May 27
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Year of the Bat 2011 – 2012

So, what is the first thing that springs to mind when you think of bats? Ugly? Scary? Spread diseases? Get tangled in your hair? Think again!            

The world’s 1100 bat species are some of our most misunderstood species, surrounded by myths and superstitions. Contrary to their rough reputation, bats help maintain and enhance biodiversity and their economic value to the agricultural industry is worth billions each year.           

The Year of the Bat 2011-2012 is a two-year campaign, launched by The UNEP Convention on Migratory Species (CMS) and The Agreement on the Conservation of Populations of European Bats (EUROBATS), to celebrate the importance of bats in healthy ecosystems and human economies, and promote a greater awareness of bat conservation.      

As the spotlight shines on the masters of the night, ARKive has teamed up with Planet Science and the Year of the Bat team to make our very own quiz! Check out why ARKive thinks bats are simply brilliant and then head to the “Big Bat Quiz” on the Planet Science website.     

Wing-tastic

Our only true flying mammals, bats have membranous wings, each supported by an arm and four elongated fingers. The large flying fox (Pteropus vampyrus) fruit bat has the largest wingspan measuring a whopping 1.8 metres. Some bats, such as Daubenton’s bat (Myotis daubentonii), have been observed using their wings or tail membrane ‘scoop up’ prey.             

Male large flying fox photo

Male large flying fox with wings outstretched

 
Most bats are small enough to fit in the palm of your hand. The smallest is Kitti’s hog-nosed bat (Craseonycteris thonglongyai), also known as the bumblebee bat, weighing less than 2 grams.           

Kitti's hog-nosed bat photo

Kitti's hog-nosed bat

Echo. . . echo. . . echo   

Many nocturnal microbats use echolocation. They emit high frequency outbursts and interpret the echoes, building an accurate ‘visual map’ to locate prey. Bat calls range in frequency from 14,000 to well over 100,000 Hz and some bats can use habitat-specific calls. The large-eared horseshoe bat (Rhinolophus philippinensis) hunts moths and other insects and has a nose-leaf and large ears which help with echolocation.           

Large-eared horseshoe bat photo

Large-eared horseshoe bat

Bug buster  

The little brown myotis (Myotis lucifugus) can consume 600-1000 insects in a single hour! Microbats are the major predators of night-flying insects, many of which are agricultural pests. As bat numbers decline, pests increase and more pesticides are used, increasing the cost of crop production.          

Little brown myotis photo

Little brown myotis in flight

Passionate about plants  

Fruit bats have excellent eyesight and a keen sense of smell to locate over-ripe fruits like mangoes, figs and guavas. More than 300 tropical plant species depend upon bats for either seed dispersal or pollination and many of these are economically important to humans for products including timber, fruits and spices.        

Nectarivorous bats are well adapted to feed on nectar as they have a long snout and tongue. The Mexican long-tongued bat (Choeronycteris Mexicana) is the main pollinator of several agave species.            

Mexican long-tongued bat feeding photo

Mexican long-tongued bat feeding at night on Agave blossom nectar

A socialite with family values  

Some bats like the hoary bat (Lasiurus cinereus) live a solitary life, but others such as the Brazilian free-tailed bat (Tadarida brasiliensis) live in colonies. Brazilian free-tailed bats form the largest warm-blooded colony in the world; one cave in Texas contains 20 – 40 million individuals! Pups are placed in maternity colonies from which a mother is able to pick out her young.      

Brazilian free-tailed bats photo

Brazilian free-tailed bats emerging at sunset

Sadly an estimated 25% of all bat species are threatened with extinction, mainly due to habitat loss and degradation.          

You can help bats by spreading the word about the Year of the Bat campaign. Why not join your local bat conservation group or build a bat house for your garden?     

Remember to have a go at the “Big Bat Quiz” to find out if  you are a bat boffin or a dingbat. Let us know your score!             

Planet Science logo Year of the Bat logo

May 25
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Spotlight on: Mimicry

In their constant struggle against predators, animals adopt a fascinating variety of strategies to avoid being eaten. Some animals may attack their predators like these African buffalo chasing away a lion, others evolve unusual body parts so they cannot be swallowed, like this porcupine pufferfish, some blend into their habitat, such as this Arctic hare, while others may try to simply avoid capture by seeing, smelling or hearing their predator before they are detected.

Photo of plain tiger (left) next to mimic butterfly (Hypolimnas missipus)

Plain tiger (left) next to mimic butterfly (Hypolimnas missipus)

Some devious animals, however, try to avoid being eaten by tricking their predators into thinking they are either dangerous or distasteful. Such strategies commonly take the form of ‘mimicry’.

What is mimicry?

Mimicry is when one species benefits from evolving a feature displayed by another species. This feature could be anything from colour or body shape, through to scent or behaviour.

Mimicry can be loosely classified into four types: defensive, aggressive, reproductive and automimicry.

Let me explain….

Defensive mimicry

In defensive mimicry, a mimicking animal tricks a predator into treating it as a something different. The most well studied forms of defensive mimicry are Batesian mimicry and Müllerian mimicry.

In Batesian mimicry, an animal mimics a trait of another organism, such that predators think it is inedible or dangerous. Often totally harmless animals develop the shape or colouration of other animals that possess a dangerous or foul-tasting toxin.

Photo of hooded malpolon with head raised

The hooded malpolon showing cobra-like defensive behaviour

For example, the hooded malpolon, or false cobra, is only mildly venomous, but it mimics the hood and defensive displays of the extremely venomous and dangerous cobras so that predators avoid it.

Photo of honey bee asleep during cold weather

Black and yellow warning colouration of the honey bee

In Müllerian mimicry, two or more species, which share anti-predator traits such as toxins, develop similar warning colourations. When a predator first eats one of these distasteful species, it soon learns to avoid eating others with the same colourations. This explains why so many bees and wasps have black and yellow stripes.

However, only female wasps and bees have stingers, and the males are harmless, which is actually an example of automimicry, leading us onto our next example.

Automimicry

Photo of African burrowing python

African burrowing boa showing similarities between the head and tail

Automimicry occurs within a single species. Male wasps are protected from predators by appearing like the venomous females. Other examples include where one part of an animal’s body resembles another. The African burrowing boa, for example, has a similar looking head and tail which confuses predators and directs their attack away from the more vulnerable head.

Aggressive mimicry

It is not just prey species that have evolved cunning tactics to deceive their predators. Some equally clever predators over the course of time have developed fascinating ways of tricking their unwitting prey.

Photo of Nepenthes holdenii upper pitcher

Close up of Nepenthes holdenii showing nectar-secreting lip

Aggressive mimicry describes predators, as well as parasites, which share the same characteristics as a harmless species, allowing them to avoid detection by their prey. Nepenthes pitcher plants, for example, secret nectar near the lip to attract feeding insects, which then slip into the pitcher and are slowly dissolved by digestive enzymes.

The cuckoo, a brood parasite that lays its eggs in the nests of other birds, which act as foster parents for the cuckoo chick, also displays aggressive mimicry. The eggs of the cuckoo bare a striking resemblance to those of the host parents. The unsuspecting host bird then incubates and feeds the impostor.   

Reproductive mimicry

Photo of fly orchid

Insect-imitating flowers of the fly orchid

Aside from predator-prey interactions, in reproductive mimicry, mimicking species improve their reproductive success by tricking other species. Some of the best examples of reproductive mimicry are found in orchids.

The fly orchid has flowers that mimic the insects that pollinate it. Male insects land on the flowers, thinking they are female insects, and make attempts to copulate. Inadvertently, the insect brushes the flower’s pollen sacs, which attach to the insect. When the insect lands on another flower, it pollinates this flower with the other’s pollen.

Give us your examples!

The examples I’ve described here are just some of the hundreds of thousands of curious species that have evolved devious and deceitful ways of tricking their predators or prey to increase their chance of survival. If you know of any other equally crafty species, then let us know, or simply look through the ARKive collection and see if you can spot any mimics.

Alex Royan, ARKive Species Text Author

May 25
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In the News: Koala threatened by public complacency

The koala may receive more public affection than any of Australia’s other wildlife, yet complacency over its status, as well as habitat loss, predation and climate change, is putting this emblematic mammal at risk of extinction. 

With an extremely wide range that encompasses much of eastern Australia, the koala has always been thought of as common. However, scientists are warning that numbers of this marsupial have dropped by up to 95 per cent since the 1990s, and there are believed to be just 43,000 individuals remaining. In southeast Queensland alone, the population of this tree-dwelling mammal has plummeted from 25,000 to 4,000 in a decade.

Photo of male koala hanging upside down

Demand for more active conservation 

Alarmed by this decline, a Senate committee began gathering evidence in February on whether the koala should be listed as an endangered species. At present, the koala is not even classed as vulnerable in Australia.

Within three months, the committee received more than 80 submissions from individuals, government departments, local councils and researchers, with many demanding urgent action by the government to save remaining koala populations. 

Scientists say that unless more energetic conservation measures are taken, the mammal’s future could be in doubt. 

This species is supposed to be common, yet it’s slipping to extinction under our noses,” said Christine Hosking, a nature conservationist at the University of Queensland.

Photo of koala sleeping

Climate challenges

Large-scale land clearing for urban development, industry and agriculture has progressively deprived the koala of much of its habitat. It has also fared badly in recent droughts and heat waves, which are expected to become more common in southern Australia as a result of climate change. To make matters worse, increased carbon dioxide in the atmosphere is reducing the nutrient content of eucalyptus leaves, the koala’s sole food source. 

Ms Hosking’s research shows that temperatures above 37ºC are intolerable for the koala. “Once you get over 37 degrees, there’s zero probability of a koala,” she said. “As we get more of these extreme temperatures and protracted droughts, the koalas simply won’t be able to cope.”

The koala also faces challenges from an HIV-type retrovirus and Chlamydia, which renders half the marsupial’s population infertile. A 2009 report predicted that koalas would become extinct within 30 years because of this disease.

Photo of koala eating eucalyptus leaves

A draw for tourism 

The image of the koala on tourist brochures attracts thousands of foreigners to Australia every year, and this cuddly critter is thought to be worth around $1 billion (£650 million) a year to the Australian economy. However, some senators have voiced concerns that protecting the koala could lead to conflicts with landowners who want to fell trees and develop their properties. 

The decision on whether to list the koala as endangered ultimately lies with the federal Sustainability Minister, Tony Burke, who is waiting for a report from the parliamentary committee. 

Listing the koala as endangered would be a first step towards developing a national action plan to safeguard its future. It would also facilitate conservation work, making it easier to protect remaining habitat and to find funding for research into a Chlamydia vaccine. 

Without better protection, koala experts fear for the species. “They’ll just become more and more rare in the wild, found at increasingly low densities, and populations will become unviable,” said Dr McAlpine, landscape ecologist at the University of Queensland. 

View more images of the koala on ARKive. 

To find out more about climate change and the species that are affected, visit ARKive’s featured climate change pages created with support from Bank of America Merrill Lynch.

Alex Royan, ARKive Species Text Author

May 24
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In the News: Poaching threat to Philippine eagles

Four illegally held Philippine eagles have been rescued in the last six months in the Philippines, prompting conservationists to warn the government about the continued threat of poaching to this Critically Endangered raptor.    

Photo of Philippine eagle

The Philippine eagle (Pithecophaga jefferyi) is the world's largest eagle, and one of the most threatened raptors

 Highest rescue rate since 2000

Dennis Salvador, the executive director of the Philippine Eagle Foundation (PEF) has said that the group has retrieved four Philippine eagles in recent months, one of the highest rates of retrievals since 2000. 

Two of the rescued eagles were seriously injured, one with missing toes and the other with missing wing feathers, while a third died due to a fungal infection. 

According to Salvador, “The abuse and harm caused on Philippine eagles illustrate our reckless management of our natural resources. If the Philippine eagle, which is already perhaps the most prominent and recognizable of Philippine wildlife species, suffers a fate as grim as the above four eagles have experienced, how much more other species? What bigger injustices could possibly be happening to the rest of the Philippine environment?” 

Photo of Philippine eagle

The current population is likely to number fewer than 250 mature individuals

Conservation laws not enforced 

Just 180 to 500 mature Philippine eagles are thought to remain in Mindanao, Luzon, Leyte and Samar islands, with forest loss and poaching the main threats to their survival. 

In the Philippines, Wildlife Act 9147 prohibits the killing, collection, possession, and maltreatment of wildlife, their byproducts and derivatives, as well as activities which threaten critical habitats, such as dumping of waste, burning, logging, quarrying, and mineral exploration and extraction. 

However, conservation laws do not appear to deter trapping of this magnificent species, and the law is not currently being strictly enforced. 

Misjudging the need for human care 

PEF spokesperson, Tatit Quiblat, highlights how important it is that eagles remain in the forest. “Many of the eagles we retrieved were reported or brought to us by individuals or groups who have good intentions for the birds. We appreciate their concern. However, this concern often translates to the incorrect thinking that we should ‘care’ for the eagle by taking it and keeping it in human care,” she adds. 

Close up photo of a captive Philippine eagle

This majestic Philippine eagle is threatened by poaching and habitat loss

Often, people surrender captured Philippine eagles, mistakenly thinking that they will get a reward. But, says Quiblat, “They should understand that transporting of eagles from their natural habitats in the forests is not a profitable deed. What we want to reward is human actions that ensure the eagles flourish in their natural habitats.” 

We are extremely distressed about these events. We call on all local government units and the media to advise their constituency on the appropriate response when a Philippine eagle has been found.” 

Visit the Philippine Eagle Foundation website 

Read the Philippine Star newspaper article on Philippine eagle poaching 

Find out more about the Philippine eagle on ARKive 

Helen Roddis, ARKive Species Text Author

May 23
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In the News: Spiders under threat

They may not be as popular as more charismatic animals such as mammals and birds, but spiders are just as vulnerable to human impacts, according to a new study.

Photo of male ladybird spider

Found in northern and central Europe, the ladybird spider is considered Endangered in Britain, but has yet to be classified by the IUCN.

Spiders in decline

The study, published in the journal Biological Conservation, looked at whether spiders are more tolerant of human actions than other species. It concluded that spiders suffer the same consequences of changes to their habitats as any other animal. However, compared to other animal groups, few spiders appear on the IUCN Red List as being in danger of extinction.

The researchers focused mainly on three ecosystems: agricultural land, pasture and forest. By combining the results of studies undertaken since the 1980s, they showed that human actions have had damaging impacts on spider numbers in farmland and pastures. The results for forests were less clear.

Photo of captive female Rameshwaram parachute spider

The Rameshwaram parachute spider, considered Critically Endangered due to the destruction of its habitat.

Growing threats

Spiders face a range of threats, including changes in vegetation structure due to fire, grazing and crop-growing. In forests, habitat fragmentation may be a problem, and the use of insecticides can also have an impact on spider populations. These threats may also affect the availability of the spiders’ prey.

The researchers proposed a number of solutions to protect spider populations, including a reduction in mechanical alterations to the land from activities such as ploughing, cutting and grazing. They also recommended that habitat fragmentation should be avoided and the use of insecticides controlled, and concluded that organic farming was likely to be of benefit to spiders.

Photo of no-eyed big-eyed wolf spider dorsal view

The intriguingly named no-eyed big-eyed wolf spider, classified as Endangered by the IUCN.

Spiders vital to ecosystems

Although spiders do not generally attract much public sympathy or attention, they play an important role as predators within terrestrial ecosystems. Spiders are also important to humans in controlling pest species.

Photo of peacock parachute spider

The peacock parachute spider is classified as Critically Endangered due to habitat destruction and degradation. It has also been collected for the pet trade.

Unfortunately, spider conservation has not been a high priority and the status of most species has not yet been formally assessed. Declining spider populations are a reminder of the importance of conserving less popular and less well-known animals, which are just as vital to natural ecosystems as their more charismatic counterparts.

View photos and videos of spiders on ARKive.

Liz Shaw, ARKive Species Text Author

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