Bat Monitoring at UPDC

Bats are among the most diverse groups of mammals on the planet, not just in terms of how many species exist, but also the variety of crucial roles they play in ecosystems. Without them, a large proportion of pollination, seed dispersal, insect control, and fertilization would be absent. This group is vital in maintaining the health of ecosystems, which is exactly what we aim to conserve and protect here at UPDC. With an estimated 85 bat species found within our geographic range, we decided it was high time to dive into identifying some of these species ourselves!

How we monitor our bats

To capture the bats we use mist nets; fine, almost invisible nets that span across trails and catch bats as they fly by in the evening. Net locations are chosen based on the vegetation around us. Dense areas of vegetation around the trail act as natural ‘funnels,’ guiding the bats into the nets. Once they’re caught, we carefully extract them and identify them based on key features like forearm length, fur color, and even their dentition. They are then released a few moments later so they can return to foraging throughout the night.

Measuring the noseleaf of Platyrrhinus albericoi, a large frugivorous bat in the family Stenodermatinae.

The wing of a juvenile bat. Examining wing characteristics can help determine a bat’s age. This wing shows minimal scarring, suggesting the bat has not lived long enough to accumulate injuries from flight or competition. In young bats, the knuckle joints remain unfused, creating small, window-like gaps that allow more light to pass through. Combining these traits with indicators such as teeth wear and fur quality can provide valuable evidence for estimating a bat’s age

Let's Meet Some Of Our Bats

After six weeks of monitoring, we’ve already built up quite an impressive species list, ranging from frugivores and insectivores to nectarivores, and even a species that eats frogs (yes, frogs!). As we continue our sampling and move through different habitats, we’re excited to see which new species we’ll encounter and what more we can learn about this fascinating group of mammals. Have a peek at some of the highlights:

Trachops cirrhosus: Known as the frog-eating bat, this species is adapted to consuming small vertebrates as part of its diet. Wart-like growths around the bat’s mouth are thought to have heightened tactile sensitivity, much like whiskers (vibrissae). This helps the bat navigate in low-light conditions and detect subtle air currents, which is crucial for identifying prey and fine-tuning its echolocation.

Platyrrhinus albericoi: The largest bat we’ve captured so far, this impressive species belongs to the Stenodermatinae family. These frugivorous bats are crucial for seed dispersal and pollination. As they move between plants, they carry pollen with them, helping plants reproduce. They also help distribute seeds, often through their faeces, dropping them far from the parent plant. This not only helps maintain plant diversity but also supports the growth and expansion of habitats by moving seeds into new areas.

Anoura aequatoris: A tiny nectar-feeding bat that belongs to the Glossophaginae family. These bats play a vital role in plant fertilization by carrying pollen from one flower to another while sipping nectar. They have a long, retractable tongue, covered in hair-like papillae, which helps them extract nectar from deep, tubular flowers.

Gardnerycteris crenulatum: A unique bat with a large spear shaped noseleaf. This species primarily eats insects. Unlike smaller insectivorous bats that catch insects whilst in flight, this species predates insects via gleaning, meaning they pluck their prey off of leaves. The large teeth help to break through tough hard-bodied beetles. Their short, broad wings also improve their agility and accuracy in flight, a useful skill when navigating through dense forest understory.

Dermanura rosenbergi: Rosenberg's fruit eating bat is another species in the Stenodermatinae family. This is a small bat, often weighing only 10-12 grams. It has specialised dentition to help consume fruit, with large flat molars perfect for crushing. Like other species in this genus D. rosenbergi roosts under modified leaf tents. They bite through the midrib of the leaf, causing it to fold inwards into a makeshift roost. Like the large Platyrrhinus albericoi, this little bat is an important seed disperser.

Final Thoughts

So what do we plan on doing with the data collected in this project? Sampling bats via netting can provide opportunities to analyse different types of data, from species assemblages to morphological variation within and between species. Due to their varied roles within an ecosystem, knowing the bat species we have here at UPDC, and in what ratio, can be a key indicator of ecosystem health. It can indicate fruit and insect availabilty through diversity of species we find, based on the diversity of niches they fill. Such research can emphasise the importance of conservation efforts here in the reserve.

In all, bats are an essential part of our ecosystem. As we continue to monitor their presence in different habitats at UPDC, we’re constantly amazed at the wide variety of species we’ve encountered. Each one plays a unique and crucial role in maintaining ecosystem balance, whether it’s through feeding on insects, pollinating plants, or dispersing seeds. Stay tuned as we continue our monitoring to see more exciting species we discover here at UPDC!