Scientists from 50 countries gathered in San José, Costa Rica, this past week for the largest bat conference ever. They discussed cutting-edge research and conservation regarding one of Latin America’s most ecologically important animals.
An estimated 650 researchers, professors and community educators gathered at the Wyndham Hotel to hear presentations on new bat species, research on behavior, dire warnings about threats and to learn how to communicate the importance of bats to the public.
One of the conference's key organizers, University of Costa Rica biology professor Bernal Rodríguez, said the conference location was a unique chance to showcase bat diversity and offer opportunities to researchers from Latin America.
“Costa Rica has a very high diversity,” Rodríguez said in an interview with The Tico Times. “The most genera in the world.”
Genera refers to the scientific classification of organisms, one level above species — the lowest level of classification. This diversity is not merely academic. Bats in Central America have the most diverse diet of any region, feeding on nectar, fruit, insects, fish, birds, mammals and blood. Because of this, bats serve a broad role in maintaining the natural environments of the region.
Rodríguez said the diversity is geographic, with Central America serving as an intersection of North and South American bats.
This marked the first time Central America had hosted an international bat conference, and it was the largest such conference to date, according to organizers.
Rodríguez noted that for up-and-coming researchers from Latin America, the conference marked a unique opening, because those researchers were unable to afford to travel to past conferences in relatively expensive places such as the United States or Europe.
“This is the best opportunity to communicate with the top researchers in the world,” Rodríguez said.
One such researcher was Eugenia Cordero, who also educates children living near the Tirimbina Biological Reserve in La Virgen de Sarapiquí, Heredia, in the interior north of Costa Rica. Cordero presented her education program, reaching out to schoolchildren living near the reserve, with a focus on the Honduran white bat.
She said the program uses the thumb-sized, leaf-dwelling bat to eradicate widely-held misconceptions.
“People don’t know that bats are mammals — either they [think bats] are birds or creatures that aren’t even considered animals,” Cordero said.
She said students can find the bats roosting in the leaves of heliconia plants within a two-minute walk from the station’s entrance. The bats chew through leaves, causing them to droop and make a tent-like structure. They roost in small groups of one male with a harem of females, according to researchers. The bats do not flee from a light disturbance, or from children coming to see them.
Cordero said she takes 500 students a year to see the bats.
“Scientists normally work in the field, but for conservation you have to work with the public,” Cordero said.
One of the stars of bat biology that many came to meet was Rodrigo Medellín, a professor at the National Autonomous University of Mexico, who has spent about 40 years studying bats and their environments.
Medellín said that every year scientists are getting a better understanding of the role bats play in their environment, which can have direct benefits for humans. Massive colonies of cave-dwelling bats, with numbers into the millions, are responsible for destroying 10 tons of insects every night, according to Medellín. This has profound effect on agriculture. Medellín said current research estimated $1 million in savings for every 10,000 acres of a crop such as cotton, due to the bats acting as a natural pesticide.
Medellín said that the agriculture industry will continue to owe a debt to bats, even as cutting-edge pesticides and genetically modified crops are developed. Currently companies like Monsanto have produced genetically-modified plants that produce their own insecticides. However, research presented at the conference showed that insects, with their vast numbers and short life-cycles, can produce rapid resistance.
The bats, however, are a fail-safe tool for agribusiness. Most insect pests on plants are problematic in their young or larval stages. Those that survive the pesticides into adulthood will fail to reproduce in great quantities if colonies of airborne insect-hungry mammals are nearby. Thus, the insects will fail to pass on their resistant genes in great quantities, according to Medellín.
“In 10, 20 years time, Monsanto even is going to be thanking the bats,” Medellín said.
The vampire bat, a blood-feeding bat that lives in Mexico and Central America, has been a problem for the image of bat conservation. Medellín lamented that the public retains the misconception that all bats feed on blood, especially when only three of the more than 100 species in the area are vampiric.
Medellín said his passion for bats started when he was a 12-year-old contestant on a Mexican television game show called "The 64,000 Peso Challenge." The show resembles “Who Wants to be a Millionaire?" but with the caveat that the contestant chooses the trivia topic. Medellín said he chose mammals and had a streak of success lasting six weeks. This drew the attention of the National Autonomous University of Mexico, which invited the young Medellín to their field research on bats.
“I never looked back really,” Medellín said of his long career.
Costa Rica’s bat diversity has offered research opportunities for biologists for decades. The overwhelming majority of bats in the United States, for example, live on a diet of only insects. In Central America, researchers can witness bats interacting with their environments in roles traditionally occupied by bees or hummingbirds.
One pioneering researcher, Merlin Tuttle, has an almost legendary status among bat researchers, driven by his wizardry in photographing bats in action.
Tuttle cited the example of one bat’s relationship with the sea bean, a tree often used by Costa Ricans to craft jewelry. The flower of the tree opens one night per year and produces a sweet nectar that attracts pollinator bats. It also produces a specifically designed part of the flower that reflects bat echolocation in a peculiar fashion. This plant feature only exists on the night when the plant is ready for pollination.
“It’s guiding him like airport landing lights at night for a pilot,” Tuttle told The Tico Times.
As the bat drinks the nectar, using an extended tongue, a lower part of the flower shoots pollen on the bat’s body, just above its feet.
“This all happens in a fraction of a second,” Tuttle said.
Tuttle said other flowers have similar structures, with their own specific territory on the bats’ bodies, shooting pollen on their faces, throats or wings.
Tuttle said he had been doing research and photography on bats for over 50 years, first coming to Costa Rica in 1987. He said he uses a studio for his photographs, capturing bats in the wild and then creating an artificial ecosystem. Tuttle said he can train the bats in as little as two hours to come to his hand and consider him a source of food.
“I don’t know if I can think of any animal in the wild that I can catch and train to come to me in two hours,” Tuttle said.
At the conference, Tuttle was excited to see some of the latest research on bat intelligence, a test of their long-term memory. One researcher played cellphone ringtones in an experiment with captured bats, giving them food if they responded to the tone. They bats were then released into the wild in Panama. After being recaptured, some gone for more than 800 days, they demonstrated an ability to remember associating the ringtone with food, in a laboratory.
Researchers hypothesized that the diverse diets of some bats, especially those that eat all manner of insects, coupled with their lifespans, upwards of 20 years, explains their need to have a sophisticated long-term memory.
A famous peculiarity of bats is their echolocation. Bats emit high-pitched noises from their mouths or sometimes noses, such as the Honduran white bat, then listen for the sound’s reflection to get a sense of their surroundings.
Cori Lausen, from Canada, teaches an acoustics course on bats and has been working with them since 1993. Because people are unable to hear the high-frequency sound of most bat echolocation, researchers have developed gadgets that modify their noises, Lausen explained.
“It sounds like a series of clicks,” Lausen said in an interview.
In their nighttime hunts, bats can detect insects, trees and other hunting bats with their sonar. However, some of the latest research shows that some bat prey have developed their own sonar in response.
Certain moths, one of the juiciest meals an insectivorous bat can find, have their own ability to detect ultrasonic sound waves.
“You can jingle keys and create ultrasound and they will drop right out of the air,” Lausen said.
Even more, other moths can project their own ultrasound back at the bat, creating what Lausen called a “sonar jamming” that confuses the predators.
One of the conference sponsors was a company making the latest gadgets in bat detection, Wildlife Acoustics. Their newest product, premiering at the conference was a small box that could attach to a smartphone or tablet. The box picks up the ultrasonic bat emissions and shows a graphical display of the sound waves on the computer. Users can then look up the call on an Internet database that can identify the bat species by its call.
“The idea is to get people excited about backyard batting,” Ian Agranat said in an interview about their products.
Gary Kwiecinski, a researcher from Pennsylvania, said he was focusing his latest studies on the intricate and bizarre faces of bats, especially the fruit-eating kind. The strange noses and wrinkles on some bats’ faces are not an accident, Kwiecinski said.
“The unusual structure of faces is for determining if food is edible or not,” Kwiecinski said in an interview.
Kwiecinski hypothesized that in those folds are receptors for touch and smell. Kwiecinski said their echolocation can also determine texture and softness of fruit.
“Bats are in flight so they can’t sit and ponder food,” Kwiecinski said.
Making one of the longest journeys to San José, New Zealand researcher Chris O’Donnell said he was also taking advantage of his time in Costa Rica. He said he had done snorkeling, saw humpback whales off the Pacific coast and saw tapirs in Corcovado National Park on southern Costa Rica's Osa Peninsula.
“I definitely know that I’m in Costa Rica now,” O’Donnell said.
At the conference, O’Donnell spoke about bats’ sophisticated behavior.
“Some bats spend all day together,” O’Donnell said. “I’ve got bats that have been living together for 10 years.”
Because most bat species sleep in groups, sometimes in caves with thousands, they develop complex social interactions, according to researchers.
“If you go into a cave at night with 1,000 bats, the mom will fly straight to her child,” O’Donnell said.
O’Donnell noted that some bats will assign a female to act as the nurse to the young bats in a colony, while others go outside to hunt. O’Donnell said bats have impressive memory, recalling feeding sites that are 10 kilometers away from their homes.
Other researchers, such as Tuttle, noted that bats’ social complexity resembles that of stereotypically intelligent mammals such as dolphins, elephants and humans.
Opportunities for Central American scientists
Jonathan Hernández is a researcher from Honduras and came with another Central American, Arnuflo Medina from Nicaragua. The two said the conference presented a tremendous advantage.
“It’s the biggest opportunity,” Hernández said, adding, “We don’t have the opportunity to travel to Africa or the U.S.”
For Hernández and Medina, the conference isn’t just an opportunity to meet famous bat researchers, it is the only opportunity to meet specialists.
Medina said Nicaragua has no established bat biologists to turn to for guidance. While researchers come to Nicaragua, few stay to disseminate their findings to the local population. Due to this, Medina said, myth such as all bats being vampires persist among many Nicaraguans.
“We don’t have any people that study bats; my point was to bring back knowledge and share it with the people,” Medina said.
The two said they run workshops in their home countries with small groups of children, and have shown that in a short time they can transform false perceptions.
José Cajas and Luis Trujillo came down from Guatemala under similar circumstances.
“The great scientists of the world are here, studying bats,” Cajas said. “We don’t normally have the opportunity to speak with them.”
The two were presenting research on artificial roosts they created in Guatemala for bats, to see if the fruit-eating bats help accelerate forest regeneration.
On the final morning of the conference, bat scientists received a dire lecture from an outsider.
Dan Janzen, from the U.S., has been working in the northwestern Costa Rica province of Guanacaste studying plant and animal interactions since 1968. On Thursday, he warned that a failure to involve local residents in the protection of wildlife reserves would result in them ceasing to exist.
“The entire system is decaying. If it keeps on like it is, in 50 years there won’t be a national park system,” he told The Tico Times.
During his presentation, Janzen stressed the need for biological reserves to provide benefit to local economies, otherwise they would be exploited in other, less environmentally friendly ways. He showed a slide of the book “A Guide to the Birds of Costa Rica,” by Gary Stiles, saying it has drawn many tourists to the country.
“Birds of Costa Rica has done more for the Costa Rican economy than has any other book published,” Janzen said.
Though Costa Rica has many large national parks and reserves, Janzen said many of them are not large enough.
“They’re just as dead as if you went today and cut them down with a chainsaw,” Janzen said.
The reserve where Janzen works is on Guanacaste's Pacific coast, in a region biologists consider dry tropical forest. The interior forests are wetter. Janzen explained that species such as the local bats rely on both regions. In the dry season, the bats migrate to the wetter forests where insect populations remain high. However, the reserve where Janzen works has no wet forest reserved, and the bats have to travel across agricultural land to reach such terrain.
Researchers at the conference widely cited habitat loss as the No. 1 threat to bat populations.
On the issue of climate change Janzen was blunt.
“Go to the top of Rincón mountains and take your pictures now,” Janzen said. “All that will be gone.”
Janzen explained that as temperatures rise, he has observed wildlife migrating from the hottest lower altitudes up. However, those at the top have nowhere to go, and will get crowded out by invaders from below.
Janzen did have some optimism, saying that if wildlife biologists can show governments and the local population that wild areas can be profitable, they will survive. Janzen estimated Costa Rica generated $2 billion a year due to wildlife tourism and study.
Richard Laval has been studying bats since he first took a course at La Selva biological station in 1968. La Selva sits in the Braulio Carrillo National Park, in the northern Caribbean side of Costa Rica. Laval has since run the Bat Jungle, an ecological park in the cloud forest paradise of Monteverde, in north-central Costa Rica.
He said the park’s bats are one of the primary attractions in Monteverde, bringing tourist and research dollars alike.
“I doubt any Latin American country has as many bat biologists as Costa Rica,” Laval said.
Laval said that many of the misperceptions remain, even in Costa Rica, which results in local populations directly attacking bats.
A newly discovered threat to bats came from one of the most seemingly benign sources — wind energy.
Frank Bonaccorso, a bat researcher since 1971, said the effect of windmills on bats is a relatively new field of study.
“It’s true that it’s relatively benign compared to coal, but we’re killing eagles, birds, bats,” Bonaccorso said.
Bonaccorso said that while windmills may appear to be moving slowly at first glance, the tips of the blades can be moving as fast as 200 miles an hour. Bonaccorso said that in Europe and North America researchers have estimated 800,000 bats have been killed since 2003.
Bats die from direct strikes from the blades or from the low air pressure created by their motion, which results in their lungs collapsing. Bonaccorso conceded that wind energy will continue to expand and hoped that further research would lead to bats coexisting with the technology.
White-nose syndrome was a popular topic at the conference. Though not a threat to tropical bats, researchers said the new disease has killed millions in North America, and may result in some species going extinct.
Mylea Bayless, with Bat Conservation International, said her organization has seen an 88 percent decline in bat numbers in the northeastern U.S. since its discovery in 2006.
She explained that the disease, a fungus that loves the cool, dark cave environment, preys upon bats that hibernate over the winter. The disease does not directly kill the bats, but rather awakens them before winter’s end. During hibernation, a bat’s system shuts down to the lowest levels, including the immune system.
“Essentially they burn through their fat before the end of the winter and they die,” Bayless said.
Normally, bats' immune systems would combat the fungus.
The disease was later discovered in caves in Europe, but was not killing the bats there.
“It appears to have been in Europe for a really long time,” Bayless said. “Now it is following that classic pattern of an invasive species.”
Bayless said scientists believe the disease first existed in Europe in the mid-2000s, and then spread to North America by cavers or scientists working in both areas.
The disease has spread as far west as Oklahoma, according to Bayless. She said her organization suspected the disease would have a hard time finding purchase among tropical bats, who do not have the same life cycle as bats that need to hibernate through a long winter. However, she said it is not impossible for the fungus to arrive.
Due to a wide range of diets, many researchers at the conference stressed how important bats are, especially in environments in Central America.
Bats play a role in combating insects – not only agriculture pests, but disease carriers, such as mosquitoes. Bats serve as pollinators, seed dispersers and as a form of population control for other animals such as frogs, rats and birds.
For Latin America, the “Red Latinoamericana para la Conservación de los Murciélagos” also seeks support.