Species of the Month

Species of July: Indiana Bat

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Three Indiana Bat skins from the Tetrapod Collection.

Indiana bats from the Tetrapod Division

by Raymond Gonzo

There’s nothing like being outdoors on a warm summer night. The sunset, the fireflies, a barbeque all make summer nights truly magical. However, there is an important part of the summer night that you won’t hear too many people reminiscing about, bats flying overhead. Bats though play an important role in making these summer nights so pleasant and memorable, they feast on mosquitoes and help keep their numbers in check.

Here in the Tetrapod collection, we have several species of bats that have been preserved and placed in a glass container with labels for each individual so that we can show them to visitors. While any of the species that we have would make for interesting conversation, I feel that it would be most interesting to discuss a species of bat that is both unique and important to the Midwest and Ohio, the Indiana Bat.

Weighing the same as approximately three pennies and with a wingspan just under one foot, the Indiana Bat (Myotis sodalis) is quite small . Despite being small, these bats can have a large impact: they are capable of eating half their body weight in insects per night and when you do the math, a bat can eat 3.75 g of mosquitoes which amounts to roughly 1,500 mosquitoes at 2.5 mg each. Thus bats are highly valuable in pest control. Like all bats, the Indiana Bat will hibernate during the winter when there are no insects to be found. These bats hibernate in very large clusters and, like their Latin name (sodalis, meaning companion) implies, are very social. When hibernating bats slow their metabolism, heart rate and breathing rate to extremely low levels to conserve energy. Given that they cannot refuel during the cold months, their energy reserves are finite and any unnecessary movement will cause them to burn more of their fat reserves than they can afford to lose. Thus during hibernation, bats absolutely cannot be disturbed. This will cause the bats to starve and die before the warmer weather with replenished food supplies returns. To find out more about the Indiana Bat in particular, you can visit the U.S. Fish and Wildlife Service’s website.

The Indiana bat, has been endangered since 1967. One of the reasons is disturbance during hibernation. There are a few different causes for disturbance of the bats’ hibernation, but the biggest threat nowadays may be white-nose syndrome.

The white-nose syndrome is a fungus that was introduced to North American caves by European spelunkers sometime in the early 2000’s. The fungus causes a white patch to grow on the bats’ nose, hence the name; this irritates the bat and may alter its behavior. Bats with this syndrome have been observed flying around in the middle of the winter, burning more fat than they normally would, which ultimately leads to death by starvation. This disease has already killed millions of bats across the U.S. and Canada and according to some researchers, it may continue to do so before we will see improvement.

According to a study conducted by Wayne E Thogmartin et al (2013) the population of the Indian Bat will be ravaged by white-nose syndrome over the next century. The study conducted was able to predict the rate at which bats will die off should conditions continue as they are, and they’ve found that the Indiana Bat will survive into the next half century, but at greatly reduced numbers. There is, however, the chance that the bats will develop immunity to the fungus, which could turn things around.

Bats of all species (the Indiana bat included) are dying due to the white-nose fungus’ rapid advancement. If we lose these bats, then we lose a very effective regulator of insect populations. The good news is that there are many ways you can help bats, starting in your own backyard in order to make it more inhabitable for bats. You can also support an organization that is working to save bats (e.g. the organization for bat conservation), and you can attend programs to learn more about bats.

At OSU Marne Titchenell, Wildlife Extension Program Specialist has studied bats and knows about their ecology and management. Marne and other naturalists periodically give talks on bat conservation at local metro parks. This weekend, join a Journey into Nature with Bats at Glacier Ridge Metro Park on Saturday July 25th at 8pm or take a bat walk at Blacklick Woods Metro Park on July 31st. Happy bat watching!

References

Thogmartin W.E., Carol A.S.R., Szymanski J.A., McKann P.C., Pruitt L., King R.A., Runge M.C., Russell R.E. 2013 White-nose Syndrome Is Likely to Extirpate the Endangered Indiana Bat over Large Parts of Its Range. Biological Conservation 160, 162-72. http://www.sciencedirect.com/science/article/pii/S0006320713000207

“Indiana Bat (Myotis Sodalis).” USFWS: Indiana Bat (Myotis Sodalis) Fact Sheet. U.S. Fish and Wildlife Service, 18 May 2015. http://www.fws.gov/midwest/endangered/mammals/inba/inbafctsht.html

“White-Nose Syndrome (WNS).” USGS National Wildlife Health Center –. U.S. Geological Survey, 13 Mar. 2015. http://www.nwhc.usgs.gov/disease_information/white-nose_syndrome/

Bruce, Heidi, and Shannan Stoll. “How to Save Bats in Your Own Backyard.” YES! Magazine. YES! Magazine, 17 July 2012. http://www.yesmagazine.org/issues/making-it-home/how-to-save-backyard-bats

Species of the Month: Cane Toad

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Picture of Cane Toad

Adult Cane Toad

by Raymond Gonzo, OSU zoology major

The other day I was working in the Amphibian section of the Tetrapod collection, when I saw two toad specimens that really stood out to me. The toads were almost the size of a Coke can, which is bigger than the American toads that you may find in your backyard. Another interesting thing I noticed about these toads was the fact that one specimen was collected in Fortin de las Flores, Mexico, and the second specimen came from Australia. How is it that these two specimens were collected on different sides of the planet? On the jars they were labeled Rhinella marinus, which struck a cord with me. I had heard that name many times before, but I couldn’t remember from where. A quick check through the Tetrapod Collection’s curatorial database revealed that the amphibian in question was none other than the infamous Cane Toad.

The Passenger Pigeon that I wrote about last month was a species that declined in numbers and went extinct due to human activities. The cane toad, Rhinella marinus, is an example of the opposite effect, a species that proliferates with human help.

Until the 1930s, the cane beetle, an Australian native whose larvae feast on the leaves of sugar cane, did excessive damage to the sugar cane crop. In order to control the beetle population, the cane toad was released as a new predator. The idea being that this toad would feast on the beetles and thus protect the sugar cane crop. However, it did not work out as planned, the cane toad became a major pest in itself.

Instead of controlling the beetles, the toads began eating everything in sight, which allowed them to thrive and reproduce at an alarming rate. If that weren’t enough, the toads are highly poisonous and release a deadly toxin if a predator, who has not evolved defense strategies against cane toad toxin, should try to eat them. In the Americas, there are predators who can eat the toads and consequently keep their population in check. For example, there are many crocodilian reptiles, snakes, and various species of fish that are both immune to the toxins and can be found in the toads’ natural habitat. Many Australian predators of frogs and toads are unfamiliar with the toxins and cannot tolerate them, which means they will often die from eating a cane toad. This has given the toads a chance to drastically increase in numbers. Interesting fact, the cane toad is in the same family (Bufonidae) as the American toad, Anaxyrus americanus, an example of related species having a very different effect on their environment, especially when displaced.

However, as recent studies show, over time species may evolve the ability to either recognize and avoid cane toads or be able to tolerate their toxins. In 2004, Ben Phillips and Richard Shine demonstrated that some Australian snake populations that are at risk of death by the cane toad have adapted to living with the invaders. The authors of this study found that snakes increased in size in areas where they co-exist with cane toads. Small individuals face a much higher risk of fatal poisoning by toads, thus over time this species has been selected for large body size. More recent studies have shown that spiders and ants may also help keep cane toad numbers in check. If you are interested in finding out more read this article in the Australian Geographic. You can also read the study conducted by Phillips and Shine.

There are hundreds of instances where animals from one part of the world are introduced to another area, and often times there are disastrous consequences. A local example of this is the Emerald ash

borer. The ash borer is a native to China, but turned into an invasive pest of ash trees in North America. Here at the Ohio State University, much research is being done on the impact these beetles are having on the local Ohio ecology. More information on the control of this pest can be found here.

When it comes to trying to control nature, mankind has a pretty mixed track record of both successes and failures. Invasive species such as the Norway rat, the feral pig, and the ball python are all examples of how carelessness can lead to the destruction of an ecosystem. The Cane Toad is just one in a long line of destructive invasive species, and with the increased inter-continental travel of the modern world, it certainly won’t be the last.

 

References

Phillips, B. L., and Shine R. 2004 Adapting to an Invasive Species: Toxic Cane Toads Induce Morphological Change in Australian Snakes. PNAS 101, 17150-7151.

http://www.pnas.org/content/101/49/17150.full