{"id":1227,"date":"2021-08-30T12:42:53","date_gmt":"2021-08-30T19:42:53","guid":{"rendered":"https:\/\/knightlab.ucsd.edu\/wordpress\/?p=1227"},"modified":"2025-08-04T15:54:01","modified_gmt":"2025-08-04T22:54:01","slug":"blood-sucking-bugs-find-bats-to-bite-thanks-to-bacteria","status":"publish","type":"post","link":"https:\/\/knightlab.ucsd.edu\/?p=1227","title":{"rendered":"Blood-Sucking Bugs Find Bats To Bite Thanks to Bacteria"},"content":{"rendered":"

Blood-sucking flies may be following chemicals produced by skin bacteria to locate bats to feed on.<\/span><\/a><\/span><\/h3>\n

 <\/p>\n

We humans aren\u2019t the only animals that have to worry about bug bites. There are thousands of insect species<\/span> that have evolved to specialize in feeding on different mammals and birds, but scientists are still learning how these bugs differentiate between species to track down their preferred prey. It turns out, the attraction might not even be skin-deep: a new study in Molecular Ecology<\/em> found evidence that blood-sucking flies that specialize on bats may be locating their preferred hosts by following the scent of chemicals produced by bacteria on the bats\u2019 skin.<\/span><\/p>\n

Holly Lutz, the paper\u2019s lead author, got the idea for the project from previous research showing that mosquitoes seem to prefer some people over others. \u201cYou know when you go to a barbecue and your friend is getting bombarded by mosquitoes, but you\u2019re fine? There is some research to support the idea that the difference in mosquito attraction is linked to your skin microbiome \u2014 the unique community of bacteria living on your skin,\u201d says Lutz, a research associate at Chicago\u2019s Field Museum and a project scientist with the labs of Jack Gilbert (who co-authored this study) and Rob Knight at the University of California, San Diego. \u201cKeeping in mind that some people are more attractive to mosquitoes than others, I wondered what makes insects attracted to some bats but not others.\u201d<\/span><\/p>\n

Lutz encountered plenty of bats during her PhD work and postdoctoral residency at the Field Museum, on fieldwork trips to bat caves in Kenya and Uganda studying malaria. \u201cIn these caves, I\u2019d see all these different bat species or even taxonomic families roosting side by side. Some of them were loaded with bat flies, while others had none or only a few. And these flies are typically very specific to different kinds of bats \u2014 you won\u2019t find a fly that normally feeds on horseshoe bats crawling around on a fruit bat,\u201d says Lutz. \u201cI started wondering why the flies are so particular \u2014 clearly, they can crawl over from one kind of bat to another, but they don\u2019t really seem to be doing that.\u201d<\/span><\/p>\n

Blind, Flightless, and Picky: The Strange Lives of Bat Flies<\/span><\/h4>\n

The flies in question are cousins of mosquitoes, and while they\u2019re technically flies, most can\u2019t actually fly. \u201cThey have incredibly reduced wings in many cases and can\u2019t actually fly,\u201d says Lutz. \u201cAnd they have reduced eyesight, so they probably aren\u2019t really operating by vision. So some other sensory mechanisms must be at play, maybe a sense of smell or an ability to detect chemical cues.\u201d<\/span><\/p>\n

\u200b\u200b\u201dHow the flies actually locate and find their bats has previously been something of a mystery,\u201d says Carl Dick, a research associate at the Field Museum, professor of biology at Western Kentucky University, and one of the study\u2019s co-authors. \u201cBut because most bat flies live and feed on only one bat species, it is clear that they somehow find the right host.\u201d<\/span><\/p>\n

Furthermore, bat flies transmit malaria between bats, and the malaria parasites are host-specific as well. It\u2019s an intricate, complex system with important parallels to other vector-borne pathways for disease transmission, such as malarial and viral transmission among humans by anopheline mosquitoes. Previous research has shown that different bacterial species associated with skin or even the disease status of individual humans can influence feeding preferences of blood-seeking mosquitoes.<\/span><\/p>\n

Lutz suspected that, similarly to what\u2019s been observed in humans, the bats\u2019 skin microbiomes may be playing a role in attracting the flies seeking them out. Skin \u2014 whether it belongs to a human or a bat \u2014 is covered with tiny microorganisms that help protect the body from invading pathogens, bolster the immune system, and break down natural products like sweat. Host species evolve alongside their skin microbiomes, leading to different species being home to different sets of bacteria.<\/span><\/p>\n

All these different kinds of bacteria produce a unique bouquet of airborne chemicals as they metabolize nutrients. And, according to Lutz\u2019s hypothesis, different kinds of insects are attracted to different chemical signals, which could help explain why some bats are more attractive to blood-sucking flies than others \u2014 just like your friend at the barbeque.<\/span><\/p>\n

To test this hypothesis, Lutz examined dozens of bats from a variety of species. \u201cWe went into a ton of different caves where they roost and used long bat nets, which are basically like super sturdy butterfly nets, to catch them,\u201d says Lutz. She and her colleagues took skin and fur samples from the bats\u2019 bodies and wings in order to examine both the bats\u2019 DNA<\/span> and the microbes living on their skin. The researchers also examined the bats for flies. \u201cYou brush the bats\u2019 fur with your forceps, and it\u2019s like you\u2019re chasing the fastest little spider,\u201d says Lutz. \u201cThe flies can disappear in a split second. They are fascinatingly creepy.\u201d<\/span><\/p>\n

\u201cThe flies are exquisitely evolved to stay on their bat,\u201d says Dick. \u201cThey have special combs, spines, and claws that hold them in place in the fur, and they can run quickly in any direction to evade the biting and scratching of the bats, or the efforts by researchers to capture them.\u201d<\/span><\/p>\n

The researchers then analyzed the specimens back at the Field Museum\u2019s Pritzker DNA Laboratory. \u201cOnce we were back at the lab, we extracted all the DNA from the bacteria and sequenced it. We basically created libraries of all the bacteria associated with each individual skin sample. Then we used bioinformatics methods to characterize the bacteria there and identify which ones are present across different bat groups, comparing bats that were parasitized by flies to those that were not,\u201d says Lutz.<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"

Blood-sucking flies may be following chemicals produced by skin bacteria to locate bats to feed on.   We humans aren\u2019t the only animals that have to worry about bug bites.<\/p>\n","protected":false},"author":1,"featured_media":1228,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5],"tags":[],"class_list":["post-1227","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news"],"_links":{"self":[{"href":"https:\/\/knightlab.ucsd.edu\/index.php?rest_route=\/wp\/v2\/posts\/1227","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/knightlab.ucsd.edu\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/knightlab.ucsd.edu\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/knightlab.ucsd.edu\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/knightlab.ucsd.edu\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1227"}],"version-history":[{"count":3,"href":"https:\/\/knightlab.ucsd.edu\/index.php?rest_route=\/wp\/v2\/posts\/1227\/revisions"}],"predecessor-version":[{"id":1668,"href":"https:\/\/knightlab.ucsd.edu\/index.php?rest_route=\/wp\/v2\/posts\/1227\/revisions\/1668"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/knightlab.ucsd.edu\/index.php?rest_route=\/wp\/v2\/media\/1228"}],"wp:attachment":[{"href":"https:\/\/knightlab.ucsd.edu\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1227"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/knightlab.ucsd.edu\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1227"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/knightlab.ucsd.edu\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1227"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}