Bat-eating spiders are common and apparently crawl across every continent except Antarctica, devouring various species of bats. Here, a dead bat caught in a female’s web on Amami-Oshima Island, Japan. There is only one place in the world to escape bat-catching spiders: Antarctica. These arachnids catch and jump on bats around the world, the researchers say. Bats are among the most successful mammalian groups, with more than 1,200 bat species comprising about one-fifth of all mammal species. Other than owls, hawks, and snakes, bats have few natural enemies.
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Still, invertebrates, creatures without backbones, have been known to prey on bats. For example, giant centipedes were seen in a cave in Venezuela killing and eating bats, and arachnids known as whip spiders were seen feeding on dead bats in Caribbean caves. Cockroaches have been observed feeding on baby bats that have fallen to the floor of caves.
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The findings were detailed online March 13 in the journal PLOS ONE, by Martin Nyffeler, a senior professor of zoology at the University of Basel in Switzerland, and Mirjam Knörnschild, of the University of Ulm in Germany.
Spider-eat-bat world
Accidental deaths of bats in cobwebs were also known, but were thought to occur very rarely. Still, spiders have been known to occasionally feed on a variety of vertebrates, creatures with backbones.
For example, fish spiders capture and eat fish and frogs; some species of wolf spiders, hunting spiders, tarantulas, and related spiders have been seen killing and eating frogs and lizards; and tarantulas and comb-footed spiders have apparently fed on snakes and mice.
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There are also numerous reports of spiders killing other flying vertebrates, ensnaring birds in large orb-webs.
Recent studies of a species of web-building spider (Argiope savignyi) and a species of tarantula (Poecilotheria rufilata) that kill small bats led researchers to suggest that captures and deaths of bats by spiders may be more frequent than expected. than was previously thought.
They then analyzed 100 years of scientific reports, interviews with bat and spider researchers and bat hospital staff, and scans of image and video sites. The search revealed 52 cases of bat-hunting spiders worldwide.
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Telarañas gigantes
Aproximadamente el 90 por ciento de las arañas cazadoras de murciélagos conocidas viven en las áreas más cálidas del globo, en la tercera parte de la Tierra que rodea el ecuador. Alrededor del 40 por ciento vive en los neotrópicos, toda América del Sur y las regiones tropicales de América del Norte, mientras que casi un tercio vive en Asia y más de un sexto vive en Australia y Papua Nueva Guinea.
Ochenta y ocho por ciento de los casos informados de capturas de murciélagos se debieron a arañas tejedoras de telarañas, con arañas tejedoras de orbes tropicales gigantes con una envergadura de patas de 4 a 6 pulgadas (10 a 15 centímetros) que se vieron atrapando murciélagos en orbes enormes y fuertes. -telas de hasta 5 pies (1,5 metros) de ancho.
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En casos vistos en Costa Rica y Panamá, las arañas habían construido sus telas cerca de edificios habitados por colonias de murciélagos. La captura de murciélagos a través de telarañas también se observó con especial frecuencia en los parques y bosques del área metropolitana de Hong Kong.
La investigación futura puede investigar si las enormes redes que a veces bloquean las entradas de las cuevas de murciélagos tropicales en el este y sureste de Asia y los neotrópicos pueden enganchar ocasionalmente a algún miembro de los enjambres gigantes de murciélagos que emergen de las cuevas por la noche.
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Un pequeño murciélago (superfamilia Rhinolophoidea) enredado en la telaraña de una araña Nephila pilipes en la cima de la colina Cockatoo cerca de Cape Tribulation, Queensland, Australia. La araña apretó la boca contra el murciélago muerto y envuelto, indicando que se estaba alimentando de él. (Crédito de la imagen: Foto de Carmen Fabro, Cockatoo Hill, Australia)
