An Adder on Your Smartphone?
A smartphone app may be on the way to help in finding animals in the environment. New Scientist (12 January 2013, page 18) reports on work in progress by Harvard biologist and computer scientist Walter Scheirer. He has designed a machine vision system that runs on a Motorola Droid X2 smartphone, that automatically recognises and counts specific animals. But how does the smartphone distinguish between a rock and a squirrel? . The system first scans an area for objects that could be animals. It looks for clumps of pixels that are new to the scene. It then examines the clump to see if they correlate with any of the animals it has been trained to identify. The algorithms do not need intensive processing and can be carried out by the smartphone.
It is early days yet, but a tool like this could be invaluable for surveying reptiles, which are notoriously secretive and hard to find.
A smartphone app may be on the way to help in finding animals in the environment. New Scientist (12 January 2013, page 18) reports on work in progress by Harvard biologist and computer scientist Walter Scheirer. He has designed a machine vision system that runs on a Motorola Droid X2 smartphone, that automatically recognises and counts specific animals. But how does the smartphone distinguish between a rock and a squirrel? . The system first scans an area for objects that could be animals. It looks for clumps of pixels that are new to the scene. It then examines the clump to see if they correlate with any of the animals it has been trained to identify. The algorithms do not need intensive processing and can be carried out by the smartphone.
It is early days yet, but a tool like this could be invaluable for surveying reptiles, which are notoriously secretive and hard to find.
Regenerated Tails
One of the extraordinary features of many reptiles is the ability to regenerate a lost tail. However, Rebecca Fisher of Arizona College of Medicine, Phoenix and colleagues have found that the regenerated tail of a greenanole lizard (Anolis carolinensis) is a poor replica. Bone was replaced by cartillage and long muscles replaced shorter ones leading to a much less flexible tail. Furthermore nerves did not regenerate along the length of the tail. Further studies should ascertin if the regenerated tails have any affect on the lizard's agility.
From New Scientist article 15 Sept
From New Scientist article 15 Sept
Variable Climate increases frog's vulnerability to Chytridiomycosis
Thomas Raffel of Oakland University, Rochester, Michigan has found that frogs subjected to random temperature changes were more susceptible to the ravages of Chytridiomycosis than frogs kept at constant or regularly changing temperature environments. Climate change is expected to cause less predictable changes in temperature, which could enhance the progress of this deadly disease.
Based on a report in New Scientist, 18 August 2012
Based on a report in New Scientist, 18 August 2012
How Did Dangerous Chytrid Infections Arise in Amphibians?
A deadly disease is wiping out amphibian populations across the globe. This comes on top of major losses of habitat such as wetlands and forest, which have put amphibian populations under pressure. It was first discovered in 1999, that the disease was caused by a fungus and recent genetic research is revealing the source of this devastating disease. Extinction rates are estimated to have increased by a factor of 40 000 over the expected rate.
The Fungus responsible Batrachochytrium dendrobatidis (Bd) is a chytrid. Most other chytrids are microbes that feed on decaying matter, but Bd has hundreds of unique genes. Some of which code for enzymes that digest proteins. Bd is not new, but it's virulence has recently increased. This could be environmental-climate change, pollution- or a new strain of Bd. Samples of Bd from different continents show marked similarity suggesting that the killer is a new strain that has rapidly become global. The fungus has no airborne stage and cannot live in salt water, so the only likely means of spread is through animals moving between continents through trade. The American bullfrog is relatively resistant to Bd and has been exported across the world for it's meat. The first record of Bd in wild frogs in the UK was in a lake where escaped bullfrogs had established a breeding colony. The first outbreak in Asia was downstream from a Philippino bullfrog farm.
There is evidence from DNA analysis that several strains of Bd are being transported by trade in amphibians and when different strains mix new hybrids arise, which may be more dangerous than their parent strains
In the wild, natural selection favours less virulent strains of pathogens, which do kill off their hosts, but in artificially high populations, where large numbers of amphibians are farmed, then virulence is favoured. Large numbers of salamanders are bred for bait and this could be a source of virulent Bd as are bullfrogs
The hunt is on for two parental strains that could give rise to the killer hybrid and perhaps provide clues for controlling the epidemic. The place to look is areas wheree mass die-off has not occurred such as mainland Asia and Africa, presumably because amphibians here have some immunity. The woory of course is that a similar process of pathogens gaining virulence, could happen in any system, plant or animal, including humans in cities, where there is artificial crowding
Based on an article 'Nowhere to Hide' in New Scientist, 7 July 2012
The Fungus responsible Batrachochytrium dendrobatidis (Bd) is a chytrid. Most other chytrids are microbes that feed on decaying matter, but Bd has hundreds of unique genes. Some of which code for enzymes that digest proteins. Bd is not new, but it's virulence has recently increased. This could be environmental-climate change, pollution- or a new strain of Bd. Samples of Bd from different continents show marked similarity suggesting that the killer is a new strain that has rapidly become global. The fungus has no airborne stage and cannot live in salt water, so the only likely means of spread is through animals moving between continents through trade. The American bullfrog is relatively resistant to Bd and has been exported across the world for it's meat. The first record of Bd in wild frogs in the UK was in a lake where escaped bullfrogs had established a breeding colony. The first outbreak in Asia was downstream from a Philippino bullfrog farm.
There is evidence from DNA analysis that several strains of Bd are being transported by trade in amphibians and when different strains mix new hybrids arise, which may be more dangerous than their parent strains
In the wild, natural selection favours less virulent strains of pathogens, which do kill off their hosts, but in artificially high populations, where large numbers of amphibians are farmed, then virulence is favoured. Large numbers of salamanders are bred for bait and this could be a source of virulent Bd as are bullfrogs
The hunt is on for two parental strains that could give rise to the killer hybrid and perhaps provide clues for controlling the epidemic. The place to look is areas wheree mass die-off has not occurred such as mainland Asia and Africa, presumably because amphibians here have some immunity. The woory of course is that a similar process of pathogens gaining virulence, could happen in any system, plant or animal, including humans in cities, where there is artificial crowding
Based on an article 'Nowhere to Hide' in New Scientist, 7 July 2012
Agressive Croatian Lizards
Two distinct species of Croatian lizard (Dalmatiam wall lizard and sharp snouted rock lizard) spend more time fighting each other than fighting amongst themselves. Simon Lailvaux of the University of New Orleans discovered that if he introduced Dalmation wall lizards into the territory of Sharp snouted rock lizard, or vice versa, the lizard whose territory had been violated was more agressive, but was more agressive to the other species than to it's own.
Oddly the two species look different and do not compete for food. They may once have competed and this behaviour has lingered on even though the species have now adapted to distinct habitats.
Oddly the two species look different and do not compete for food. They may once have competed and this behaviour has lingered on even though the species have now adapted to distinct habitats.
Some lizards may benefit from climate change
Joshua Amiel and Richard Shine, University of Sydney, have found that not only do scincid lizards (Bassiana duperreyi) grow larger if their eggs are incubated at higher temperatures, but they also learn better.
Eggs incubated at temperatures 6deg C higher produced lizards which were significantly better at finding accesible hideouts, when frightened by a paintbrush touching their tail. However the news is not all good, elsewhere, warming is thought to have caused major population declines. Biology Letters, DO1:10.1098/rsbi2011.11
Eggs incubated at temperatures 6deg C higher produced lizards which were significantly better at finding accesible hideouts, when frightened by a paintbrush touching their tail. However the news is not all good, elsewhere, warming is thought to have caused major population declines. Biology Letters, DO1:10.1098/rsbi2011.11
Artificial Refugia
Rose Revera of Cardiff university has published findings on the effectiveness of refugia in the latest ARG newsletter. She reports that the area of the refugia was an important factor in surveying. 1sq m refugia were more effective overall accounting for 63% of findings and especially so for adders and grassnakes, but the smaller refugia produced higher numbers of sightings of common toads, slowworms and common lizards.
More at http://www.arguk.org/news/
More at http://www.arguk.org/news/
Kidneys involved in newt sex
Sex in male red spotted newts, a native of eastern US, seems to involve the kidneys. Dustin Siegel of South East Missouri State University has found that the kidneys of male newts secrete a liquid glycoprotein only during the mating season. Further tubes within the kidney thickened and changed shape at the same time. The ducts drain into the Wolffian ducts that house sperm. The liquid may affect sperm motilty or lifetime, or may act as a pheromone. More details at:
http://www.newscientist.com/article/dn21677-zoologger-meet-the-amphibian-with-sexual-kidneys.html
http://www.newscientist.com/article/dn21677-zoologger-meet-the-amphibian-with-sexual-kidneys.html
