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Transcription
The transcript is about a podcast episode on the black-flying fox, a nocturnal mammal. It discusses the bat's physical characteristics, diet, and geographic range. The black-flying fox has a high genetic diversity and low levels of linkage disequilibrium compared to other mammals. Its high recombination rate contributes to this. The bat's resilience and ability to recover from population changes make it an indicator species for detecting environmental stress and climate change. The podcast concludes by highlighting the black-flying fox's importance and adaptation skills. This is Wildlife After Dark with your host, the knock-knock, Jason Weber, your local podcast that brings you information all about nocturnal mammals. This episode, I will be talking about the black-flying fox with the guest speaker, Liam Zizzo. Liam has been studying these fascinating creatures for the past 35 years. Liam, great to have you here today. Can you please tell us a little bit about the black-flying fox? Of course, of course. The black-flying fox, or the pteropus alecto, is part of the fruit bat family and is one of the largest bats in the world. Their wingspan can grow up to six feet and can weigh a little over three pounds. Their diet consists of flour, pollen, and nectar from eucalyptus trees as well as other types of trees. Let me guess, they're from Australia? You would be correct. Always Australia. Yeah, yeah. Their geographic range distributes not just in Australia, but also southern Papua New Guinea and the Indonesian islands. This species is one of five bats to occupy an area of land over one million kilometers squared. Wow, that's impressive. I mean, bats are already one of the most successful mammalian groups spread across the world. It's just another attribute to add to their resume, along with the only mammalian group with the ability of sustained flight, plus they have many physiological traits such as long lifespan, echolocation, and ability to co-evolve with many deadly viruses. Yeah. A recent study has discovered that the black-flying fox has a much higher genetic diversity and lower levels of linkage disequilibrium than most mammalian species. Liam, can you please describe what linkage disequilibrium is for those back home who don't know what that is? Yeah, of course. Linkage disequilibrium is the non-random association of alleles. In other words, some alleles are more likely to be associated, meaning that frequencies of a chromosome cannot be predicted by the known frequencies of alleles. This discovery was calculated from a random sample of 50 individual black-flying foxes in Brisbane, Australia. The calculated average genetic diversity of the species came to be 0.006. Really? That seems pretty low. You might think that, Liam, but compared to other mammalian species, this is a very high level. Humans are only around 0.001. A wild rat has roughly a value of 0.0012, and wolves 0.0013, and other mammals are at 0.003. Wow, so the genetic diversity of the black-flying fox is significantly higher than other mammal species. Precisely, and their high recombination rate may explain for their low levels of linkage disequilibrium. Recombination is the process of genes or crossing over chromosomes during meiosis. Their recombination rate was found to be much higher than other mammalian species, even humans and dogs. This high rate may be the driver for such a low level of linkage disequilibrium of 0.1, where other animals are near 0.2 and higher. Altogether, the black-flying fox has higher genetic diversity, lower levels of disequilibrium, and a larger effective population size compared to many other mammalian groups. Yeah, these traits make these bats very resilient to environmental catastrophes, and really good at recovering from severe changes in their population. Because of this, researchers are able to relate the fluctuations in their population to natural disasters like glacial cycles and volcanic eruptions that impact the populations of all species in the region. The Mount Toba eruption caused a large decrease in the population of the black-flying fox. The population rebounded from the sharp decrease after this catastrophic event. The black-flying foxes are resilient but are also good identifiers for changes as the population can fluctuate in response to even minor events that would impact their habitats. This means that the black-flying fox is an indicator species, meaning they can be analyzed to help detect and predict similar events like climate change and other things that could harm a region's species. In other words, the indicator species will indicate if a natural disaster or change in the Earth's climate is occurring, and the species population will reflect these changes when they occur. There are some limitations of fully knowing whether black-flying foxes can detect the effects of climate change, but there is some correlation between their recent declination and climate change. There is no doubt that this species can serve as a powerful indicator species that is able to quickly respond to environmental stress without being trapped into a bottleneck or going fully extinct. This is clearly one of the greatest bat species on this planet, and its resilience and adaptation skills will continue to help indicate environmental stress. Thank you for tuning in today's episode of Wildlife After Dark, hopefully we'll see you nocturnal mammals later. The article referenced in this episode is Population Genomic Analysis Reveals Distinct Demographics and Recent Adaptation in the Black-Flying Fox by Weiwei Zai.
