Captures Ancient Chemical Battle

It appears that chemical warfare has been around a lot longer than poison arrows, mustard gas or nerve weapons -- about 100 million years, give or take a little.

A new study by researchers at Oregon State University has identified a soldier beetle, preserved almost perfectly in amber, which was in the process of using chemical repellents to fight off an attacker when an oozing flow of sap preserved the struggle for eternity.

An ancient example of “chemical warfare” about 100 million years old is captured in this sample of amber, in which a soldier beetle is exuding a certain toxin to protect itself from an attacker.
(Credit: Image courtesy of Oregon State University)

The discovery is the earliest fossil record of a chemical defense response, scientists say, and indicates that this type of protective mechanism -- now common in the insect world and among other animal species -- has been around for more than 100 million years. It's a sophisticated form of defense that clearly was in good working order while dinosaurs still roamed the Earth.

"The chance of these circumstances all coming together at the exact right second was pretty slim," said George Poinar, Jr., a courtesy professor of zoology at OSU and one of the world's leading experts on distant life forms preserved in amber. "You have a prehistoric insect being attacked, using its defenses to ward off the predator and the whole event becoming captured in action as sap flowed down a tree. It's quite remarkable."

The beetle was a small insect, about one-quarter inch long, which may have been in the process of becoming lunch for a giant roach or some other larger insect that apparently was 2-3 inches long, judging by the length of an antenna from the other insect also found in the specimen. The other insect either escaped the sap or was preserved in a different piece of amber, in these samples of Burmese amber that came from the Hukawng Valley in Myanmar.

"This particular insect is now extinct, but the broader family of soldier beetles still exists, and they still use this same type of chemical defense mechanism," Poinar said. "That this type of defense has been preserved through 100 million years of evolution is evidence that it works pretty well."

At the time of this event in the Early Cretaceous Period, huge animals such as dinosaurs still dominated the Earth, but scurrying beneath them were early mammals and large numbers of terrestrial invertebrates, such as these insects. Soldier beetles, then as now, were omnivores that lived on things like aphids, other tiny insects or plant pollen. Among other things, this finding pushes back the known existence of this type of beetle by about 60 million years. And at that distant time, they had already evolved ways to defend themselves.

"This beetle was able to exude a sticky chemical substance that was irritating to potential predators, and caused them to go away or leave it alone," Poinar said. "It could even conserve its excretions and control the direction of the defense; in other words, produce the substance only on its left rear side if that was where the attack was coming from."

Building on these types of early defense mechanisms, Poinar said, modern insects now have a wide range of defensive chemical arsenals -- things that are distasteful, nauseating or caustic, from chemicals such as phenols, aldehydes and ketones. Some contemporary soldier beetles can produce types of carboxylic acid, as well as triglycerides and glyceride esters.

In insects, these types of defensive mechanisms are often a key to their survival.

Amber provides a unique mechanism to preserve specimens such as this. Beginning as viscous sap from certain kinds of trees, it can trap small animals or other materials, acts as a natural embalming agent, and eventually can turn into a semi-precious stone that displays these ancient life forms in nearly perfect, three-dimensional form. The phenomena has been invaluable in scientific and other ecological research, allowing experts to help re-create more accurate pictures of ancient ecosystems based on the insect life that lived then.

"Insects give us a fascinating window to the world, and they are survivors," Poinar said. "This particular species lived right on through the K-T Boundary at 65 million years ago, when the dinosaurs and many other species disappeared."

"These insects were here a long time before humans, and we can learn a great deal from their remains," he said. "And they'll probably still be here a long time after our species is gone."

The findings were just published in the Journal of Chemical Ecology.

SOURCE : Oregon State University

Amber Fossils Reveal Ancient France Was A Jungle

Research on a treasure trove of amber has yielded evidence that France once was covered by a dense tropical rainforest with trees similar to those found in the modern-day Amazon. The 55-million-year-old pieces of amber was discovered in the Oise River area in northern France.

In the new study, Akino Jossang and colleagues used
laboratory instruments to analyze the fossilized tree sap in an effort to link specific samples of amber to specific kinds of trees. The amber remained intact over the ages, while the trees from which it oozed disappeared. Efforts to make such connections have been difficult because amber from different sites tended to have very similar chemical compositions.

The report describes discovery of a new organic compound in amber called "quesnoin," whose precursor exists only in sap produced by a tree currently growing only in Brazil's Amazon rainforest.

Researchers say that amber probably seeped out of a similar tree growing in a tropical forest that covered France millions of years ago before Earth's continents drifted into their current positions.

"The region corresponding to modern France could have been found in a geographically critical marshy zone belonging to Africa and a tropical zone 55 million years ago extending through North Africa to the Amazon," the report states.

The study "Quesnoin, a Novel Pentacyclic ent-Diterpene from 55 Million Year Old Oise Amber" is scheduled for the Jan. 4 issue of ACS' Journal of Organic Chemistry.

SOURCE : American Chemical Society