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Trophic niche and diet of Natalus mexicanus (Chiroptera: Natalidae) in a tropical dry forest of Western Mexico

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Torres-Flores J. W. , Lopez-Wilchis R.

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nr 2

EN

Trophic specialization is an evolutionary pathway of niche partitioning and one of the main pillars of diversification that enables species coexistence. One of the major challenges in understanding the evolution of Neotropical bats is the ability to successfully examine trophic specialization in species that are widely distributed and coexist with many other species in complex communities. In this study Natalus mexicanus is examined as an example of an insectivorous bat commonly associated in communities made up of hundreds or thousands of individuals of several species. We analyzed the diet and feeding patterns of N. mexicanus through fecal examination, direct observation, and availability of potential food sources. Our data show that N. mexicanus is a substrate insectivore that forages among vegetation, mainly picking insects from surfaces while hovering or flying slowly, also following a hunting strategy known as ‘slow hawking’. In addition, this species has a special diet that is mainly composed of arachnids, a resource that is not commonly consumed by bats, allowing it to coexist with other species that have different feeding preferences.

2

Activity of insectivorous bats associated with cattle ponds at La Michilia Biosphere Reserve, Durango, Mexico: implications for conservation

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Lopez-Gonzalez C. , Gomez-Ruiz E. P. , Lozano A. , Lopez-Wilchis R.

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tom 17

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nr 1

EN

Most bats depend strongly on surface water to survive and reproduce, and thus it is a limiting resource in markedly seasonal environments, such as semiarid and temperate Mexico. Cattle ranching, an important activity in these areas has resulted in construction of rainwater reservoirs that may represent the only available surface water during the dry season. Using acoustic detectors we measured activity in cattle ponds at La Michilía Biosphere Reserve, Durango, Mexico to assess patterns of use by insectivorous bats. We tested for differences in activity between ponds and seasons, and for relationships between bat activity and a set of environmental and pond variables. Bat activity was significantly higher at ponds in the dry season; ponds were used by aerial, trawling, and gleaning insectivores. In the rainy season gleaners did not use ponds, and the other guilds used them less frequently. Larger, older ponds with aquatic vegetation were used more frequently in the dry season, whereas maximum temperature and moon phase affected use in the rainy season. Cattle ponds are common in rangelands and forests of northern Mexico; they constitute important foraging and drinking resources in an area that harbors the largest populations of insectivorous bats in the world

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Activity of Insectivorous bats is related to water availability in a highly modified Mexican temperate forest

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Lopez-Gonzalez C. , Lozano A. , Gomez-Ruiz E. P. , Lopez-Wilchis R.

Acta Chiropterologica

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2016

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tom 18

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nr 2

EN

Artificial ponds are important foraging and drinking resources for bats at La Michilía, a temperate forest with a marked seasonal drought. Using acoustic data we tested the hypothesis that water availability restricts bat activity in the dry season to ponds, whereas in the rainy season resources are widely available and therefore used throughout the area. We compared bat activity at six ponds with that of a 500-meter transect perpendicular to each pond. We predicted that activity would be higher at ponds in the dry season, whereas in the rainy season activity should be equal or higher at transects. Also, all species guilds would use ponds in the dry season, whereas gleaners, edge aerial and open aerial foragers would be more frequent at transects in the rainy season. In no instance activity was higher at transects than at ponds during the rainy season. Open areas showed little or no bat activity in the dry season, but were very active in the rainy season. One transect located in dense forest and one near human dwellings were active both seasons. Open aerial foragers were present mostly on ponds in the dry season, and on ponds and transects in the rainy season; edge aerial bats were common in ponds in the dry season, but rare in transects in the rainy season. Trawling bats used ponds and transects in both seasons; and gleaners were rare over ponds and transects in both seasons. Because bats use the local habitat differently depending on season and feeding guild, and climate and seasonality vary greatly in Mexican temperate forests, conservation strategies can not be generalized, but should be implemented on a case-by-case basis.

4

Conservation units of Pteronotus davyi (Chiroptera: Mormoopidae) in Mexico based on phylogeographical analysis

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Guevara-Chumacero L. M. , Lopez-Wilchis R. , Juste J. , Ibanez C. , Martinez-Mendez L. A. , Barriga-Sosa I. D. L. A.

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tom 15

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nr 2

EN

The analysis of genetic diversity is routinely used to identify divergent intraspecific units and contribute to the knowledge base of biodiversity. In this study we used mitochondrial genetic diversity to propose three management units (MUs) for the Davy's nakedbacked bat (Pteronotus davyi), an insectivorous forest-dwelling species that is distributed in tropical and subtropical areas of America. We analyzed a 555 bp segment of the mitochondrial DNA (mtDNA) control region in 144 individuals from 18 localities spread across the species distribution range in Mexico. Our results demonstrated that the mitochondrial genetic diversity of P. davyi is distributed in three MUs, namely Gulf North, Pacific-Veracruz and Southeastern, with conservation priority, due to either the high mitochondrial genetic diversity or the high proportion of unique haplotypes, for the following populations: Playa de Oro, Arroyo del Bellaco and Catemaco in the Pacific-Veracruz region, and Agua Blanca, Sardina, Calakmul, Calcehtok and Kantemó from the Southeastern region. The Gulf North unit shows signs of the recent loss of genetic variability. These proposed conservation units could be considered a generalized model of conservation for other species of cave-dwelling bats that share the same habitats.

5

Taxonomic status assessment of the Mexican Populations of Funnel-Eared Bats, Genus Natalus (Chiroptera: Natalidae)

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Lopez-Wilchis R. , Guevara-Chumacero L. M. , Perez N. A. , Juste J. , Ibanez C. , Barriga-Sosa I. D. L. A.

Acta Chiropterologica

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2012

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tom 14

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nr 2

EN

Due to its morphological conservatism, the American funnel-eared bats of the genus Natalus have had a complex taxonomic history. In Mexico only one species, N. stramineus, has traditionally been recognized. But recently a new endemic species, N. lanatus, was described in the region as a sympatric sibling species of N. stramineus. Natalus stramineus, with a geographic distribution extending from Mexico to Panama, was subsequently reassigned to N. mexicanus. In this study, we analyzed morphological and molecular characters to determine if two distinct species of funnel-eared bats (N. lanatus and N. mexicanus) occur in Mexico. We found that the proposed diagnostic morphological characters that separate the two taxa are not consistent and rarely differentiate between the two forms. Likewise, phylogenetic analyses do not support the separation of Natalus into two species in Mexico, but there is clearly geographic structure when all Mexican haplotypes are combined. The genetic distance between the haplotypes that could be ascribed to N. lanatus and N. mexicanus was typically within the range of conspecifics and not distinct species. To summarize, the results of both morphological and molecular analyses point to the presence of a single species of Natalus in Mexico.

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Evolutionary scenarios associated with the Pteronotus parnellii cryptic species-complex (Chiroptera: Mormoopidae)

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Lopez-Wilchis R. , Flores-Romero M. , Guevara-Chumacero L. M. , Serrato-Diaz A. , Diaz-Larrea J. , Salgado-Mejia F. , Ibanez I. , Salles L. O. , Juste J.

Acta Chiropterologica

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2016

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tom 18

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nr 1

EN

One of the major challenges to understanding the evolution of Neotropical bats concerns our capacity to successfully scrutinize phylogenetic patterns associated with cases of cryptic species complexes. In this study Pteronotus parnellii is examined as a selected example of a known lineage of mormoopid bat that potentially contains several cryptic species. A samples of 452 individuals from 83 different localities, essentially covering its entire mainland distribution, was evaluated using two genetic markers: COI (mitochondrial) and DBY (nuclear) genes. The findings of this study strongly support the hypothesis of high genetic variability and identify at least six lineages within P. parnellii, some of which appear to be cryptic species.

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Intraspecific evolutionary relationships and diversification patterns of the Wagner's Mustached bat, Pteronotus personatus (Chiroptera: Mormoopidae)

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Zarate-Martinez D. G. , Lopez-Wilchis R. , Ruiz-Ortiz J. D. , Barriga-Sosa I. D. L. A. , Diaz A. S. , Ibanez C. , Juste J. , Guevara-Chumacero L. M.

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tom 20

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nr 1

EN

Wagner's mustached bat (Pteronotus personatus) is an insectivorous bat distributed throughout America from Mexico to Brazil, which inhabits a range of habitats from rain forests to dry deciduous forests. There are two currently recognized species within the P. personatus complex, for which we examined 235 cytochrome oxidase I (COI) sequences and 138 cytochrome b (Cytb) sequences in order to explore its genetic variation in Mexico as well as in Central and South America. Our results reveal considerable differences in the genetic structure inside this species complex, indicating five genetic lineages: 1) Gulf of Mexico and the Mexican Pacific coastal plain to the Isthmus of Tehuantepec, 2) Southeastern Mexico, 3) Guatemala, 4) Guyana and Suriname-COI/Guyana and Venezuela-Cytb, and 5) Guyana, Suriname, French Guiana and Brazil. In addition, we used the isolation-with-migration coalescent method to estimate divergence times. The results indicate that vicariant events occurred roughly 1,624,000–2,450,000 years ago during the Early Pleistocene, wherein Central America was the center of two separate diversification processes, one toward Mexico and the other South America. The intraspecific lineages obtained for P. personatus demonstrate the need to reevaluate the species complex limits of this taxon.