Mosquito Eating in Bats

8/9/18
By Merlin Tuttle

For decades, bat biologists have debated the extent to which bats prey on, and potentially reduce mosquito populations. However, recent research suggests bats may be eating far more mosquitoes than yet suspected. Amy Wray and associates (2018) relied on newly refined techniques that provide greater sensitivity. In their paper, titled “Incidence and taxonomic richness of mosquitoes in the diets of little brown and big brown bats,” they reported that these common species eat a greater variety of mosquitoes, and catch them more frequently than previously suspected.

A little brown myotis (Myotis lucifugus) in Wisconsin. Just one of these bats can catch 1,000 mosquito-sized insects in a single hour.

They tested guano samples from 22 locations in a range of habitats, across the State of Wisconsin, from May 17 through July 29. Seventy-two percent of little brown myotis (Myotis lucifugus) samples contained mosquitoes representing 15 species, more than twice as many as big brown bats (Eptesicus fuscus). But even the larger big brown bats, previously thought to feed mostly on beetles and moths evidenced mosquito-eating in 33 percent of samples. Frequency of mosquito-eating remained constant throughout the active season in big brown bats but declined slightly in little browns.

Little brown myotis (Myotis lucifugus) from Tennessee.
A third of big brown bats (Eptesicus fuscus) in Wisconsin fed on mosquitoes.

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Bat Flash! Smithsonian Promotes Misleading Virus Hunter Claims

By Merlin Tuttle
8/3/18

 

The July 11, 2018 edition of Smithsonian.com contains another highly misleading story on virus hunters protecting us from pandemics. The story by Katherine J. Wu is titled, “A Never-Before-Seen-Virus Has Been Detected in Myanmar’s Bats.” Wu claims that to prevent the next Pandemic, we need to pinpoint it at the source. She then reports that “researchers in Myanmar have hit pay dirt with a never-before-seen virus that infects wrinkle-lipped bats—a virus in the same family as the ones that cause SARS and MERS.”

Merlin with a young Black flying fox (Pteropus alecto).

After further extolling the virtues of virus hunting, she quotes Chelsea Wood, reportedly a conservation ecologist, as saying that, “Tropical rainforests [in particular] are just cesspools of viral diversity—the highest viral diversity on the planet.” The headline and rhetoric in this article sound more like grocery store tabloid writing than something one would expect from America’s leading institution of science.

This story is a complete contradiction of a paper by epidemiologists, Edward Holmes, Andrew Rambaut, and Kristian Andersen, titled “Pandemics: spend on surveillance, not prediction” which appeared in the Journal Nature on June 7, 2018. [1] Referring to virus hunting, they conclude that “given the rarity of outbreaks and the complexity of host-pathogen interactions, it is arrogant to imagine that we could use such surveys to predict and mitigate the emergence of disease.” They emphasize that broad surveys of animal viruses have little practical value when it comes to disease prevention. They conclude that such approaches are an extremely costly waste of limited public health funds and warn that “Trust is undermined when scientists make overblown promises.”

New viruses can be found wherever we look. Many are innocuous or even beneficial, [2]  including some that are closely related to deadly ones. [4] The number of viruses found in bats is not necessarily indicative of risk. [5] Nevertheless, promoters of virus hunting make low risks seem imminent and extreme. And since few people understand bats or viruses, the combination is ideal for manipulation used to justify outrageously large misappropriation of funds. [1]

Historically, bats have an outstanding track record. They rarely transmit disease to humans, even where millions closely associate with people in cities. [3] Yet virus hunters are creating a self-perpetuating cycle of fear that threatens their future. That people seldom protect, and often kill animals they fear, especially in the case of bats, is historically well documented.

The Smithsonian.com story follows a familiar virus hunter pattern of promotion. It begins with a scary, headline-grabbing title, followed by speculation of potentially great danger to be prevented, and appears to be confirmed by reported-to-be-independent colleagues. At the end, they add an apparent disclaimer. This one is typical, stating that viral discovery studies can lead to demonizing animals, noting that, “Just because they carry nasty diseases doesn’t mean we should kill these species.”

It’s time to end costly virus hunts that squander public health resources and needlessly create fear of already declining, but ecologically essential bats. As our nation’s highest institution of science, when the Smithsonian publishes misinformation it is particularly damaging.

TAKE ACTION!

Our combined voices can make a difference. Choose any or all means of contact to reach out to the staff at Smithsonian.com and politely share your opinion in your own words. Editors do take notice. Remember, your response can be very simple such as, “I don’t appreciate speculation that creates needless fear of bats.” Editors just need to know you like or dislike an article in order for you to have impact. It’s numbers that count. Bats need all of you!

 

This series of photos show me radio-tracking a bat to its roost in a giant, hollow tree in the Smithsonian’s Barro Colorado Island rainforest, than squeezing inside to photograph the colony. If rainforests, and the bats that live there were truly “cesspools of dangerous viruses,” I should have died a horrible death long ago!

Little big-eared bat (Micronycteris megalotis) and Seba’s short-tailed fruit bat (Carollia perspicillata) roosting in the hollow tree.

 

 

References

[1] E. Holmes, A. Rambout and K. Andersen, “Pandemics: spend on surveillance, not prediction,” Nature, no. 558, pp. 180-182, 2018.
[2] J. Enriquez and S. Gullans , ““Viruses, the Roadrunners of Evolution”,” in Evolving Ourselves, New York, NY: Penguin Group, 2015, pp. 99-103.
[3] M. Tuttle, “Fear of Bats and its Consequences,” Journal of Bat Research and Conservation, vol. 10, no. 1, 2017.
[4] M. Miranda and N. Miranda, “Reston ebolavirus in humans and animals in the Philippines: A review.,” Journal of Infectous Diseases, vol. 204, no. 3, pp. S757-S760, 2011.
[5] K. Kupferschmidt, “Bats may be carrying the next SARS pandemic,” Science, 2013.

 

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Epidemiologists Acknowledge Virus Hunting as a Costly Waste

By Merlin Tuttle
6/15/18

Leading epidemiologists are finally acknowledging that the recently huge expenditures for virus hunting (mostly focused on bats) have little practical value in disease prevention. The June 7 issue of Nature contains a key paper titled, “Pandemics: spend on surveillance, not prediction.” In it Edward Holmes, Andrew Rambaut, and Kristian Anderson combine their expertise to advocate a much-needed change of course in prevention of viral transmission from animals to humans, one that may also considerably brighten the future of bats.

They emphasize that broad surveys of animal viruses have little practical value when it comes to disease prevention and warn that “Trust is undermined when scientists make overblown promises about disease prevention.” They “urge those working on infectious disease to focus funds and efforts on a much simpler and cost-effective way to mitigate outbreaks—proactive, real-time surveillance of human populations.”

Bats have an exceptional record of living safely with humans. But, they have been disproportionately searched, and victimized by virus hunter speculation, apparently because they are unpopular and easy to sample. This is an Angolan free-tailed bat (Mops condylurus), a species targeted for eradication following premature speculation linking it to the 2014 Ebola outbreak.

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Bats and Chocolate Production

By Merlin Tuttle
6/6/18

While conducting her Ph.D. thesis research, Bea Maas and her team (Maas et al. 2013) collected data that would surprise even her. When insect-eating bats and birds were excluded from cacao trees in Sulawesi, Indonesia, the crop yield fell by 31 percent. And when she compared losses due to night versus daytime exclusion, bats versus birds, she discovered that bats accounted for 22 percent of the prevented losses.

A control site in the same study (poles without netting).

To obtain such data, Bea selected 15 plantations where she enclosed 120 cacao trees in 60 exclosures (like huge, mesh cages) constructed of nylon mesh. There were four exclosure treatments per plantation, one daytime, one nighttime, one day and night, and one always left open as a control.

A bat/bird exclosure in Sarawak, Indonesia, built with bamboo poles and commercial nylon monofilament netting with a mesh size of 2 x 2 cm. These were opened and closed like curtains daily.

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Thanks to Mongabay for Balanced Nipah Reporting

By Merlin Tuttle
5/31/18

We greatly appreciate Mongabay for its handling of the Nipah virus outbreak in Kerala, India. Its story, “Nipah infection in Kerala: Don’t blame the bats alone; improve public health,” appeared on May 30, authored by Haritha John and Gopikrishna Warrier. Needless alarm was avoided by balanced reporting. As so often is the case, the rarest threats make the biggest news. Fortunately, in this instance, the news was accurate, so did not cause needless panic.

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Bat Flash! Respond to Reuters News Release Blaming Bats for New Ebola Outbreak

By Merlin Tuttle
5/15/18

 

I share Benoit Nyemba and Fiston Mahamba’s concern regarding a potential resurgence of Ebola in the Democratic Republic of Congo, as Reuters News reported on May 8. Nevertheless, continuing to blame bats as the source is likely to reverse conservation progress essential to  ecosystem health (Lopez-Baucells et al. 2018) and delay successful Ebola prevention. Understanding the true source is essential.

A male straw-colored fruit bat (Eidolon helvum). This is the species that was first erroneously blamed for infecting the two-year-old toddler identified as the index case that triggered the 2013-2014 Ebola outbreak. In the end no one could explain how a bat that never enters buildings and has a three-foot wingspan could have contacted a toddler without anyone knowing about it!

Bats can indeed transmit deadly diseases like rabies and Nipah to humans, though transmission is exceedingly rare and easily avoided. In the case of Ebola, bats have been too easily assumed guilty. A wide variety have been tested at outbreak locations. But, “Ebolavirus has yet to be isolated from bats, and no direct evidence links bats to Ebolavirus infection in humans.” (Spengler et al. 2016) Virologists still know “nothing about where it comes from and how it causes outbreaks.” (Kupferschmidt 2017).

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Bat Flash! Encouragement for Positivity in Cambodia

This powerful article in Southeast Asia Globe, by Claire Baker-Munton, on the value of artificial bat roosts in Southeast Asia deserves much praise. With the help of Merlin’s photos, this article clearly promotes a better understanding of bats and their values. At a time when so many media headlines are attempting to grab readership by speculating potential linkage of bats to scary diseases, positive stories like this are crucial. In reality, as Claire points out, Cambodians have found bats to be highly valued neighbors.

TAKE ACTION!

Choose any or all means of contact to reach out with your praise and encouragement on behalf of bats.

 

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Major Addresses Reach Leadership Audiences from Brazil to Chile

By Paula Tuttle
12/3/17

While the public continues to be pummeled with scary claims of dire threats of disease from bats, Merlin has been rallying crucial leadership collaboration from within the international research community. In September, he provided an hour lecture, followed by an enthusiastic hour-long discussion, for virologists and epidemiologists at Brazil’s Oswaldo Cruz Foundation in Rio de Janeiro. And several days later he provided the keynote address for a joint annual meeting of Brazil’s Bat and Mammal Societies, with special attention to helping conservation-minded students.

Merlin Tuttle presenting keynote address for joint meeting of Brazil’s Bat and Mammal Societies in Pirenopolis.

In November, Merlin presented the inaugural address for a joint meeting of the Biology and Ecology Societies of Chile. A key concern there involved how to prevent bat killing due to irresponsible warnings of disease. Amazingly, even in a country where only one person in all history had died of a bat disease (rabies), fear of bats due to exaggerated media stories reportedly is posing a serious threat to conservation progress. Concerned attendees at the conference were delighted to learn of our disease resources and other information and photos available for their use. They were also most appreciative for advice on expanding threats from  wind energy and pesticides. Merlin additionally agreed to provide photos for the bat section of a new book on Chilean mammals.

Merlin Tuttle speaking to virologists and epidemiologists at the Oswaldo Cruz Foundation in Rio de Janeiro, Brazil. A very friendly and helpful discussion followed.

 

Merlin providing the inaugural address for the 2017 joint meeting of the Biology and Ecology Societies of Chile, held in Puerto Varas, Patagonia.

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Education is Key to Flying Fox Survival

Merlin Tuttle
10/25/17

In response to the Mongabay article of August 29 titled, “Bats and viruses: Beating back a bad reputation,” Dr. Sheema Abdul Aziz, commented as follows on September 5:

Sheema in a durian tree.

“Actually this article neglected to mention another huge problem caused by these negative representations of bats. It’s not just about deliberate human killings of bats – even where bats are not being killed by people, the repercussions of this negative reputation are still damaging in indirect ways because it affects efforts and funding for research and conservation. I am currently the only person working on the conservation ecology of Pteropus in Malaysia, where there has been such a disproportionate amount of attention, effort, and money put into researching ONLY the virology and public health aspects of these bats. Hardly anyone is interested in looking at the conservation ecology aspect; never mind that these bats are important pollinators and seed dispersers, and are severely threatened by hunting – all topics which desperately require more attention and work. I can’t tell you how frustrating it is to be constantly approached by other researchers who are only interested in collaborating on virology, or to be told that I can only get funding if I include a disease and public health aspect in my project. Ultimately these bats will go extinct if people – including researchers and funders – are simply too focused on worrying about whether we’re going to catch diseases from them, instead of trying to mitigate the threats that we humans present to them. This kind of attitude is very, very damaging to bat conservation.”

Dr. Aziz explaining flying fox pollination to Mak Long, owner of the durian orcharad where her Ph.D. rhesis research was conducted. MTBC photos are playing a vital role in educating islanders to a better appreciation of flying foxes.
Sheema using a light microscope to look for pollen grains in flying fox droppings.

Dr. Aziz is one of a very few researchers in her part of the world dedicated to helping people understand the economic and ecological importance of conserving flying foxes. Her research titled, “Pollination by the locally endangered island flying fox (Pteropus hypomelanus) enhances fruit production of the economically important durian (Durio zibethinus),” recently appeared in the journal Ecology and Evolution.

In her paper, she provides information critical to convincing islanders to protect flying foxes, namely that they are playing a key role as pollinators of one of Southeast Asia’s most valued crops, not causing damage as previously believed. She used camera and video traps to document that island flying foxes (Pteropus hyomelanus) do not damage durian flowersas even some researchers had suspected. Video traps clearly absolved the bats. Island flying foxes and cave nectar bats (Eonycteris spelaea) are major pollinators. The damage was caused by plantain squirrels (Callosciurus notatus) who often ate immature flowers.

 

Aziz also notes that flying foxes sometimes can become a nuisance when roosting too near people, causing both noise and odor problems. She hopes to find a way to harmlessly convince these bats to move farther away, so they will be more welcome. There is an urgent need for education to minimize negative biases while solving legitimate nuisances. Aziz emphasizes the need to find solutions to real problems instead of needlessly scaring people about rare threats.

Large flying foxes (Pteropus vampyrus) have wingspans of nearly six feet, the largest of any bat. They are widespread in Southeast Asia, Borneo and the Philippines, but are in alarming decline due to over-harvesting for human food, and are often needlessly killed when entering orchards.

She reports, “I have been using your [Merlin Tuttle’s] photos, especially the amazing shots of P. vampyrus, in all the presentations I give. It’s enormously helpful because the only shots I have of that species are the poor dead ones shot by a hunter, and it’s not a very nice picture at all. I think it would be almost impossible for me to get a good photo of P. vampyrus here in Malaysia! Your close-up shots of Pteropus pollinating and feeding on fruit are also particularly useful for illustrating bat ecosystem services – I used these in a public talk I gave, at an event organized by the Malaysian Heritage and History Club, which was very well received. And of course, I also used your photos in the awareness video! I now use them anytime I want to talk about bat ecosystem services.”

An island flying fox (Pteropus hypomelanus), the focus of Dr. Azizes’ primary research.

Aziz is devoting her career to helping people solve problems while benefiting from the essential contributions of flying foxes. If bats are to survive in sufficient numbers to fulfil their critical environmental and ecological roles, Aziz, and many more like her will need all the help they can get. Just saving a few endangered remnants is not enough!

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“Bat Girl” Alexis Hitting It Big for Bats

10/25/17

Alexis Valentine won the 2nd Place award at the 14th Annual Jr. Foresters Science/Research Competition in Moscow, Russia.

We first met Alexis Valentine and her mother Amy, when Merlin spoke at an annual Discover Life in America conference in Gatlinburg, Tennessee in 2014. We’ve kept in touch ever since, encouraging her research and competition in local and regional science fairs. We were thrilled to hear that she had been awarded a full scholarship to represent the U.S. at the 14th Annual Jr. Foresters Science/Research Competition in Moscow, Russia. Forty-five participants from 28 countries and five continents presented projects, September 2-10 and Alexis won second place out of 40 awards. At 15, she was the youngest competitor to win an award, and also was the highest ranking American contestant in the competition’s history.

Ian Agranat, Alexis Valentine and Merlin Tuttle at the Wildlife Acoustics display.

Last week, she did a fine job of presenting her research on the impact of white-nose syndrome on bats in the Great Smoky Mountains National Park at the annual teacher’s workshop held in conjunction with the NASBR 47th Annual Symposium on Bat Research in Knoxville, Tennessee.

Knowing Alexis had long dreamed of owning her own ultrasonic bat detectors for her research and public presentations, Merlin took the opportunity to introduce her to Ian Agranat, President of Wildlife Acoustics, the worlds’ largest producer of wildlife monitoring devices. Their Echo Meter Touch 2 Pro bat detector is one on Merlin’s favorite tools for introducing the public to bats, and he was delighted when Ian made Alexis’ long-time dream of owning her own equipment come true through his generous gifts which covered all her needs.

 

Keep it up, BatGirl, we’re proud of you!

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