Stacking the odds : light pollution may shift the balance in an ancient predator-prey arms race

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dc.contributor.author Minnaar, Corneile
dc.contributor.author Boyles, Justin G.
dc.contributor.author Minnaar, I.A. (Ingrid Ane)
dc.contributor.author Sole, Catherine L.
dc.contributor.author McKechnie, Andrew E.
dc.date.accessioned 2016-02-10T05:33:02Z
dc.date.issued 2015-04
dc.description.abstract 1. Artificial night-lighting threatens to disrupt strongly conserved light-dependent processes in animals and may have cascading effects on ecosystems as species interactions become altered. Insectivorous bats and their prey have been involved in a nocturnal, coevolutionary arms race for millions of years. Lights may interfere with anti-bat defensive behaviours in moths, and disrupt a complex and globally ubiquitous interaction between bats and insects, ultimately leading to detrimental consequences for ecosystems on a global scale. 2. We combined experimental and mathematical approaches to determine effects of light pollution on a free-living bat–insect community. We compared prey selection by Cape serotine bats Neoromicia capensis in naturally unlit and artificially lit conditions using a manipulative field experiment, and developed a probabilistic model based on a suite of prey-selection factors to explain differences in observed diet. 3. Moth consumption by N. capensis was low under unlit conditions (mean percentage volume ± SD: 5.91 ± 6.25%), while moth consumption increased six-fold (mean percentage volume ± SD: 35.42 ± 17.90%) under lit conditions despite a decrease in relative moth abundance. Predictive prey-selection models which included high-efficacy estimates for eared-moth defensive behaviour found most support given diet data for bats in unlit conditions. Conversely, models which estimated eared-moth defensive behaviour as absent or low, found more support given diet data for bats in lit conditions. Our models therefore suggest the increase in moth consumption was a result of light-induced, decreased eared-moth defensive behaviour. 4. Policy implications. In the current context of unyielding growth in global light pollution, we predict that specialist moth-eating bats and eared-moths will face ever-increasing challenges to survival through increased resource competition and predation risk, respectively. Lights should be developed to be less attractive to moths, with the goal of reducing effects on moth behaviour. Unfortunately, market preference for broad-spectrum lighting and possible effects on other taxa make development of moth-friendly lighting improbable. Mitigation should therefore focus on the reduction of temporal, spatial, and luminance redundancy in outdoor lighting. Restriction of light inside nature reserves and urban greenbelts can serve as dark refugia for moth-eating bats and moths, and may become important for their persistence. en_ZA
dc.description.embargo 2016-04-30
dc.description.librarian hb2015 en_ZA
dc.description.sponsorship Bat Conservation International and the South African National Research Foundation (grant number 74604). en_ZA
dc.description.uri http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1365-2664 en_ZA
dc.identifier.citation Minnaar, C, Boyles, JG, Minnaar, IA, Sole, CL & McKechnie, AE 2015, 'Stacking the odds : light pollution may shift the balance in an ancient predator-prey arms race', Journal of Applied Ecology, vol. 52, no. 2, pp. 522-531. en_ZA
dc.identifier.issn 0021-8901 (print)
dc.identifier.issn 1365-2664 (online)
dc.identifier.other 10.1111/1365-2664.12381
dc.identifier.uri http://hdl.handle.net/2263/51297
dc.language.iso en en_ZA
dc.publisher Wiley en_ZA
dc.rights © 2014 British Ecological Society. This is the pre-peer reviewed version of the following article : Stacking the odds : light pollution may shift the balance in an ancient predator-prey arms race,Journal of Applied Ecology, vol.52, no. 2, pp. 522-531. 2015. doi :10.1111/1365-2664.12381. The definite version is available at : http://onlinelibrary.wiley.comjournal/10.1111/(ISSN)1365-2664. en_ZA
dc.subject Arms race en_ZA
dc.subject Cape serotine bat en_ZA
dc.subject Coevolution en_ZA
dc.subject Eared moth en_ZA
dc.subject Light pollution en_ZA
dc.subject Neoromicia capensis en_ZA
dc.subject Predator–prey interactions en_ZA
dc.subject Prey selection en_ZA
dc.subject Lepidoptera en_ZA
dc.title Stacking the odds : light pollution may shift the balance in an ancient predator-prey arms race en_ZA
dc.type Postprint Article en_ZA


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