Flight Speeds of Three Species of Neotropical Bats: Glossophaga Soricina, Natalus Stramineus, and Carollia Subrufa
Total Page:16
File Type:pdf, Size:1020Kb
Acta Chiropterologica, 9(2): 477–482, 2007 PL ISSN 1508-1109 © Museum and Institute of Zoology PAS Flight speeds of three species of Neotropical bats: Glossophaga soricina, Natalus stramineus, and Carollia subrufa JAMES B. AKINS1, MICHAEL L. KENNEDY1, GARY D. SCHNELL2, 6, CORNELIO SÁNCHEZ-HERNÁNDEZ3, MARÍA DE LOURDES ROMERO-ALMARAZ4, MICHAEL C. WOOTEN5, and TROY L. BEST5 1Ecological Research Center, Department of Biology, University of Memphis, Memphis, Tennessee 38152, USA 2Sam Noble Oklahoma Museum of Natural History and Department of Zoology, University of Oklahoma, Norman, Oklahoma 73072, USA 3Departamento de Zoología, Instituto de Biología, Universidad Nacional Autónoma de México, A.P. 70-153, Coyoacán, México, D.F., 04510, México 4Escuinapa No. 92 bis. Col. Pedregal de Santo Domingo, C.P. 04360, México, D.F., México 5Department of Biological Sciences, 331 Funchess Hall, Auburn University, Alabama 36849, USA 6Corresponding author: E-mail: [email protected] Flight speeds of Pallas’s long-tongued bat (Glossophaga soricina), the Mexican funnel-eared bat (Natalus stramineus), and the gray short-tailed bat (Carollia subrufa) were measured in Colima, Mexico, during January 2006. Bats from an abandoned mine tunnel were transported to a nearby simulated flyway, where speeds were determined over a known distance. For G. soricina, average speeds for 26 males and 14 females were 4.85 and 4.80 m/s, respectively (P > 0.05), which are similar to those reported by other investigators. Averages for N. stramineus were 2.84 m/s for 40 males and 2.39 m/s for 23 females, values that were statistically different (P < 0.05) despite the fact that body masses for the sexes were similar. For C. subrufa, three males and three females averaged 3.67 and 3.52 m/s, respectively. Speeds were unrelated to body mass for any of the species. Speeds for N. stramineus and C. subrufa are the first reported, whereas those for G. soricina are the first recorded under near-field conditions. Key words: Glossophaga, Natalus, Carollia, flight speed, Mexico, Neotropics INTRODUCTION seasonal movements (Kennedy and Best, 1972). Previous investigators (e.g., Norberg, All aspects of the biology and natural 1987; Sahley et al., 1993; Winter, 1999; history of bats are integrally related to their Hopkins et al., 2003) have summarized ability to fly (Feldhamer et al., 2004). Bats much of the available literature relating to generally are characterized as slow and flight speeds for bats, but many species re- highly maneuverable in flight when com- main unstudied. Hopkins et al. (2003) noted pared to birds, but the manner of flight of the limited accounts of flight speeds of bats bats varies. Knowledge of flight speed helps in the Neotropics of Mexico. Because much with respect to our understanding of feed- of the habitat in this region is diverse and ing habits, homing ability, home range, and threatened by high rates of deforestation 478 J. B. Akins, M. L. Kennedy, G. D. Schnell, C. Sánchez-H., M. de Lourdes Romero-A., et al. associated with a multitude of human activ- encouraged them to fly toward the darkened end of ities (Ceballos and Garcia, 1995), and there the passage, which was open. is a paucity of information relating to the We identified each bat to species, determined its sex and age, and recorded body mass with a Pesola speed in flight of many species of bats in the scale just before release, which occurred between region, we investigated three species — 20:00 and 23:00 h. After release at the beginning of Pallas’s long-tongued bat (Glossophaga so- the tunnel, individuals were given a distance of 15 m ricina), the Mexican funnel-eared bat (Na- within the flyway to attain normal flight. Elapsed talus stramineus), and the gray short-tailed times from release to 15 m and to 20 m were record- bat (Carollia subrufa) — that have not been ed with stopwatches, thus enabling us to determine the time required for the bat to traverse the final 5-m investigated or have been little studied with section of the tunnel. Only results of more-or-less di- regard to flight speed in the field. rect and level flights of adults were recorded. Winter (1999) reported speeds for six Individual bats were tested only once and were not re- G. soricina, not differentiating between sex- captured after release. es, and Lindhe Norbert and Winter (2006) Statistical differences for variables between sexes were tested using a single-classification ANOVA. studied in detail its flight characteristics, in- Associations of body mass to fight speed were exam- cluding speeds of two females. Sahley et al. ined using Pearson’s product-moment correlation (1993) noted the need for additional infor- coefficient. A few observations that were greater than mation relating to flight habits of glos- 3 SDs from the mean were considered outliers and sophagine bats. Our investigation provides possibly mismeasurements (Burt and Barber, 1996); new information relating to flight speed for they were removed from the data set. three species. Specifically, we obtained ad- ditional flights speeds for G. soricina (dif- RESULTS ferentiating between males and females) un- der near-field conditions in a habitat where Speeds for 109 bats were recorded this species had not been previously tested. (Table 1). Intraspecifically, none of the spe- We also report the first speeds in flight for cies exhibited significant associations of N. stramineus and C. subrufa. flight speed with body mass (r = 0.18, 0.60, and -0.15 for G. soricina, N. stramineus, and C. subrufa, respectively; all P > 0.05). MATERIALS AND METHODS No difference in flight speed or body On 5 January 2006, individuals of G. soricina, mass between males and females was de- N. stramineus, and C. subrufa were captured in an tected for G. soricina. For N. stramineus, abandoned mine tunnel (túnel de mina Paredón Alto) there was no statistical difference in body about 1 km NE Cardona, Colima, Mexico (19°13’N, mass between males and females. However, 103°39’W, elevation 438 m). These bats were cap- tured, handled, and examined following methods sexes differed significantly in flight speed, described by Kennedy et al. (1977) and Sánchez- with males averaging 2.84 m/s and females Hernández et al. (2006). They were obtained during 2.39 m/s (F1, 61 = 6.07, P = 0.02). Small a 1.5 h period following the end of civil twilight sample sizes for C. subrufa preclud- (17:55) from the wall of the tunnel by hand or with ed meaningful assessment of possible dif- a small hand-held net. On capture the bats were placed in cloth bags (5 to 10 per bag) and transported ferences in flight speeds of males and fe- 75 m to a simulated cave passage or flyway located males. beneath the forest canopy in an area clear of under- story shrubbery. The flyway was a tunnel comprised DISCUSSION of plastic tarps that was 20 m long, 1.5 m wide, and 1.5 m high. Gas lanterns and a 12-volt light were placed at the beginning of the flyway and provided Wilson (1997) reported that flight speeds light that made bats visible during flight. As suggest- of bats under captive conditions usually are ed by Kennedy et al. (1977), the lights probably within the range of 2.2 to 4.4 m/s. For each Flight speeds of three species of Neotropical bats 479 TABLE 1. Flight speed (m/s) and body mass g) of in several different-sized and shaped flight G. soricina, N. stramineus, and C. subrufa recorded in enclosures. Average flight speed was 3.39 Colima, Mexico m/s in a simulated passage for bats moving Flight speed Body mass n Sex between two feeders at opposite ends of 0 SD Range 0 SD a U-shaped flyway 14 m long; average in- G. soricina stantaneous speeds at midsections of fly- 26 YY 4.85 1.43 2.7–7.6 10.3 1.0 14 XX 4.80 1.57 3.2–7.9 10.8 1.8 ways of several lengths ranged from 4.63 to N. stramineus 8.29 m/s, with some variation attributed to 40 YY 2.84 0.79 1.3–4.7 5.6 0.8 differences among enclosures, among indi- 23 XX 2.39 0.53 0.9–3.3 5.6 0.7 viduals, and between nights for individual C. subrufa bats. He recorded average speeds of 3.12 3 YY 3.67 0.46 3.2–4.1 14.3 1.2 3 XX 3.52 0.85 2.8–4.5 14.3 1.5 and 3.31 m/s for Glossophaga commissari- si and G. longirostris, respectively, flying from feeder to feeder in the U-shaped fly- of the three species reported herein, some way; instantaneous average speeds were individuals flew faster than represented by 4.38 and 4.72 m/s, respectively. Lindhe this range (Table 1). For N. stramineus and Norberg and Winter (2006) recorded speeds C. subrufa, the fastest speeds recorded were of 1.23 to 7.52 m/s for two G. soricina. slightly greater than the 4.4 m/s, and aver- Speeds we recorded for G. soricina (Table age flight speeds for these two species were 1) are similar to those recorded for Glosso- well within the range indicated by Wil- phaga by these authors. son (1997). Several of the flight speeds of N. stramineus were slower than 2.2 m/s. Winter (1999) demonstrated that enclo- Many speeds of G. soricina were consider- sure size affects speeds of G. soricina. ably higher than the high-end value of 4.4 Mean speeds ranged from 4.6 m/s in a 7-m m/s, with even the averages of both males half-section of the 14-m U-turn tunnel (2 m and females being higher (i.e., 4.85 and high × 1 m wide) to 7.3 m/s in a 50-m flight 4.80 m/s, respectively).