Author's personal copy A new tabanid trap applying a modified concept of the old flypaper: Linearly polarising sticky black surfaces as an effective tool to catch polarotactic horseflies Ádám Egri a , Miklós Blahó a , Dénes Száz a , András Barta b , György Kriska c,d , Györgyi Antoni e , Gábor Horváth a,⇑ a Environmental Optics Laboratory, Department of Biological Physics, Physical Institute, Eötvös University, Pázmány sétány 1, H-1117 Budapest, Hungary b Estrato Research and Development Ltd., Mártonlak utca 13, H-1121 Budapest, Hungary c Group for Methodology in Biology Teaching, Biological Institute, Eötvös University, Pázmány sétány 1, H-1117 Budapest, Hungary d Danube Research Institute, Centre for Ecological Research, Hungarian Academy of Sciences, Alkotmány út 2-4, 2163 Vácrátót, Hungary e Center for Innovation and Grant Affairs, Eötvös University, Szerb utca 21-23, H-1056 Budapest, Hungary article info Article history: Received 29 September 2012 Received in revised form 2 February 2013 Accepted 4 February 2013 Available online 13 March 2013 Keywords: Horsefly Tabanid trap Sticky black surface Polarotaxis Water detection Host choice abstract Trapping flies with sticky paper sheets is an ancient method. The classic flypaper has four typical char- acteristics: (i) its sticky paper is bright (chamois, light yellow or white), (ii) it is strip-shaped, (iii) it hangs vertically, and (iv) it is positioned high (several metres) above ground level. Such flypapers, however, do not trap horseflies (tabanids). There is a great need to kill horseflies with efficient traps because they are vectors of dangerous diseases, and due to their continuous annoyance livestock cannot graze, horses cannot be ridden, and meat and milk production from cattle is drastically reduced. Based on earlier findings on the positive polarotaxis (attraction to linearly polarised light) in tabanid flies and modifying the concept of the old flypaper, we constructed a new horsefly trap called ’’horseflypaper’’. In four field experiments we showed that the ideal horseflypaper (i) is shiny black, (ii) has an appropriately large (75 Â 75 cm 2 ) surface area, (iii) has sticky black vertical and horizontal surfaces in an L-shaped arrange- ment, and (iv) its horizontal surface should be at ground level for maximum effectiveness. Using imaging polarimetry, we measured the reflection-polarisation characteristics of this new polarisation tabanid trap. The ideal optical and geometrical characteristics of this trap revealed in field experiments are also explained. The horizontal part of the trap captures water-seeking male and female tabanids, while the vertical part catches host-seeking female tabanids. Ó 2013 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved. 1. Introduction It is a well-known fact that certain flies can be trapped by a sticky paper strip hanging vertically from the ceiling. This ancient trap is called ‘‘flypaper’’ and has been used from the beginning of the history of mankind (Beavis, 1988). Several different types of such flytraps are used to catch various insect species/groups for scientific purposes (Jactel et al., 2006; Kamarudin and Arshad, 2006; Chadee and Ritchie, 2010; Faiman et al., 2011), or for practi- cal reasons in agriculture (Coli et al., 1985; Stejskal, 1995; Cross et al., 2006; Moreau and Isman, 2012). Depending on their applica- tion, the material (paper or plastic), colour, shape (e.g. rectangular or circular), stickiness (more or less tacky), alignment (vertical, tilted or horizontal) and position (e.g. laid on the ground, on an ele- vated substrate or hanging high in the air) of these flytraps differ. Classic flypapers possess four typical characteristics: (i) their sticky paper is usually bright (chamois, light yellow or white), (ii) their shape is a strip, (iii) they hang vertically in the air, and (iv) they are positioned several metres above the ground so they will not disturb people and/or animals in the vicinity. Although these classic flypapers catch numerous different in- sect species, they do not trap tabanid flies. However, there is a great need to kill tabanids with effective traps because they are vectors of dangerous diseases (Foil, 1989; Luger, 1990; Hall et al., 1998; Sasaki, 2001; Lehane, 2005). Also, their continuous annoy- ance to livestock prevents grazing; horses cannot be ridden and meat and milk production from cattle is drastically reduced (Hunter and Moorhouse, 1976; Harris et al., 1987; Lehane, 2005). Several different trap types have been developed to reduce the number of tabanids (Malaise, 1937; Gressitt and Gressitt, 1962; Wilson et al., 1966; Catts, 1970; Roberts, 1977; von Kniepert, 1979; Hayakawa, 1980; Wall and Doane, 1980; Hribar et al., 1991, 1992; Moore et al., 1996; Mihok, 2002). There are three main kinds of conventional tabanid traps: (i) flight interception traps, (ii) chemically baited canopy traps, and (iii) optically baited canopy traps. The common feature of these traps is that they are designed to attract female tabanids visually with shiny black objects and/or 0020-7519/$36.00 Ó 2013 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.ijpara.2013.02.002 ⇑ Corresponding author. Tel.: +36 30 64 64 371; fax: +36 1 372 2757. E-mail address: gh@arago.elte.hu (G. Horváth). International Journal for Parasitology 43 (2013) 555–563 Contents lists available at SciVerse ScienceDirect International Journal for Parasitology journal homepage: www.elsevier.com/locate/ijpara