The Hawaiian islands are an extremely isolated oceanic archipelago, and their fauna has long served as models of dispersal in island biogeography. While molecular data have recently been applied to investigate the timing and origin of dispersal events for several animal groups including birds, insects, and snails, these questions have been largely unaddressed in Hawai'i’s only native terrestrial mammal, the Hawaiian hoary bat, Lasiurus cinereus semotus. Here, we use molecular data to test the hypotheses that (1) Hawaiian L. c. semotus originated via dispersal from North American populations of L. c. cinereus rather than from South American L. c. villosissimus, and (2) modern Hawaiian populations were founded from a single dispersal event. Contrary to the latter hypothesis, our mitochondrial data support a biogeographic history of multiple, relatively recent dispersals of hoary bats from North America to the Hawaiian islands. Coalescent demographic analyses of multilocus data suggest that modern populations of Hawaiian hoary bats were founded no more than 10 kya. Our finding of multiple evolutionarily significant units in Hawai'i highlights information that should be useful for re-evaluation of the conservation status of hoary bats in Hawai'i.

We examine the genetic history and population status of Hawaiian Hoary bats (Lasiurus semotus), the most isolated bats on Earth, and their relationship to Northern Hoary bats (L. cinereus), through whole-genome analysis of single-nucleotide polymorphisms (SNPs) mapped to a de novo-assembled reference genome. Profiles of genomic diversity and divergence indicate that Hawaiian Hoary bats are distinct from Northern Hoary bats, and form a monophyletic group, indicating a single ancestral colonization event 1.34 Mya, followed by substantial divergence between islands beginning 0.51 Mya. Phylogenetic analysis indicates Maui is central to the radiation across the archipelago, with the southward expansion to Hawaiʻi and westward to Oʻahu and Kauaʻi. Because this endangered species is of conservation concern, a clearer understanding of the population genetic structure of this bat in the Hawaiian Islands is of timely importance.

Multi-state occupancy modeling can often improve assessments of habitat use and site quality when animal activity or behavior data are available. We examine the use of the approach for evaluating foraging habitat suitability of the endangered Hawaiian hoary bat (Lasiurus cinereus semotus) from classifications of site occupancy based on flight activity levels and feeding behavior. In addition, we used data from separate visual and auditory sources, namely thermal videography and acoustic (echolocation) detectors, jointly deployed at sample sites to compare the effectiveness of each method in the context of occupancy modeling. Video-derived observations demonstrated higher and more accurate estimates of the prevalence of high bat flight activity and feeding events than acoustic sampling methods. Elevated levels of acoustic activity by Hawaiian hoary bats were found to be related primarily to beetle biomass in this study. The approach may have a variety of applications in bat research, including inference about species-resource relationships, habitat quality and the extent to which species intensively use areas for activities such as foraging.

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The family Pteropodidae (Old World fruit bats) comprises >200 species distributed across the Old World tropics and subtropics. Most pteropodids feed on fruit, suggesting an early origin of frugivory, although several lineages have shifted to nectar-based diets. Pteropodids are of exceptional conservation concern with >50% of species considered threatened, yet the systematics of this group has long been debated, with uncertainty surrounding early splits attributed to an ancient rapid diversification. Resolving the relationships among the main pteropodid lineages is essential if we are to fully understand their evolutionary distinctiveness, and the extent to which these bats have transitioned to nectar-feeding. Here we generated orthologous sequences for >1400 nuclear protein-coding genes (2.8 million base-pairs) across 114 species from 43 genera of Old World fruit bats (57% and 96% of extant species- and genus-level diversity, respectively), and combined phylogenomic inference with filtering by information content to resolve systematic relationships among the major lineages. Concatenation and coalescent-based methods recovered three distinct backbone topologies that were not able to be reconciled by filtering via phylogenetic information content. Concordance analysis and gene genealogy interrogation shows that one topology is consistently the best supported, and that observed phylogenetic conflicts arise from both gene tree error and deep incomplete lineage sorting. In addition to resolving long-standing inconsistencies in the reported relationships among major lineages, we show that Old World fruit bats have likely undergone at least seven independent dietary transitions from frugivory to nectarivory. Finally, we use this phylogeny to identify and describe one new genus.