Publications by authors named "Gabriel E Machovsky-Capuska"

18 Publications

  • Page 1 of 1

Detrimental effects of urbanization on the diet, health, and signal coloration of an ecologically successful alien bird.

Sci Total Environ 2021 Jul 2;796:148828. Epub 2021 Jul 2.

School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW 2308, Australia.

Theory suggests that overcrowding and increased competition in urban environments might be detrimental to individual condition in avian populations. Unfavourable living conditions could be compounded by changes in dietary niche with additional consequences for individual quality of urban birds. We analysed the isotopic signatures, signal coloration, body condition, parasitic loads (feather mites and coccidia), and immune responsiveness of 191 adult common (Indian) mynas (Acridotheres tristis) captured in 19 localities with differing levels of urbanization. The isotopic signature of myna feathers differed across low and high urbanized habitats, with a reduced isotopic niche breadth found in highly urbanized birds. This suggests that birds in high urban environments may occupy a smaller foraging niche to the one of less urbanized birds. In addition, higher degrees of urbanization were associated with a decrease in carotenoid-based coloration, higher ectoparasite loads and higher immune responsiveness. This pattern of results suggests that the health status of mynas from more urbanized environments was poorer than mynas from less modified habitats. Our findings are consistent with the theory that large proportions of individual birds that would otherwise die under natural conditions survive due to prevailing top-down and bottom-up ecological processes in cities. Detrimental urban ecological conditions and search for more favourable, less crowded habitats offers the first reasonable explanation for why an ecological invader like the common myna continues to spread within its global invasive range.
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http://dx.doi.org/10.1016/j.scitotenv.2021.148828DOI Listing
July 2021

Plastic ingestion as an evolutionary trap: Toward a holistic understanding.

Science 2021 Jul;373(6550):56-60

Laboratório de Ictiologia, Universidade Federal do Espírito Santo, Goiabeiras 29075-910, Vitória, ES, Brazil.

Human activities are changing our environment. Along with climate change and a widespread loss of biodiversity, plastic pollution now plays a predominant role in altering ecosystems globally. Here, we review the occurrence of plastic ingestion by wildlife through evolutionary and ecological lenses and address the fundamental question of why living organisms ingest plastic. We unify evolutionary, ecological, and cognitive approaches under the evolutionary trap theory and identify three main factors that may drive plastic ingestion: (i) the availability of plastics in the environment, (ii) an individual's acceptance threshold, and (iii) the overlap of cues given by natural foods and plastics.
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http://dx.doi.org/10.1126/science.abh0945DOI Listing
July 2021

Eat yourself sexy: how selective macronutrient intake influences the expression of a visual signal in common mynas.

J Exp Biol 2021 05 4;224(9). Epub 2021 May 4.

School of Psychology, University of Newcastle, Callaghan, NSW 2308, Australia.

Producing colored signals often requires consuming dietary carotenoid pigments. Evidence that food deprivation can reduce coloration, however, raises the question of whether other dietary nutrients contribute to signal coloration, and furthermore, whether individuals can voluntarily select food combinations to achieve optimal coloration. We created a two-way factorial design to manipulate macronutrient and carotenoid access in common mynas (Acridotheres tristis) and measured eye patch coloration as a function of the food combinations individuals selected. Mynas had access to either water or carotenoid-supplemented water and could either eat a standard captive diet or choose freely between three nutritionally defined pellets (protein, lipid or carbohydrate). Mynas supplemented with both carotenoids and macronutrient pellets had higher color scores than control birds. Male coloration tended to respond more to nutritional manipulation than females, with color scores improving in macronutrient- and carotenoid-supplemented individuals compared with controls. All mynas consuming carotenoids had higher levels of plasma carotenoids, but only males showed a significant increase by the end of the experiment. Dietary carotenoids and macronutrient intake consumed in combination tended to increase plasma carotenoid concentrations the most. These results demonstrate for the first time that consuming specific combinations of macronutrients along with carotenoids contributes to optimizing a colorful signal, and point to sex-specific nutritional strategies. Our findings improve our knowledge of how diet choices affect signal expression and, by extension, how nutritionally impoverished diets, such as those consumed by birds in cities, might affect sexual selection processes and, ultimately, population dynamics.
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http://dx.doi.org/10.1242/jeb.241349DOI Listing
May 2021

Exploring plastic-induced satiety in foraging green turtles.

Environ Pollut 2020 Oct 5;265(Pt B):114918. Epub 2020 Jun 5.

The Charles Perkins Centre, The University of Sydney, NSW, 2006, Sydney, Australia.

In the last decade many studies have described the ingestion of plastic in marine animals. While most studies were dedicated to understanding the pre-ingestion processes involving decision-making foraging choices based on visual and olfactory cues of animals, our knowledge in the post-ingestion consequences remains limited. Here we proposed a theoretical complementary view of post-ingestion consequences, attempting to connect plastic ingestion with plastic-induced satiety. We analyzed data of plastic ingestion and dietary information of 223 immature green turtles (Chelonia mydas) from tropical Brazilian reefs in order to understand the impacts of plastic ingestion on foraging behavior. Generalized linear mixing models and permutational analysis of variance suggested that plastic accumulations in esophagus, stomach and intestine differed in their impact on green turtle's food intake. At the initial stages of plastic ingestion, where the plastic still in the stomach, an increase in food intake was observed. The accumulation of plastic in the gastrointestinal tract can reduce food intake likely leading to plastic-induced satiety. Our results also suggest that higher amounts of plastics in the gastrointestinal tract may led to underweight and emaciated turtles. We hope that adopting and refining our proposed framework will help to clarify the post-ingestion consequences of plastic ingestion in wildlife.
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http://dx.doi.org/10.1016/j.envpol.2020.114918DOI Listing
October 2020

Linking cadmium and mercury accumulation to nutritional intake in common dolphins (Delphinus delphis) from Patagonia, Argentina.

Environ Pollut 2020 Aug 1;263(Pt A):114480. Epub 2020 Apr 1.

Instituto de Investigaciones Marinas y Costeras, Departamento de Ciencias Marinas, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, CONICET, Funes 3350, Mar del Plata, B7602AYL, Argentina; Laboratorio de Ecotoxicología, Departamento de Ciencias Marinas, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Mar del Plata, Argentina.

Bioaccumulation of Hg and Cd from food is a complex ecological process that has been oversimplified in the past. Common dolphins (Delphinus delphis) provide a powerful model to biomonitor metal concentrations in marine environments worldwide. We combined proportions-based nutritional geometry with metal analysis, stomach content analysis and the proximate composition of prey, to yield novel insights into the accumulation of Hg and Cd. Our analysis showed an age-related accumulation trend for Cd and Hg in kidney and liver, with highest concentrations found at 18 years of age. When viewed through the lens of nutritional ecology, Argentine anchovy (58.1 Mass %) and South American long-finned squid (22.7 Mass %), provided most of the dietary intake of protein (P) and lipids (L) (P:L ratio = 2.6:1.0) and also represented the main source for Cd and Hg levels accumulated in their bodies. This study presents unprecedented evidence on metal accumulation in relation to age and nutritional intake in a marine predator.
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http://dx.doi.org/10.1016/j.envpol.2020.114480DOI Listing
August 2020

Biologging Special Feature.

J Anim Ecol 2020 01;89(1):6-15

Department of Biology, Memorial University of Newfoundland, St. John's, NL, Canada.

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http://dx.doi.org/10.1111/1365-2656.13163DOI Listing
January 2020

Debris ingestion and nutritional niches in estuarine and reef green turtles.

Mar Pollut Bull 2020 Apr 6;153:110943. Epub 2020 Feb 6.

Instituto de Ciências Biológicas e da Saúde, Universidade Federal de Alagoas, Av. Lourival Melo Mota, s/n, Cidade Universitária, 57072-900 Maceió, AL, Brazil.

Little attention has been drawn toward the effects of marine debris ingestion in relation to nutrient acquisition and fitness consequences. We tested whether anthropogenic debris ingestion influence the nutritional niches of endangered green turtles (Chelonia mydas) in estuarine and reef habitats on the Brazilian coast. Our results showed that estuarine turtles consumed diets with lower proportional wet mass composition of protein (P) and water (W) than their reef conspecifics. The amounts of debris, mostly plastics, retrieved from the digestive tracts of estuarine turtles were higher compared with those individuals from reefs. The realized nutritional niche from estuarine turtles was subject to the debris density in the environment, lack of benthic food resources available and the surface foraging behavior, likely preventing them from reaching their nutritional goals and resulting in lower fitness. The study provides critical information for the management and conservation of ecologically threatened individuals, populations, and their natural habitats.
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http://dx.doi.org/10.1016/j.marpolbul.2020.110943DOI Listing
April 2020

The Nutritional Ecology of Marine Apex Predators.

Ann Rev Mar Sci 2020 01 5;12:361-387. Epub 2019 Sep 5.

Charles Perkins Centre, The University of Sydney, Sydney, New South Wales 2006, Australia; email:

Apex predators play pivotal roles in marine ecosystems, mediated principally through diet and nutrition. Yet, compared with terrestrial animals, the nutritional ecology of marine predators is poorly understood. One reason is that the field has adhered to an approach that evaluates diet principally in terms of energy gain. Studies in terrestrial systems, by contrast, increasingly adopt a multidimensional approach, the nutritional geometry framework, that distinguishes specific nutrients and calories. We provide evidence that a nutritional approach is likewise relevant to marine apex predators, then demonstrate how nutritional geometry can characterize the nutrient and energy content of marine prey. Next, we show how this framework can be used to reconceptualize ecological interactions via the ecological niche concept, and close with a consideration of its application to problems in marine predator research.
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http://dx.doi.org/10.1146/annurev-marine-010318-095411DOI Listing
January 2020

A nutritional perspective on plastic ingestion in wildlife.

Sci Total Environ 2019 Mar 28;656:789-796. Epub 2018 Nov 28.

The University of Sydney, Charles Perkins Centre, Sydney, Australia; The University of Sydney, School of Life and Environmental Sciences, Sydney, Australia.

Although the perils of plastics to living organisms including humans have been neglected for decades, they have recently been recognized as a major environmental problem worldwide. Little progress has been made on understanding the factors that drive species' and populations' susceptibilities to the ingestion of plastic. Here, we propose using nutritional ecology as a multidisciplinary framework for bridging the gaps that link nutrition, behavior, plastics, physiology and ecology. We show that nutritional niches are tightly linked to plastic ingestion, illustrating the application of our framework in the context of nutritional niche theory, habitat-specific foraging from species to populations, and transfer patterns in food webs.
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http://dx.doi.org/10.1016/j.scitotenv.2018.11.418DOI Listing
March 2019

The nutritional nexus: Linking niche, habitat variability and prey composition in a generalist marine predator.

J Anim Ecol 2018 09 3;87(5):1286-1298. Epub 2018 Jul 3.

Charles Perkins Centre, The University of Sydney, Sydney, NSW, Australia.

Our understanding of the niche concept will remain limited while the quantity and range of different food types eaten remain a dominant proxy for niche breadth, as this does not account for the broad ecological context that governs diet. Linking nutrition, physiology and behaviour is critical to predict the extent to which a species adjusts its nutritional niche breadth at the levels of prey ("prey composition niche," defined as the range of prey compositions eaten) and diet ("realized nutritional niche" is the range of diets composed through feeding on the prey). Here, we studied adult chick-rearing Australasian gannets Morus serrator to propose an integrative approach using sea surface temperature anomalies (SSTa), geographic location and bathymetry over different years, to explore their relationship with the nutritional composition of prey and diets (i.e. prey composition and nutritional niche breadth), habitat use and foraging behaviour. We found that gannets feed on prey that varied widely in their nutritional composition (have a broad prey composition niche), and composed diets from these prey that likewise varied in composition (have a broad realized nutritional niche), suggesting generalism at two levels of macronutrient selection. Across seasons, we established "nutritional landscapes" (hereafter nutriscapes), linking the nutritional content of prey (wet mass protein-to-lipid ratio-P:L) to the most likely geographic area of capture and bathymetry. Nutriscapes varied in their P:L from 6.06 to 15.28, over time, space and bathymetry (0-150 m). During warm water events (strong positive SSTa), gannets expanded their foraging habitat, increased their foraging trip duration and consumed prey and diets with low macronutrient content (wet mass proportions of P and L). They were also constrained to the smallest prey composition and realized nutritional niche breadths. Our findings are consistent with previous suggestions that dietary generalism evolves in heterogeneous environments, and provide a framework for understanding the nutritional goals in wild marine predators and how these goals drive ecological interactions and are, in turn, ultimately shaped by environmental fluctuations.
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http://dx.doi.org/10.1111/1365-2656.12856DOI Listing
September 2018

A preliminary study to estimate contact rates between free-roaming domestic dogs using novel miniature cameras.

PLoS One 2017 27;12(7):e0181859. Epub 2017 Jul 27.

Sydney School of Veterinary Science, The University of Sydney, Camden, Australia.

Information on contacts between individuals within a population is crucial to inform disease control strategies, via parameterisation of disease spread models. In this study we investigated the use of dog-borne video cameras-in conjunction with global positioning systems (GPS) loggers-to both characterise dog-to-dog contacts and to estimate contact rates. We customized miniaturised video cameras, enclosed within 3D-printed plastic cases, and attached these to nylon dog collars. Using two 3400 mAh NCR lithium Li-ion batteries, cameras could record a maximum of 22 hr of continuous video footage. Together with a GPS logger, collars were attached to six free roaming domestic dogs (FRDDs) in two remote Indigenous communities in northern Australia. We recorded a total of 97 hr of video footage, ranging from 4.5 to 22 hr (mean 19.1) per dog, and observed a wide range of social behaviours. The majority (69%) of all observed interactions between community dogs involved direct physical contact. Direct contact behaviours included sniffing, licking, mouthing and play fighting. No contacts appeared to be aggressive, however multiple teeth baring incidents were observed during play fights. We identified a total of 153 contacts-equating to 8 to 147 contacts per dog per 24 hr-from the videos of the five dogs with camera data that could be analysed. These contacts were attributed to 42 unique dogs (range 1 to 19 per video) which could be identified (based on colour patterns and markings). Most dog activity was observed in urban (houses and roads) environments, but contacts were more common in bushland and beach environments. A variety of foraging behaviours were observed, included scavenging through rubbish and rolling on dead animal carcasses. Identified food consumed included chicken, raw bones, animal carcasses, rubbish, grass and cheese. For characterising contacts between FRDD, several benefits of analysing videos compared to GPS fixes alone were identified in this study, including visualisation of the nature of the contact between two dogs; and inclusion of a greater number of dogs in the study (which do not need to be wearing video or GPS collars). Some limitations identified included visualisation of contacts only during daylight hours; the camera lens being obscured on occasion by the dog's mandible or the dog resting on the camera; an insufficiently wide viewing angle (36°); battery life and robustness of the deployments; high costs of the deployment; and analysis of large volumes of often unsteady video footage. This study demonstrates that dog-borne video cameras, are a feasible technology for estimating and characterising contacts between FRDDs. Modifying camera specifications and developing new analytical methods will improve applicability of this technology for monitoring FRDD populations, providing insights into dog-to-dog contacts and therefore how disease might spread within these populations.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0181859PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5547700PMC
October 2017

The Multidimensional Nutritional Niche.

Trends Ecol Evol 2016 05 16;31(5):355-365. Epub 2016 Mar 16.

Charles Perkins Centre, The University of Sydney, Sydney, Australia; Faculty of Veterinary Science, The University of Sydney, Sydney, Australia; School of Biological Sciences, The University of Sydney, Sydney, Australia.

The dietary generalist-specialist distinction plays a pivotal role in theoretical and applied ecology, conservation, invasion biology, and evolution and yet the concept remains poorly characterised. Diets, which are commonly used to define niche breadth, are almost exclusively considered in terms of foods, with little regard for the mixtures of nutrients and other compounds they contain. We use nutritional geometry (NG) to integrate nutrition with food-level approaches to the dietary niche and illustrate the application of our framework in the important context of invasion biology. We use an example that involves a model with four hypothetical nonexclusive scenarios. We additionally show how this approach can provide fresh theoretical insight into the ways nutrition and food choices impact trait evolution and trophic interactions.
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http://dx.doi.org/10.1016/j.tree.2016.02.009DOI Listing
May 2016

Geometry of nutrition in field studies: an illustration using wild primates.

Oecologia 2015 Jan 30;177(1):223-34. Epub 2014 Nov 30.

Faculty of Veterinary Science, The Charles Perkins Centre, School of Biological Sciences, University of Sydney, Sydney, Australia,

Nutritional geometry has shown the benefits of viewing nutrition in a multidimensional context, in which foraging is viewed as a process of balancing the intake and use of multiple nutrients. New insights into nutrient regulation have been generated in studies performed in a laboratory context, where accurate measures of amounts (e.g. eaten, converted to body mass, excreted) can be made and analysed using amounts-based nutritional geometry. In most field situations, however, proportional compositions (e.g. of foods, diets, faeces) are the only measures readily available, and in some cases are more relevant to the problem at hand. For this reason, a complementary geometric method was recently introduced for analysing multi-dimensional data on proportional compositions in nutritional studies, called the right-angled mixture triangle (RMT). We use literature data from field studies of primates to demonstrate how the RMT can provide insight into a variety of important concepts in nutritional ecology. We first compare the compositions of foods, using as an example primate milks collected in both the wild and the laboratory. We next compare the diets of different species of primates from the same habitat and of the same species (mountain gorillas) from two distinct forests. Subsequently, we model the relationships between the composition of gorilla diets in these two habitats and the foods that comprise these diets, showing how such analyses can provide evidence for active nutrient-specific regulation in a field context. We provide a framework to relate concepts developed in laboratory studies with field-based studies of nutrition.
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http://dx.doi.org/10.1007/s00442-014-3142-0DOI Listing
January 2015

Nutritional ecology of obesity: from humans to companion animals.

Br J Nutr 2015 Jan 21;113 Suppl:S26-39. Epub 2014 Nov 21.

The Charles Perkins Centre and School of Biological Sciences, The University of Sydney,Sydney,NSW,Australia.

We apply nutritional geometry, a framework for modelling the interactive effects of nutrients on animals, to help understand the role of modern environments in the obesity pandemic. Evidence suggests that humans regulate the intake of protein energy (PE) more strongly than non-protein energy (nPE), and consequently will over- and under-ingest nPE on diets with low or high PE, respectively. This pattern of macronutrient regulation has led to the protein leverage hypothesis, which proposes that the rise in obesity has been caused partly by a shift towards diets with reduced PE:nPE ratios relative to the set point for protein regulation. We discuss potential causes of this mismatch, including environmentally induced reductions in the protein density of the human diet and factors that might increase the regulatory set point for protein and hence exacerbate protein leverage. Economics--the high price of protein compared with fats and carbohydrates--is one factor that might contribute to the reduction of dietary protein concentrations. The possibility that rising atmospheric CO₂ levels could also play a role through reducing the PE:nPE ratios in plants and animals in the human food chain is discussed. Factors that reduce protein efficiency, for example by increasing the use of ingested amino acids in energy metabolism (hepatic gluconeogenesis), are highlighted as potential drivers of increased set points for protein regulation. We recommend that a similar approach is taken to understand the rise of obesity in other species, and identify some key gaps in the understanding of nutrient regulation in companion animals.
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http://dx.doi.org/10.1017/S0007114514002323DOI Listing
January 2015

The contribution of private and public information in foraging by Australasian gannets.

Anim Cogn 2014 Jul 14;17(4):849-58. Epub 2013 Dec 14.

The Charles Perkins Centre and Faculty of Veterinary Science and School of Biological Sciences, University of Sydney, Sydney, Australia,

Predators that forage on foods with temporally and spatially patchy distributions may rely on private or public sources of information to enhance their chances of foraging success. Using GPS tracking, field observations, and videography, we examined potential sites and mechanisms of information acquisition in departures for foraging trips by colonially breeding Australasian gannets (Morus serrator). Analyses of the bill-fencing ceremony between mated pairs of breeding gannets did not detect correlations between parameters of this reciprocal behavior and foraging trips, as would have been predicted if gannets used this behavior as a source of private information. Instead, 60% of the departing birds flew directly to join water rafts of other conspecific en route to the feeding grounds. The departure of solitary birds from the water rafts was synchronized (within 60 s) with the arrival of incoming foragers and also among departing birds. Furthermore, solitary departing birds from the rafts left in the same directional quadrant (90º slices) as the prior arriving (67%) and also prior departing forager (79%). When associated plunge dives of conspecific were visible from the colony, providing a public source of information, gannets more often departed from the water rafts in groups. Our study thus provides evidence for the use of water rafts, but not the nest site, as locations of information transfer, and also confirms the use of local enhancement as a strategy for foraging flights by Australasian gannets.
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http://dx.doi.org/10.1007/s10071-013-0716-xDOI Listing
July 2014

Visual accommodation and active pursuit of prey underwater in a plunge-diving bird: the Australasian gannet.

Proc Biol Sci 2012 Oct 8;279(1745):4118-25. Epub 2012 Aug 8.

Nutritional Ecology Research Group, Massey University, Private Bag 102 904 North Shore MSC, Auckland, New Zealand.

Australasian gannets (Morus serrator), like many other seabird species, locate pelagic prey from the air and perform rapid plunge dives for their capture. Prey are captured underwater either in the momentum (M) phase of the dive while descending through the water column, or the wing flapping (WF) phase while moving, using the wings for propulsion. Detection of prey from the air is clearly visually guided, but it remains unknown whether plunge diving birds also use vision in the underwater phase of the dive. Here we address the question of whether gannets are capable of visually accommodating in the transition from aerial to aquatic vision, and analyse underwater video footage for evidence that gannets use vision in the aquatic phases of hunting. Photokeratometry and infrared video photorefraction revealed that, immediately upon submergence of the head, gannet eyes accommodate and overcome the loss of greater than 45 D (dioptres) of corneal refractive power which occurs in the transition between air and water. Analyses of underwater video showed the highest prey capture rates during WF phase when gannets actively pursue individual fish, a behaviour that very likely involves visual guidance, following the transition after the plunge dive's M phase. This is to our knowledge the first demonstration of the capacity for visual accommodation underwater in a plunge diving bird while capturing submerged prey detected from the air.
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http://dx.doi.org/10.1098/rspb.2012.1519DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3441088PMC
October 2012

Ultraviolet visual sensitivity in three avian lineages: paleognaths, parrots, and passerines.

J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2012 Jul 26;198(7):495-510. Epub 2012 Apr 26.

Biopsychology and Behavioral Neuroscience Program, The Graduate Center of City University of New York, 365 Fifth Ave, New York, NY 10016-4309, USA.

Ultraviolet (UV) light-transmitted signals play a major role in avian foraging and communication, subserving functional roles in feeding, mate choice, egg recognition, and nestling discrimination. Sequencing functionally relevant regions of the short wavelength sensitive type 1 (SWS1) opsin gene that is responsible for modulating the extent of SWS1 UV sensitivity in birds allows predictions to be made about the visual system's UV sensitivity in species where direct physiological or behavioral measures would be impractical or unethical. Here, we present SWS1 segment sequence data from representative species of three avian lineages for which visually based cues for foraging and communication have been investigated to varying extents. We also present a preliminary phylogenetic analysis and ancestral character state reconstructions of key spectral tuning sites along the SWS1 opsin based on our sequence data. The results suggest ubiquitous ultraviolet SWS1 sensitivity (UVS) in both paleognaths, including extinct moa (Emeidae), and parrots, including the nocturnal and flightless kakapo (Strigops habroptilus), and in most, but not all, songbird (oscine) lineages, and confirmed violet sensitivity (VS) in two suboscine families. Passerine hosts of avian brood parasites were included both UVS and VS taxa, but sensitivity did not co-vary with egg rejection behaviors. The results should stimulate future research into the functional parallels between the roles of visual signals and the genetic basis of visual sensitivity in birds and other taxa.
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http://dx.doi.org/10.1007/s00359-012-0724-3DOI Listing
July 2012

UVS is rare in seabirds.

Vision Res 2011 Jun 20;51(12):1333-7. Epub 2011 Apr 20.

Nutritional Ecology Research Group, Institute of Natural Sciences, Massey University, North Shore MSC, Auckland, New Zealand.

Ultraviolet-sensitive vision (UVS), believed to have evolved from an ancestral state of violet-sensitive vision (VS), is widespread among terrestrial birds, where it is thought to play a role in orientation, foraging, and sexual selection. Less is known, however, about the distribution and significance of UVS in seabirds. To date UVS has been definitively demonstrated only in two families (Laridae and Sternidae), although indirect evidence has been used to argue for a more widespread occurrence. In this study we analyzed short-wavelength sensitive (SWS1) opsin DNA sequences to determine the distribution of ancestral (VS) and derived (UVS) amino acid spectral tuning sites in 16 seabird species representing 8 families with diverse ecological niches. Our results revealed sequences associated with UVS pigments (UVSs) in the Black-backed gull (Larus dominicanus), providing further evidence of its widespread occurrence within the Laridae. The Caspian tern (Hydroprogne caspia) and White-fronted tern (Sterna striata), however, were found to have VSs, suggesting an evolutionary reversion to the ancestral state within Sternidae. VSs were also detected in an additional six families. Our results raise interesting questions about the functions of UV vision in marine environments.
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http://dx.doi.org/10.1016/j.visres.2011.04.008DOI Listing
June 2011
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