A chromosome-level genome assembly of an avivorous bat species (Nyctalus aviator).

Currently, three carnivorous bat species, namely Ia io, Nyctalus lasiopterus, and Nyctalus aviator, are known to actively prey on seasonal migratory birds (hereinafter referred to as "avivorous bats"). However, the absence of reference genomes impedes a thorough comprehension of the molecular adaptations of avivorous bat species. Herein, we present the high-quality chromosome-scale reference genome of N. aviator based on PacBio subreads, DNBSEQ short-reads and Hi-C sequencing data. The genome assembly size of N. aviator is 1.77 Gb, with a scaffold N50 of 102 Mb, of which 99.8% assembly was anchored into 21 pseudo-chromosomes. After masking 635.1 Mb repetitive sequences, a total of 19,412 protein-coding genes were identified, of which 99.3% were functionally annotated. The genome assembly and gene prediction reached 96.1% and 96.1% completeness of Benchmarking Universal Single-Copy Orthologs (BUSCO), respectively. This chromosome-level reference genome of N. aviator fills a gap in the existing information on the genomes of carnivorous bats, especially avivorous ones, and will be valuable for mechanism of adaptations to dietary niche expansion in bat species.

Linking changes in individual specialization and population niche of space use across seasons in the great evening bat (Ia io).

BACKGROUND: The niche breadth of an animal population comprises both within-individual and between-individual variation (individual specialization). Both components can be used to explain changes in population niche breadth, and this has been extensively investigated in dietary niche dimension studies. However, little is known about how changes in food resources or environmental factors across seasons affect changes in individual and population space use within the same population. METHODS: In this study, we used micro-GPS loggers to capture the space use of individuals and of a population of the great evening bat (Ia io) in summer and autumn. We used I. io as a model to investigate how individual spatial niche breadth and spatial individual specialization affect changes in population niche breadth (home range and core area sizes) across seasons. Additionally, we explored the drivers of individual spatial specialization. RESULTS: We found that the population home range and the core area of I. io did not increase in autumn when insect resources were reduced. Moreover, I. io showed different specialization strategies in the two seasons: higher spatial individual specialization in summer and lower individual specialization but broader individual niche breadth in autumn. This trade-off may maintain the dynamic stability of the population spatial niche breadth across seasons and facilitate the population response to changes in food resources and environmental factors. CONCLUSIONS: Like diet, spatial niche breadth of a population also may be determined by a combination of individual niche breadth and individual specialization. Our work provides new insights into the evolution of niche breadth from the spatial dimension.

First record of the flat-skulled woolly bat Kerivouladepressa and the Indochinese woolly bat K.dongduongana (Chiroptera, Vespertilionidae) in China.

Recent studies have revealed that the Kerivouladepressa complex should be divided into two species, K.depressa distributed mainly in Myanmar, Vietnam, Laos and Cambodia, and K.dongduongana found only in the Annamite Mountains of Vietnam, Laos and Cambodia. In November 2018 and April 2019, 24 woolly bats were collected by two-band harp traps in Xishuangbanna, Yunnan, China. Based on morphological, morphometric, and phylogenetic (COI, Cytb, and RAG2 gene sequences) analyses, these bats were identified as K.depressa and K.dongduongana, representing two new species records for the country. Including the new records, six Kerivoula species have been recorded in China, namely K.depressa, K.dongduongana, K.furva, K.kachinensis, K.picta and K.titania. To facilitate their identification and biological research in the future, we have provided an up-to-date key to all Kerivoula species occurring in China.

Behavioral innovation and genomic novelty are associated with the exploitation of a challenging dietary opportunity by an avivorous bat.

Foraging on nocturnally migrating birds is one of the most challenging foraging tasks in the animal kingdom. Only three bat species (e.g., Ia io) known to date can prey on migratory birds. However, how these bats have exploited this challenging dietary niche remains unknown. Here, we demonstrate that I. io hunts at the altitude of migrating birds during the bird migration season. The foraging I. io exhibited high flight altitudes (up to 4945 m above sea level) and high flight speeds (up to 143.7 km h-1). I. io in flight can actively prey on birds in the night sky via echolocation cues. Genes associated with DNA damage repair, hypoxia adaptation, biting and mastication, and digestion and metabolism have evolved to adapt to this species' avivorous habits. Our results suggest that the evolution of behavioral innovation and genomic novelty are associated with the exploitation of challenging dietary opportunities.

First record of disk-footed bat Eudiscopus denticulus (Chiroptera, Vespertilionidae) from China and resolution of phylogenetic position of the genus.

The disk-footed bat Eudiscopus denticulus(Osgood, 1932) is a rare species in Southeast Asia. During two chiropteran surveys in the summer of 1981 and 2019, eight and three small Myotis-like bats with distinct disk-like hindfeet were collected from Yunnan Province, China, respectively. External, craniodental, and phylogenetic evidence confirmed these specimens as E. denticulus, representing a new genus in China. The complete mitochondrial genome consistently showed robust support for E. denticulus as a basal lineage within Myotinae. The coding patterns and characteristics of its mitochondrial genome were similar to that of other published genomes from Myotis. The echolocation signals of the newly collected individuals were analyzed. The potential distribution range of Eudiscopus in Southeast Asia inferred using the MaxEnt model indicated its potential occurrence along the southern border region of Yunnan, China.

The complete mitochondrial genome of the tube-nosed bat Murina cyclotis (Chiroptera: Vespertilionidae) in China.

In this study, the complete mitochondrial genome of a male individual of Murina cyclotis from Guangxi province, China, was sequenced and analyzed. The genome is a circular molecule of 16,463 bp length, containing 13 protein-coding genes, 2 ribosomal RNA genes, 22 transfer RNA genes, and a control region. Most of the genes were encoded on the H-strand, except for 8 tRNA and ND6 genes. Phylogenetic trees of the complete mitochondrial genome were constructed using RAxML. Our result suggests that M. cyclotis is closely related to M. leucogaster from Korea. The complete mitochondrial genome sequence of M. cyclotis will be helpful for future taxonomic and phylogenetic studies on Murina.

Mitochondrial genome of Murina shuipuensis (Chiroptera: Vespertilionidae) from Shuifu Village, Guizhou, China (type locality).

Murina shuipuensis, a small-sized forest bat with distinct bright orange-yellow ventral fur, is only found from its type locality thus far. In this study, a complete mitochondrial genome of a male individual of M. shuipuensis from Shuifu Village, Libo, Guizhou China (type locality) was sequenced using Illumina Hiseq. Total length of its genome is 16,585 bp, including two rRNA genes, 22 tRNA genes, 13 protein-coding genes, and a control region. The general arrangement of genes is similar to the other chiropteran mitochondrial genomes. The phylogenetic inference indicates M. shuipuensis and M. leucogaster have closer phylogenetic relationship than other taxa that deposited in NCBI-nt. The complete mitochondrial genome provides valuable information for further taxonomic and phylogenetic researches.