BATS Spring 02 Insides.2

Sound Wa r s Cultivating Bats Distinguished Service Aw a r d s W W W . B A T C O N . O R G S P R I N G 2 0 0 2 BAB A T C O N S E R VAT I O NT I N T E R N AST I O N A L Bat Conservation Intern a t i o n a l P.O. Box 162603, Austin, Texas 78716 512-327-9721 • Fax 512-327-9724 www.batcon.org Publications Staff BATS Volume 20, No. 1, Spring 2002 Managing Editor: Robert Locke Consulting Editor: David Baxter Photo Editor: Elaine Acker Publications Designer: Elysia Wright Davis Visual Resources Manager: Kristin Hay Visual Resources Coord i n a t o r : Sandra Forston FEATURES B AT S welcomes queries from writers. Send your article proposal with a brief outline and a description of any photos to the address 1 Sound Wars above or via e-mail to: [email protected]. Bats and Bugs Evolve New Weapons and Defenses M e m b e r s : Please send changes of address and all correspondence to the address above or via e-mail to [email protected]. Please By Brock Fenton include your label, if possible, and allow six weeks for the change of address. 5 The Virtual Bat Founder & Pre s i d e n t : Dr. Merlin D. Tuttle Digital Deception Repels Insects and Attracts Hungry Bats Executive Dire c t o r : Steven M. Walker B o a rd of Tru s t e e s : By Gary F. McCracken, John K. Wilhelmina E. Robertson, Chairperson Westbrook and Paul G. Schleider John D. Mitchell, Vice-Chairman Verne R. Read, Chairman-Emeritus Peggy Phillips, Secretary 7 Cultivating Bats Mark T. Ritter, Treasurer BCI Research Explores Airborne Jeff Acopian; Mark A. Adkins; Eugene L. Ames, Jr.; Charles Chester; Eugenio Clariond Reyes; Michael L. Cook; Robert E. Alternatives to Pesticides Gerrie; Nancy Harte; Joan Kelleher; Travis Mathis; Scott By Mark and Selena Kiser McVay; Thomas Read; Verne R. Read; Lee Schmitt; Patsy Steves; Dr. Merlin D. Tuttle; Roy Vaughan; Marc Weinberger Counting the Bats of Britain Page 10 Membership Manager: Amy McCartney 10 Development Dire c t o r : Denise Meikel A Pioneering Program Spreads Across the United Kingdom By Allyson Walsh Scientific Advisory Board : D r. Eduard Yavrouian, A r m e n i a ; D r. Leslie S. Hall, Greg Richards, Bruce Thomson, Australia; Dr. Irina K. DEPARTMENTS R a k h m a t u l i n a , Azerbaijan; D r. Wilson Uieda, Brazil; Dr. M. Brock Fenton, Canada; Dr. Jiri Gaisler, Czech Republic; Dr. Uwe Schmidt, Germany; Dr. G. Marimuthu, Dr. Shahroukh Mistry, India; Dr. Rodrigo A. Medellín, Dr. 13 Members in Action Arnulfo Moreno, Mexico; Ir. Herman Limpens, Netherlands; Texas Cavers Apply TLC to Bracken Bat Cave Dr. Armando Rodriguez-Duran, Puerto Rico; Dr. Ya-Fu Lee, Taiwan; Dr. Paul A. Racey, United Kingdom; Dr. Denny G. Constantine, Robert Currie, Dr. Theodore H. Fleming, Dr. 14 BCI Distinguished Service Awards 2002 Thomas H. K u n z, Dr. Gary F. McCracken, Dr. Don E. Wilson, United States; Dr. José R. Ochoa G., Venezuela. B AT S (ISSN 1049-0043) is published quarterly by Bat Conservation International, Inc., a nonprofit corporation supported by tax-deductible contributions used for public 16 News and Notes education, research, and conservation of threatened and NASA’s Echo the Bat, BATS’ New Editor, Bat Coffee, Spotted Bats endangered bats. ©Bat Conservation International, 2002. All rights reserved. Study, Devil’s Sinkhole, BCI’s Wish List. Bat Conservation International is dedicated to conserving and restoring bat populations and habitats around the world. Using non- confrontational approaches, we educate people about the ecological and economic values of COVER PHOTO bats, advance scientific knowledge about bats and the ecosys- The greater false vampire bat (M e g a d e rma lyra) is among the very few carn i v o rous bat species. Found tems that rely on them, and preserve critical bat habitats through win-win solutions that benefit both humans and bats. f rom India, Sri Lanka, and eastern Pakistan into southeastern China, it enjoys a remarkably diverse diet that includes fish, birds, frogs, rodents, lizards, spiders, insects, and even other bats. To avoid alerting pre y A subscription to BATS is included with BCI membership: Senior, Student or Educator $25; Basic $30; Friends of BCI $40; to its presence, the greater false vampires avoid using echolocation calls whenever possible (see “Sound Supporting $50; Contributing $100; Patron $250; Sustaining Wars,” page 1), depending instead on their excellent vision and hearing to identify targets. $500; Founder’s Circle $1,000. Third-class postage paid at Photo © Merlin D. Tuttle, BCI / 206-4403 Austin, Texas. Send address changes to Bat Conservation International, P.O. Box 162603, Austin, TX 78716. BATS is printed on a 50/20 chlorine-free recycled paper with a water-based coating on the cover. SSoo uu nndd A Mexican free-tailed bat (Tadarida brasiliensis) uses echolocation calls to pursue a corn earw o rm moth in this composite photo. WWaa rr ss How Bats and Bugs Evolve New Weapons and Defenses by Brock Fenton ats and bugs are locked in a biological arms race of sort s . Insect-eating bats evo l ved new sonar tech n o l o gie s for tra cking night-flying insects,w h i ch then Bd eveloped better bat detectors and tri ckier defe n s e s , d riving the bats into stealthier attack plans, and so on. I t ’s been going on for at least 50 million ye a rs . These sound- based interactions must be among the most complex pre d a t o r - p rey adaptations in nature . E cholocation — emitting sounds, m o s t ly ab ove the ra n ge of human heari n g , and analy z i n g the echoes that bounce back — allows aeri a l - feeding bats to detect, t ra ck , and assess poten- tial prey. It lets them hunt flying insects under nighttime conditions that ra n ge from the con- founding shadows of moonlight to the unifo rm d a rkness of an ove rcast night. But there are two great disadvantages to echolocation. First, the dissipation of sound as it moves through air sharply limits the operational range of echolocation by bats. Most probably cannot detect a medium-sized insect beyond about 15 to 30 feet (roughly 5 to 10 meters). We know, for instance, that big brown bats (Eptesicus fuscus) first spot a three-quarter-inch (19-millimeter) sphere at 16.5 feet (5 meters). One way to extend the range is to boost the strength of the signal. But that introduces the second disadvantage of echolocation: information leakage.The stronger the signal, the more likely it will be detected. Consider that the little brown bat (Myotis lucifugus) produces about 20 echolo- A computer displays the sound waves of echolocation calls collected with an Anabat Detector by cation signals a second, each one registering 110 to 120 BCI’s Janet Tyburec. S P R I N G 2 0 0 2 1 B A T S decibels when measured about fo u r signal is strong and the threat immi- lem.The insects can’t hear the low-fre- inches (10 centimeters) in front of the nent,the moth’s response is dramatic:It quency sonar signals (concentra t e d b a t . ( T h a t ’s louder than the smoke begins flying erratically and may dive around 10 kHz) of spotted bats until detector in your home, w h i ch hits steeply toward the ground. the predator closes to within a few about 108 decibels.) Echolocation By ex p e r i m e n t a l ly deafening bat- m e t e r s . E cho location calls of some signals make bats conspicuous and detecting moths, scientists confi rm e d other aerial-feeding bats also use calls allow us to monitor them with elec- that moths with wo rking ears have mu ch that are mostly below 20 kHz. These tronic bat detectors that collect sounds less chance of being caught by bats than include many free-tailed bats, such as beyond the range of human hearing. those whose ears are damage d . Red bats we s t e r n bonneted bats (Eumops Almost anywhere in the world, an (L a s i u r us bore a l i s ) and hoary bats perotis) from the American Southwest, observer with a tunable bat detector (L a s i u rus cinere u s) , for ex a m p l e , m i s s Midas free-tailed bats (Mops midas) can eavesdrop on most aerial-feeding about 60 percent of their attacks on f rom A f r i c a , and white-striped fre e - bats by selecting any fre q u e n c y moths with bat-detecting ears . tailed bats (Tadarida australis) from between 20 and 60 kilohertz.That band- So what is the poor bat to do? The Australia. The penalty for using lower width seems to give bats the best com- answer lies partly in those bats whose frequency sounds is that they have promise between range and resolution. calls go unheard by bat detectors.There longer wavelengths, which provide less Yet, depending on where you were lis- are at least five strategies that help bats detail about targets and probably miss tening, you might notice that some bats thwart the hearing-based defenses of smaller objects altogether.

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