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Bats: Misunderstood Protectors of the Night - October 23, 2016

               Over the centuries, bats have become associated with sinister beings such as vampires, witches, and the dead. This dark reputation, however; is undeserved and could not be much further from the truth. Bats play a large role in ecosystems and are considered to be a keystone species; a species that have a disproportionately large effect on other species in an ecosystem.

                Bats provide many ecosystem functions, such as pest control. Many bats are insectivores and prey on nocturnal insects. Several of these insects are considered nuisance insects that are extremely detrimental to agriculture.  Mexican free-tailed bats eat one such insect, the corn earworm moth that damages a variety of crops in the southwest. The cost of this crop damage is estimated to be more than $1 billion a year worldwide. In the United States alone, bats provide more than $3.7 billion a year in pest control services. Locally, bats prey on a wide variety of insects including mosquitos, mayflies, crickets, beetles, ants, cicadas, stoneflies, and termites. Depending on the species, bats can eat anywhere from 2,000 to 5,000 insects in a single night.

                Another ecosystem function that bats perform is to act as pollinators. Nectar-feeding bats pollinate a wide variety of plants worldwide. Many species rely solely on bats for pollination and without them the plants could die, which would lead to a domino effect in the ecosystem. Foods such as peaches, cloves, agave, and bananas all rely on bats for pollination. Bats also aid in the seed dispersal of many of the fruits they eat. Unlike birds which may only disperse seeds over a short distance, bats can cover large distances at night and spread seeds out much further from the parent plant. The plants dispersed by bats are often pioneer plants that will provide shelter for other species to eventually grow. Bats can account for up to 95 percent of primary succession in some ecosystems. Bats disperse the seeds of plants such as avocados, cashews, figs, and dates.

                Unfortunately, the populations of these ecologically vital species are rapidly declining. Loss of habitat, disease, overexploitation, and slow reproduction are all factors leading to their decline. Over 1,000 bat species are listed as vulnerable, endangered, or critically endangered. Loss of habitat is the leading cause for the decline in bat populations. Deforestation removes valuable habitat for roosting and feeding. Guano (bat droppings) mining, if done inappropriately, can disturb the nesting or hibernation of bats and force them out of their roosts. In some areas of Southeast Asia and Indonesia, bats are overhunted as commercial bushmeat or for some folk medicines. In Latin America, whole bat colonies are killed out of the fear that bats are vampires.

                Locally, a major cause of bat decline is White-nose Syndrome, which is caused by the fungus Geomyces destructans. In North America, almost 6 million bats have been killed due to the fungus. It grows around the bats’ nose and ears during hibernation and causes them to rouse from hibernation.  When this occurs, the bats will burn through their fat stores at a faster rate which causes them to die from starvation in the food deficient winter. This fungus is found in twenty-nine states and the mortality is up to 100 percent in some areas.  The little brown bat, a common species on the Eastern Shore, is predicted to be reduced to just 1% of its pre-White-nose Syndrome population size by 2030.

                In addition to their dark reputation, another reason bats have come to be feared is rabies. Reports of rabies in bat populations are very uncommon, with less than 0.5% of bats testing positive for the virus. In Worcester County, only two confirmed cases of rabies in bats have been reported in the last seven years. During the same time period, there were 169 rabid raccoons, 17 rabid foxes, and 7 rabid cats. While it is uncommon for bats to have rabies, it is still best to proceed with caution when confronted with one. Abnormal behavior is often a symptom of rabies in bats. Such behavior includes being active during the day, being unable to fly, or finding them on the ground. The most common way people become bitten by a bat is by picking them up or handling them with their bare hands.  

                The fall season is when local bat species begin to prepare for either migration or hibernation. Of the ten species of bats found in Maryland, only three of them migrate south for the winter. During this time of transition, bats can be found roosting on man-made structures such as attics, chimneys, and eves. Often bats that find their way into our homes, do not have a happy ending. They are either killed outright or trapped inside and left to die. If a home owner wishes to remove bats from their property, is it important to hire a responsible bat removal company. Bats are protected by law and can only be removed using special eviction techniques. For recommendations on bat removal companies, go to www.savelucythebat.org.   

                Bats are extremely ecologically beneficial animals and should not be feared. Some ways to help your local bats is to install bat boxes on your property, plant a night garden, or simply help preserve their habitat. Your friendly neighborhood pest control will appreciate the effort!

Phillips is the Program Manager for the Maryland Coastal Bays Program.



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