ABSTRACT
Ixodes acutitarsus is regarded as the largest Ixodes tick around the world. I. acutitarsus is capable to transmit a wide range of animal and human pathogens. This research pioneered sequencing of the complete mitochondrial genome of I. acutitarsus. With a length of 14,475 bp, the complete mitochondrial genome encodes 13 protein-coding genes (PCGs), two ribosomal RNA genes (rRNAs), 22 transfer RNA genes (tRNAs), and one replication-initiating region. The phylogenetic relationship was established using the Maximum-likelihood method to indicate that I. acutitarsus and the others of the genus Ixodes fit into the same branch, which confirms the inclusion of I. acutitarsus in the genus Ixodes. The complete mitogenome of sequenced I. acutitarsus provides molecular evidence for the taxonomic status and phylogenetic position of several Ixodes species.
ABSTRACT
The altitudinal distribution of biodiversity in alpine ecosystems has captured academic attention, especially in streams because of their sensitivity to climate change. In the past years, research mainly focused on understanding the role played by alpine streams' internal factors such as aquatic environmental variables, as well as physical and hydrological conditions, on the shaping of benthic macroinvertebrate communities. More recently, external factors such as terrestrial environments were included in analyses worldwide. In particular, the inherent properties constituting the ecological niche of specific species were considered as factors regulating dispersal and influencing community construction. The objective of this study was to reveal the distribution pattern and the driving factors regulating aquatic biodiversity in alpine streams. We hypothesized that the altitudinal distribution of aquatic macroinvertebrates could be explained by the interaction of the aquatic environment with both species' ecological niche and the terrestrial environment surrounding their habitat, and that rare species display a more pronounced pattern than widespread dominant species. To test these hypotheses, samples were collected from two alpine streams situated on opposite slopes of Biluo Snow Mountain in Yunnan Province, China. Results of statistical analyses showed poor explanatory power from aquatic environmental factors, while the differences in vegetation type and the ecological niche of the species played an important role in determining the distribution pattern of aquatic biodiversity. Furthermore, we found that the altitudinal distribution pattern of aquatic biodiversity exhibits a bimodal type, with rare species fitting the bimodal peaks. These findings call for a better inclusion and further investigation on the effects of the terrestrial environment on aquatic ecosystems.
