Freshwater biodiversity is declining faster than marine or terrestrial diversity, yet its drivers are much less known. Although dams were shown to negatively affect river habitats, fragmentation by bridges has received less attention and is not as well understood. We tested whether and how bridges present barriers to aquatic insects by studying mass swarmings of Palingenia longicauda mayflies on river Tisza (NE-Hungary). Behavioural observations showed that upon approaching the bridge, upstream-flying mayflies typically turned back and 86% of them never crossed the bridge. Lack of physical contact showed that the bridge was an optical, rather than a mechanical barrier for the polarotactic mayflies. Imaging polarimetry showed that the bridge disrupted the horizontally polarizing channel guiding the flight of mayflies above the river. Energy loss, demonstrated by calorimetry, and time constraints forced females to lay eggs only downstream from the bridge. Counts of larval skins shed by swarming individuals showed nearly 2 to 1 female per male downstream from the bridge, while sex ratio above the bridge was slightly male-biased. We suggest that the surplus of parthenogenetic females, that produce only female larvae, downstream from the bridge may have led to the observed sex-ratio bias since the construction of the bridge (1942). Our results demonstrate that bridges can be optical barriers for aquatic insects and can cause population-level impacts, such as biased sex ratios, in natural populations. Sex ratio biases due to bridges may decrease effective population size and genetic variability, which may have contributed to the recent extinction of this species from most of Europe.
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Andrikovics S, Turcsányi I (2001) The Long-tailed Mayfly–Ecology of an endangered species, vol 10. Tisza Klub, Szolnok
Barber-James HM, Gattolliat J-L, Sartori M, Hubbard MD (2008) Global diversity of mayflies (Ephemeroptera, Insecta) in freshwater. Hydrobiologia 595:339–350
Bernáth B, Szedenics G, Wildermuth H, Horváth G (2002) How can dragonflies discern bright and dark waters from a distance? The degree of polarization of reflected light as a possible cue for dragonfly habitat selection. Freshw Biol 47:1707–1719
Bernáth B, Kriska G, Suhai B, Horváth G (2008) Wagtails (Aves: Motacillidae) as insect indicators on plastic sheets attracting polarotactic aquatic insects. Acta Zoologica Academiae Scientarum Hungaricae 54(Suppl 1):145–155
Brittain JE, Saltveit SJ (1989) A review of the effect of river regulation on mayflies (Ephemeroptera). Regul Riv Res Manag 3:191–204
Brodskiy AK (1973) The swarming behavior of mayflies (Ephemeroptera). Entomol Rev 52:33–39
Clutius A (1634) De Hemerobio sive Ephemero Insecto & Majali Verme. Opuscula duo singularia. I. De nuce medica II. Jacob Charpentier, Amsterdam
Csabai Z, Boda P, Bernáth B, Kriska G, Horváth G (2006) A ‘polarisation sun-dial’ dictates the optimal time of day for dispersal by flying aquatic insects. Freshw Biol 51:1341–1350
Dudgeon D, Arthington AH, Gessner MO, Kawabata ZI, Knowler DJ, Leveque C, Naiman RJ, Prieur-Richard A-H, Soto D, Stiassny MLJ, Sullivan CA (2006) Freshwater biodiversity: importance, threats, status and conservation challenges. Biol Rev 81:163–182
Dynesius M, Nilsson C (1994) Fragmentation and flow regulation of river systems in the Northern third of the world. Science 266:753–762
Gillies MT, Knowles RJ (1990) Colonization of a parthenogenetic mayfly (Caenidae: Ephemeroptera) from Central Africa. In: Campbell IC (ed) Mayflies and Stoneflies. Kluwer Academic Publishers, Dordrecht, pp 341–345
Horváth G, Varjú D (1997) Polarization pattern of freshwater habitats recorded by video polarimetry in red, green and blue spectral ranges and its relevance for water detection by aquatic insects. J Exp Biol 200:1155–1163
Horváth G, Varjú D (2004) Polarized light in animal vision–polarization patterns in nature. Springer, Heidelberg
Horváth G, Zeil J (1996) Kuwait oil lakes as insect traps. Nature 379:303–304
Horváth G, Bernáth B, Molnár G (1998) Dragonflies find crude oil visually more attractive than water: multiple-choice experiments on dragonfly polarotaxis. Naturwissenschaften 85:292–297
Horváth G, Majer J, Horváth L, Szivák I, Kriska G (2008) Ventral polarization vision in tabanids: horseflies and deerflies (Diptera: Tabanidae) are attracted to horizontally polarized light. Naturwissenschaften 95:1093–1100
Horváth G, Kriska G, Malik P, Robertson B (2009) Polarized light pollution: a new kind of ecological photopollution. Front Ecol Environ 7:317–325
Horváth G, Blahó M, Egri Á, Kriska G, Seres I, Robertson B (2010) Reducing the maladaptive attractiveness of solar panels to polarotactic insects. Conserv Biol 24:1644–1653
Kriska G, Horváth G, Andrikovics S (1998) Why do mayflies lay their eggs en masse on dry asphalt roads? Water-imitating polarized light reflected from asphalt attracts Ephemeroptera. J Exp Biol 201:2273–2286
Kriska G, Csabai Z, Boda P, Malik P, Horváth G (2006) Why do red and dark-coloured cars lure aquatic insects? The attraction of water insects to car paintwork explained by reflection-polarized signals. Proc R Soc B 273:1667–1671
Kriska G, Bernáth B, Horváth G (2007) Positive polaritaxis in a mayfly that never leaves the water surface: polarotactic water detention in Palingenia longicauda (Ephemeroptera). Naturwissenschaften 94:148–154
Kriska G, Bernáth B, Farkas R, Horváth G (2009) Degrees of polarization of reflected light eliciting polarotaxis in dragonflies (Odonata), mayflies (Ephemeroptera) and tabanid flies (Tabanidae). J Insect Physiol 55:1167–1173
Ladócsy K (1930) The mating flight of the Tisza mayfly (Palingenia longicauda, Oliv.) in 1929 in Szeged, part 2. Fishery 31:28–30
Landolt P, Sartori M, Studemann D (1997) Palingenia longicauda (Ephemeroptera, Palingeniidae): from mating to the larvulae stage. In: Landolt P, Sartori M (eds) Ephemeroptera and plecoptera: biology-ecology-systematics. Mauron, Tinguely and Lachat SA, Fribourg, pp 15–20
Lengyel S (1998) An overview of the literature on the biological effects of dams. Természetvédelmi Közlemények 7:19–32
Lengyel S, Kiss B, Müller Z, Aradi C (2004) Colony location, colony structure, and population status of the Long-tailed Mayfly on certain sections of the upper Tisza river. Természetvédelmi Közlemények 11:233–240
Lerner A, Meltser N, Sapir N, Erlick C, Shashar N, Broza M (2008) Reflected polarization guides chironomid females to oviposition sites. J Exp Biol 211:3536–3543
Ligon FK, Dietrich WE, Trush WJ (1995) Downstream ecological effects of dams. Bioscience 45:183–192
Malik P, Hegedüs R, Kriska G, Horváth G (2008) Imaging polarimetry of glass buildings: Why do vertical glass surfaces attract polarotactic insects? Appl Opt 47:4361–4374
Málnás K, Lengyel S, Dévai G (2005) Study of the factors influencing the occurrence of the larvae of the Long-tailed Mayfly [Palingenia longicauda (Olivier)]. Hidrológiai Közlöny 85:91–93
Petts GE (1984) Impounded rivers: perspectives for ecological management. Wiley, Chichester
Prill É, Farkas A, Jakab T, Nagy SA, Dévai G (2008) Analysis of calorimetry results in dragonflies (Odonata). Hidrológiai Közlöny 6:158–161
Russev B (1959) Vol de compensation pour la ponte de Palingenia longicauda (Oliv.) (Ephem.) contre courant du Danube. Comptes Rendus de l’Academie Bulgare des Sciences 12:165–168
Salas M, Dudgeon D (1999) Parthenogenesis in some Hong Kong mayflies (Ephemeroptera). Memoirs Hong Konk Nat His Soc 22:165–169
Sartori M, Landolt P (1998) Memorandum concernant la candidature de Palingenia longicauda (Olivier, 1791) (Insecta Ephemeroptera) a son inscription en annexe de la Convention de Berne. Document T-PVS (98) 15, Council of Europe, Strasbourg
Sartori M, Keller L, Thomas AGB, Passera L (1992) Flight energetics in relation to sexual differences in the mating behaviour of a mayfly, Siphlonurus aestivalis. Oecologia 92:172–176
Sartori M, Landolt P, Lubini V, Ruffieux L (1995) Biological studies of Palingenia longicauda (Olivier) (Ephemeroptera: Palingeniidae) in one of its last European refuges–Abiotic characteristics and description of the habitat. In: Corkum LD, Ciborowski JJH (eds) Current directions in research on ephemeroptera. Canadian Scholars’ Press, Inc., Toronto, pp 263–272
Schwind R (1991) Polarization vision in water insects and insects living on a moist substrate. J Comp Physiol A 169:531–540
Schwind R (1995) Spectral regions in which aquatic insects see reflected polarized light. J Comp Physiol A 177:439–448
Soldán T, Putz M (2000) Karyotypes of some Central European mayflies (Ephemeroptera) and their contribution to phylogeny of the order. Acta Societas Zoologicae Bohemicae 64:437–445
Sweeney BW, Vannote RL (1982) Population synchrony in mayflies: a predator satiation hypothesis. Evolution 36:810–821
Turcsányi I, Szentkirályi F, Bernáth B, Kádár F (2009) Flight of mayflies towards horizontally polarised and unpolarised light. Aquatic Insects 31(Suppl 1):301–310
Wehner R, Labhart T (2006) Polarization vision. In: Warrant EJ, Nilsson DE (eds) Invertebrate vision. Cambridge University Press, Cambridge, pp 291–348
Wildermuth H (1998) Dragonflies recognize the water of rendezvous and oviposition sites by horizontally polarized light: a behavioural field test. Naturwissenschaften 85:297–302
Wildermuth H (2007) Polarotaktische Reaktionen con Coenagrion puella und Libellula quadrimaculata auf Erdbeerkulturen als ökologische Falle (Odonata: Coenagrionidae, Libellulidae). Libellula 26:143–150
World Wildlife Fund (2008) Living Planet Report 2008. Gland
Zwick P (1992) Stream habitat fragmentation–a threat to biodiversity. Biodivers Conserv 1:80–97
We thank the Upper Tisza Inspectorate for Environment, Nature and Water for permits and Z. Barta for comments on the manuscript. Financial support was provided by a grant from the Hungarian Scientific Research Fund (OTKA K-6846) to GH and GK and by the BioFresh EU FP7 research programme (http://www.freshwaterbiodiversity.eu) to SL. Polarimetric equipment was provided by the Alexander von Humboldt Foundation, Germany to GH. RH was supported by a SCAR 6CI fellowship by the International Polar Foundation, and SL by a Bolyai Research Fellowship from the Hungarian Academy of Sciences and by two OTKA-Norway Financing Mechanism grants (NNG 78887, 85562) during manuscript preparation.
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Málnás, K., Polyák, L., Prill, É. et al. Bridges as optical barriers and population disruptors for the mayfly Palingenia longicauda: an overlooked threat to freshwater biodiversity?. J Insect Conserv 15, 823–832 (2011). https://doi.org/10.1007/s10841-011-9380-0
- Aquatic insects
- Ephemeroptera: Palingeniidae
- Polarization vision
- Energy use in insect flight
- Sex ratio