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The intricate interplay between predators and prey has long fascinated ecologists, with bats and their diverse prey offering insight into co‐evolutionary dynamics. While bats have evolved sophisticated strategies for prey capture, they also face predation pressure. Among their predators, spiders stand out for their diversity of predatory tactics, ranging from hunting assaults and web ensnarement to the deployment of venom. Yet, bat predation records by spiders are mostly from tropical regions, and cases remain notably scarce in temperate regions. Here, we report four new incidences of bat predation and mortality by spiders and their webs in Europe. Our observations include detailed photograph and video documentation of the first record of a spider capturing and consuming a bat pup in Spain, as well as accounts of bats entangled in spider webs on a building and inside bat boxes in the United Kingdom. These findings shed light on understudied predator–prey dynamics, offering valuable insights into spider predation on bats in European ecosystems. Our study emphasises the importance of continued research to improve our understanding of ecological interactions between these elusive and primarily nocturnal taxa. [ABSTRACT FROM AUTHOR]

The noble false widow spider Steatoda nobilis is a globally invasive species with implications for public health and possibly for native ecosystems. Here, we report on a case of predation on a protected species of vertebrate, a pygmy shrew Sorex minutus in Britain. The importance and novelty of this report are: (1) this is the third documented case of S. nobilis preying on a vertebrate in five years, suggesting that small vertebrates are likely to be a more frequent component of their diet than previously thought; (2) this is the first case of a Theridiidae spider preying on a shrew in Britain; and (3) this is the first case of predation on shrews by the genus Steatoda globally. Overall, S. nobilis fits the profile of a habitual vertebrate‐eating spider. [ABSTRACT FROM AUTHOR]

Abstract The noble false widow spider Steatoda nobilis is a globally invasive species with implications for public health and possibly for native ecosystems. Here, we report on a case of predation on a protected species of vertebrate, a pygmy shrew Sorex minutus in Britain. The importance and novelty of this report are: (1) this is the third documented case of S. nobilis preying on a vertebrate in five years, suggesting that small vertebrates are likely to be a more frequent component of their diet than previously thought; (2) this is the first case of a Theridiidae spider preying on a shrew in Britain; and (3) this is the first case of predation on shrews by the genus Steatoda globally. Overall, S. nobilis fits the profile of a habitual vertebrate‐eating spider.

Venom compositions include complex mixtures of toxic proteins that evolved to immobilize/dissuade organisms by disrupting biological functions. Venom production is metabolically expensive, and parsimonious use is expected, as suggested by the venom optimisation hypothesis. The decision-making capacity to regulate venom usage has never been demonstrated for the globally invasive Noble false widow Steatoda nobilis (Thorell, 1875) (Theridiidae). Here, we investigated variations of venom quantities available in a wild population of S. nobilis and prey choice depending on venom availability. To partially determine their competitiveness, we compared their attack rate success, median effective dose (ED50) and lethal dose (LD50), with four sympatric synanthropic species: the lace webbed spider Amaurobius similis, the giant house spider Eratigena atrica, the missing sector orb-weaver Zygiella x-notata, and the cellar spider Pholcus phalangioides. We show that S. nobilis regulates its venom usage based on availability, and its venom is up to 230-fold (0.56 mg/kg) more potent than native spiders. The high potency of S. nobilis venom and its ability to optimize its usage make this species highly competitive against native European spiders sharing the same habitats. [ABSTRACT FROM AUTHOR]

The noble false widow spider Steatoda nobilis continues to expand its range globally with possible implications for public health and native species. Of the European Union list of 66 species of invasive plants and animals, none are spiders. S. nobilis is invasive around the world, but its impact on native species has not been fully assessed. Here, we report on the predation of a protected species of pipistrelle bat by S. nobilis in Britain. To our knowledge, this is the first recorded case of a Theridiidae spider preying on a bat globally, the first case of a Theridiidae spider preying on a vertebrate in Britain, and the first global case of a Steatoda preying on a mammal. [ABSTRACT FROM AUTHOR]

Abstract The noble false widow spider Steatoda nobilis continues to expand its range globally with possible implications for public health and native species. Of the European Union list of 66 species of invasive plants and animals, none are spiders. S. nobilis is invasive around the world, but its impact on native species has not been fully assessed. Here, we report on the predation of a protected species of pipistrelle bat by S. nobilis in Britain. To our knowledge, this is the first recorded case of a Theridiidae spider preying on a bat globally, the first case of a Theridiidae spider preying on a vertebrate in Britain, and the first global case of a Steatoda preying on a mammal.

The noble false widow spider Steatoda nobilis originates from the Macaronesian archipelago and has expanded its range globally. Outside of its natural range, it may have a negative impact on native wildlife, and in temperate regions it lives in synanthropic environments where it frequently encounters humans, subsequently leading to envenomations. S. nobilis is the only medically significant spider in Ireland and the UK, and envenomations have resulted in local and systemic neurotoxic symptoms similar to true black widows (genus Latrodectus). S. nobilis is a sister group to Latrodectus which possesses the highly potent neurotoxins called α-latrotoxins that can induce neuromuscular paralysis and is responsible for human fatalities. However, and despite this close relationship, the venom composition of S. nobilis has never been investigated. In this context, a combination of transcriptomic and proteomic cutting-edge approaches has been used to deeply characterise S. nobilis venom. Mining of transcriptome data for the peptides identified by proteomics revealed 240 annotated sequences, of which 118 are related to toxins, 37 as enzymes, 43 as proteins involved in various biological functions, and 42 proteins without any identified function to date. Among the toxins, the most represented in numbers are α-latrotoxins (61), δ-latroinsectotoxins (44) and latrodectins (6), all of which were first characterised from black widow venoms. Transcriptomics alone provided a similar representation to proteomics, thus demonstrating that our approach is highly sensitive and accurate. More precisely, a relative quantification approach revealed that latrodectins are the most concentrated toxin (28%), followed by α-latrotoxins (11%), δ-latroinsectotoxins (11%) and α-latrocrustotoxins (11%). Approximately two-thirds of the venom is composed of Latrodectus-like toxins. Such toxins are highly potent towards the nervous system of vertebrates and likely responsible for the array of symptoms occurring after envenomation by black widows and false widows. Thus, caution should be taken in dismissing S. nobilis as harmless. This work paves the way towards a better understanding of the competitiveness of S. nobilis and its potential medical importance.

The noble false widow spider Steatoda nobilis originates from the Macaronesian archipelago and has expanded its range globally. Outside of its natural range, it may have a negative impact on native wildlife, and in temperate regions it lives in synanthropic environments where it frequently encounters humans, subsequently leading to envenomations. S. nobilis is the only medically significant spider in Ireland and the UK, and envenomations have resulted in local and systemic neurotoxic symptoms similar to true black widows (genus Latrodectus). S. nobilis is a sister group to Latrodectus which possesses the highly potent neurotoxins called α-latrotoxins that can induce neuromuscular paralysis and is responsible for human fatalities. However, and despite this close relationship, the venom composition of S. nobilis has never been investigated. In this context, a combination of transcriptomic and proteomic cutting-edge approaches has been used to deeply characterise S. nobilis venom. Mining of transcriptome data for the peptides identified by proteomics revealed 240 annotated sequences, of which 118 are related to toxins, 37 as enzymes, 43 as proteins involved in various biological functions, and 42 proteins without any identified function to date. Among the toxins, the most represented in numbers are α-latrotoxins (61), δ-latroinsectotoxins (44) and latrodectins (6), all of which were first characterised from black widow venoms. Transcriptomics alone provided a similar representation to proteomics, thus demonstrating that our approach is highly sensitive and accurate. More precisely, a relative quantification approach revealed that latrodectins are the most concentrated toxin (28%), followed by α-latrotoxins (11%), δ-latroinsectotoxins (11%) and α-latrocrustotoxins (11%). Approximately two-thirds of the venom is composed of Latrodectus-like toxins. Such toxins are highly potent towards the nervous system of vertebrates and likely responsible for the array of symptoms occurring after envenomation by black widows and false widows. Thus, caution should be taken in dismissing S. nobilis as harmless. This work paves the way towards a better understanding of the competitiveness of S. nobilis and its potential medical importance. [ABSTRACT FROM AUTHOR]