Team returns from Costa Rica

Ada and Leith have returned from a successful trip to La Selva Biological Station, Costa Rica! This field trip was part of our project investigating the coevolution between plant chemical signals and frugivorous bats. The team collected  scent samples from fruits, and conducted behavioral experiments to measure what scents bats prefer.  They were joined by our collaborators at the Dávalos and Rossiter labs, who are working on the sensory genomics of tropical bats.

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Summer of Fieldwork: Grenada 2015

Grenada is a 344 Km2 island located in the Southeastern Caribbean. Despite its small size, it is famous for being one of the major producers of nutmeg and mace in the world. Exotic trees of many commercially important fruits, including the iconic Myristica fragrans, have been planted throughout the island’s mountainous landscape. For fruit bats, this means one thing: lots and lots of food.

Leith and I visited Grenada last summer thanks to an invitation to Saint George’s University by Dr. Sonia Cheetam Brow and Dr. Diana Stone. Sonia and Diana are virologists at SGU’s School of Veterinary Medicine, and they were interested in doing research on viruses that may be hosted by Grenadian bats. This research is very important because bats in Grenada are abundant and use many man-made structures for roosting, putting them in close proximity to humans. Additionally, we were interested in surveying what bat species still live in Grenada. Very few studies have characterized the island’s bat fauna and the last inventory precedes the damage caused by Hurricane Ivan to the region.

Much of our efforts went into finding bat roosting sites nearby population settlements, while at the same time spanning all of Grenada’s parishes to get a full coverage of the island major habitats. Our collaborators put a lot of effort networking with locals to find bat roosting sites. While people in Grenada are very familiar with the presence of bats, locating bat colonies proved trickier. First, there is little knowledge about natural roosts, with the exception of one small cave that is home to hundreds of Artibeus jamaicensis and Glossophaga longirostris. Second, bats are considered “pests” by most locals, and any group of roosting bats found in or near a house is usually exterminated quickly.

Luckily for us and the bats, natural disasters and economic downturns have resulted in many buildings (e.g., large vacation houses, bars, barns) to be left completely abandoned throughout the island. We found that these structures now provide new and relatively conflict-free roosts for hundreds of bats in Grenada. Walking into some of these houses felt sort of post-apocalyptic: lianas and other plants growing inside, bats hanging from the ceiling or flying around by the dozens, walls covered in guano, and floors covered in a thick layer of bat-dispersed seeds that were meant to grow in the forest.

In all, through roost searches and mistnetting, we collected only four species of the 12 that have been previously reported in Grenada: Artibeus lituratus, Artibeus jamaicensis, Glossophaga longirostris, and Molossus molossus. It is unclear if the diversity of bats has decreased due to human activity and natural disasters in the island, or if the findings are due to the need of a bigger sampling effort.

While in Grenada, we were also able to give guest lectures at SGU, talk with locals about bats, learn methods for necropsy and pathobiology sampling, and learn about the rich Grenadian history and culture. Leith and Sonia are now creating a guide to the bats of Grenada, which we hope can contribute to educating the population on the importance of bats for ecosystems and aid in their conservation.

Summer of fieldwork: Costa Rica

In July, Jeff Riffell, David Villalobos and I went to La Selva Biological Station in Costa Rica to work on our NSF-funded project “Chance or necessity? Adaptive vs. non adaptive evolution in plant-frugivore interactions”. Going in the middle of the rainy season during an El Niño year made for a very stormy, wet, muddy and soggy couple of weeks. In what I’d like to call “the field season triathlon” (hiking, trawling, and reaching up), we were able to collect Volatile Organic Compounds (VOC) from the fruits of over a dozen species of Piper and other bat-dispersed plants, and fecal and tissue samples from nearly 100 bats. While mapping the VOC profiles onto phylogenies will enable us to investigate how fruit scent evolves in this system, analyses of the bat fecal samples will allow us to expand our current understanding of how much the bats rely on the different Piper species for food.

This autumn, Leith Miller and Ada Kaliszewska are continuing sample collection and analysis for this project in La Selva. Meanwhile, Laurel Yohe (a PhD student at our collaborating lab) gave a talk at the North American Symposium for Bat Research in which she presented preliminary results  on the olfactory receptors of short-tailed fruit bats.

Summer of fieldwork: The Philippines

Time flies when you’re having fun, or if you are catching bats around the world, which is basically the same thing. This is the first post reporting our fieldwork trips this summer, which included four countries across four ecogeographic regions!

It all started with a trip to the Philippines with a team composed by the Sears, Dávalos, Dumont and Santana labs, Dr. Susan Tsang, and colleagues from the National Museum of the Philippines. Our main goal was to collect Old World fruit bats (Pteropodidae) for a study that will contribute to understanding why these bats have much lower cranial diversity than their New World counterparts (Phyllostomidae). Answering this question involves integrating studies on cranial development, bite force and feeding behavior across a range of pteropodid and phyllostomid species.

What impressed me the most upon arriving to the Philippines was the overwhelming population density (Luzon is the 4th most populated island in the world). Our field sites were near, Liliw, a highland town in the southern portion of the Laguna province. Even several hours away from the capital, there were no apparent sights of the kind of habitats that I would expect could sustain bats. Yet, despite the loss of habitat and the pollution, some bat species still seem to fly through this landscape and take advantage of fruiting trees during their nightly foraging activities. Using mist nets suspended a few dozen meters above the ground, and skipping on any form of night sleep, we were able to collect five of these bat species: Cynopterus brachyotis, Eonycteris spelaea, Macroglossus minimus, Ptenochirus jagori, and Rousettus amplexicaudatus. Though this was a considerably lower diversity than what I’m used to experiencing in the Neotropics, it was astonishing to see these species live for the first time.

From the beginning, it was quite evident that pteropodids are a different ballgame than phyllostomids when it comes to recording performance and feeding behavior. Although both Cynopterus and Ptenochirus were reminiscent of Neotropical Artibeus species in their extravagant use of distress calls in the mist net, their approach towards scary things (like a bite force meter) seemed quite different. These species, as well as the rest of the pteropodids we caught, tended to rely more on their flight response when faced with experimental situations – cue adorable bat covering its face with its wings. With much patience and creativity, however, we were able to get bite force data for new species to complement previous datasets for our study. Likewise, Karen Sears and Dan Urban set up a lab in the field that allowed them to conduct unprecedented experiments and observations on the skull development of several pteropodid species.

My favorite catch of this trip was Rousettus, despite the fact that their activity peaked between 2-4 AM, sending the sleep-deprived team into panic mode to quickly release dozens of bats from the nets before sunrise. Rousettus were extremely gentle bats, and it was a treat to hear their tongue clicks (a form of echolocation) as they flew about and while we handled them. The young of at least one species of Rousettus may learn vocalizations in similar ways to the way human babies do. What’s not to love?

The data and samples collected during this trip will serve for dozens of studies that will expand the understanding of this diverse and still obscure group of bats. As it often happens, I came back with many more research questions than when I left. Here’s to hoping there will be more pteropodids in our future.

Notes from the field: La Selva

Leith, Rochelle, and an adorable Ectopylla alba

La Selva has been a fascinating place to visit. While Rochelle and I both had impressions of what a tropical rainforest would be like, we were both amazed at the lush, complex habitat and the organismal diversity that goes along with it. For me, I learned an extensive amount, not only about the ecological dynamics in the wet rainforest, but also more about the diversity of bats. We had the wonderful opportunity to work with Dr. Gloriana Chaverri.  She gave us an opportunity to study the acoustic properties of neotropical bat distress calls, (primarily phyllostomids). Then, we conducted playback experiments to investigate how surrounding bats (intraspecifics and interspecifics) respond to these calls . In addition to our research, we were also busy working with Day’s Edge Production to produce a short film portraying the story of our research experience at La Selva. Check out the link below to see our video!

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Notes from the field: Ectophylla alba

Ectophylla alba, the Honduran white bat, is a unique species of Neotropical leaf-nosed bat. Not only they are among the very few species of bats that are almost completely white, but they are extremely specialized in their diets and roosting ecology. Males and females of the species skillfully construct delicate tents from the leaves of Heliconia plants, and their diet is restricted to fruits of Ficus colubrinae plants. During our most recent trip to Costa Rica, we had the opportunity to record and measure these bats as they frantically fed from a F. colubrinae fruiting tree (below). Fruiting events in Ficus plants occur in short bursts and are scattered throughout the landscape, and E. alba likely choose places to “camp out” according to the potential for food availability.

 

Costa Rica 2013

After the Belize warm up, I went to Costa Rica to work at two main sites, the Tirimbina Forest Reserve and OTS La Selva research station. The major goal of this trip was to collect fecal samples for molecular dietary analyses in foliage-gleaning bats, along with performance data across bats and other mammals. These data will allow us to understand patterns and mechanisms of food resource partitioning within and across dietary guilds. With the help of collaborator Dr. Bernal Rodríguez Herrera and his students at the Universidad de Costa Rica, we were able to collect data for a total of 24 species of bats, plus several kinkajous.

One of the trip highlights included catching Honduran white bats (Ectophylla alba), a very small frugivore that builds tents in the vegetation. Findings about Ectophylla’s tent construction behavior have changed the paradigm that only male bats build these roosts as part of a resource-defense polygynous system; female Ectophylla also contribute to building tents. A second high point was collecting a wrinkle-faced bat (Centurio senex), a very rare and morphologically derived stenodermatine that is built to bite. Just as impressive, the second largest bat in the Neotropics (Phyllostomus hastatus) made its appearance in our nets and contributed to our dataset. With such stunning biodiversity, we are very much looking forward to continue work and collaborations in Costa Rica. Pura vida!

Belize 2013

The field season 2013 started with a bang! This May, I joined an international team of over 40 bat biologists in an expedition to Lamanai, Belize. The trip was led by Dr. Brock Fenton, a bat expert from the University of Western Ontario who has been visiting the site for over 20 years. Lamanai is impressive with biodiversity and archeological remains;  jaguar faces not only decorate the Mayan temples, but these animals can be seen around the area as well.

With a few dozen bat researchers in the group, projects were as diverse as the bats: morphology of wings, muscles, skulls and reproductive tracts, echolocation, feeding behavior, diet, flight aerodynamics, radio tracking, viruses, and more. We caught around 500 bats from 28 species, the great majority of which were released unharmed. The voucher specimens that were kept will serve as the basis of studies in labs across five institutions, which is an impressive use of field-collected specimens. These will continue to be available to researchers at the American Museum of Natural History’s Mammal Collection.