Dietary Shifts Research Articles

Molecular Markers and Their Applications in Marker-Assisted Selection (MAS) in Bread Wheat (Triticum aestivum L.)

As one of the essential cereal crops, wheat provides 20% of the calories and proteins consumed by humans. Due to population expansion, dietary shift and climate change, it is challenging for wheat breeders to develop new varieties for meeting wheat production requirements. Marker-assisted selection (MAS) has distinct advantages over conventional selection in plant breeding, such as being time-saving, cost-effective and goal-oriented. This review makes attempts to give a description of different molecular markers: sequence tagged site (STS), simple sequence repeat (SSR), genotyping by sequencing (GBS), single nucleotide polymorphism (SNP) arrays, exome capture, Kompetitive Allele Specific PCR (KASP), cleaved amplified polymorphic sequence (CAPS), semi-thermal asymmetric reverse PCR (STARP) and genotyping by target sequencing (GBTS). We also summarize some quantitative trait loci (QTL)/genes as well as their linked markers, which are potentially useful in MAS. This paper provides updated information on some markers linked to critical traits and their potential applications in wheat breeding programs.

Natal Origin Differentiation Using Eye Lens Stable Isotope Analysis

AbstractNatal origin determination can be critical to understanding the movement, recruitment, and stock discrimination of fish populations. We investigated the utility of eye lens stable isotope analysis as a natural marker to determine natal origins, specifically the differentiation of stocked versus naturally reproduced individuals. We compared isotopic values for stocked and naturally reproduced Rainbow Trout Oncorhynchus mykiss in the North Platte River (Wyoming, USA) and found that the metabolically inert core of the eye lens retained hatchery feed values as the fish grew poststocking. The stable isotope values of eye lens cores from stocked Rainbow Trout were >15‰ higher for δ34S and >4‰ higher for δ13C than naturally reproduced fish. The values for δ15N proved to be a less useful indicator for natal origin than sulfur and carbon. These high carbon and sulfur isotopic values were retained in the core, despite subsequent lens layers showing a dietary shift to natural prey items poststocking. Rainbow Trout formed over 10 layers at age 0, decreasing to an estimated one to two layers during subsequent years. Eye lens stable isotope analysis represents an additional tool for researchers and managers to use natural isotopic markers to accurately assess natal origins and hatchery contributions to fish populations.

Seasonal variation of population and individual dietary niche in the avivorous bat, Ia io

The variation in niche breadth can affect how species respond to environmental and resource changes. However, there is still no clear understanding of how seasonal variability in food resources impacts the variation of individual dietary diversity, thereby affecting the dynamics of a population's dietary niche breadth. Optimal foraging theory (OFT) and the niche variation hypothesis (NVH) predict that when food resources are limited, the population niche breadth will widen or narrow due to increased within-individual dietary diversity and individual specialization or reduced within-individual dietary diversity, respectively. Here, we used DNA metabarcoding to examine the composition and seasonality of diets of the avivorous bat Ia io. Furthermore, we investigated how the dietary niches changed among seasons and how the population niche breadth changed when the availability of insect resources was reduced in autumn. We found that there was differentiation in dietary niches among seasons and a low degree of overlap, and the decrease of insect resource availability and the emergence of ecological opportunities of nocturnal migratory birds might drive dietary niche shifts toward birds in I. io. However, the population's dietary niche breadth did not broaden by increasing the within-individual dietary diversity or individual specialization, but rather became narrower by reducing dietary diversity via predation on bird resources that served as an ecological opportunity when insect resources were scarce in autumn. Our findings were consistent with the predictions of OFT, because birds as prey for bats provided extremely different resources from those of insects in size and nutritional value. Our work highlights the importance of size and quality of prey resources along with other factors (i.e., physiological, behavioral, and life-history traits) in dietary niche variation.

A new journal dedicated to the science of sustainable food proteins

Harjinder Singh, Editor-in-Chief In the next decade, we will see a dramatic dietary shift toward more plant-based and alternative proteins. Global population growth and the dietary changes associated with rising standards of living are placing tremendous pressure on the systems that provide our proteins. How will we reconcile the creation of new protein foods that are not only sustainable but also affordable and highly nutritious? Sustainable Food Proteins (SFP) is a new international, open access, peer-reviewed journal focused on the research attempting to answer this question. The journal publishes high-quality original research articles, reviews, and opinion pieces on all aspects of the science dedicated to the advancement of sustainably derived protein foods. It covers the entire spectrum from protein sourcing to food formulations, to analytical characterization, to digestion and nutrition, and the nuanced research in between. The food industry is clamoring for knowledge on novel protein sources, structures, and functionality to inform formulations, as well as sensory information that may drive consumer perceptions. We are interested in manuscripts on these topics, as well as on novel techniques used to characterize and enhance these functionalities. For example, we are accepting papers on processing and extraction technologies, especially for edible proteins that are not sourced from traditionally farmed livestock. We welcome submissions on recombinant technologies for protein production (in bacteria, yeast, or plants) and cell culture-based production of animal protein. We also seek papers on addressing scientific challenges in food product formulations and product development using alternative protein ingredients. We welcome research on the digestibility, nutritional quality, and health impacts of alternative proteins and protein-based foods. There is currently a significant focus on protein science and innovation to transform our food system to become more environmentally sustainable. The academic community and scientists in the food industry now have a dedicated forum to showcase their important work. The editorial board of SFP is eager to share those findings in our journal and our goal is for SFP to be the leading journal where anyone interested in this burgeoning field can find cutting-edge protein research.

Can smaller predators expand their prey base through killing juveniles? The influence of prey demography and season on prey selection for cheetahs and lions

Smaller predators may overcome body size restrictions on their prey base by selecting for juveniles of larger prey species. However, traditional prey selection models ignore demographic classes within prey species. We refined these models for two predators with contrasting body sizes and hunting strategies, by including seasonal consumption and availability of prey demographic classes. We predicted that cheetahs would select for smaller neonate and juvenile prey especially of larger species, while lions would select for larger, adult prey. We further predicted seasonal diet shifts in cheetah, but not lion. We recorded species-specific demographic class prey use (kills) via direct observation and GPS cluster of cheetahs and lions fitted with GPS collars. Species-specific demographic class prey availability was estimated from monthly driven transects, and species-specific demographic class prey preferences were estimated. The availability of prey demographic classes varied seasonally. Cheetahs preferred neonates, juveniles, and sub-adults during the wet season, but adults and juveniles during the dry season. Lions preferred adult prey irrespective of season, with sub-adults, juveniles, and neonates killed relative to their abundance. This confirms that traditional prey preference models do not adequately account for demographic-specific prey preference. This is particularly important for smaller predators, like cheetahs, that focus on smaller prey but can expand their prey base by killing juveniles of larger species. For these smaller predators, prey availability will vary strongly seasonally, making them more vulnerable to processes that influence prey reproduction, like global change.

Complex Life Histories Alter Patterns of Mercury Exposure and Accumulation in a Pond-Breeding Amphibian.

Quantifying how contaminants change across life cycles of species that undergo metamorphosis is critical to assessing organismal risk, particularly for consumers. Pond-breeding amphibians can dominate aquatic animal biomass as larvae and are terrestrial prey as juveniles and adults. Thus, amphibians can be vectors of mercury exposure in both aquatic and terrestrial food webs. However, it is still unclear how mercury concentrations are affected by exogenous (e.g., habitat or diet) vs endogenous factors (e.g., catabolism during hibernation) as amphibians undergo large diet shifts and periods of fasting during ontogeny. We measured total mercury (THg), methylmercury (MeHg), and isotopic compositions (δ 13C, δ15N) in boreal chorus frogs (Pseudacris maculata) across five life stages in two Colorado (USA) metapopulations. We found large differences in concentrations and percent MeHg (of THg) among life stages. Frog MeHg concentrations peaked during metamorphosis and hibernation coinciding with the most energetically demanding life cycle stages. Indeed, life history transitions involving periods of fasting coupled with high metabolic demands led to large increases in mercury concentrations. The endogenous processes of metamorphosis and hibernation resulted in MeHg bioamplification, thus decoupling it from the light isotopic proxies of diet and trophic position. These step changes are not often considered in conventional expectations of how MeHg concentrations within organisms are assessed.

Dietary Sugar Shifts Mitochondrial Metabolism and Small RNA Biogenesis in Sperm.

Aims: Increasing concentrations of dietary sugar results in a linear accumulation of triglycerides in male Drosophila, while inducing a U-shaped obesity response in their offspring. Here, using a combination of proteomics and small RNA (sRNA) sequencing, we aimed at understanding the molecular underpinning in sperm for such plasticity. Results: Proteomic analysis of seminal vesicles revealed that increasing concentrations of dietary sugar resulted in a bell-shaped induction of proteins involved in metabolic/redox regulation. Using stains and in vivo redox reporter flies, this pattern could be explained by changes in sperm production of reactive oxygen species (ROS), more exactly mitochondria-derived H2O2. By quenching ROS with the antioxidant N-acetyl cysteine and performing sRNA-seq on sperm, we found that sperm miRNA is increased in response to ROS. Moreover, we found sperm mitosRNA to be increased in high-sugar diet conditions (independent of ROS). Reanalyzing our previously published data revealed a similar global upregulation of human sperm mitosRNA in response to a high-sugar diet, suggesting evolutionary conserved mechanisms. Innovation: This work highlights a fast response to dietary sugar in mitochondria-produced H2O2 in Drosophila sperm and identifies redox-sensitive miRNA downstream of this event. Conclusions: Our data support a model where changes in the sperm mitochondria in response to dietary sugar are the primary event, and changes in redox homoeostasis are secondary to mitochondrial ROS production. These data provide multiple candidates for paternal intergenerational metabolic responses as well as potential biomarkers for human male fertility. Antioxid. Redox Signal. 38, 1167-1183.

Impact across ecosystem boundaries – Does Bti application change quality and composition of the diet of riparian spiders?

Emerging aquatic insects link aquatic and adjacent terrestrial food webs by subsidizing terrestrial predators with high-quality prey. One of the main constituents of aquatic subsidy, the non-biting midges (Chironomidae), showed altered emergence dynamics in response to the mosquito control agent Bacillus thuringiensis var. israelensis (Bti). As riparian spiders depend on aquatic subsidy, they may be affected by such changes in prey availability. Thus, we conducted a field study in twelve floodplain pond mesocosms (FPMs), six were treated with Bti (2.88 × 109 ITU/ha, VectoBac WDG) three times, to investigate if the Bti-induced shift in chironomid emergence dynamics is reflected in their nutritional value and in the diet of riparian spiders. We measured the content of proteins, lipids, glycogen, and carbohydrates in emerged Chironomidae, and determined the stable isotope ratios of female Tetragnatha extensa, a web-building spider living in the riparian vegetation of the FPMs. We analysed the proportion of aquatic prey in spiders' diet, niche size, and trophic position. While the content of nutrients and thus the prey quality was not significantly altered by Bti, effects on the spiders' diet were observed. The trophic position of T. extensa from Bti-treated FPMs was lower compared to the control while the aquatic proportion was only minimally reduced. We assume that spiders fed more on terrestrial prey but also on other aquatic organisms such as Baetidae, whose emergence was unaffected by Bti. In contrast to the partly predaceous Chironomidae, consumption of aquatic and terrestrial primary consumers potentially explains the observed lower trophic position of spiders from Bti-treated FPMs. As prey organisms vary in their quality the suggested dietary shift could transfer previously observed effects of Bti to riparian spiders conceivably affecting their populations. Our results further support that anthropogenic stressors in aquatic ecosystems may translate to terrestrial predators through aquatic subsidy.

Mercury bioaccumulation in thresher sharks from the eastern tropical Pacific: Influences of body size, maturation stage, and feeding habitat

Sharks, as top order predators, provide a guidance on how contaminants such as mercury bioaccumulate in marine environments. This study assessed the bioaccumulation of mercury (total mercury, THg) in the muscle, liver, red blood cells (RBC), and plasma of pelagic and bigeye thresher sharks (Alopias pelagicus and A. superciliosus) from eastern tropical Pacific. Additionally, the concentration of methylmercury (MeHg) in muscle was also determined to assess risks for human consumption. For both species, muscle THg concentrations (4.05 ± 2.15 and 4.12 ± 1.84 μg g−1 dry weight for pelagic and bigeye thresher shark) were higher than that in other tissues. THg concentrations for all tissues were significantly correlated with precaudal length, with higher accumulation rates after maturity in pelagic than bigeye thresher sharks, suggesting an associated dietary shift at maturation. Correlations among tissues in both species suggested similar transportation and distribution patterns in internal tissues. The δ13C values in muscle, RBC and plasma suggested that habitat shifts influenced Hg accumulation, whereas trophic position, estimated by δ15N values, had limited effects on patterns of Hg bioaccumulation. Diet shifts towards prey more cephalopods that content higher Hg than small fishes (large fishes: 1.77 μg g−1; cephalopods: 0.66 μg g−1 and small fishes 0.48 μg g−1, dry weight) increased Hg accumulation rates in adult pelagic thresher sharks. Concentrations of MeHg in the muscle of both thresher shark (3.42 ± 1.68 μg g−1 in A. pelagicus and 3.78 ± 2.13 μg g−1 in A. superciliosus) exceeded the recommended levels for human consumption. This research provides insight into the factors influencing mercury bioaccumulation in thresher sharks, which are essential for the management and conservation of these species.

3D printing of salmon fillet mimic: Imparting printability via high-pressure homogenization and post-printing texturization via transglutaminase

Sustainability and environmental concerns towards animal protein production demands urgency in dietary shifts towards plant-based meat and seafood analogues. This study aimed to develop plant-protein based salmon mimics through three-dimensional (3D) printing of plant protein-based food inks coupled with post-printing transglutaminase (TGase) treatment. The simulant for the myosepta (white fat tissue) was developed as a pea protein emulsion with 5.5% protein content. To impart post-printing structural stability via high pressure homogenization (HPH), a minimum oil content of 30% was required. The myosepta simulant was then assembled with a red lentil protein emulsion which serves as the myomere simulant (orange muscle tissue) via 3D printing to form the salmon fillet mimic. Post-printing structural stability for the myomere simulant was conferred through gelation of its high protein content of 22%. Post-printing incubation at 55 °C substantially stimulated TGase to transform the emulsions from printable pastes to solids with texture profile comparable to real salmon fillet. Confocal imaging reflected the formation of porous protein networks in both simulants. In the texturized salmon mimic, the myosepta simulants with 5.5% protein content and 30–45% oil content achieved resemblance as a protein-stabilized oil droplet network with comparable mean oil droplet diameter d of below 1 μm. Whereas, the myomere simulant yielded a fibrous hierarchical structure resembling salmon myofiber and its constituent myofibrils through printing-induced alignment of protein aggregates. 3D printing with HPH ink plus post-printing texturization are critical contributors towards developing a plant-based mimic with macronutrient content, physicochemical properties and texture comparable to real salmon fillet.

From fork to farm: Impacts of more sustainable diets in the EU‐27 on the agricultural sector

AbstractThe implications of dietary changes for the environment and for human health are well documented, but the impacts on the agricultural sector are less well researched. We fill this gap by specifying scenarios in which European consumers' diets approximate the EAT‐Lancet dietary recommendations to varying degrees and estimate the effects on agricultural production, incomes and emissions using an agro‐economic modelling framework. The combination of different models allows for a detailed assessment of consequences for the agricultural sector from the global through European NUTS2 level to the farm level at different time scales. Shifting European consumption towards the EAT‐Lancet recommendations leads to decreasing production of animal‐based products, while production of fruits and vegetables increases sharply. The results indicate that the agricultural sector could benefit from a dietary shift, though the results are mixed at country, regional and farm levels. In particular, countries and regions that are highly specialised in animal farming are likely to lose income—at least in the short run—while regions with higher shares of vegetable and fruit farms can expect income gains. In Germany, pig and poultry farms may experience losses of up to 34% of their income, whereas farms with a high share of vegetables could gain more than 30% in income. Our results have implications for the policies to assist these extensive structural adjustments in response to widespread dietary changes.

Maternal and host effects mediate the adaptive expansion and contraction of the microbiome during ontogeny in a holometabolous, polyphagous insect

Abstract Polyphagous, holometabolous insects adapt to rapid diet shifts imposed by their ecology and their life cycle. One shift is linked to development, as larvae and adults usually dwell and feed in different environments, using different resources. The second is caused by changes in larval hosts, often occurring at each generation. Studies show that the insect's microbiome also changes in relation to development and larval host. However, parental and larval host contributions to its structure and trans‐generational dynamics remain uncharted. We investigated the sources of variation of the microbiome of the highly polyphagous Mediterranean fruit fly by tracking microbiome structure and its potential functional impact in fly lineages over generations and fruit host shifts, using 16S rRNA gene amplicon single variant analysis. Bacterial community alpha‐diversity expanded and contracted cyclically in a life stage‐dependent manner with the mothers' microbiome community ‘resetting’ to the same structure across generations. Expansion occurred at the larval stage, while alpha‐diversity decreased in tenerals, and significantly in mothers. In contrast, richness was highest in mothers, with rare taxa expanding in larvae depending upon fruit type. Metabolic predictions using PICRUSt pointed to increased metabolism of vitamins in mothers, and of aromatic compouds in larvae and tenerals, while indicator species analysis suggested fruit host composition‐dependent potential functional adaptations. Our data indicate lineage, fruit host and their interactions as the main sources of microbiome variation and provide examples of possible metabolic developmental and ecological adaptations. Taken together, these data support the hypothesis that microbiome diversity and microbiome‐driven local adaptations act as a mechanism sustaining polyphagy. Read the free Plain Language Summary for this article on the Journal blog.

Many losers and a few winners: polymorphic life-history of non-native largemouth bass is explained by ontogenetic diet shift and prey growth rate

Many losers and a few winners: polymorphic life-history of non-native largemouth bass is explained by ontogenetic diet shift and prey growth rate

A roadmap to achieve the global methane pledge

The Global Methane Pledge (GMP), launched in 2021 and signed by 149 countries and the European Union, aims to reduce global anthropogenic methane emissions by 30% in 2030 compared to 2020 levels. However, the GMP does not specify the contribution of countries or methane-emitting sectors (fossil fuel production, agriculture and waste) to achieve this global goal. Nationally determined contributions (NDCs) describe countries’ climate change commitments, and 86% of countries include methane within the scope of these targets. This paper aims to assess whether a roadmap (i.e. a set of mitigation actions) to achieve the GMP can be developed from those methane-targeted mitigation actions included within NDCs. The 476 methane-focussed mitigation actions within the 168 NDCs analysed are targeted in countries and sectors emitting approximately 40% of global methane. These mitigation actions are not specified in NDCs with implementation targets and timelines that are currently collectively sufficient to achieve the GMP goal. However, if all 476 mitigation actions are implemented to their maximum technical mitigation potential, their implementation could reduce global emissions by ∼31%. Therefore, mitigation actions in NDCs could achieve the GMP goal, but only if implemented to their fullest possible extent. There are also multiple opportunities to increase methane mitigation ambition further. Additional commitments to implement technical methane mitigation measures could lead to mitigation in excess of the GMP goal. Behavioural measures, such as dietary shifts and reduction in waste generation could further reduce methane, and are included in few NDCs currently.

Domestic Cattle in a National Park Restricting the Sika Deer Due to Diet Overlap.

Managers need to know the extent of the conflict between livestock and wild animals. Although many studies have reported the conflict between livestock and wild animals, few have checked the extent of the conflict. Cattle raising in the Northeast Tiger and Leopard National Park is considered one of the main driving forces behind the restricted distribution of sika deer. To understand whether foraging competition is contributing to avoidance patterns between sika deer and cattle, we investigated their feeding habits using DNA barcoding and high-throughput sequencing. Our study shows that although cattle are grazers in the traditional division of herbivores, their diet shifted to a predominance of dicotyledonous woody plants, and this diet shift resulted in a high degree of dietary overlap between sika deer and cattle. Moreover, compared to sika deer, cattle diets are more diverse at the species level with a wider ecological niche. Our results confirm that overlapping dietary niches and the superior competitive abilities of cattle contribute to the restricted distribution of the sika deer, which has critical implications for the conservation of their predators. Our study suggests that cattle grazing should be prohibited in the Park and effective measures should be taken for the benefit of sika deer.

A microbial tale of farming, invasion and conservation: on the gut bacteria of European and American mink in Western Europe

One of the threats that the critically endangered European mink (Mustela lutreola) faces throughout its relict range, including the occidental population, is the impact of the American mink (Mustela vison) invasion in its natural habitat. We aimed to explore the differences in microbiota and genetic diversity between European and American mink to test phylosymbiosis theory. We investigated the gut microbiota composition of European and American mink in controlled environments (captive breeding compounds and fur farms respectively) to account for the impact of the environment on gut bacterial composition. We compared them to the gut microbiota of both mink species in the natural environment across habitats. Our exploratory results showed differences between free-ranging and captive individuals, with more extreme changes in American mink compared to European mink. However, feral American mink from a long-established population exhibited gut bacterial composition closer to the free-ranging native species compared to more recently established feral populations. This result could be explained by dietary shifts in the area sampled based on prey availability through different landscape, but also to a lesser extent due to greater genetic differentiation. This exploratory work contributes to the scarce literature currently available on the dynamics between gut microbiota and mammal invasion.

Dietary trends and the decline in male reproductive health.

Over the twentieth century, male reproductive health has suffered a substantial decline, as evidenced by decreases in sperm counts and testosterone levels and increases in reproductive pathologies. At the same time, the prevalence of chronic diseases such as obesity, diabetes, and metabolic syndrome has risen dramatically. Metabolic and reproductive health are highly interconnected, suggesting that their respective trends are intertwined and, given the timeframe of such trends, environmental and not genetic factors are most likely to be the primary causes. Industrialization, which began in Europe in the mid-eighteenth century, has resulted in profound changes to our diet, lifestyle, and environment, many of which are causal factors in the rise in chronic diseases. Industrialization results in a nutrition transition from an agricultural unprocessed to a modern processed diet, incorporating increases in sugar, vegetable oils, ultra-processed foods, linoleic acid, trans-fats, and total energy. This dietary shift has incurred numerous adverse effects on metabolic and reproductive health, characterized by chronic inflammation, oxidative stress, and insulin resistance. Moreover, these effects appear to multiply across subsequent generations via epigenetic inheritance. Men's fertility is markedly affected by obesity and diabetes, with an increase in total energy via processed food intake arguably being the key factor driving the diabesity pandemic. In contrast, wholefoods rich in micronutrients and phytonutrients support male fertility and a healthy body weight. Therefore, men wanting to maximize their fertility should consider making positive dietary changes, such as replacing processed foods with unprocessed foods that support metabolic and reproductive health.

Ecological flexibility and adaptation to past climate change in the Middle Nile Valley: A multiproxy investigation of dietary shifts between the Neolithic and Kerma periods at Kadruka 1 and Kadruka 21.

Human responses to climate change have long been at the heart of discussions of past economic, social, and political change in the Nile Valley of northeastern Africa. Following the arrival of Neolithic groups in the 6th millennium BCE, the Northern Dongola Reach of Upper Nubia witnessed a cultural florescence manifested through elaborate funerary traditions. However, despite the wealth of archaeological data available from funerary contexts, including evidence for domesticated animals and plants as grave goods, the paucity of stratified habitation contexts hinders interpretation of local subsistence trajectories. While it is recognised archaeologically that, against the backdrop of increasing environmental deterioration, the importance of agriculture based on Southwest Asian winter cereals increased throughout the Kerma period (2500-1450 BCE), the contribution of domesticated cereals to earlier Neolithic herding economies remains unclear. This paper presents direct dietary data from a total of 55 Middle Neolithic and Kerma period individuals from Kadruka 21 and Kadruka 1. Microbotanical data obtained from human dental calculus and grave sediments are integrated with human and faunal stable isotopes to explore changes in dietary breadth over time. The combined results demonstrate the consumption of wild plant species, including C4 wetland adapted grasses, by Middle Neolithic individuals at Kadruka 1. Despite existing evidence for domesticated barley in associated graves, the results obtained in this study provide no clear evidence for the routine consumption of domesticated cereals by Middle Neolithic individuals. Rather, direct microparticle evidence for the consumption of Triticeae cereals is only associated with a single Kerma period individual and corresponds with an isotopic shift indicating a greater contribution of C3-derived resources to diet. These results provide evidence for Neolithic dietary flexibility in Upper Nubia through the persistence of foraging activities and support existing evidence linking increased agricultural reliance to the development of the Kerma culture.

Web-sourced photographic methods reveal dietary composition and shifts in resident and migrant Coracias rollers in southern Africa

Closely related species coexisting in the same niche often have dietary overlap and interspecific competition can result in resource partitioning e.g., dietary shifts, migration or phenological changes. Traditional methods to study avian diets are typically costly, difficult, and invasive. Using web-sourced photographs is an emerging, non-invasive method to study avian foraging ecology. We used this approach, along with photographic road surveys, to study prey composition of migratory European Rollers Coracias garrulus and resident Lilac-breasted Rollers Coracias caudatus where they co-occur in southern Africa. These insectivorous sister species are frequently photographed with prey in their bills because of their conspicuous perch-and-wait foraging behaviour and bright plumage coloration. We collated over 250 photographs of rollers holding prey and identified prey items representing 15 animal orders. Lilac-breasted Roller diet contained six unique orders of prey during the Austral summer (when the European Roller is present), and only one during winter (when the European Roller has migrated north). This suggests that Lilac-breasted Rollers may broaden their diet seasonally to alleviate competition with European Rollers during summer. Additionally, Lilac-breasted and European Rollers had an 84% overlap in dietary composition, potentially representing high interspecific competition - even during wet savanna summers when resource abundance is high - that might have originally driven the evolution of migratory behaviour in the European Roller. Our findings expand the current knowledge of roller diets and highlighting the growing role of social media in ecological studies.

Lakescape connectivity: Mobile fish consumers link Lake Michigan coastal wetland and nearshore food webs

AbstractIn large lake ecosystems, fish movement between coastal littoral habitats such as wetlands and the adjacent open‐water nearshore represents an understudied but potentially important linkage supporting energy flow and fisheries production. We hypothesized that yellow perch (Perca flavescens), an ecologically and economically important sport fish in the Laurentian Great Lakes, transport energy from highly productive wetlands to nearshore food webs, but that their role changes with ontogenetic shifts in diet and habitat use. We also predicted that the relative strength of such fish‐mediated habitat linkages would vary depending on physical connectivity across habitats. We collected perch and potential prey resources from seven paired coastal wetland–nearshore sites across three regions of Lake Michigan and quantified resource and habitat use with Bayesian stable isotope mixing models and otolith microchemistry. We found that juvenile perch collected in nearshore habitats showed high use of wetland resources, and that diets of wetland‐collected juveniles typically contained a smaller proportion of nearshore resources than did more mobile adults from the same wetland. The least hydrologically connected sites had lower cross‐habitat resource use (e.g., wetland‐collected perch consumed fewer nearshore resources and vice versa) compared with sites with greater levels of hydrological connectivity. Otolith microchemistry confirmed the linkages revealed by stable isotopes, suggesting that a dual approach can increase understanding of habitat linkages in large lakes. Quantifying the importance of multiple lentic habitats (i.e., “lakescape connectivity”) for fisheries production is critical for developing comprehensive large lake food web models and providing managers with information to prioritize locations for conservation and restoration.