| Worm seeks worm: Chemical cues drive aggregation in nematodes |
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Scientists have long seen evidence of social behavior among many species of animals, both on the earth and in the sea. Dolphins frolic together, lions live in packs, and hornets construct nests that can house a large number of the insects. And, right under our feet, it appears that nematodes -- also known as roundworms -- are having their own little gatherings in the soil. Until recently, it was unknown how the worms communicate to one another when it's time to come together. Now, however, researchers from the California Institute of Technology (Caltech) and the Boyce Thompson Institute at Cornell University have identified, for the first time, the chemical signals that promote aggregation.
"We now have an expanded view of a very fundamental type of communication, which is recognizing other members of the same species and getting together with them," says Jagan Srinivasan, a senior research fellow in biology at Caltech and lead author of the study detailing this process, which was published in the January issue of PLoS Biology.
The researchers looked at the lab-friendly Caenorhabditis elegans worm -- a relatively safe version of the phylum, whose parasitic cousins include hookworms, whipworms, and trichinas, which cause trichinosis -- to gather data.
According to Paul Sternberg, Thomas Hunt Morgan Professor of Biology at Caltech and a corresponding author on the paper, nearly 25 percent of the world's human population is infected with some type of parasitic nematode; animals and plants can fall prey to the nasty worms, too. Since nematode parasites live inside a host and attack it internally, knowing how the worms communicate via chemicals could be very important to the fields of biomedicine and agriculture.
"One of the ways to eradicate them would be to have some sort of a chemical that can attract them in order to kill them more efficiently," explains Srinivasan.
Sternberg and Srinivasan are not new to the idea of chemical signaling among C. elegans. In 2008, their research showed how the worms secrete chemicals as a sexual attractant. This time, they worked to find che... |
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| Wandering albatross alters its foraging due to climate change |
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Wandering albatrosses have altered their foraging due to changes in wind fields in the southern hemisphere during the last decades. Since winds have increased in intensity and moved to the south, the flight speed of albatrosses increased and they spend less time foraging. As a consequence, breeding success has improved and birds have gained 1 kilogram. These are the results of the study of an international research team published in the latest issue of the Science journal. However, these positive consequences of climate change may last short if future wind fields follow predictions of climate change scenarios, researchers warn.
For this study, biologists had combined data on the duration of foraging trips and breeding success over the last 40 years, as well as foraging and body mass over the last 20 years of wandering albatross (Diomedea exulans) breeding in Crozet Islands. This archipelago lies approximately in the heart of the southern Indian Ocean (halfway between Madagascar and Antarctica). It belongs to the French Southern Territories and it is located in the windiest part of the Southern Ocean. The new findings are the result of an international research team from the French National Centre for Scientific Research (CNRS-CEBC) and the German Helmholtz-Centre for Environmental Research (UFZ).
Thanks to miniaturised tracking devices, researchers were able to track the foraging movement of albatrosses at a distance of 3500 kilometers from the colony. They found that albatross have altered their search patterns following changes in wind conditions over the past two decades. Females used increasingly more poleward and windy areas for foraging. As a consequence their travel speed increased while the total distance covered during foraging flights did not change. "This means that they spend less time at sea while incubating the egg and thus the breeding success increases" explains Dr. Henri Weimerskirch of the French National Centre for Scientific Research (CNRS-CEBC). Researchers were surprised that both females and males have increased their body mass in one kilogram, which corresponds ... |
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