Danny Haelewaters, a 2018 PhD graduate from Harvard University, is currently associated with Purdue University and the University of South Bohemia (Czech Republic). His Twitter handle is @dhaelewa.
Capturing Bats to Find Fungi on Flies
By Danny Haelewaters
It was the fourth night of fieldwork in the Chucantí Nature Reserve cloud forests in the Darién Province. The expedition at Chucantí was part of a three-month collecting trip in Panama, funded by the David Rockefeller Center of Latin American Studies, the Smithsonian Tropical Research Institute, and the Mycological Society of America. Cerro Chucantí had been under severe threat of logging, farming, and cattle ranching activities, until it was purchased by Guido Berguido and his colleagues at Asociación Adopta el Bosque Panama (ADOPTA). Now, the area is recovering, and many Panamanian and international researchers are studying plants, invertebrates, amphibians, reptiles, and fungi. Some of the species that are discovered are new to science and often endemic, such as the Chucantí salamander or Bolitoglossa chucantiensis.
I and five field assistants had captured 120 bats during the three previous nights and were ready for more. We set up our mist nets at what we called Camp Site. Mist nets are almost like volleyball nets but instead of being tight, they form baggy pockets. When a bat hits the net, it falls in one of the pockets and becomes entangled. Sadly, it was a quiet night for numbers of bats. We captured 16 bats in total, significantly less compared to the other nights. However, we captured six species, including Myotis riparius, one of the cutest bats you can imagine. They have a fluffy look with their long and woolly fur and you could easily fit five or six such fluff balls in the palm of your hand. This species can vary in color between reddish and blackish, which we were able to witness at Chucantí. In addition, we also captured more common species, such as Carollia perspicillata and Artibeus jamaicensis, which are both fruit-eating bats and can accelerate forest regeneration because they are important dispersers of seeds. We also captured a Trachops cirrhosis, the frog-eating bat, and two Carollia brevicauda bats, which are abundant but less common than C. perspicillata.
You should know that I am not particularly interested in bats. I think they are adorable and they are absolutely fascinating in terms of adaptations that allow them to fly and to be nocturnal. But I am not a mammologist. No, I study fungi. So then why capture bats? Well, bats serve as hosts for a lineage of flies that suck on blood. They are all referred to as “bat flies” although there are two families, Streblidae and Nycteribiidae. The bat flies that we find in the neotropics are all streblids. Again, I am not so much interested in the flies, but rather in the fungal ectoparasites that can occur on them. These fungi—categorized as Laboulbeniales—are unique among related fungi in that they do not form hyphae but instead produce multicellular unit of determinate growth, or thalli. Now what was so interesting about that fourth night at Chucantí? Well, those two Carollia brevicauda bats each carried a Trichobius joblingi bat fly that was infected with Laboulbeniales. This bat fly is relatively common, and I find Laboulbeniales on this species all the time. However, one of these two bat flies was infected with what I originally thought of as an undescribed species of Laboulbeniales!
Of the currently known species of Laboulbeniales, less than 1% are described based on molecular data. That is a problem in an age we are finding more and more species that cannot be circumscribed based on morphology. Such species are often referred to as being cryptic. To make things more complicated, also the opposite is true—a single phylogenetic species can have multiple morphologies. This we call polymorphism. As a result, I knew I had to generate sequence data of my presumed new species. I extracted DNA and amplified the large subunit “barcode,” the region of the genome that is useful for successful identification to species level. To my surprise, the presumed undescribed species was identical to a species I had previously described even though morphologically they were very different. In the end, I described the fungus on Trichobius joblingi from Carollia brevicauda as a morpho-type. Its formal name is Gloeandromyces pageanus forma alarum. The epithet “alarum” refers to the growing position of this morpho-type; it only grows on the base of the soft wings.
With this research, I not only hope to discover new species, but I also want to gain a better understanding of multitrophic interactions. We take data from every specimen that goes through our hands; all bats that we ever captured and all bat flies that we collected, infected and uninfected, are entered in a database, along with a number of traits, such as ecology and diet. Based on information from inaccessible areas like Chucantí Nature Reserve but also from places that are heavily disturbed by human activities, one of the main questions I would like to answer is what traits affect parasitism of bat flies by Laboulbeniales fungi. That is a very broad question, and so we can ask several sub-questions, such as: Does roosting behavior of bat hosts affect parasite prevalence of Laboulbeniales on bat flies? Does habitat alteration affect parasitism by Laboulbeniales? And how does parasitism change in bat species thriving in altered habitats relative to those species critically threatened or endangered?
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