A recent study on body size in leaf-nosed bats from the Solomon Islands has uncovered unexpected genetic diversity among very similar species living on different islands. The research was conducted by a team of evolutionary biologists from the University of Melbourne, Australia, and the University of Kansas, who collected specimens in the field, conducted genetic analysis, and co-wrote the research article.The journal Evolution featured a study about a genus of bats known as Hipposideros, which has multiple species scattered across Southeast Asia in the Pacific. Rob Moyle, a co-author of the study and senior curator of ornithology at the KU Biodiversity Institute and Natural History Museum, explained that their research was primarily conducted in the Solomon Islands, where they found that each island can be home to four or five different species of the Hipposideros bats, categorized by body size. Moyle noted that on one island in particular, they identified five different species, leading to the categorization of small, medium, large, and extra-large bats.
Moyle, a professor of evolutionary biology at KU, pointed out that previous researchers had studied the physical traits of the bats and concluded that they were all the same species. “You go from one island to the next, and the medium-sized species is identical to the other islands,” he said. “Biologists have always looked at those and said, ‘OK, it’s obvious. There’s a small, medium and large size species distributed across multiple islands.'” However, Moyle and his colleagues had more advanced DNA analysis at their disposal. They sequenced the DNA of bats they collected from the field and found new evidence.
Through analyzing specimens from museum collections, the team discovered that the large and extra large bat species were not closely related.
“This means that these populations ended up with the same body size and appearance not through close relation — but typically, we associate similar appearances with close relation,” Moyle explained. “This raises questions about what makes these islands unique that would result in the convergence of body size and appearance into consistent size classes on various islands.”
The team conducted accurate measurements on bats from different islands, validating previous research.The study was conducted by scientists in the Solomon Islands. Moyle, one of the scientists involved, mentioned that the large species from different islands all had similar measurements, indicating that earlier biologists may have made a mistake by assuming they were the same. However, after measuring them, it was found that they were all clustered together despite being different species, confirming the earlier morphological work. Collaborators in the study included lead author Tyrone Lavery from the University of Melbourne and KU’s Biodiversity Institute and Natural History Museum, among others.Participants in the study were Devon DeRaad, a doctoral student, and Lucas DeCicco, a collections manager, both from the Biodiversity Institute and Natural History Museum. Karen Olson from both KU and Rutgers University also took part in the study. Other participants included Piokera Holland from Ecological Solutions Solomon Islands, Jennifer Seddon from James Cook University, and Luke Leung from the Rodent Testing Centre in Gatton, Australia.
The genetic analysis, which revealed that the bats were not closely related, was conducted at KU’s Genome Sequencing Core.
According to the researchers, the family trees created using the bats’ DNA showed that what was previously thought to be just one species of large bat in the Solomon Islands was actually multiple species.Lavery said that they found a case where larger bats had evolved from smaller species multiple times across different islands. They believe that these larger bats may be evolving in order to take advantage of prey that the smaller bats do not eat. DeRadd commented that this research could be very important for conservation efforts in identifying evolutionarily significant units in this group. He also mentioned that body size had created confusion in the taxonomy, as it turns out that each island’s population of extra-large bats is genetically unique and deserving of conservation. Understanding this is crucial, especially with issues such as deforestation. If this information is not known, it could be detrimental to the conservation efforts.ther these populations are unique, it’s difficult to determine whether we should prioritize conservation efforts for them.”
DeCicco noted that the new insights into leaf-nosed bats were intriguing on a purely theoretical level.
“We examine the evolutionary processes that contribute to biodiversity,” he explained. “This demonstrates the complexity of nature. Humans are eager to identify patterns, and researchers strive to establish rules that can be applied to various organisms. It’s incredibly fascinating when we come across exceptions to these rules. These patterns are evident across a wide range of taxa on numerous islands, regardless of size.”The study found that parallel evolution is common in island environments, where species that are closely related develop different traits to coexist. This can be seen in various evolutionary scenarios, all leading to the same outcome. The research, titled “Parallel evolution in an island archipelago revealed by genomic sequencing of Hipposideros leaf-nosed bats,” was published in the journal Evolution in 2024. The DOI for the article is http://dx.doi.org/10.1093/evolut/qpae039.The link to the article is: 10.1093/evolut/qpae039