Comment on Dunbar et al. (2022) “Webslinger vs. Dark Knight: First record of a false widow spider Steatoda nobilis preying on a pipistrelle bat in Britain”

Abstract

Abstract. A recent publication in Ecosphere claimed to report the first case of a predation event by a theridiid spider on a bat globally and the first case of a member of the genus Steatoda preying on a mammal globally, and the paper concludes with possible implications for public health. Predation is typically understood to mean “capture, kill, and eat”. However, none of these aspects had been observed. Moreover, key aspects of bat biology were not taken into account, including that the bat in question was a flightless newborn, the capture of which would require some explanation. We revisit this interesting observation considering both bat and spider ecology.

Editorial: Pay to criticise? Rebuttal articles in open-access journals should be published for free

“…However, given the extraordinary circumstances of this case, we decided that it would be in the interest of science to make an exception. Two external reviewers agreed with the observations made in the rebuttal article, and the rebuttal was published in Web Ecology shortly after (Dool and Uhl, 2022).…”

Caught in the web: Exploring spider predation on bats in Europe

“…They compensate for their size by using potent venom that can paralyse and kill small vertebrates and construct extremely sticky and strong webs (Nyffeler & Gibbons, 2022). The false noble widow spider preys on European small mammals, including pygmy shrews (Dugon et al., 2023) and a disputed case of predation on bats (Dool & Uhl, 2022; Dunbar et al., 2022). We contribute a record of capture of an adult bat in the web of a false noble widow, but further research is needed to document these interactions and establish whether these spiders consume the bats they capture in their webs.…”

“…Such structures lack sticky threads and require a fast response of the spider to successfully capture their prey hitting the web, which mainly consists of soft‐bodied arthropods such as butterflies, bees, wasps and flies (Nentwig, 1987). Newborn non‐volant bat pups are considerably vulnerable without their mothers, unable to thermoregulate (Racey & Entwistle, 2000) and with limited mobility to escape from predators (Dool & Uhl, 2022). This makes them easy to capture by ground‐dwelling predators when they accidentally fall from the roost.…”

“…A subsequent case was reported in the United Kingdom by Dunbar et al (2022), although the predation in this case has been questioned (Dool & Uhl, 2022). These occurrences all involve small Myotis and Pipistrellus species entangled in spider webs and have been interpreted as opportunistic rather than deliberate acts of predation, and possibly even cases of non-predation death with no involvement of the spider (Dool & Uhl, 2022;Nyffeler & Knörnschild, 2013).…”

“…(2022), although the predation in this case has been questioned (Dool & Uhl, 2022). These occurrences all involve small Myotis and Pipistrellus species entangled in spider webs and have been interpreted as opportunistic rather than deliberate acts of predation, and possibly even cases of non‐predation death with no involvement of the spider (Dool & Uhl, 2022; Nyffeler & Knörnschild, 2013). Nonetheless, the limited documentation and understanding of these mortality events, highlights an unknown area of ecological interactions within European ecosystems.…”