THE hot dog is a New York staple. But we are not the only ones who like a sausage in a bun. Armies of ants do a very important job – they clean up food litter left by messy eaters of hot dogs, cookies and potato crisps.

In fact, ants and other arthropods on Manhattan’s Broadway and West streets can remove food litter equivalent to the weight of about 60,000 hot dogs or 600,000 potato crisps in a year ().

The US spends an estimated $11.5 billion annually on cleaning up rubbish. Large cities dispose of about 10 kilograms of litter per person per year. This means the contribution of ants to keeping the streets clean is “modest but notable”, the authors say.

from North Carolina State University in Raleigh and her colleagues placed three commonly dropped foods – potato crisps, cookies and hot dogs – at dozens of sites in Manhattan’s parks and islands of greenery between lanes of traffic.

Arthropods removed as much as 59 per cent of the food within a day. More food was eaten at traffic islands than in parks, even though parks were more biodiverse. This may be down to the , which lives in big colonies and likes these islands.

“Recycling is among the least glamorous of ecosystem services provided by arthropods, and this was a great study highlighting both its magnitude and importance,” says of the University of Illinois at Urbana-Champaign.

Such findings could be useful for urban policy and planning, says of Azim Premji University in Bangalore, India. “Most of us have seen ants laboriously lugging away fragments of a potato crisp or a cookie, but they have certainly not featured much in discussions about how to manage food waste in our cities,” she says.

This article appeared in print under the headline “Armies of ants keep New York squeaky clean”

There’s hope for India’s imperilled vultures. There has been a big reduction in the use of veterinary diclofenac, a painkilling drug given to livestock that is deadly to vultures that dine on their carcasses. The situation in Europe is less clear, however, as a death of a Eurasian griffon vulture in Spain was recently attributed to a similar drug.

Vulture populations in India have plummeted by more than 99 per cent since the 1990s. In 2004, scientists linked these deaths to kidney failure resulting from feeding on the carcasses of animals that had been treated with the drug. Following pressure from conservationists, the Indian government banned veterinary diclofenac in 2006.

Between 2005 and 2009, Rhys Green at the University of Cambridge and his team looked for diclofenac in more than 6000 liver samples collected from livestock carcasses across India. During that time, the presence of diclofenac in carcasses fell by 50 per cent, and the presence of meloxicam – a vulture-safe drug – increased by 44 per cent. In addition, the sites in which diclofenac presence declined the most overlapped with those where meloxicam use had increased ().

That should be helping: in a previous survey, Green’s team found that population decline had slowed or ceased in some parts of the Indian subcontinent between 2007 and 2011 (). But wild populations still remain precariously low, warns Green.

Call for enforcement

To save India’s vultures, the ban on diclofenac needs to be more effective, says Chris Bowden, co-chair of the of the International Union for Conservation of Nature. “The problem is that human diclofenac is sold in large phials that are completely unnecessary for humans, and convenient for vets to buy and use illegally,” he says.

Meloxicam is also more expensive than diclofenac. Moreover, most current pharmaceutical manufactures make meloxicam formulations that are less acceptable to vets, says Green. “There are good formulations available,” adds Bowden, “but it’s not our role as conservationists to promote one brand above another, so it’s difficult for us to address this.”

Despite diclofenac’s toxicity in vultures and other birds, and its ban in India, the drug was recently authorised for use in Spain and Italy. Other anti-inflammatory drugs, also potentially deadly to vultures, continue to be used in Europe. A study published this month identified one such drug, flunixin, as the potential cause of death in a Eurasian griffon vulture in Spain ().

According to Mark Taggart at the Environmental Research Institute in Thurso, UK, who co-authored the study, there is an urgent need to test the safety of drugs like flunixin in vultures in Europe. Field monitoring to quantify how many medicated carcasses end up in carcass dumps in Spain is also necessary. “At the moment, we simply don’t know,” he says.

Poaching gangs are using India’s train networks to smuggle tiger parts across the country undetected. That’s according to research that has mapped the hubs of illegal tiger poaching and trafficking activities.

Researchers analysed 40 years’ worth of tiger trade data, collected by the (WPSI), and found that today’s trafficking hotspots form a corridor running from southern and central India right up to the country’s border with Nepal. This porous border is thought to be the main international hub for trafficking tiger parts into China.

The illegal trade in tiger parts continues to flourish in India, driven by the high demand for tiger parts elsewhere in Asia. The study identified 73 districts in India which may be active hubs for tiger poaching and illegal trafficking. These hubs were not limited to areas near tiger habitats: 17 districts were active but distant hubs, including the Delhi region.

Trafficking was higher in districts closer to railway routes than highways. “Poaching gangs and middlemen prefer to use trains to transport tiger parts, since trains are well-connected to remote forested areas and usually crowded,” says Belinda Wright from WPSI. “Buses, in comparison, carry fewer people and can be easily stopped and checked.”

Detection-avoidance

In 2012, WPSI recorded 32 cases of poaching and trafficking of wild-tiger parts, rising to 42 in 2013. But an increasing number does not necessarily mean that actual tiger trafficking has gone up, stresses the study’s lead author, of the Nature Conservation Foundation in Mysore, India. The number of reported cases depends on how many are detected, which can fluctuate according to levels of law enforcement. Over the 40-year study period, the number of cases decreased in some years, but this might be because poachers and buyers were using newer techniques to avoid detection.

Poaching is insidious, says Wright. “It can wipe out entire populations of tigers before the management even knows that such a threat exists in the area.” This happened to the Sariska Tiger Reserve in north-west India in 2004.

The researchers hope that their findings will help enforcement agencies crack down on poaching and monitor their enforcement strategies.

According to , director of the Centre for Wildlife Studies in Bangalore, protecting tigers will require improved preventative patrols, rather than only chasing traders after they have killed a tiger.

He adds that, for India’s tigers, depletion of prey in tiger habitats could be an even bigger threat to the species.

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Video: Foraging seals hunt around wind farms

There’s a new hunting ground for seals: offshore wind farms. It seems seals pop in for a bite to eat because fish gather around the turbine arrays.

of the University of St Andrews, UK, and her colleagues tracked more than 100 and seals in the North Sea with GPS.

They observed 11 seals in two wind farms – Germany’s and the UK’s . Three swam in grid-like patterns from one turbine to another, sometimes stopping to feed. The video above shows the path of one such seal around Sheringham Shoal. A further six fed along sub-sea pipelines for days.

It is the first time seals have been seen heading to individual undersea structures, says Russell. Offshore constructions like oil rigs are also known to attract animals like corals and fish.

The seals probably aren’t targeting wind farms specifically, but simply visiting areas with lots of fish, says of Ocean Science Consulting in Dunbar, UK. She has seen seals eating fish around oil rigs.

A possible downside is that seals may find the noise from wind farms stressful. We don’t know how the turbines will affect the seals in the long run, says of the University of Exeter, UK.

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Video: Frisky flower uses bellows to blast pollen at birds

For one group of plants, having brightly coloured flowers isn’t enough to guarantee being pollinated. When birds rip bits out of the flowers to eat them, special bellow-like organs blast pollen onto their feathers.

The male parts of flowers produce pollen, which insects and birds pick up and carry to the female parts, either of the same flower or a different one, as they dive into flowers in search of nectar or pollen. Normally this is a passive process on the part of the plants: the animal must rummage around in the flower to pick up the pollen. But the colourful flowers in plants of the genus take matters into their own hands, perhaps because birds tend to eat the pollen-covered male parts in their entirety.

When a bird grabs one of the bulbous stamens that sit inside an Axinaeaflower, this male organ explodes, spraying a messy jet of pollen onto the bird’s beak, face and neck (see video, above). As the bird feeds, brushing past various parts of the flower as it grabs the next mouthful, the pollen gets dusted onto the female reproductive organs.

of the University of Vienna in Austria and his colleagues observed and videoed pollinators visiting Axinaea in Ecuador and Costa Rica. They also analysed the flowers’ stamen structures and their contents.

Squirt of pollen

Most other plants of the family, to which Axinaea belongs, are pollinated by bees, whose vibrating flight muscles cause anthers to expel pollen. But Axinaea anthers work like paper bags full of air. “If you press the bag, the air flushes into the pollen chamber and then out through a pore at the other end of the anther of the stamen, blasting pollen at the birds,” says Schönenberger.

The birds visit the flowers because the bulbous stamens reward them with a rich, sugary concoction. “I was surprised that the yellow food bodies on the male parts of these flowers contain so much sugar,” says of the Ludwig Maximilian University of Munich in Germany. “Birds feed on them as if they were berries. I just assumed that bees would visit the flowers to collect pollen.”

The birds completely eat the stamens and all its pollen, which makes it more difficult for the female parts of the plant to get pollinated. The bellow mechanism may ensure that the pollen gets onto the bird quickly, before the bird eats the flower’s entire male reproductive organ, says Schönenberger.

“These specialised bellow organs simultaneously serve as food sources and pollen placement machinery,” says of the University of Colorado in Boulder.

It’s not clear why Axinaea switched from bee pollination to bird pollination. But Schönenberger says it may be because Axinaea live at high altitudes, where bees are less common.

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Eavesdropping may be rude, but snooping on honeybee conversations could reveal a lot about the environment. Their unique mode of communication, the waggle dance, contains clues about the health of the landscape they live in. In effect, the bees are giving a thumbs-up or thumbs-down to different methods of conservation.

A worker honeybee performs the waggle dance to tell her hive mates where the best food is located. That suggests the dance can indicate areas of the landscape that are healthy, at least in terms of food for pollinators.

To test this, and her colleagues from the University of Sussex in Brighton, UK, videoed and decoded 5484 waggle dances from three laboratory-maintained honeybee colonies living in 94 square kilometres of rural and urban landscapes. They divided the area into various conservation schemes, regulated by the UK government, and mapped which areas were most frequented by the bees over two years.

“Using honeybee colonies as biomonitors for environmental health is an idea that researchers have been interested in,” says from the University of California, San Diego. “However, this study uses a far larger sample size and examines the data in a more sophisticated way.”

Happy foraging

Most honeybees cast their votes for , a nature reserve rich in wildflowers, 2 kilometres from the hives. The bees also preferred to feed on farms covered by schemes. Such farms are supposed to set aside part of their land for wildlife and wildflowers, which may explain why the bees liked them.

However the bees did not seem particularly enticed by farms covered by . While organic farming may seem harmonious with healthy wildlife, these schemes involve regular cutting and mowing in the first few years. “What that probably means for honeybees is that there are no flowers at all, just short grass,” says Couvillon.

Listening in on honeybee conversations could be a quick and cost-effective way of evaluating costly management schemes that aim to make lands more wildlife-friendly, Couvillon says. What’s more, honeybees are generalists, so identifying areas that they prefer could help other pollinators like bumblebees and butterflies.

But honeybees may not tell us everything we need to know, says of Queen Mary, University of London. He says they probably prefer whichever area offers the most nectar or pollen, regardless of whether it is a diverse wildflower meadow or a vast monoculture. “So what’s good for the honeybee is not necessarily good for any other species.”

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