Archive for the ‘Zoology’ Category
The origin of polar bears (Ursus maritimus) as independent species occurred about 600,000 years, as revealed by an international investigation in which participated the CSIC. Their evolutionary history is, therefore, five times older than previously thought, as reflected in the article that graces the cover of the journal Science.
Previous articles were found similarities in mitochondrial DNA (from the mother) between polar bears and brown bears (Ursus arctos). As a result, it was assumed that Arctic species belonged to a lineage split from their brown cousins made between 166,000 and 111,000 years and had experienced a rapid adaptation to polar conditions.
The new research is based on the analysis of nuclear DNA from 19 samples of polar bear, brown bear 18 aircraft and seven copies of black bear (Ursus americanus). The differences detected between the genomes indicate that the polar and brown species diverged from a common ancestor about 600,000 years. Read the rest of this entry »
The willingness and enthusiasm of bees foraging in search of food and household manifested at the molecular level. A U.S. group of scientists has shown that these insects have different personality depending on how they express their genetic information.
Insects also have personality, and bees are very artful. For the collectors of honey (Apis mellifera), the willingness and enthusiasm of the most audacious is vital to the survival of the hive. This emerges from a study published this week in Science, linking their behavior to specific differences in gene expression.
The experiments tested six colonies of bees in search of food resources and new locations. On the one hand, the results showed that between 5% and 25% of the colony sought food-regardless of their resources. Furthermore, less than 5% of the swarm explored new places to get a nest in a crisis situation. Read the rest of this entry »
It has been discovered in northwest Tasmania, Australia, after some mapping work, the existence of a mysterious border geographical line between the occupied territories separately by two species of millipedes.
This line is so sharp and detached from physical traits as if it were a human frontier between nations. Both species are common in their respective “countries”, but rarely cross into the territory of the other.
The perimeter of the boundary runs along some 230 kilometers, and the thickness of the boundary line, or the width of the “common area”, where individuals of both species converge, has less than 100 meters. The mapping was carried out over a period of two years by Bob Mesibov, specialist in millipedes and researcher at the Queen Victoria Museum in Launceston, Tasmania. Read the rest of this entry »
Bad eating habits are a lot of people more than the human being is unique, although in this case is worse. Now the results of a new study of a predator illustrate that even carnivores seeking a balanced diet.
An international team of scientists from the universities of Exeter and Oxford in the United Kingdom, Sydney in Australia, Aarhus in Denmark and in Massey in New Zealand, investigated the dietary preferences of the beetle Anchomenus dorsalis, an insect garden well known, that feeds on slugs, aphids, moths, ants and even larvae of other beetles.
The team of Kim Jensen, University of Exeter, female beetles collected wild and divided into two groups in the laboratory. Half of the beetles were offered a set of different foods, some protein-rich and some are high in fat, so you chose to your liking. Read the rest of this entry »
A species of crab that dwells within 300 meters below the surface of the Pacific Ocean near Costa Rica, live bacteria that thrive in its claws. And these unique crabs are not limited to exploit the situation but that is actively encouraged.
Of way seemed to a farmer watering its orchard, the crabs “water” exposing these bacteria to methane and sulfide from fumaroles at the bottom of the sea. This unusual behavior “farmer” has just been described in detail for the first time. This species of crab, called Kiwa puravida, was discovered in 2006. Read the rest of this entry »
Note with a part of the body object to attract attention, it is a natural ability that had only been observed in people and our closest evolutionary relatives, the apes. Now, add the raven in this select club.
No surprise at all unexpected, as the crows outnumbers most other bird species in terms of intelligence. Its efficiency in several tests of intelligence is similar to that achieved by the apes.
Simone Pika of the Max Planck Institute for Ornithology in Germany, and Thomas Bugnyar from the University of Vienna in Austria, have now shown that crows (Corvus corax) also use this kind of gestures to see the interest of a potential mate or strengthen a relationship existing with it. Read the rest of this entry »
The work of U.S. scientists has revealed that the paper wasp has the ability to distinguish the faces of their co-species, which has only been observed so far in mammals. This skill helps maintain peace in the colony.
Specifically, have shown that paper wasp, Polistes fuscatus, is able to learn to recognize the facial features of their fellow colony. The study is published in the latest issue of science.
“Being able to distinguish faces efficiently is an advantage for this type of wasps because it regulates social interactions within the nest. In addition, to recognize other wasps individually reduce aggression in the colony, thus helping to maintain peace”, said Michael J. Sheehan, a researcher at the University of Michigan (USA) and author of the work. Read the rest of this entry »
Molluscs have existed for a long time (at least 500 million years). They are common both on land and in water (from wet sites where you can find garden snails, to the depths of the sea), and many are very valuable to people as a food source. Therefore, one might believe that scientists have learned virtually everything about these animals.
However, it is not at all. For example, there are many gaps in the evolutionary tree of mollusks, and only now has a reasonably complete tree, the most comprehensive so far achieved. This tree has been developed by Casey Dunn, an evolutionary biologist at Brown University in United States, specializing in the construction of evolutionary trees, together with experts from the university and other institutions. Read the rest of this entry »
The diversification of the webs has been linked to the expansion of its main prey, insects, and flowering plants. Now a study published in the journal Proceedings of the Royal Society reveals that “the modifications of the cobwebs seek to occupy new habitats more efficiently and make better use of food resources in ecosystems”, explains Miquel A. Arnedo, Institute for Research on Biodiversity (IRBio) at the University of Barcelona (UB).
To do this, these insects make use of silk threads that will “serve to anchor, move, build nests and protect spawning. It is to weave webs which allowed the diversification of spiders, but to produce silk, and is not the same”, explains the expert. Read the rest of this entry »
The aroma of the fruit not only guides the Drosophila melanogaster to food, but that also makes its libido increased.
A team led by researchers at the CNRS in France, has identified and analyzed an unexpected mechanism of olfactory perception by which an odor present in the fruit eaten by the male sexual appetite-stimulating them.
Yael Grosjean’s team has shown that phenylacetic acid, a substance associated with odors from foods (found in flowers, fruits, honey, etc.), has a specific olfactory molecular receptor (IR84a) located on the antennae of the flies male. Read the rest of this entry »