{"id":463757,"date":"2026-05-23T18:21:12","date_gmt":"2026-05-23T18:21:12","guid":{"rendered":"https:\/\/www.newsbeep.com\/ie\/463757\/"},"modified":"2026-05-23T18:21:12","modified_gmt":"2026-05-23T18:21:12","slug":"this-acoustic-assault-appears-to-be-an-effective-deterrent-to-stop-it-from-being-eaten-by-its-host-and-the-host-from-losing-its-friend-with-benefits","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/ie\/463757\/","title":{"rendered":"“This acoustic assault appears to be an effective deterrent to stop it from being eaten by its host and the host from losing its friend with benefits…”\u00a0"},"content":{"rendered":"

There\u2019s a fly that doesn\u2019t have wings and a bat that doesn\u2019t use the ones it has as much as you might expect. Both these evolutionary oddballs live side by side in a weird marriage made in heaven\u2026 or rather New Zealand.<\/p>\n

The New Zealand bat fly (Mystacinobia zelandica) is found hanging around and on the furry bodies of the country\u2019s only endemic mammals, bats<\/a>, and one species in particular: The New Zealand lesser short-tailed bat, with which it shares an intimate and unique relationship.<\/p>\n

The concept of a fly on a bat isn\u2019t surprising, as bats worldwide are riddled with all kinds of ectoparasitic flies, as well as mites, lice and fleas. Most of these flies feed on bats\u2019 blood, but not in New Zealand. It is thought that the ancestors of the country\u2019s bats arrived before parasites<\/a> had evolved to exploit them \u2013 about 79 million years ago, when New Zealand parted company with Gondwana. Consequently, living in isolation on these islands, they\u2019ve developed a totally different relationship with a totally different fly.<\/p>\n

The New Zealand bat fly was only discovered in 1973 when a kauri tree containing a roost of New Zealand lesser short-tailed bats fell over, bringing the rare community into view<\/p>\n

\"LesserThe New Zealand bat fly shares an intimate relationship with the lesser short-tailed bat (pictured here). Illustration credit: Peter David Scott\/The Art Agency
\nWhat is a New Zealand bat fly?<\/p>\n

The New Zealand bat fly is different in many ways. For a start, it doesn\u2019t look like a fly at all, lacking a pair of wings. It has given up flight and appears to be more like a scuttling spider missing a pair of legs. <\/p>\n

It doesn\u2019t need eyes either. Instead, it is equipped with bristles to sense and feel, and each leg is adorned with large hooks \u2013 helpful if you need to cling onto a bat\u2019s fur. But it\u2019s the fly\u2019s behaviour that is of particular interest to biologists.\u00a0<\/p>\n

\u201cIt is more like a scuttling spider missing a pair of legs\u201d<\/p>\n

\"NewInstead of eyes, the New Zealand bat fly is equipped with bristles to sense and feel. Illustration credit: Peter David Scott\/The Art Agency
\nWhat do New Zealand bat flies eat?<\/p>\n

In nature, when you find two unrelated species living in such intimacy, there is often a transaction of some kind going on \u2013 most often a parasitism. But unlike so many of their kind, New Zealand bat flies don\u2019t appear to be freeloading off their hosts. Analysis of their stomach contents showed they didn\u2019t contain any bat blood, just fruit and pollen. All they were stealing was a little body heat, which may not be insignificant in New Zealand\u2019s often cool and temperate climate.<\/p>\n

Still, without wings and without a hematophagous habit, it was a puzzle that had scientists miffed. What were they feeding on? How did they get pollen if they couldn\u2019t fly about? Conversely, the bats\u2019 stomachs didn\u2019t contain any bat flies \u2013 odd for an animal more than partial to munching on invertebrates. So what was going on?\u00a0<\/p>\n

The relationship between fly and bat<\/p>\n

It turns out that the bat colonies are a warm, secure home for the flies, with plenty of food provided in the form of bat droppings, and in consuming this rich, gloopy soup, the flies are, in turn, providing a clean-up service for the bats. The droppings might not look or smell that appetising to us, but they are delicious and nutritious to a bat fly. The omnivorous diet of the lesser short-tailed bats explains the pollen in the flies\u2019 stomachs.<\/p>\n

Living in this prosperous fly utopia has also given the flies the opportunity to evolve something akin to the \u2018caste system\u2019 of more famous social insects such as bees<\/a>, a unique feature among flies. <\/p>\n

Members vary considerably in size and the beefy mature males take on colony guard-duty. When disturbed by a bat, they move towards the intruder and buzz like a furious dentist\u2019s drill. The high-pitched sound is produced by the muscles housed in their chunky thorax. These muscles would have powered the wings of their distant ancestors, but they haven\u2019t atrophied as might be expected and have been repurposed as a kind of sonic gun. This acoustic assault appears to be an effective deterrent to stop the bat fly from being eaten by its host and the bat from losing its friend with benefits.\u00a0<\/p>\n

The lesser short-tailed bat<\/p>\n

The lesser short-tailed bat is one of only three native species of terrestrial mammal found in New Zealand, the others being the short-tailed bat and the greater long-tailed bat (the latter is presumed extinct having last been seen in 1967). <\/p>\n

The lesser short-tailed bat has filled a niche that is exploited by mice and shrews on the continents. It spends much of its time scurrying around on the forest floor feeding on flowers, fruits and insects.<\/p>\n

Illustration credit: Peter David Scott\/The Art Agency<\/p>\n","protected":false},"excerpt":{"rendered":"There\u2019s a fly that doesn\u2019t have wings and a bat that doesn\u2019t use the ones it has as…\n","protected":false},"author":2,"featured_media":463758,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[61,60,82],"class_list":["post-463757","post","type-post","status-publish","format-standard","has-post-thumbnail","category-science","tag-ie","tag-ireland","tag-science"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts\/463757","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/comments?post=463757"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts\/463757\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/media\/463758"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/media?parent=463757"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/categories?post=463757"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/tags?post=463757"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}