Taxonomic distinctness in the diet of two sympatric marine turtle species

Stringell, Thomas B.; Clerveaux, W.; Godley, Brendan J.; Kent, Flora; Lewis, Emma D. G.; Marsh, Jessica E.; Phillips, Quinton; Richardson, Peter B.; Sanghera, Amdeep; Broderick, Annette C.

doi:10.1111/maec.12349

Cited by 24 publications

(15 citation statements)

References 71 publications

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“…In any case, the fast acquisition after settlement in coastal areas of a microbiota adapted to ferment polysaccharides should enable green turtles to adopt an herbivorous diet soon after recruitment. This is the pattern reported from tropical areas [ 25 , 83 ], but in warm temperate and subtropical regions, juvenile green turtles are best described as plant-based omnivore and only adults are primarily herbivores [ 19 – 21 , 23 , 33 , 34 , 37 , 84 , 85 ]. The results presented here indicate an increase in the taxonomic richness of the gut microbiome as turtles grow, but this is an unlikely explanation by the progressive ontogenetic dietary shift, because even small turtles had a high abundance of Ruminococcaceae and Lachnospiraceae .…”

Section: Discussionmentioning

confidence: 53%

Fast acquisition of a polysaccharide fermenting gut microbiome by juvenile green turtles Chelonia mydas after settlement in coastal habitats

et al. 2018

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BackgroundTetrapods do not express hydrolases for cellulose and hemicellulose assimilation, and hence, the independent acquisition of herbivory required the establishment of new endosymbiotic relationships between tetrapods and microbes. Green turtles (Chelonia mydas) are one of the three groups of marine tetrapods with an herbivorous diet and which acquire it after several years consuming pelagic animals. We characterized the microbiota present in the feces and rectum of 24 young wild and captive green turtles from the coastal waters of Brazil, with curved carapace length ranging from 31.1 to 64.7 cm, to test the hypotheses that (1) the ontogenetic dietary shift after settlement is followed by a gradual change in the composition and diversity of the gut microbiome, (2) differences exist between the composition and diversity of the gut microbiome of green turtles from tropical and subtropical regions, and (3) the consumption of omnivorous diets modifies the gut microbiota of green turtles.ResultsA genomic library of 2,186,596 valid bacterial 16S rRNA reads was obtained and these sequences were grouped into 6321 different operational taxonomic units (at 97% sequence homology cutoff). The results indicated that most of the juvenile green turtles less than 45 cm of curved carapace length exhibited a fecal microbiota co-dominated by representatives of the phyla Bacteroidetes and Firmicutes and high levels of Clostridiaceae, Prophyromonas, Ruminococaceae, and Lachnospiraceae within the latter phylum. Furthermore, this was the only microbiota profile found in wild green turtles > 45 cm CCL and in most of the captive green turtles of any size feeding on a macroalgae/fish mixed diet. Nevertheless, microbial diversity increased with turtle size and was higher in turtles from tropical than from subtropical regions.ConclusionsThese results indicate that juvenile green turtles from the coastal waters of Brazil had the same general microbiota, regardless of body size and origin, and suggest a fast acquisition of a polysaccharide fermenting gut microbiota by juvenile green turtles after settlement into coastal habitats.Electronic supplementary materialThe online version of this article (10.1186/s40168-018-0454-z) contains supplementary material, which is available to authorized users.

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Section: Discussionmentioning

confidence: 53%

Fast acquisition of a polysaccharide fermenting gut microbiome by juvenile green turtles Chelonia mydas after settlement in coastal habitats

et al. 2018

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“…species richness) has been a common practice in ecological studies for the past couple of decades (Von Euler & Svensson 2001, Heino et al 2005, Winter et al 2013. But despite its potential application as a measure of diversity in species diets, to our knowledge TD has only been implemented as a measure of diet breadth in 1 recent study involving the diet of turtles (Stringell et al 2016). In the present study, we found that diet TD (represented by the TD among prey families in the diet) was the secondbest predictor of tapeworm species richness in sharks following diet breadth (prey family richness), and similar to general diet breadth, diet TD showed a highly significant positive effect on tapeworm richness when PICs were used to control for confounding of phylogenetic relationships among sharks.…”

Section: Discussionmentioning

confidence: 99%

Host diet influences parasite diversity: a case study looking at tapeworm diversity among sharks

Rasmussen¹,

Randhawa²

2018

Mar. Ecol. Prog. Ser.

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In theory, animal diets may act as important filters for different parasite species. However, there is currently a lack of empirical research looking at host diet as a potential predictor of parasite diversity among different host species. The aim of this study was to assess the influence of several host diet features (including diet breadth, diet composition, and trophic level) on tapeworm diversity in sharks, relative to other key factors, including host size, habitat, phylogeny, latitude, and depth. Data on these host features were compiled from a comprehensive analysis of literature records including 91 different shark species, and 3 measures of tapeworm diversity were examined: tapeworm species richness, tapeworm taxonomic distinctness (TD), and variance in tapeworm TD. The diet breadth of a shark species was revealed to be a better predictor of tapeworm species richness than other host features examined to date. Host size, trophic level, diet TD, latitudinal range, and the mid-point of a shark's depth range also significantly influenced tapeworm richness when analyses were ad justed to prevent confounding by phylogenetic re lation ships between hosts. The TD of tapeworm assemblages was influenced by diet breadth, diet TD, host size, and depth range when analysed independently of host phylogeny. Overall, our findings demonstrate that aspects of host diet have important consequences for parasite diversity in sharks. We em phasise that studies of parasite diversity in other systems should more seriously consider including aspects of host diet (particularly diet breadth) as potential key predictors of parasite diversity.

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“…An expanded version of Seagrass dominant. Seagrass contribution to diet is greatest in the following sub-regions: Indian SW (mean = 95.0%; n = 1; Stokes et al 2019), Indian NW (mean = 83.3%; SE = 9.6; n = 4; e.g., Hasbún et al 2000), Indian NE (mean = 65.1%; n = 1; Whiting et al 2014), Pacific SW (mean = 59.3%; SE = 10.4; n = 13; e.g., Fuentes et al 2006;Prior et al 2016), Atlantic NW (mean = 57.5%; SE = 8.2; n = 19; e.g., Mortimer 1981;Stringell et al 2016) and Mediterranean (mean = 46.0%; SE = 19.4; n = 5; e.g., Karaa et al 2012). All studies that recorded no seagrass (or virtually none) in the diet are from regions with limited documented seagrass distribution (e.g., Pacific E and Atlantic SW) ( Fig.…”

Section: Global Review Of Green Turtle Dietmentioning

confidence: 99%

“…In the literature, spatial variation in green turtle diet has often been explained by a combination of environment (e.g., food availability, different habitats) and characteristics of the gastrointestinal microbiome which are influenced by diet (Bjorndal 1997;Price et al 2017). For example, seagrass Thalassia testudinum dominates the Caribbean benthos and is the dominant food item (e.g., Stringell et al 2016); while in the Galapagos (Carrión-Cortez et al 2010) and at Heron Reef Australia (Forbes 1996), the benthos is dominated by macroalgae which comprise most of the diet. Recent advances in knowledge indicate, however, that regardless of diet, the microbiome in green turtles contains the same bacterial phyla although bacterial community composition changes over time in response to diet (Ahasan et al 2017;Campos et al 2018;Bloodgood et al 2020).…”

Section: Gut Microfloramentioning

confidence: 99%

A global review of green turtle diet: sea surface temperature as a potential driver of omnivory levels

et al. 2020

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To better understand dietary requirements, trophic shifts, and trophic interactions of the threatened green turtle (Chelonia mydas), we conducted a comprehensive global review and literature tabulation (177 studies) reporting diets of individuals > 25 cm carapace length. We analysed those studies involving natural sites and healthy animals that reported relative proportions of all diet components (67 studies, 89 datasets at 75 sites, 13 geographic sub-regions, 3 oceans). We compared diets by sub-region and foraging site relative to four diet components, i.e., seagrass, macroalgae, terrestrial plants (including mangroves) and animal matter. To assess sea surface temperature (SST) as an environmental driver, values were extracted from satellite data (single year) and site-specific observations (study durations) and examined relative to diet composition. Satellite data indicated that at warmer sites with temperatures > 25 °C (≥ 6 months annually), diet was predominantly herbivorous (mean = 92.97%; SE = 9.85; n = 69 datasets). At higher latitude sites and in cold-water currents with SST < 20 °C (≥ 6 months annually), dietary animal matter featured prominently (mean = 51.47%; SE = 4.84; n = 20 datasets). Site-specific observations indicated that SST had a small but significant effect on contributions of animal matter (r2 = 0.17, P = < 0.001) and seagrass (r2 = 0.24, P = < 0.001) but not macroalgae and terrestrial plants. Our study presents the first quantitative evidence at a global scale that temperature may be an important driver of omnivory, providing a new perspective on variations in green turtle diet, especially in light of global warming and climate change.

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Taxonomic distinctness in the diet of two sympatric marine turtle species

Cited by 24 publications

References 71 publications

Fast acquisition of a polysaccharide fermenting gut microbiome by juvenile green turtles Chelonia mydas after settlement in coastal habitats

Fast acquisition of a polysaccharide fermenting gut microbiome by juvenile green turtles Chelonia mydas after settlement in coastal habitats

Host diet influences parasite diversity: a case study looking at tapeworm diversity among sharks

A global review of green turtle diet: sea surface temperature as a potential driver of omnivory levels

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