Folio N° 869

Folio N° 869 ANTECEDENTES ENTREGADOS POR ÁLVARO BOEHMWALD 1. ANTECEDENTES SOBRE BIODIVERSIDAD • Ala-Laurila, P, (2016), Visual Neuroscience: How Do Moths See to Fly at Night?. • Souza de Medeiros, B, Barghini, A, Vanin, S, (2016), Streetlights attract a broad array of beetle species. • Conrad, K, Warren, M, Fox, R, (2005), Rapid declines of common, widespread British moths provide evidence of an insect biodiversity crisis. • Davies, T, Bennie, J, Inger R, (2012), Artificial light pollution: are shifting spectral signatures changing the balance of species interactions?. • Van Langevelde, F, Ettema, J, Donners, M, (2011), Effect of spectral composition of artificial light on the attraction of moths. • Brehm, G, (2017), A new LED lamp for the collection of nocturnal Lepidoptera and a spectral comparison of light-trapping lamps. • Eisenbeis, G, Hänel, A, (2009), Chapter 15. Light pollution and the impact of artificial night lighting on insects. • Gaston, K, Bennie, J, Davies, T, (2013), The ecological impacts of nighttime light pollution: a mechanistic appraisal. • Castresana, J, Puhl, L, (2017), Estudio comparativo de diferentes trampas de luz (LEDs) con energia solar para la captura masiva de adultos polilla del tomate Tuta absoluta en invernaderos de tomate en la Provincia de Entre Rios, Argentina. • McGregor, C, Pocock, M, Fox, R, (2014), Pollination by nocturnal Lepidoptera, and the effects of light pollution: a review. • Votsi, N, Kallimanis, A, Pantis, I, (2016), An environmental index of noise and light pollution at EU by spatial correlation of quiet and unlit areas. • Verovnik, R, Fiser, Z, Zaksek, V, (2015), How to reduce the impact of artificial lighting on moths: A case study on cultural heritage sites in Slovenia. • Stavenga, D, Foletti, S, Palasantzas, G, (2006), Light on the moth-eye corneal nipple array of butterflies. Current Biology Folio N° 870 Dispatches 11. Whitney, H.M., Bennett, K.M.V., Dorling, M., relevant cue in plant-pollinator signaling? New floral region. South Africa. Ann. Bot. Lond. 100, Sandbach, L., Prince, D., Chittka, L., and Phytol. 205, 18–20. 1483–1489. Glover, B.J. (2011). Why do so many petals 14. Thomas, M., Rudall, P., Ellis, A., Savolainen, have conical epidermal cells? Ann. Bot. Lond. 16. Dafni, A., Bernhardt, P., Shmida, A., Ivri, Y., V., and Glover, B.J. (2009). Development of a 10, 609–616. Greenbaum, S., O’Toole, C., and Losito, L. complex floral trait: the pollinator-attracting (1990). Red bowl-shaped flowers: 12. Whitney, H.M., Chittka, L., Bruce, T.J., petal spots of the beetle daisy, Gorteria convergence for beetle pollination in the and Glover, B.J. (2009). Conical epidermal diffusa (Asteraceae). Am. J. Bot. 96 , 2184– Mediterranean region. Israel J. Bot. 39, 81–92. cells allow bees to grip flowers and 2196. increase foraging efficiency. Curr. Biol. 19, 948–953. 15. van Kleunen, M., Na¨ nni, I., Donaldson, J.S., 17. Lunau, K., Piorek, V., Krohn, O., and Pacini, E. and Manning, J.C. (2007). The role of beetle (2015). Just spines – mechanical defence of 13. van der Kooi, C.J., Dyer, A.G., and Stavenga, marks and flower colour on visitation by malvaceous pollen against collection by D.G. (2015). Is floral iridescence a biologically monkey beetles (Hopliini) in the greater cape corbiculate bees. Apidologie 46 , 144–149. Visual Neuroscience: How Do Moths See to Fly at Night? Petri Ala-Laurila1,2 1Department of Biosciences, University of Helsinki, Helsinki, Finland 2Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland Correspondence: Petri.Ala-Laurila@helsinki.fi http://dx.doi.org/10.1016/j.cub.2016.01.020 A new study shows that moth vision trades speed and resolution for contrast sensitivity at night. These remarkable neural adaptations take place in the higher-order neurons of the hawkmoth motion vision pathway and allow the insects to see during night flights. We spend most of our waking time in In these conditions, visual The basic trick for enhancing the daylight or in the well-lit indoor spaces of signals originating in a small number of quality of photos at night is well known modern life. Under these conditions vision photoreceptor cells have to be detected to all photographers: pooling photons provides us with a reliable representation against neural noise originating in a much in space (increasing ‘pixel size’) and of the world around us rich in colors larger number of such cells, as well as in time (prolonging the exposure time) will and spatial details. But imagine being in the neural circuitry processing these sparse boost the signals. There are mechanisms the wilderness far from the city lights. signals. The randomness of rare photon implementing similar pooling at multiple Everything changes at sunset. The arrivals makes it even harder to form reliable levels of the visual systems of both comfortable certainty of daytime vision visual percepts in dim light. Yet many invertebrates and vertebrates. In our own is replaced by the uncertainty hidden in the species show remarkable visual capabilities retina, rod photoreceptors used mainly at deep shadows of twilight. As the sun’s last at extremely low light levels. The classic low light levels have a longer integration rays create a faint golden rim on the horizon study by Selig Hecht and his colleagues [2] time than cone photoreceptors that we your visual experience becomes less showed that dark-adapted humans can use in daytime. This is one example of dominant. The sounds of the night awaken detect just a few light quanta absorbed receptor-level temporal summation. your imagination and can cause even a on a small region of the peripheral retina. Spatially, the visual circuits mediating slight sensation of fear of the invisible Dark-adapted toads can capture their rod signals in our own eyes pool signals inhabitants of the wilderness hidden in the prey easily in starlight [3].Nocturnal from thousands of rods at the lowest dark. Suddenly something passes you in Central American sweat bees can find light levels, whereas our highest the air flying — a hawkmoth! How on earth their nest in the jungle at night resolution foveal cone vision relies on can a moth fly at these extremely low light [4]. Cockroaches show visually guided one-to-one connections between the levels? An answer to this question is behaviour at light levels where only a few cones and the midget ganglion cells at provided in this issue of Current Biology:a photons are captured among hundreds the retinal output. In many invertebrates, new study by Sto¨ ckl et al. [1] shows that of photoreceptors [5]. Nocturnal African the migration of screening pigments neural adaptations taking place in higher- dung beetles can navigate with the aid allows dynamic control of the spatial order neurons of the moth motion vision of polarized moonlight [6]. In all of summation at the receptor level [7]. It has pathway enable them to see ‘on the wing’ these cases, the striking behavioral also been proposed that the electrical even in incredibly low light. performance of animals in dim lightexceeds coupling of rod photoreceptors in the Seeing under very dim light poses a that of individual receptor cells at their vertebrate eye is more extensive at night formidable challenge for the visual system. visual inputs by orders of magnitude. time [8]. Current Biology 26 , R229–R246, March 21, 2016 ª2016 Elsevier Ltd All rights reserved R231 CurrentFolio Biology N° 871 Dispatches blown flowers at night. Taking together the findings of these two beautiful studies, we now have a perfect answer. The Sto¨ ckel et al. [1] paper provides the neural account for this earlier behavioral result by directly showing that the moth brain slows down in the dark. These two studies [1,9] together suggest that the neural mechanisms of the moth visual system have been matched perfectly to the requirements of its environment. What neural mechanisms underlie the spatial and temporal summation in Spatial summation the moth motion vision pathway? Sto¨ ckl et al. [1] do not give a direct answer to Visual this question. However, their modeling information predicts that the neural mechanism is Temporal summation supralinear, giving more advantage to contrast sensitivity than a simple linear Image at visual input Motion vision pathway Processed image summation of temporal and spatial effects would predict. This exciting prediction is in line with the idea that Figure 1. Visual processing in the motion vision pathway of a nocturnal hawkmoth. optimal performance at visual threshold The noisy image with low contrast present at the level of hawkmoth photoreceptors (inset, left) is enhanced in contrast (inset, right) by spatial and temporal summation taking place in the higher-order neurons. These relies on elegant nonlinear neural neural computations are supralinear, producing higher contrast sensitivity than predicted by a simple computations taking place in the visual linear model relying on spatial and temporal pooling only. circuits. Earlier literature in the vertebrate visual system showed that the detection of Unfortunately, there is no free lunch — the photoreceptors on contrast sensitivity the weakest lights relies to a large extent especially not in biology. Pooling signals in and to compare these constraints to the on nonlinear noise filtering mechanisms at space and time comes with fundamental contrast sensitivity measured at the level multiple levels of the neural circuit [10,11]. limitations. First, although spatial pooling of the moth brain in the wide-field motion It remains to be seen in future studies how increases signals arising from photons, it detecting neurons. This unique approach exactly the computations revealed by also increases neural noise. Second, the allowed them to quantify the amount of Sto¨ ckl et al. [1] are implemented and what more you pool in time and space the neural summation taking place in the visual noise sources truly limit detection under slower your vision is and the fewer fine pathway of the moth across a 10,000-fold these conditions.

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