Myotis Occultus Research Articles

Richness and activity of arthropodophagous bats in an arid landscape of central México

The insectivorous bats of arid and semi-arid ecosystems have been poorly studied in Mexico. The aim of this work was to determine the richness and activity of insectivorous bats in arid landscapes of central Mexico over an annual cycle and identify the landscape and environmental features related to relative abundance patterns of bats. We carried out captures with mist nets and active acoustic monitoring in 10 transects, semi-active monitoring in eight stations, and passive monitoring in two desert grassland and scrub sites in Aguascalientes and Jalisco, from January to December 2012. The activity index of each insectivorous species was calculated and related to the local features at the landscape level. An automated monitoring weather station was established in the study area to explore the potential effect of environmental conditions on activity through time. Two species of insectivorous bats were captured: Myotis melanorhinus and Myotis occultus; seven additional species belonging to three families were acoustically identified, with Tadarida brasiliensis as the most active species. Activity levels were concentrated during the spring (April-June) and from mid-summer to late fall (August-October). The null activity in winter (January-March) and the increased activity of T. brasiliensis in the spring suggest migratory movements of the species in the region. The highest values of the activity index were recorded in the proximity of water bodies and ravines. Overall activity was recorded at temperatures between 6.8 and 20.3 °C, and under wind speeds between 1.6 and 24.1 km/h.

Day Roosts of Myotis (Mammalia: Chiroptera) in an Arid Riparian Corridor in Southwestern New Mexico

Riparian corridors in the western United States harbor diverse biological communities that are threatened by reductions in available freshwater, changes to natural disturbance regimes, and anthropogenic disturbances. Limited data are available about bat roosts in riparian habitats in the southwestern United States. We examined day roosts of 3 sympatric Myotis species, the southwestern myotis (Myotis auriculus), Arizona myotis (Myotis occultus), and Yuma myotis (Myotis yumanensis), along the Mimbres River in southwestern New Mexico. We tracked 3 M. auriculus, 3 M. occultus, and 1 M. yumanensis to 16 Fremont's cottonwoods (Populus fremontii), 2 velvet ash (Fraxinus velutina), and 1 Arizona walnut (Juglans major) within the floodplain. Roost trees generally had a greater diameter and greater likelihood of exhibiting fire damage than nearby trees. Moreover, several roosts were in tree species not previously known to be used by these bat species, and bats did not roost in human-made structures in this arid riparian corridor.

First Record of Myotis occultus (Vespertilionidae) in the State of Guanajuato, Mexico

The bat, Myotis occultus (Vespertilionidae) is a rare and small-sized bat. The known distribution of M. occultus extends from the semi-arid areas of the southwestern United States down as far as the middle half of Mexico, not having beeing previously registered in the state of Guanajuato in Mexico. In August 2008 and February 2013, we collected bats using mist nets in the locality of Llanos de Santa Ana located within the municipality of Guanajuato, Gto., Mexico. We collected twelve specimens of M. occultus at the entrance of an abandoned mine in the municipality of Guanajuato, which represents the first documented record of the species in Guanajuato and confirms its presence for the state as predicted by potential distribution maps of the species. It is a small-sized bat, with few records in Mexico and, according to previous studies, its distribution is confirmed for the states of Chihuahua, Zacatecas, Mexico State, Mexico City, and now Guanajuato.

Population Characteristics of Big Brown Bat and Arizona Myotis Using Artificial Roosting Structures in Northern Arizona

Big brown bats (Eptesicus fuscus) and a close relative of Arizona myotis (Myotis occultus), the little brown bat (Myotis lucifugus) in the eastern United States, are among those species experiencing unprecedented population declines related to white-nose syndrome (WNS). Determining population characteristic baselines for big brown bat and Arizona myotis is paramount in detecting population declines before they reach critical levels. We targeted 2 bat species strongly associated with ponderosa pine forests in northern Arizona. Big brown bats and Arizona myotis readily utilize human-made structures and have a cosmopolitan distribution across the ponderosa pine (Pinus ponderosa) ecosystem of northern Arizona (Adams 2003). Between 2005 and 2012 we installed artificial bat roosts at Camp Navajo near Flagstaff, Arizona. We captured bats at these roosting structures and marked them using modified bird bands. We established baseline population characteristics on Camp Navajo by utilizing a 7-year mark-and-recapture data set. We also provide a measure of population status that may be compared across temporal scales within the study area. In essence, this study provides the basis for an early warning system for WNS in Arizona.

Bats in Riparian-Restoration Sites Along the Lower Colorado River, Arizona

During 2007–2010, we captured the western red bat (Lasiurus blossevillii) and Arizona myotis (Myotis occultus) in riparian-restoration areas along the lower Colorado River. Previously, the western red bat had not been reported along the lower Colorado River and the Arizona myotis was presumed to be extirpated from that area.Durante los años 2007–2010, capturamos el murciélago rojo occidental (Lasiurus blossevillii) y el murciélago de Arizona (Myotis occultus) en sitios de restauración riparia ubicados a lo largo del río Colorado. El murciélago rojo occidental no ha sido registrado en el tramo inferior del río Colorado y el murciélago de Arizona se presumía ausente del área.

Use of Bridges by Bats (Mammalia: Chiroptera) in the Rio Grande Valley, New Mexico

During a 2-year study, we documented eight species of bats using bridges in the lower Rio Grande Valley of New Mexico. Of 17 bridges surveyed, 15 (88%) contained day-roosting bats and ≥8 bridges (47%) contained maternity colonies with one or more species, including the Arizona myotis (Myotis occultus), Yuma myotis (Myotis yumanensis), and Brazilian free-tailed bat (Tadarida brasiliensis). The pallid bat (Antrozous pallidus), big brown bat (Eptesicus fuscus), silver-haired bat (Lasionycteris noctivagans), California myotis (Myotis californicus), and fringed myotis (Myotis thysanodes) roosted infrequently in bridges. Use of bridges by day-roosting bats differed seasonally, with most individuals occupying bridges April–October. During November–March, relatively few individuals of only three species (L. noctivagans, M. yumanensis, and T. brasiliensis) occupied bridges. Individuals roosted at many sites in bridges, but 99.9% roosted in narrow cracks and crevices. A total of 36,629 day-roosting bats was counted, with 99.8% observed in bridges constructed from timbers and 0.2% observed in I-beam bridges constructed from concrete, metal, or both. Paucity of bats in I-beam bridges reflected lack of narrow spaces. Our study demonstrates that some bridges represent important roosting sites for bats in southern New Mexico. Bridges throughout the southwestern United States likely serve similar life-history functions for bats and should be managed as a resource, especially those occupied by maternity colonies or large numbers of individuals.

Ectoparasites of the Occult Bat,Myotis occultus(Chiroptera: Vespertilionidae)

Only a single previous study has examined ectoparasites of the occult bat (Myotis occultus), from which only 2 species of fleas were identified. For our study, we examined 202 individuals, 52 fresh hosts and 150 museum specimens, from New Mexico and southern Colorado for ectoparasites. We recorded 2158 ectoparasites, 634 from fresh hosts and 1524 from museum specimens. Ectoparasites belonged to 10 families and 13 genera of insect or acari and represent new host and locality records. In general, ectoparasites collected from fresh hosts and museum specimens were represented by 4 major species of mite: Macronyssus crosbyi, Alabidocarpus calcaratus, Acanthophthirius lucifugus, and Alabidocarpus nr. eptesicus. From our study, we found fresh hosts to have significantly greater prevalence values for Myodopsylla gentilis (flea), Chiroptonyssus robustipes (mite), and Leptotrombidium myotis (chigger), whereas museum specimens had significantly greater prevalence values for A. calcaratus (mite) and A. nr. eptesicus (mite). There were no significant differences between prevalence values for 4 mites including M. crosbyi, A. lucifugus, Pteracarus nr. minutus, and Cryptonyssus sp. Our study represents the only extensive study of ectoparasites on M. occultus and provides evidence for the importance of examining fresh hosts and museum specimens in future ectoparasite studies.

Coronavirus Antibodies in Bat Biologists

Coronavirus Antibodies in Bat Biologists

Detection of Group 1 Coronaviruses in Bats in North America

The epidemic of severe acute respiratory syndrome (SARS) was caused by a newly emerged coronavirus (SARS-CoV). Bats of several species in southern People's Republic of China harbor SARS-like CoVs and may be reservoir hosts for them. To determine whether bats in North America also harbor coronaviruses, we used reverse transcription-PCR to detect coronavirus RNA in bats. We found coronavirus RNA in 6 of 28 fecal specimens from bats of 2 of 7 species tested. The prevalence of viral RNA shedding was high: 17% in Eptesicus fuscus and 50% in Myotis occultus. Sequence analysis of a 440-bp amplicon in gene 1b showed that these Rocky Mountain bat coronaviruses formed 3 clusters in phylogenetic group 1 that were distinct from group 1 coronaviruses of Asian bats. Because of the potential for bat coronaviruses to cause disease in humans and animals, further surveillance and characterization of bat coronaviruses in North America are needed.

SYSTEMATICS OF MYOTIS OCCULTUS(CHIROPTERA: VESPERTILIONIDAE) INFERRED FROM SEQUENCES OF TWO MITOCHONDRIAL GENES

The systematic relationship between Myotis lucifugus carissima and Myotis occultus has been the subject of multiple studies. Although several studies, including a recent allozyme study, concluded that M. occultus is a subspecies of M. lucifugus, this view has not been universally accepted. We reexamined the relationships of these 2 taxa by sequencing the mitochondrial cytochrome-b (cyt-b) and cytochrome oxidase II (COII) genes of specimens from the allozyme study. The results suggest that M. occultus represents an evolutionarily distinct monophyletic lineage and provide support to arguments that M. occultus is a distinct species.

Taxonomic Status of Myotis occultus

The taxonomic status of the Arizona myotis ( Myotis occultus ) is uncertain. Although the taxon was described as a distinct species and currently is regarded as such by some authors, others have noted what they interpreted as intergradation with the little brown bat ( M. lucifugus carissima ) near the Colorado-New Mexico state line. In this study, we used protein electrophoresis to compare bats of these nominal taxa. We examined 20 loci from 142 specimens referable to M. occultus and M. lucifugus from New Mexico, Colorado, and Wyoming. Nine of the 20 loci were polymorphic. Results show that there were high similarities among samples, no fixed alleles, and minor divergence from Hardy-Weinberg equilibrium. Our results suggest that the two nominal taxa represent only one species and that M. occultus should be regarded as a subspecies of M. lucifugus .

Unusual Dentition in Myotis occultus

Unusual Dentition in Myotis occultus

A Maternity Colony of Myotis occultus

A Maternity Colony of Myotis occultus

Myotis occultus and Myotis yumanensis Breeding in New Mexico

There appears to be no record in the literature of the breeding of Myotis occultus . Cockrum (Trans. Kansas Acad. Sci., 58 : 495, 1955) listed none, nor have I found any other reference. A pregnant …

Remarks on Myotis occultus in California

Remarks on Myotis occultus in California