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Inbreeding sabotages rare species' sperm

Image
© Clive Postlethwaite/Rex
Inbreeding among Asiatic lions hampers their reproductive success by sabotaging their sperm.

It's a triple whammy for male animals on the brink of extinction: not only are there fewer mates around to have sex with, but, to make things worse, their sperm are more likely to carry genetic abnormalities and less likely to be good swimmers, research shows.

"It is logical that endangered species are inbred and suffer reductions in fitness, but we don't have a clear idea of what is the driving force behind this," says John Fitzpatrick of the Centre for Evolutionary Biology at the University of Western Australia in Perth.

Fitzpatrick and colleague Jonathan Evans compared existing data on sperm fitness for 20 endangered and non-endangered species of mammals, including the Florida panther, Asiatic lion and cheetah. Scientists have previously observed extreme reductions in sperm quality for each of these big cats - all of which also suffered huge reductions in population size that led to inbreeding.

Bug

Lazy Spider Steals From the Mouths of Ants

Menemerus
© Simon Pollard
Menemerus bivittatus is one of three species of jumping spider that steal food from ant columns.
Forget stealing from the mouths of babes, zoologists have observed a similarly heinous crime - spiders stealing food from the mouths of ants.

At Mbita Point on the shores of Lake Victoria in Kenya, the walls of the buildings and other surfaces are covered with insects, including thousands of tiny lake flies. Within the throng lurks Menemerus, one of the jumping spiders or saltacids.

These predatory spiders adopt an approach similar to the big cats when hunting. They move very slowly, with their body close to the ground, before leaping on their prey.

Stalking is helped by extremely good vision: there are eight eyes in total, and importantly, two that face forward. These anterio-medial eyes have a visual acuity about one sixth as good as humans and let them "see like a primate and hunt like a lion," says Simon Pollard from the University of Canterbury in Christchurch, New Zealand, who led the study.

Jumping spiders are also are known to be capable of solving cognitively complex tasks.

Bizarro Earth

5.0 Earthquake Strikes Southeastern Greece

Greek authorities say a strong earthquake struck the southeastern Aegean overnight, but did not cause any damage or injuries.

The Athens Geodynamic Institute says the quake had a preliminary magnitude of 5 and struck just after midnight on Tuesday morning (2200GMT Monday).

Its epicenter was located beneath the seabed 170 miles (300 kilometers) southeast of Athens, between the islands of Kos and Astypalaia.

Bizarro Earth

Wenchuan Earthquake Mudslides Emit Greenhouse Gas

Mudslides that followed the 12 May 2008 Wenchuan, China earthquake, ranked by the US Geological Survey as the 11th deadliest earthquake ever recorded, may cause a carbon-dioxide release in upcoming decades equivalent to two percent of current annual global carbon emissions from fossil fuel combustion, a new study shows.

Mudslides wipe away plants and topsoil, depleting terrain of nutrients for plant regrowth and burying swaths of vegetation. Buried vegetable matter decomposes and releases carbon dioxide and other gases to the atmosphere.

The expected carbon dioxide release from the mudslides following the Wenchuan earthquake is similar to that caused by Hurricane Katrina's plant damage, report Diandong Ren, of the University of Texas at Austin, and his colleagues, who used a computer model to predict the ecosystem impacts of the mudslides.

Bizarro Earth

4.8 Earthquake Jolts Southern Philippines

An offshore earthquake measuring 4. 8 on the Richter scale hit the southern Philippines this morning, but no casualty or damage was reported.

The quake was recorded at 05:15 a.m. local time ( 2115 GMT on Monday), and the epicenter was 160 km southeast of Davao, Mindanao, or 1,125 km southeast of Manila at a depth of 35. 0 km, said the United States Geological Service.

The Philippines is hit regularly by earthquakes, and most of them are low in magnitude and cause little damage.

The Southeast Asian country is part of the so-called Pacific Ring of Fire, a string of islands on the Pacific Ocean rim that were formed by the eruptions of undersea volcanoes.

Bizarro Earth

Magnitude 5.3 Earthquake Hits Guam

Guam
© Unknown
An earthquake measuring 5.3 on the Richter scale hits Guam on Tuesday, March 03, 2009 at 05:10:48 UTC (Coordinated Universal Time) and Tuesday, March 03, 2009 at 03:10:48 PM at epicenter local time.

The epicenter of the quake was 105 km (65 miles) WSW of Hagatna, 185 km (115 miles) SW of Rota, Northern Mariana Islands, 305 km (190 miles) SW of SAIPAN, Northern Mariana Islands, and 410 km (255 miles) SSW of Anatahan, Northern Mariana Islands, according to the US Geological Survey.

On Tuesday, 24 February 2009, a 6.1 magnitude earthquake struck about 105 miles East-North-East of Guam, but nary a shiver was felt on the island.

Bizarro Earth

UK: 2.8 Earthquake Shakes Kent

Kent
© Peter Macdiarmid/Getty Images
Folkestone residents sit in the street after an earthquake damaged houses in April 2007.
Krakatoa, east of Maidstone? Not exactly, but tremor did reach 2.8 on Richter scale.

People in Folkestone, Kent were shaken, but not stirred, by a small earthquake in their vicinity yesterday.

A tremor measuring 2.8 on the Richter scale was registered but there were no reports of any damage to buildings or any injuries.

Kent police said: "We have had ­telephone calls and obviously people were concerned that it might be a bomb, but we can confirm it was indeed a tremor."

Frog

Male Lizards Disguise as Females to Avoid Attack

Lizard
© Discovery News
Male Lizard
Young, male lizards desperate to mate, access women and avoid attack from older males by pretending to be one of the girls, a new study said.

According to the study published in the Proceedings of the Royal Society B, young male Augrabies flat lizards (Platysaurus broadleyi) hide their colors so as to imitate plain, brown females.

"In this system the adult males are extremely colorful and extremely territorial and the females are a plain brown," said co-author Scott Keogh, of the School of Biological Sciences at the Australian National University. "Young males purposefully only develop colors on their belly, so they reach sexual maturity by still looking like a female."

Imitating a female allows the juvenile lizards to mate with females, without being detected and driven away by the larger, territorial, adult males, who will chase and bite their young rivals.

Info

Gutsy bloodworms pump out laughing gas

Bloodworms
© Christian Lott / MPI Bremen / HYDRA
Bloodworms are just one type of water-dwelling animal that produces laughing gas.

They may be no match for methane-burping cows, but bloodworms are doing their best to make a name for themselves with climate scientists. New research shows that their guts leak "laughing gas" - a powerful greenhouse gas - albeit in amounts too small to significantly affect the climate.

Previously, no water-dwelling animal was known to produce the gas, more properly known as nitrous oxide (N20).

Some land invertebrates such as earthworms are known to produce nitrous oxide, so to see if water invertebrates are also a source, Peter Stief and his colleagues at Aarhus University in Denmark surveyed seven aquatic sites including freshwater creeks, lakes and the seashore.

They collected a wide range of worms, larvae and bugs, placed them in closed vials, and analysed what came off. They found not only that N20 is produced, but that the amount increased with time.

Fish

Fish numbers outpace human population

Image
© Israel Sun/Rex Features
Fish in the confines of a fish farm, Eilat, Israel.

It's increasingly likely that the fish you eat was farmed not caught wild, according to the latest statistics of the UN Food and Agriculture Organization.

The group's two-yearly assessment of world fisheries, published today, comes with mitigated good news.

The outlook for wild ocean fish remains gloomy: 80% of all fisheries are at or beyond their maximum yields, and over-fishing continues to climb. Yet the amount of fish available to eat is growing faster than the human population, thanks to a boom in fish farming.

The FAO calculates that, for the first time, fish farms produce half the fish we eat, up from less than a third in 2002. With wild-catch fisheries maxed out, any more increases in fish production will depend on farms.