Slay, Fong & Kottmyer
Meta ovalis (Araneae: Tetragnathidae) observed preying on a troglobiotic milliped, Causeyella (Chordeumatida: Trichopetalidae)
Michael E. Slay1, Daniel W. Fong2, and Mark D. Kottmyer1
1The Nature Conservancy, 601 North University Avenue, Little Rock, AR 72705 USA. Email: [email protected] (MES), [email protected] (MDK) 2Department of Biology, American University, 4400 Massachusetts Avenue, NW, Washington, DC 20016 USA. Email: [email protected]
Key Words: Square Cave, Marion County, Arkansas, Arachnida, Diplopoda, predation
Meta ovalis (Gertsch) is a long-jawed orb weaving spider with a distribution extending from the northeast provinces of Canada south through the United States from the Appalachian Mountains to the Ozark Plateaus1. The species is a common inhabitant of entrances and twilight zones of caves in the eastern United States2-5. At more northern latitudes within its distribution, M. ovalis is also found in basements and old houses6. Little is known about feeding habits or prey consumed by M. ovalis. In a cave in Georgia, prey included unspecified Diplopoda and Carabidae5. The European species, Meta menardi (Latreille), has been studied more extensively in caves, and a number of invertebrates were reported as prey including Coleoptera, Diptera, Myriapoda, and even Gastropoda7-12. However, neither species were reported to prey on troglobionts, or cave limited species. Because Meta are typically found in entrances or twilight areas of caves, predatory interactions with troglobiotic invertebrates are limited. However, from June 10-14, 2008, we observed an individual of M. ovalis hanging on a web in total darkness, 26 m from the entrance of Square Cave, Marion County, Arkansas. On June 13, the spider was feeding on a troglobiotic milliped (Figure 1) in the genus Causeyella (Chordeumatida: Trichopetalidae). This milliped was most likely C. youngsteadtorum Shear, because Square Cave occurs well within the range for this cave species13. Yoshida and Shinkai described the predatory behavior of M. menardi in which four different attach sequences were documented14. In sequence 1, spiders bit prey and then carried prey to feeding sites without wrapping prey in silk. In sequence 2, spiders bit prey, wrapped prey in silk, and then transported prey to feeding areas. In sequence 3, spiders first wrapped prey in silk, bit prey, and then carried prey to feeding areas. In sequence 4, spiders wrapped prey in silk, but transported prey to feeding sites without biting. For our observation in Square Cave, it is unclear which attack sequence was used on Causeyella. In Figure 1, M. ovalis is clearly feeding, which indicates the prey has already been moved to a feeding area. The lack of silk wrapped around the milliped suggests M. ovalis might have used attack sequence 1. In a laboratory study, Causeyella millipeds actively roamed15, and our field observations confirm similar behavior. In caves, they are often observed crawling over
2009 Speleobiology Notes 1: 3-5 3 Slay, Fong & Kottmyer moist walls, floors, or ceilings. The active behavior of Causeyella suggests it has a high potential to come in contact with spider predators. However, the frequency of M. ovalis occurring beyond entrances and twilight areas has not been studied, and Causeyella may not be a consistent prey species for this spider.
Figure 1. On June 13, 2008, Meta ovalis (Araneae: Tetragnathidae) was observed feeding on a cave milliped, Causeyella (Chordeumatida: Trichopetalidae), in Square Cave, Marion County, Arkansas. Photo by Michael E. Slay.
Acknowledgements: We thank Chuck Bitting, Buffalo National River, National Park Service, for providing access to the site. Partial funding for this study was provided by Arkansas Game and Fish Commission, The Nature Conservancy (Arkansas Field Office), Cave Conservancy of the Virginias, and the Karst Waters Institute.
Literature Cited: 1. Ubick, D. et al. (Eds). Spiders of North America: an Identification Manual. American Arachnological Society. 377 pp. (2005). 2. Graening, G. O., Slay, M. E. & Bitting, C. Cave fauna of the Buffalo National River. Journal of Cave and Karst Studies 68, 153–163 (2006).
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3. Holsinger, J. R. & Culver, D. C. The invertebrate cave fauna of Virginia and a part of eastern Tennessee: zoology and ecology. Brimleyana 14, 1–162 (1998). 4. Lewis, J. J., Moss, P., Tecic, D. & Nelson, M. E. A conservation focused inventory of subterranean invertebrates of the southwest Illinois Karst. Journal of Cave and Karst Studies 65, 9–21 (2003). 5. Reeves, W. K, Jensen, J. B. & Ozier, J. C. New faunal and fungal records from caves in Georgia, USA. Journal of Cave and Karst Studies 62, 169–179 (2000). 6. Hutchinson, R. Découverte d'une population de Meta menardi (Latreille) dans une vieille cave à Port-au-Saumon (Charlevoix-Est). Pirata 2, 18 (1993). 7. Rogers, C. Meta menardi in underground systems in the south west of England. Studies in Speleology 11, 13–41 (2000). 8. Smithers, P. & Fox Smith, M. Observations on the behaviour of second instars of the cave spider Meta menardi (Latreille, 1804). Newsletter of the British Arachnological Society 81, 4–5 (1998). 9. Smithers, P. Observations of the prey of the cave spider Meta menardi (Latreille, 1804) in South Devon. Newsletter of the British Arachnological Society 77, 12–14 (1996). 10. Smithers, P. Some observations on the distribution of Meta menardi (Latreille) in disused mines in SW Devon. Newsletter of the British Arachnological Society 73, 6 (1995). 11. Smithers, P. The early life history and dispersal of the cave spider Meta menardi (Latreille, 1804) (Araneae: Tetragnathidae). Bulletin of the British Arachnological Society 13, 213–216 (2005). 12. Smithers, P. The diet of the cave spider Meta menardi (Latreille, 1804) (Araneae: Tetragnathidae). Journal of Arachnology 33, 243–246 (2005). 13. Shear, W. A. The millipede family Trichopetalidae, Part 1: introduction and genera Trigenotyla Causey, Nannopetalum n. gen., and Causeyella n. gen. (Diplopoda: Chordeumatidae, Cleidogonoidea). Zootaxa 321, 1–36 (2003). 14. Yoshida, M., & Shinkai, A. Predatory behavior and web structure of Meta menardi (Araneae: Tetragnathidae). Acta Arachnologica 42, 21–25 (1993). 15. Youngsteadt, N. W. Laboratory observations on the behavior of two troglobitic millipede species in the genus Causeyella (Chordeumatida: Trichopetalidae) from the southern Ozarks. Transactions of the Kansas Academy of Science 111, 136– 140 (2008).
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