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PubMed1999

Encephalization, adaptation and evolution of chiroptera: A statistical analysis with further evidence for bat monophyly.

As part of a large-scale study on brain morphometrics and adaptations in mammals, we addressed the problem of chiropteran evolution. A specific statistical framework was designed to test which of two competing hypotheses (bat monophyly vs. diphyly) is more strongly supported by quantitative brain data. Our analyses, based on 120 species, revealed that megabats and microbats were more closely related to each other than to primates, and illustrated the convergent adaptations of the brain of bats to similar trophic (i.e. feeding related) niches. Ecologically-corrected characters were then used to derive a new phylogeny which also supports the chiropteran clade. The monophyletic origin of bats is the preferred hypothesis to explain brain quantitative evolution in chiropterans and primates.

Adaptation, Physiological↗
PubMed1980

Brain center correlations among Chiroptera.

Correlations between progression indices of five categories of nuclei and brain centers indicate that Megachiroptera rely primarily on vision and olfaction while Microchiroptera rely primarily on audition. Among Microchiroptera, some rely more heavily on olfaction than on vision as a secondary sense, and vice-versa. There may have been compensatory effects, in the course of evolution, regarding the choice of the primary and secondary information channels.

Animals↗
PubMed1996

Karyotypic patterns of seven species of molossid bats (Molossidae, Chiroptera)

G- and C-banding patterns of seven species of the bat family Molossidae, Eumops glaucinus, E. perotis, Molossops abrasus, M. temminckii, Molossus ater, M. molossus, and Nyctinomops laticaudatus, were identified. Comparisons among the karyotypes of these species showed extensive homologies between E. perotis, M. ater, M. molossus, M. abrasus, and N. laticaudatus, demonstrating inter- and intrageneric conservatism, and a lesser degree of homologies in M. temminckii and E. glaucinus, reflecting intrageneric variation. Chromosomal variation was due to inversions, Robertsonian rearrangements, translocations, and variations in the location of constitutive heterochromatin and nucleolus organizer regions. The chromosome corresponding to No. 5 in the M. ater karyotype is discussed. We suggest that the Nyctinomops and Molossops karyotypes represent the primitive condition and that Molossus and Eumops have derived karyotypes.

Animals↗
PubMed1993

Digital morphology in the Chiroptera: the passive digital lock.

Most bats hang from their hindlimb digits for extended periods of time during a variety of activities. Many species possess digital locking mechanisms consisting of modified digital flexor tendons and tendon retinacula. When the digits are flexed, scales or tubercles on the tendon surface engage transverse ribs which invest the inner surfaces of the tendon retinacula. This locks the tendon in place and prevents the digit from extending. Theoretically, by locking the digits during hanging, energy normally spent maintaining contraction of the digital flexor muscles is conserved. In this study, digits from 10 species of bats from 5 families were examined by dissection and scanning electron microscopy. Variation in digital morphology was observed in species that exhibit ecological diversity. It is proposed that hibernation and body weight are important selection pressures for possession of the passive digital lock. In nonhibernating species the mechanism may be present, modified or absent. The passive digital lock is absent in the vampire bats, a group whose feeding habits require substantially altered forms of locomotion. It is hypothesized that the passive digital lock has helped enable many species of bats to occupy habitats inaccessible to most other animals and that species lacking it may exhibit alternative mechanisms that allow them to hang in an energy-efficient manner.

Animals↗
PubMed2005

Testing the hindlimb-strength hypothesis: non-aerial locomotion by Chiroptera is not constrained by the dimensions of the femur or tibia.

In the evolution of flight bats appear to have suffered a trade-off; they have become poor crawlers relative to terrestrial mammals. Capable walking does occur in a few disparate taxa, including the vampire bats, but the vast majority of bats are able only to shuffle awkwardly along the ground, and the morphological bases of differences in crawling ability are not currently understood. One widely cited hypothesis suggests that the femora of most bats are too weak to withstand the compressive forces that occur during terrestrial locomotion, and that the vampire bats can walk because they possess more robust hindlimb skeletons. We tested a prediction of the hindlimb-strength hypothesis: that during locomotion, the forces produced by the hindlimbs of vampire bats should be larger than those produced by the legs of poorly crawling bats. Using force plates we compared the hindlimb forces produced by two species of vampire bats that walk well, Desmodus rotundus (N=8) and Diaemus youngi (N=2), to the hindlimb forces produced during over-ground shuffling by a similarly sized bat that is a poor walker (Pteronotus parnellii; N=6). Peak hindlimb forces produced by P. parnellii were larger (ANOVA; P<0.05; N=65) and more variable (93.5+/-36.6% body weight, mean +/- s.d.) than those of D. rotundus (69.3+/-8.1%) or D. youngi (75.0+/-6.2%). Interestingly, the vertical components of peak force were equivalent among species (P>0.6), indicating similar roles for support of body weight by the hindlimbs in the three species. We also used a simple engineering model of bending stress to evaluate the support capabilities of the hindlimb skeleton from the dimensions of 113 museum specimens in 50 species. We found that the hindlimb bones of vampires are not built to withstand larger forces than those of species that crawl poorly. Our results show that the legs of poorly crawling bats should be able to withstand the forces produced during coordinated crawling of the type used by the agile vampires, and this indicates that some mechanism other than hindlimb bone thickness, such as myology of the pectoral girdle, limits the ability of most bats to crawl.

Analysis of Variance↗
PubMed2005

Functional and structural optimization of the respiratory system of the bat Tadarida brasiliensis (Chiroptera, Molossidae): does airway geometry matter?

We studied structure and function of the respiratory system in the bat Tadarida brasiliensis and compared it with those of two species of rodents, Abrothrix andinus and A. olivaceus. Tadarida brasiliensis had lower resting oxygen consumption, but higher maximum oxygen consumption and aerobic scope, than the rodents. The blood-gas barrier of the bat was thinner and its relative lung size was larger; however, alveolar surface density was similar among the three species. In consequence, T. brasiliensis has an oxygen diffusion capacity two or three times higher than that of the rodents. In Tadarida brasiliensis the characteristics of the lung were accompanied by geometrical changes in the proximal airway, such as high physical optimization as a consequence of small variations in the symmetry and the scaling ratio of the bronchial diameters. These may constitute an efficient way to save energy in respiratory mechanics and are the first report of airway adjustments to decrease entropy generation in bats.

Animals↗
PubMed1993

What ears do for bats: a comparative study of pinna sound pressure transformation in chiroptera.

Using a moveable loudspeaker and an implanted microphone, we studied the sound pressure transformation of the external ears of 47 species of bats from 13 families. We compared pinna gain, directionality of hearing and interaural intensity differences (IID) in echolocating and non-echolocating bats, in species using different echolocation strategies and in species that depend upon prey-generated sounds to locate their targets. In the Pteropodidae, two echolocating species had slightly higher directionality than a non-echolocating species. The ears of phyllostomid and vespertilionid species showed moderate directionality. In the Mormoopidae, the ear directionality of Pteronotus parnellii clearly matched the dominant spectral component of its echolocation calls, unlike the situation in three other species. Species in the Emballonuridae, Molossidae, Rhinopomatidae and two vespertilionids that use narrow-band search-phase echolocation calls showed increasingly sharp tuning of the pinna to the main frequency of their signals. Similar tuning was most evident in Hipposideridae and Rhinolophidae, species specialized for flutter detection via Doppler-shifted echoes of high-duty-cycle narrow-band signals. The large pinnae of bats that use prey-generated sounds to find their targets supply high sound pressure gain at lower frequencies. Increasing domination of a narrow spectral band in echolocation is reflected in the passive acoustic properties of the external ears (sharper directionality). The importance of IIDs for lateralization and horizontal localization is discussed by comparing the behavioural directional performance of bats with their bioacoustical features.

Animals↗
PubMed2001

Composition and structure of helminth communities in two populations of Pipistrellus pipistrellus (Chiroptera: Vespertilionidae) from Spain.

The community composition and structure of helminths of Pipistrellus pipistrellus (Schreber, 1774) from two widely separated Spanish localities, El Saler (n = 42) and the San Pedro pothole (n = 34), were determined and compared. Five species of trematodes, Plagiorchis (Plagiorchis) sp., Lecithodendrium (Lecithodendrium) linstowi Dollfus, 1931, Prosthodendrium (Prosthodendrium) sp., Pycnoporus heteroporus (Dujardin, 1845) and Parabascus semisquamosus (Braun, 1900), and one species of cestode, Hymenolepis pipistrelli López-Neyra, 1941, were found. The two bat populations harboured the same helminth species and showed the same trematode dominance, but the most important differences between the two helminth community structures were attributable to L. (L.) linstowi and H. pipistrelli. The mean species richness in the two localities was not significantly different. The mean number of helminth species per infected bat, mean infracommunity abundance and mean infracommunity diversity showed significant differences between both localities. The number of helminths per bat in both populations displayed an aggregated distribution. Results indicate that the different characteristics of the P. pipistrellus foraging area in both localities are important in determining the composition and structure of helminth communities in this bat species. This is the first study of a Palaearctic bat helminth community.

Animals↗
PubMed1986

The primary structure of a mouse-eared bat (Myotis velifer, Chiroptera) hemoglobin.

The hemoglobin of the Mouse-Eared Bat Myotis velifer consists of one component. We present the primary structures of the alpha- and beta-globin chains which have been separated by chromatography on carboxymethyl-cellulose CM-52. The sequences have been determined by Edman-degradation with the film technic or the gas phase method, using the native chains and the tryptic peptides, as well as the C-terminal prolyl-peptides obtained by acid hydrolysis of the Asp-Pro-bonds. Compared to the corresponding human chains we found only 13 substitutions in the alpha-chains, but 27 in the beta-chains. The amino-acid residues substituted in the alpha-chains are not involved in any contacts, whereas in the beta-chains, one exchange involves a heme contact, three alpha 1/beta 1- and one alpha 1/beta 2-contacts, the latter [beta 43(CD2)-Glu----Thr] brings for the first time threonine in this position of the beta-chains. Comparison with the Egyptian Fruit Bat (Rousettus aegyptiacus) shows 12 and 25 substitutions in the alpha- and beta-chains, respectively, suggesting a large phylogenetic distance between Micro- and Megachiroptera. We consider this primary structure as a contribution towards solving the problem of the origin of bats and their relation to primates.

Amino Acid Sequence↗
PubMed1987

Primary structure and functional properties of the hemoglobin from the free-tailed bat Tadarida brasiliensis (Chiroptera). Small effect of carbon dioxide on oxygen affinity.

The hemoglobin of the Free-Tailed Bat Tadarida brasiliensis (Microchiroptera) comprises two components (Hb I and Hb II) in nearly equal amounts. Both hemoglobins have identical beta-chains, whereas the alpha-chains differ in having glycine (Hb I) or aspartic acid (Hb II) in position 115 (GH3). The components could be isolated by DEAE-Sephacel chromatography and separated into the globin chains by chromatography on carboxymethyl-cellulose CM-52. The sequences have been determined by Edman degradation with the film technique or the gas phase method (the alpha I-chains with the latter method only), using the native chains and tryptic peptides, as well as the C-terminal prolyl-peptide obtained by acid hydrolysis of the Asp-Pro bond in the beta-chains. The comparison with human hemoglobin showed 18 substitutions in the alpha-chains and 24 in the beta-chains. In the alpha-chains one amino-acid exchange involves an alpha 1/beta 1-contact. In the beta-chains one heme contact, three alpha 1/beta 1- and one alpha 1/beta 2-contacts are substituted. A comparison with other chiropteran hemoglobin sequences shows similar distances to Micro- and Megachiroptera. The oxygenation characteristics of the composite hemolysate and the two components, measured in relation to pH, Cl-, and 2,3-bis-phosphoglycerate, are described. The effect of carbon dioxide on oxygen affinity is considerably smaller than that observed in human hemoglobin, which might be an adaptation to life under hypercapnic conditions.

Amino Acid Sequence↗
PubMed1987

The primary structure of the pallid bat (Antrozous pallidus, Chiroptera) hemoglobin.

The complete primary structure of the hemoglobin from the Pallid Bat (Antrozous pallidus, Microchiroptera) is presented. This hemoglobin consists of two components with identical amino-acid sequences, differing, however, in the N-terminus which is formylated in 12.5% of the beta-chains. The alpha- and beta-chains were separated by reversed phase high performance liquid chromatography. The sequences of both chains were established by automatic Edman degradation with the film technique or gas phase method using the native chains and the tryptic peptides. The formylation of a part of the N-terminal peptide of the beta-chains was determined by mass spectrometric examination. Compared to the corresponding human chains we found 14 substitutions in the alpha-chains and 21 in the beta-chains. One substitution in the alpha-chains and three in the beta-chains are involved in alpha 1/beta 1-contacts. Among these the exchange beta 123(H1)Thr----Cys is unusual because cysteine was so far not found in this position of mammalian beta-chains. Compared to the hemoglobin of Myotis velifer, another representative of the family Vespertilionidae, 5 residues are replaced in the alpha-chains and 18 in the beta-chains.

Amino Acid Sequence↗
PubMedDate not supplied

Volatile compounds in shoulder gland secretions of male flying foxes, genus Pteropus (Pteropodidae, Chiroptera).

The shoulder gland secretions of captive males of the Indian flying fox (Pteropus giganteus), the little golden-mantled flying fox (P. pumilus), the island flying fox (P. hypomelanus), and the large flying fox (P. vampyrus) were examined by gas chromatography-mass spectrometry. Sixty-five compounds, including hydrocarbons, carboxylic acids, alcohols, aldehydes, ketones, esters, and amides, were identified among the four species. Many of these compounds, such as squalene, cholesterol, and C5-C16 straight- and branched-chain carboxylic acids, are typical of tetrapod epidermal products. Aldehydes, which were detected in all four Pteropus species, and some straight- and branched-chain ketones, which were detected in P. hypomelanus and P. pumilus, are known from other mammalian skin glands. Acetophenone, 4-acetoxyacetophenone, and 4-hydroxyacetophenone were observed in P. pumilus; the last compound comprised 37.1% of the total ion current. 2,3-Butanediol, a prominent component (5.2-19.3%) in the secretions of P. giganteus, P. hypomelanus, and P. pumilus, and C10 and C12 isopropyl esters and C10-C14 1-methylbutyl esters, observed in P. hypomelanus and P. vampyrus, have not previously been reported from vertebrates. alpha-Methyl-4-methoxybenzyl alcohol and dihydro-5-phenyl-2(3H)-furanone, from P. giganteus and P. pumilus, are new natural products. 1-Chloro-3-methyl-2-butene, another new natural product, and five C5 compounds exhibiting a similar isoprenoid structure were observed in P. giganteus. Striking contrasts were observed in the chemical profiles of the species we examined, with even general chemical classes differentially represented among them.

Alcohols↗