Predation by a Brown Widow Spider, Latrodectus Geometricus
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Herpetology Notes, volume 14: 291-296 (2021) (published online on 09 February 2021) Predation by a Brown Widow Spider, Latrodectus geometricus (Koch, 1841), on a Common Dwarf Gecko, Lygodactylus capensis (Smith, 1849), with a review of the herpetofaunal diet of Latrodectus spiders Daniel van Blerk1, John Measey1,*, and James Baxter-Gilbert1 The Common Dwarf Gecko, Lygodactylus capensis box (Fig. 1A). The lizard was initially found at 17:13 h, (Smith, 1849), is a small, diurnal gekkonid with a writhing in the web and suspended above its autotomised wide African distribution, ranging from Kenya to tail, which lay on the base of the electrical box. At this northeastern South Africa and extending westward time, the spider was present on the electrical box, but not into Namibia and Angola (Rebelo et al., 2019). This in contact with the lizard. Shortly after being observed species is naturally absent from western South Africa, and identified, the spider retreated into the refuge of the but invasive populations have been observed scattered electrical box. By 17:18 h the lizard was motionless and across much of the country – including in large urban appeared dead, its hind legs having been wrapped against centres such as Bloemfontein, Cape Town, East London, the body with spider silk (Fig. 1B). On the final visit to George, Makhanda (formerly Grahamstown), and Port the electrical box at 17:48 h, the deceased lizard had been Elizabeth (Rebelo et al., 2019; Conradie et al., 2020). removed from its original position in the web and could The successful spread of L. capensis may be attributed not be seen. We presume the spider had pulled the body to this lizard’s proclivity for urban ecosystems and other further into its refuge to feed on it safely without further heavily human-modified habitats, as these lizards are able disturbance. to exploit novel resources and can capitalise on human Previous reports have stated that these lizards are transportation networks to facilitate extralimital range frequent prey items for a variety of vertebrates, including expansions (Rebelo et al., 2019). This anthropophilic birds, lizards, mammals, and snakes (Simbotwe, 1983; behaviour, however, may also result in L. capensis Maritz and Maritz, 2020a,b), as well as predatory encountering other urbanised taxa more frequently – invertebrates, including Rain Spiders (genus Palystes), including potential predators such as Latrodectus spiders. Baboon Spiders (genus Harpactirella), Crab Spiders Here we report one such encounter, during which a L. (genus Misumena), and mantids (genus Sphodromantis) capensis was seen to have been attacked by a Brown (Warren, 1923; Bauer, 1990; Maritz and Maritz, 2020a,b). Widow Spider, Latrodectus geometricus (Koch, 1841), To the best of our knowledge, this is the first observation in one of the lizard’s invasive populations near George, of a predation event by L. geometricus on L. capensis. South Africa (centred on 33.99°S, 22.45°E). Latrodectus geometricus has a near-global distribution On 19 August 2020 at a private residence in Heather related to its anthropophilic nature, with known invasive Park, George, Western Cape, South Africa (33.9581°S, populations in North and South America, Hawaii, and 22.4213°E), the first author observed an adult dwarf across Australasia (Taucare-Ríos et al., 2016), and it gecko (L. capensis) entangled within a brown widow (L. is presumed to be native to southern Africa (see Garb geometricus) web inside an outdoor dual-socket electrical et al., 2004; Brown et al., 2008; Measey et al., 2020). Across its native and invasive range, L. geometricus has been seen to feed on a wide variety of herpetofauna (Table 1). Known African reptile prey items in the 1 Centre for Invasion Biology, Department of Botany and native range include Herald Snakes, Crotaphopeltis Zoology, Stellenbosch University, Stellenbosch, Western hotamboeia (Laurenti, 1768), Brown House Snakes, Cape, South Africa. Boaedon capensis (Boie, 1827), and Kalahari Tree * Corresponding author. Email: [email protected] Skinks, Trachylepis spilogaster (Peters, 1882) (Bayliss, © 2021 by Herpetology Notes. Open Access by CC BY-NC-ND 4.0. 2001; Maritz and Maritz 2020a,b). Observations of 292 Daniel van Blerk et al. Figure 1. A live adult Common Dwarf Gecko, Lygodactylus capensis, entangled in the web of a Brown Widow Spider, Latrodectus geometricus, at Heather Park, George, Western Cape, South Africa. The lizard was alive at 17:13 h (A) and appeared to be dead by 17:18 h (B). Upon first observation, the spider was seen and identified, however it retreated before it could be photographed and remained reluctant to emerge. The autotomised tail can be seen suspended in the web between the switches as indicated by the red arrow in (A). L. geometricus feeding on herpetofauna within their frenatus in Mexico (de Luna et al., 2020) or L. capensis. invasive ranges in the Americas include Scarlet Snakes, The increasing expansion of urban areas globally Cemophora coccinea (Blumenbach, 1788) (Stevenson (Chen et al., 2020), along with continued transport and and Crook, 2018), Asian House Geckos, Hemidactylus propagation of invasive species (Seebens et al., 2017), have frenatus Duméril & Bibron, 1836 (de Luna et al., 2020), led to novel predator-prey interactions in anthropogenic Brahminy Blindsnakes, Indotyphlops braminus (Daudin, habitats. Although in general both L. capensis and L. 1803) (Martínez-Coronel and Navarrete-Jiménez, 2018), geometricus are native southern African species, the fact and Black-headed Snakes, Tantilla melanocephala that they both capitalise on human habitats may result in (Linneaus, 1758) (Rocha et al., 2017). Taken together, increased interactions between them, especially as urban it is clear that these spiders are formidable predators of populations in their native and invasive ranges expand. small-bodied reptiles. Overall, this observation adds both to the growing list of In general, spiders of the genus Latrodectus have known predators for L. capensis and known vertebrate a global reputation for feeding on vertebrate prey, prey for Latrodectus spiders. including a variety of herpetofauna – encompassing frogs, lizards, and snakes (Table 1). As a group, these Acknowledgments. We thank Robin and Bryan Maritz for their insight into the variety of known predators of L. capensis and spiders possess potent venom and strong webs, enabling access to their Predation Records Online Data Repository, which them to capture and kill prey items considerably larger was immensely helpful in writing this manuscript. We would also than themselves (O’Shea and Kelly, 2017; Nyffeler and like to thank the DSI-NRF Centre of Excellence for Invasion Vetter, 2018). Furthermore, Latrodectus spiders have a Biology for their support. tendency to thrive in anthropogenic habitats, possibly associated with beneficial structural, thermal, and hydric References conditions associated with urban landscapes, which has Arteaga-Tinoco, I., Anguiano-Peña, J., Raya-García E., Alvarado- further expanded their cosmopolitan distribution (Vink et Díaz, J. (2016): Natural history notes. Hyla eximia (Mountain al., 2011). Thus, it is unsurprising that they have been Tree Frog). Predation. Herpetological Review 47: 641–642. regularly seen feeding on other anthropophilic taxa, such Bayliss, P.S. (2001): Natural history notes. Lamprophis fuliginosus as invasive and human-commensal herpetofauna, like H. (Brown House Snake). Predation. Herpetological Review 32: 48–49. Table 1. Amphibian and reptile prey of Latrodectus spiders. Latrodectus Prey Taxon Latrodectus Species Reference Predation on Amphibians andReptiles Predationon FROGS Hylidae Dryophytes eximius (Baird, 1854) L. mactans Fabricius, 1775 Arteaga-Tinoco et al., 2016 LIZARDS Anguidae Elgaria multicarinata (Blainville, 1835) L. hesperus Chamberlin & Ivie, 1935 Thill and Feldman, 2019 Gekkonidae Christinus marmoratus (Gray, 1845) L. hasselti Thorell, 1870 König, 1987; Orange, 2007 Gehyra variegata (Duméril & Bibron, 1836) L. hasselti Orange, 2007 Hemidactylus frenatus (Duméril & Bibron, 1836) L. geometricus de Luna et al., 2020 Lacertidae Acanthodactylus erythrurus (Schinz, 1833) L. lilianae Melic, 2000 Hódar and Sánchez-Piñero, 2002 Mesalina guttulata (Lichtenstein, 1823) L. pallidus Charitonov, 1954 Blondheim and Werner, 1989 Mesalina guttulata L. revivensis Shulov, 1948 Zilberberg, 1988 Podarcis melisellensis (Braun, 1877) L. tredecimguttatus Rossi, 1790 Schwammer and Baurecht, 1988 Psammodromus algirus (Linnaeus, 1758) L. lilianae Hódar and Sánchez-Piñero, 2002 Psammodromus hispanicus Fitzinger, 1826 L. lilianae Hódar and Sánchez-Piñero, 2002 Phrynosomatidae Phrynosoma hernandesi Girard, 1858 L. hesperus Painter and Kamees, 2010 Uta stansburiana Baird & Girard, 1852 L. mactans Wilson, 1991; Lane, 2012 Phyllodactylidae Tarentola mauritanica (Linnaeus, 1758) L. lilianae Hódar and Sánchez-Piñero, 2002 Scincidae Anomalopus verreauxii Duméril, 1851 L. hasselti Raven, 1990 Chalcides ocellatus (Forskal, 1775) L. tredecimguttatus Colombo, 2013 Cryptoblepharus pulcher (Sternfeld, 1918) L. hasselti Cook, 1973; Raven, 1990 Hemiergis quadrilineata (Duméril & Bibron, 1839) L. hasselti Orange, 2007 Lampropholis delicata (De Vis, 1888) L. hasselti Metcalfe and Ridgeway, 2013 Lampropholis guichenoti (Duméril & Bibron, 1839) L. hasselti Copland, 1953 293 Lygosoma sp. L. hasselti McKeown, 1943 294 Table 1 (cont.) Prey Taxon Latrodectus Species Reference Scincidae (cont.) Scincella lateralis (Say, 1822) L. mactans Neill, 1948 Saproscincus