Microchiropteran Bats Research Articles

The functional anatomy of the rodent larynx in relation to audible and ultrasonic cry production

Rodents are well known for the production of physically quite different audible and ultrasonic cries. Both of these cries are known to be produced in the larynx, but the anatomy of the larynx is practically unknown, it thus being difficult to analyse how the cries are produced. The anatomy of the larynx of Mus musculus is described in detail and is found to be essentially typical of that of other mammals that can fix the thorax and make independent use of the forelimbs. Unlike the larynx of microchiropteran bats, no modifications for ultrasound production are apparent, although the laryngeal structure is ideal for the production of audible cries. However, the audible and ultrasonic cries differ so markedly that they are unlikely to be produced by the same mechanism. The lack of laryngeal specialization therefore makes the ultrasound production mechanism largely an enigma.

Functional osteology and myology of the wing of the dog-faced bat Rousettus aegyptiacus (�. Geoffroy) (Mammalia, Chiroptera)

The muscles moving, directly or indirectly, the anterior extremity, the action of the muscles, and the skeletal elements on which these muscles attach are described in Rousettus aegyptiacus (E. Geoffrey) (Pteropodidae). On the whole the morphological pattern and action of the muscles are the same as in microchiropteran bats, though there are some differences. The description, high-speed films, and flash photographs are made the basis of functional aspects. 1. Rousettus aegyptiacus has a very low midventral sternal ridge. The sternum also has three keels, on which a median ligamentous sheet attaches. This ligament and the keels form an enlarged area of attachment for the pectoralis muscle without any appreciable increase in weight. 2. The cross sections of the digits are described. The digits are shaped in such a way as to have their largest diameters in those planes where the bending forces are largest, thereby keeping low the weight while still possessing rigidity in the important directions. However, this flattening of the digits in certain planes is less pronounced in Rousettus aegyptiacus than in many micro chiropteran species. 3. The metacarpals are short in relation to the entire digits, as compared with many microchiropteran species. This permits the bat to get a potentially high camber of the wing during the downstroke. During the later part of the upstroke the digits are highly flexed, folding the hand wing, to reduce the drag. A relatively short metacarpal contributes to giving a small area of the hand wing meeting the airstream during the upstroke. 4. The rigid unit formed by the second and third digits is very broad in megachiropteran bats. Musculus palmaris longus is very powerful in Rousettus aegyptiacus in comparison with most microchiropteran bats so far investigated. These features contribute to giving high camber of the wing. 5. Rousettus aegyptiacus has a powerful flexor muscle of the radius, Musculus brachio-radialis, which is unusual in microchiropteran bats. 6. Megachiropteran bats, so far investigated, possess more powerful membrane muscles than do the small microchiropteran bats.

Studies of auditory neurophysiology in non-echolocating bats, and adaptations for echolocation in one genus, Rousettus

1. Six species of New Guinea megachiropteran bats have been studied electrophysiologically. Five are non-echolocating, one (Rousettus amplexicaudatus) has evolved an echolocation capability independent of echolocating microchiropteran bats. The purpose of the study was to compare auditory responses of non-echolocating bats with those of the echolocating bats studied to date, and to determine what adaptations have occured in Rousettus to permit echolocation. 2. Evoked potentials were recorded from the posterior colliculus and more peripheral levels in anesthetized preparations. 3. Emitted sounds of each species were recorded and are described (Fig. 1). All bats emit sounds at frequencies up to 60 kc/s or higher. 4. All species were found to have similar audiograms, broadly tuned with greatest sensitivity around 45–50 kc/s. Rousettus was unexceptional (Fig. 2). No “off”-responses were seen. 5. All species showed capabilities of frequency resolution comparable to that seen in microchiropteran bats emitting FM pulses (Fig. 3). Rousettus was not conspicuously different in this respect. 6. The non-echolocating bats showed very slow recovery of responsiveness following an initial sound (Fig. 4) and poor ability to follow trains of stimuli at a high repetition rate compared with echolocating bats. Rousettus differed dramatically from its non-echolocating relatives in recovering quickly and in following with little reduction in response amplitude at a frequency of 200/sec. In all species, recovery rate was inversely related to stimulus intensity. In Rousettus even stimuli 20–30 db fainter than an initial sound elicited good responses at 2 msec or greater intervals (Fig. 5). 7. Rousettus and its non-echolocating relatives showed generally smaller changes in sensitivity with changes in stimulus angle than are seen in microchiropteran bats. Greatest sensitivity was uniformly at 60–80° to one side, with relatively reduced sensitivity to sounds coming from directly in front, consistent with pinna position and with the lack of necessity for hearing sounds from directly ahead. Rousettus did not differ in any apparent way from the non-echolocating bats (Figs. 7, 8). 8. It is concluded that non-echolocating bats, like other small mammals, lack several of the auditory adaptations considered to be adaptations for echolocation: sharp restriction of sensitivity to the region of emitted sounds, sensitivity at extremely high frequencies, fast temporal resolution, facilitation of responsiveness to the second of a pair of sounds, and sharply directional hearing in front of the bats. 9. The only conspicuous difference between Rousettus and its non-echolocating relatives was in recovery rate. This suggests that fast temporal resolution is perhaps the most important of the necessary neural adaptations for echolocation.

Bat wing structures important for aerodynamics and rigidity (Mammalia, chiroptera)

From comparisons between bat wing structures and aerofoils and high-lift devices with known aerodynamic data, from the aeronautical literature, deductions are made regarding the function of some bat wing structures. Special arrangements in the hand wing add to rigidity and reduce the demands for powerful muscles and thick digits, thereby reducing the mass of the wing. 1. The anterior part of the wing, formed by the membrane parts anterior to the arm and third digit, is proportionally broad in megachiropteran bats as well as in many broad-winged microchiropteran bats. These parts can be lowered by the thumb and by pronation of the manus, and may together function as a leading edge flap. Leading edge flaps of aeroplanes permit, when lowered, higher angles of attack without separation, and thus higher lift coefficients. The leading edge in bats is very sharp, which increases the effectiveness of the leading edge flap. 2. The Reynolds number of bat wings lies in an interesting range, where the lift coefficient can be improved by induced turbulence of the boundary layer. The arm and digits, projecting markedly over the dorsal surface of the wing, and hair may function as turbulence generators. 3. The tension forces of the membrane on the digits have different effects upon the different digits, depending on the tautness of the surrounding membrane parts. The second digit and distal phalanx of the third digit are exposed mostly to bending in the membrane plane. The phalanges of the fourth and fifth digits are exposed to large dorsoventral bending. 4. Two arrangements add to relieving the distal part of the wing of large tension forces, thereby reducing the demand for a powerful extensor muscle of the distal phalanx (-ges) of the third digit: 1. The fourth and fifth digits act to alter the direction of tension. 2. By splitting the wing membrane in several parts by the digits, the second and third phalanges (the second in fruit-bats) of the third digit, which constitute the distal part of the wing's leading edge, are exposed to tension forces transformed from forces only from the nearest patagium. If the wing membrane would be outstretched only by one digit, as was the case in pterosaurs, the leading edge digit would have to resist the tension forces transformed from forces from the entire membrane posterior to the arm. 5. The fourth digit is angled in such a way that the proximal part of the membrane between the third and fourth digits is kept very taut, and the fourth metacarpophalangeal and interphalangeal joints are held very steady without any need of large muscular forces.

Physiological responses to high environmental temperatures in three species of microchiropteran bats

1. 1. Body temperature ( T B ), oxygen consumption and evaporative water loss were measured at ambient temperatures ( T A 's) between 35° and 45°C in three bats, Myotis yumanensis, Tadarida brasiliensis and Antrozous pallidus. 2. 2. At T A 's up to 40°C, T B 's rose gradually and were maintained 1–2.5°C above T A without apparent distress. When T A = 41.5°C, T B was kept below 42.5°C by intermittent panting, salivating and licking. 3. 3. A T B of 43.5°C was lethal within 1 hr. When T A > 42.5°C survival depended upon maintaining T B ⩽ T A by extensive evaporative cooling and minimizing metabolic heat production by remaining quiet. Resting bats dissipated up to 200 per cent of metabolic heat by evaporation. Elevated humidity increased heat stress.

Temperature Regulation in the Vampire Bat, Desmodus rotundus

Previous articleNext article No AccessTemperature Regulation in the Vampire Bat, Desmodus rotundusCharles P. Lyman, and William A. WimsattCharles P. Lyman Search for more articles by this author , and William A. Wimsatt Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by Volume 39, Number 2Apr., 1966 Article DOIhttps://doi.org/10.1086/physzool.39.2.30152422 Views: 9Total views on this site Citations: 16Citations are reported from Crossref Journal History This article was published in Physiological Zoology (1928-1998), which is continued by Physiological and Biochemical Zoology (1999-present). Copyright 1966 University of ChicagoPDF download Crossref reports the following articles citing this article:Guangxu Du, Yuhua Tian, Zhihao Yao, Simon Vu, Jie Zheng, Longhui Chai, KeWei Wang, Shilong Yang A specialized pore turret in the mammalian cation channel TRPV1 is responsible for distinct and species-specific heat activation thresholds, Journal of Biological Chemistry 295, no.2828 (Jul 2020): 9641–9649.https://doi.org/10.1074/jbc.RA120.013037Mark A. Hayes, Antoinette J. Piaggio, Danilo Russo Assessing the potential impacts of a changing climate on the distribution of a rabies virus vector, PLOS ONE 13, no.22 (Feb 2018): e0192887.https://doi.org/10.1371/journal.pone.0192887Teri J. Orr, Marlene Zuk Does delayed fertilization facilitate sperm competition in bats?, Behavioral Ecology and Sociobiology 67, no.1212 (Jul 2013): 1903–1913.https://doi.org/10.1007/s00265-013-1598-2 Shane K. Maloney , Gary N. Bronner , and Rochelle Buffenstein Thermoregulation in the Angolan Free‐Tailed Bat Mops condylurus: A Small Mammal That Uses Hot Roosts S. K. Maloney, G. N. Bronner, and R. Buffenstein, Physiological and Biochemical Zoology 72, no.44 (Jul 2015): 385–396.https://doi.org/10.1086/316677Cristina Busch Consumption of blood, renal function and utilization of free water by the vampire bat, Desmodus rotund us, Comparative Biochemistry and Physiology Part A: Physiology 90, no.11 (Jan 1988): 141–146.https://doi.org/10.1016/0300-9629(88)91019-5Gary P. Bell, George A. Bartholomew, Kenneth A. Nagy The roles of energetics, water economy, foraging behavior, and geothermal refugia in the distribution of the bat,Macrotus californicus, Journal of Comparative Physiology B 156, no.33 (May 1986): 441–450.https://doi.org/10.1007/BF01101107D.J. Howell Weight loss and temperature regulation in clustered versus individual Glossophaga soricina, Comparative Biochemistry and Physiology Part A: Physiology 53, no.22 (Jan 1976): 197–199.https://doi.org/10.1016/S0300-9629(76)80055-2Eugene H Studier, Michael J O'Farrell Biology of Myotis thysanodes and M. lucifugus (Chiroptera: Vespertilionidae)—I. Thermoregulation, Comparative Biochemistry and Physiology Part A: Physiology 41, no.33 (Mar 1972): 567–595.https://doi.org/10.1016/0300-9629(72)90014-XEugene H Studier, Don E Wilson Thermoregulation in some neotropical bats, Comparative Biochemistry and Physiology 34, no.22 (May 1970): 251–262.https://doi.org/10.1016/0010-406X(70)90164-7Wayne H. Davis Hibernation: Ecology and Physiological Ecology, (Jan 1970): 265–300.https://doi.org/10.1016/B978-0-12-758001-2.50013-7Charles P. Lyman Thermoregulation and Metabolism in Bats**Since this chapter was submitted an excellent article by B. K. McNab, entitled “The economics of temperature regulation in neotropical bats,” has appeared in Comparative Biochemistry and Physiology, Vol. 31, pp. 227–268, 1969, and the reader is referred to this for further information., (Jan 1970): 301–330.https://doi.org/10.1016/B978-0-12-758001-2.50014-9Brian K. McNab The economics of temperature regulation in neutropical bats, Comparative Biochemistry and Physiology 31, no.22 (Oct 1969): 227–268.https://doi.org/10.1016/0010-406X(69)91651-XWilliam N. McFarland, William A. Wimsatt Renal function and its relation to the ecology of the vampire bat, Desmodus rotundus, Comparative Biochemistry and Physiology 28, no.33 (Mar 1969): 985–1006.https://doi.org/10.1016/0010-406X(69)90543-XRoger E. Carpenter, Jeffrey B. Graham Physiological responses to temperature in the long-nosed bat, Leptonycteris sanborni, Comparative Biochemistry and Physiology 22, no.33 (Sep 1967): 709–722.https://doi.org/10.1016/0010-406X(67)90764-5Paul Licht, Philip Leitner Physiological responses to high environmental temperatures in three species of microchiropteran bats, Comparative Biochemistry and Physiology 22, no.22 (Aug 1967): 371–387.https://doi.org/10.1016/0010-406X(67)90601-9Philip Leitner, John E. Nelson Body temperature, oxygen consumption and heart rate in the Australian false vampire bat, Macroderma gigas, Comparative Biochemistry and Physiology 21, no.11 (Apr 1967): 65–74.https://doi.org/10.1016/0010-406X(67)90115-6