Feeding Traits Research Articles

Which traits optimize plant benefits? Meta‐analysis on the effect of partner traits on the outcome of an ant–plant protective mutualism

Abstract Theoretical models on mutualism dynamics predict that partner traits may influence the outcome of mutualistic interactions. However, most empirical data on this issue is restricted to case studies, limiting our ability to reach a more widespread comprehension of the role of partner traits on the dynamic of mutualisms. We investigated how the outcome of protective mutualisms between ants and plants bearing extrafloral nectaries (EFNs) is influenced by the traits of EFNs and ants feeding on EFNs. We used a meta‐analytical approach based on 35 studies investigating the effect of ant attendance on the herbivores and reproductive performance of EFN‐bearing plants. We evaluated how variation in the EFN vascularization and location on plants and the ant aggressiveness can modulate the effect of ant attendance on the plants. Both plant and ant traits investigated here drove the outcome of the protective mutualism for EFN‐bearing plants. Plants exclusively bearing EFNs near reproductive organs benefited more from ant attendance than plants bearing EFNs on vegetative or vegetative and reproductive organs. Ants had a higher positive impact on the reproductive performance of plants bearing non‐vascularized EFNs than plants bearing vascularized EFNs, although their effects on herbivores had been similar in both plant types. Regarding the ant behaviour, plants often attended by more aggressive ant species had a higher reproductive performance than plants often attended by less aggressive ones. Synthesis. Our results highlight that the selective pressures and evolutionary routes in ant‐plant protective mutualisms may depend on the pool of traits exhibited by partner species. Although some studies have already reported some impact of species traits on the outcome of ant‐plant mutualisms, this is the first time that a generalization about the role of species traits on the net balance of ant attendance was proposed. Due to this generalization, it was possible to advance our knowledge about the evolution of facultative mutualisms by showing that the role of species traits on the mutualistic outcome can vary in intricate ways due to a particular trait combination found among partners in communities where the interactions are embedded in.

To Save Pangolins: A Nutritional Perspective.

Pangolins are one of the world's most trafficked mammals. Since pangolins are highly adapted to ants and termites, they are important for controlling forest termite infestations. In addition to their ecological value, pangolins have economic and medicinal value. Currently, poaching and habitat destruction have radically reduced the number of pangolins, and Manis pentadactyla, Manis javanica, and Manis culionensis are now considered the most threatened pangolin species. In addition to the control of hunting and illegal trade, ex situ breeding is also a useful conservation method. However, many technical obstacles still limit the success of ex situ pangolin breeding. The special feeding traits of pangolins require a diet that meets nutritional and ethological needs. Based on the existing literature and practical experience, this review aims to compare the natural diet and successful diet in the human care of pangolins, to outline the key factors of successful ex situ maintenance from a dietary perspective, and the strategies to improve their conservation success in animal care centers and in the wild. The type of food used in successful pangolin protection agencies is quite variable in nutritional composition. In the diet of pangolins in the wild, the nutrient profile of different species of termites and ants and even the same species of termites and ants but different types (queens, soldiers, etc.) also displays differences. The crude protein content of some ants is higher than that of other foods, such as eggs, milk, and common cat food. The mineral and vitamin concentrations of ants also exceed many common food items, such as oil, meat, and eggs. However, not much is known about the bioavailability of minerals from ants and termites. Based on comparisons between foods, it is clear that the main difference between diets in the wild and in human care of pangolins is that the latter contains fewer insects and vitamins, such as vitamin E, vitamin A, and vitamin B2, and more carbohydrates and non-protein substances than the former. Although many successful dietary formulae have been developed, the pangolin's nutritional needs are still less well studied. A diet with the nutrient concentrations observed in the wild may add to successful ex situ conservation.

Life History Metrics for Culex tarsalis (Diptera: Culicidae) and Culicoides sonorensis (Diptera: Ceratopogonidae) Are Not Impacted by Artificial Feeding on Defibrinated Versus EDTA-treated Blood.

Artificial blood feeding is a common practice for the study and maintenance of blood-feeding arthropod colonies. Commercially purchased blood is often treated to prevent clot-formation using either mechanical or chemical means. For many hematophagous insects, the effect that different anticoagulation methods may have on life history metrics is unclear. In the current study, Culex tarsalis Coquillett and Culicoides sonorensis Wirth & Jones were fed blood treated with either mechanical (defibrination) or chemical (K2 EDTA) anticoagulation methods. Several blood feeding and life history metrics were evaluated between treatment groups including proportion blood feeding, fecundity, fertility, and mortality. No significant differences were found for any of the measured life history metrics for either species. For experiments measuring aspects of these blood feeding and life history traits, blood treated using either defibrination or K2 EDTA anticoagulants should not impact experimental outcomes.

Eutrophication induces functional homogenization and traits filtering in Chinese lacustrine fish communities

Rapid anthropogenic nutrient enrichment has caused widespread ecological problems in aquatic ecosystems and the resulting eutrophication has dramatically changed fish communities throughout the world. However, few studies addressed how fish communities responded to eutrophication in terms of multidimensional functional and taxonomic structure, especially how eutrophication acted as an environment filter on functional traits. The aim of the present study was to investigate the effects of eutrophication on fish species composition, community metrics and species functional traits in 26 shallow lakes from the middle reaches of Yangtze River basin, China. This study validated that eutrophication is an important factor shaping the fish community structure. Regression analyses showed that eutrophication favored higher total biomass and lower functional diversity of fish communities but had little effect on species richness. Despite the fact that some pelagic zooplanktivorous species were more abundant in the most eutrophic lakes, multivariate analyses of the relationships between species traits and environmental variables revealed weak relationships between feeding traits and eutrophication. In contrast, species with a benthic life stage were negatively associated with eutrophication while those with a large body size and high absolute fecundity showed the opposite trend. Due to demersal habitat degradation, and to a lesser degree, to changes in trophic resources availability, eutrophication caused functional simplification of fish communities by increasing functional traits homogeneity among the most tolerant species. Some relationships between functional traits and eutrophication well established in the western palearctic have not been observed in this study, emphasizing the importance of biases resulting from specific evolutionary histories. This work will provide useful insights on on-going restoration and management of shallow lakes in the Yangtze River basin.

Genome-wide association analysis of milk production, somatic cell score, and body conformation traits in Holstein cows.

Milk production and body conformation traits are critical economic traits for dairy cows. To understand the basic genetic structure for those traits, a genome wide association study was performed on milk yield, milk fat yield, milk fat percentage, milk protein yield, milk protein percentage, somatic cell score, body form composite index, daily capacity composite index, feed, and leg conformation traits, based on the Illumina Bovine HD100k BeadChip. A total of 57, 12 and 26 SNPs were found to be related to the milk production, somatic cell score and body conformation traits in the Holstein cattle. Genes with pleiotropic effect were also found in this study. Seven significant SNPs were associated with multi-traits and were located on the PLEC, PLEKHA5, TONSL, PTGER4, and LCORL genes. In addition, some important candidate genes, like GPAT3, CEBPB, AGO2, SLC37A1, and FNDC3B, were found to participate in fat metabolism or mammary gland development. These results can be used as candidate genes for milk production, somatic cell score, and body conformation traits of Holstein cows, and are helpful for further gene function analysis to improve milk production and quality.

Genetic correlations between harvest weight and secondary traits in a silver carp (Hypophthalmichthys molitrix) genetic improvement program

In 2017, the base population of a family-based silver carp (Hypophthalmichthys molitrix) genetic improvement program was spawned in Bangladesh. This program aims to improve the growth rate of silver carp under polyculture production systems, through direct selection on the primary trait of harvest-age weight. The objective of this study was to quantify genetic variation in, and genetic correlations between, harvest-age weight (assessed on 8012 fish from 184 families) and a set of secondary traits (assessed on 1603 fish from 175 families). Secondary traits examined included feeding and digestive system traits (i.e. gill raker sponginess and gut length as a ratio of standard length), a morphometric trait (i.e. extent of overlap of pectoral and pelvic fins) and health traits (i.e. presence of Lernaea and prevalence of red spots — sites of inflammation/haemorrhaging). Despite not being under direct selection, genetic change in secondary traits is possible across generations in closed genetic improvement populations as a result of a correlated response to selection for the primary trait (i.e. indirect selection), adaptation to culture conditions, inbreeding and/or genetic drift. It was found that the additive genetic variance within genetic groups was significantly different from zero for all but the studied health traits. Heritability estimates for harvest-age weight and pectoral/pelvic fin overlap were moderate (0.24 and 0.22, respectively) but were low for gill raker score and relative gut length (0.12 and 0.09, respectively). Genetic correlations between harvest-age weight and secondary traits were not significantly different from zero, indicating that selection for harvest-age weight will not result in a correlated response to selection in the studied secondary traits.

Thermal traits of freshwater macroinvertebrates vary with feeding group and phylogeny

Abstract Functional traits of organisms, especially feeding traits, influence how organisms mediate ecosystem processes. As climate change, landscape modification and industrial waste heat release continue to increase water temperatures, shifts in the composition of feeding traits within aquatic macroinvertebrate communities may alter ecosystem processes. However, it is unclear whether thermal traits of macroinvertebrates vary systematically across functional feeding groups (FFGs; i.e., categories based on feeding ecology such as herbivores, shredders, predators, etc.) or phylogeny. We used previously published datasets on hundreds of macroinvertebrate taxa to evaluate how thermal traits differed across FFGs. We also examined the strength of phylogenetic signal in both FFG and thermal traits, using a new phylogeny of insect taxa. Then, we tested whether phylogenetic patterns offered a plausible explanation for differences in thermal traits among FFGs by comparing phylogenetic and non‐phylogenetic regressions. Shredders tended to have lower temperature preferences, optima and maxima (three of five of the thermal traits evaluated) than other FFGs. Patterns for other FFGs differed by thermal trait, but predators, collector‐gatherers and filterers had some of the highest thermal trait values. FFG explained 40% of the variation in critical thermal maximum, but <12% of the variation in the four other thermal traits. Phylogeny explained 26%–88% of the variation in thermal and feeding traits. For the subset of taxa and trait data that were available, phylogeny explained more than double the variation in thermal traits relative to FFG, but comparison of phylogenetic and non‐phylogenetic regressions highlighted that FFG explained variation in thermal traits that was independent of phylogeny. Our results highlight phylogeny and FFG as predictors of thermal traits in aquatic macroinvertebrates. Our results suggest that warmer water temperatures could favour predators, filterers and collector‐gatherers over shredders. Furthermore, our results confirm that certain orders of macroinvertebrates, such as Diptera, may be better suited to warmer temperatures than other orders, such as Plecoptera.

Sex and male breeding state predict intraspecific trait variation in mouth-brooding fishes.

Sex‐specific reproductive roles contribute to sexual dimorphic morphological trait variations. In uniparental mouth‐brooding fishes, the mouth performs a reproductive function in addition to its key roles in feeding and respiration, resulting in the potential for sex‐specific functional performance trade‐offs. Trait differences related to parental care may occur when the individual matures or be restricted to periods when the parent is mouth‐brooding. This study explored sexual dimorphism and morphological trait adaptations related to feeding, breeding, respiration and locomotion performance in two paternal mouth‐brooding freshwater fishes (Glossamia aprion and Neoarius graeffei). Eight morphological traits were evaluated for sexual dimorphism (non‐brooder males vs. females) and male breeding state differences (brooders vs. non‐brooders). Male breeding state was a significant predictor of trait variation in both species. Brooders differed in buccal volume and in several feeding and locomotory traits compared to non‐brooder males. Non‐brooder males had bigger buccal volumes and relative eye diameters (G. aprion) and larger relative gape sizes (N. graeffei) compared to females, a potential response to both mouth‐brooding and feeding requirements. Although there were clear trait differences between brooder and non‐brooder males, further research is required to confirm whether individuals return to their former morphology once mouth‐brooding has ceased or if trait differences are maintained post‐brooding. This study highlights the importance of considering the potential impacts of intraspecific trait variation on the performance of critical life functions, such as feeding, respiration and locomotion across the life history.

Feeding ecology of the endangered Apennine Yellow-bellied Toad (Bombina pachypus) in central Italy

Anurans are generalist opportunistic consumers, but many species show some degree of diet specialization. Within populations, individuals may specialize in specific dietary resources (individual specialization). Indeed, generalist populations may be composed of individuals using the whole range of available resources or of diverse individuals exploiting specific food items. Based on the niche variation hypothesis (NHV), an increase in population niche width may be related to a higher incidence of individual specialization. We analyzed the feeding ecology of the endangered Apennine Yellow-bellied Toad ( Bombina pachypus (Bonaparte, 1838)) in central Italy. This species showed a generalist feeding strategy, wide trophic niche, high individual generalization, and a predominant use of terrestrial resources. The study species inhabits seasonal habitats determining variation in food availability and diversity, and this may have driven toads to be unselective and consume almost any encountered palatable item. The absence of sexual size dimorphism may explain the absence of trophic differentiation between sexes. The analysis of individual feeding traits revealed a week's degree of individual specialization positively correlated to niche width, partly supporting the NHV. The obtained information can be used for the implementation of effective conservation strategies of locally imperilled species, especially those breeding in temporary ponds.

10 Deep Learning for Multi-Behavioral Video Classification of Interactive Behaviors of Pigs in Single-Spaced Automatic Feeders

Abstract Automatic pig feeders record individual feeding behavior traits that can be used in genetic selection. However, these feeders cannot measure how feeding traits are affected by behavioral interactions between animals. Moreover, recording behavioral interactions can improve the estimation of social genetic effects. This motivated our assessment of computer vision to classify 4 types of interactions at the feeder: head-to-body contact (HB) including head knocking, tail biting, pushing, gentle nosing and casual contact between head/ears of a pig with a feeding pig; levering (L) where the feeding pig was lifted from behind by another pig; mounting (M) where the feeding pig was mounted by another pig; and no-contact (NC) when a second pig entered the feeder without touching the feeding pig. Behavior at the feeder was filmed twice, 3 weeks apart, for 2 consecutive days each week in 6 groups of grow-finish pigs (10 per group) housed in pens equipped with FIRE feeders. Video segments that involved 2 pigs in the feeder were selected, and labeled as HB (n=10,114), L (n=925), M (n=1,242) and NC (n=3,398). Due to the sparse data available for training and the complex nature of the behavioral interactions, we utilized pretrained convolutional neural networks for automatic spatial feature extraction followed by long short-term memory for temporal feature extraction from sequences of frames. Focal loss, a loss function that assigns different weights to hard/easily misclassified examples to handle class imbalance problem, was used in this study. Accuracy, recall, and precision of behavior classification were obtained from 5 random cross-validations. The overall accuracy was 0.967±0.002. The average recalls for HB, L, M, and NC were 0.977±0.004, 0.866±0.047, 0.969±0.011, and 0.964±0.009 respectively, while average precisions were 0.976±0.002, 0.901±0.029, 0.956±0.018, and 0.963±0.012. The proposed algorithm accurately classified multiple interactive behaviors in an automated feeding stall from digital videos.

A Cretaceous balloon lifts the veil on the antiquity and evolution of nuptial gifts

Nuptial gift-giving is one of the most remarkable traits to have evolved among animal mating systems, and has brought about numerous hypotheses regarding their evolution and influence. Yet, their study has been confined to the modern fauna owing to their ephemeral nature and lack of traces on the environment suitable for preservation. Here we report the first paleontological and earliest evidence of nuptial gift-giving behavior from a male fly of Alavesia (Diptera: Empidoidea) that is an obligate flower visitor in Cretaceous amber carrying his gift, an empty frothy balloon. The fossil demonstrates the antiquity of this behavior, its occurrence in early diverging lineages of Empidoidea, and its maintenance over 99 million years. The nature of the fossil gift provides clues into the function of swarming and the diversity of gifts employed. Based on the phylogenetic pattern of feeding and mating traits, it is inferred that the gift initially alleviated nutrient pressure on females and may have been empty and secreted from male salivary glands in the first place, those with prey items inside were derived later. The evolution of these mating systems may have been a response to maximizing the usage of exogenous nutrients and for signal transmission.

Examining differentiation of sympatricSchizothoraxfishes reveals low differentiation in internal compared to external feeding traits

AbstractIn the process of sympatric species differentiation, which feeding traits are most differentiated? The complete feeding process of capture, ingestion, and digestion requires certain external, as well as internal traits. Therefore, comprehensive comparisons are needed to study fish feeding habits. This study systematically investigated the adaptive radiation and parallel evolution ofSchizothoraxfishes, and quantified the external, frame, pharyngeal bone, and digestive traits of the systematically differentiated omnivorousSchizothorax davidiand herbivorousS. wangchiachii. A member of their sister genus, the carnivorousPercocypris pingi, was used as an outgroup control to explore the feeding differentiation of sympatricSchizothoraxfishes. The results showed that these species had highly differentiated external traits, while the internal traits (pharyngeal bone and digestive traits) showed low differentiation, indicating that predatory traits diverged first in the differentiation of sympatricSchizothoraxfishes, while chewing and digestive traits were slower to diverge. Furthermore, we screened 16 continuous feeding traits, and the quantified values of these traits progressively increased or decreased with increasing nutritional level of food. These findings provide a reference for the selection of quantitative indicators in future studies of sympatric species differentiation.

Seasonal and functional variation in the trophic base of intermittent Alpine streams

AbstractIn high‐altitude Alpine streams, seasonal cycles of snowmelt, glacial melt, and rainfall drive variation in the availability of algal food resources. Yet, high‐altitude streams also exhibit varying degrees of flow intermittency, ranging from solely winter‐drying streams to others that dry periodically throughout summer and autumn. These environmental drivers may interact in different ways to determine the functional trophic base of macroinvertebrates inhabiting high‐altitude streams. Here, we estimated the proportional contribution of autochthonous resources to the assimilated diets of benthic macroinvertebrates in 26 headwater streams of Val Roseg, a high Alpine glacial catchment, using stable isotope analysis (δ13C and δ15N) of different macroinvertebrate families and their potential food sources. We compared dietary estimates along a gradient of flow intermittency and across three seasons (Alpine spring, summer, and autumn). Assimilation from autochthonous sources was highest for collector‐gatherers and filter feeders in spring, and for grazers in summer. Grazers had higher estimated assimilation from autochthonous sources in intermittent streams than in perennial streams, particularly in summer, while collector‐gatherers showed little effect of flow intermittency on dietary estimates. However, responses were highly taxon‐specific, with different responses to variation in flow intermittency and season across families within functional groups. Our results suggest that frequent summer‐drying events represent tradeoffs between greater access to algal food resources and a higher risk of desiccation, but that differing life history and functional feeding traits across macroinvertebrate taxa drive marked variation in the risks or benefits associated with inhabitants of drying streams.

Comparative Evaluation of Growth Performance and Feed Utilization of Improved Nigerian Indigenous Broiler and Different Crossbreds

The study was carried out as part of efforts to improve the performance of the Nigerian indigenous chicken and improve potentials of indigenous broiler strains to provide higher quality of meat at a reduced cost. The study compared the growth and feeding traits of three different chicken crossbreds with the generated lines of Improved Nigerian indigenous broiler (FUNAAB-Alpha) using the Arbor Acre broiler as the experimental control. Males of three broiler breeds types (Kuroiler, Sasso and Arbo Acre) were mated with a total of 120 improved Nigerian indigenous pullets (FUNAAB-Alpha) to generate 360 crossbred broilers. 120 each of Arbor Acre and FUNAAB-Alpha improved line were also reared in a separate pen for comparison. Growth performance, feed intake, body weight gain and feed conversion efficiency of all the chicken breeds were recorded for 8 weeks and compared. Two way analysis of variance (ANOVA) was used for the analysis with consideration of the effect of breeds, sex and its interaction. The results revealed a significant (P < 0.05) influence of the breeds on the traits across all ages. FUNAAB-Alpha broiler consumed the least quantity of feed/bird/day followed by the Sasso-FUNAAB-Alpha crossbred throughout the period of the experiment. However, Sasso-FUNAAB-Alpha chicken had the highest mean value for body weight and other linear body parameters among the crossbreds. Despite of the improvements achieved in FUNAAB-Alpha crosses, there is a need for further analysis and research in order to achieve the maximum potential of the improved broiler strain

Plasticity of feeding behaviour traits in response to production environment (temperate vs. tropical) in group-housed growing pigs

Heat stress affects pig metabolism, health and welfare, resulting in reduced growth and important economic losses. The present experiment aimed to evaluate the effects of two climatic environments [temperate (TEMP) vs. tropical humid (TROP)] on feeding behaviour in growing pigs. The feeding behaviour traits were measured with automated feeders and included: daily feed intake, daily eating time, feeding rate, daily number of meals, feed intake per meal, and feeding time per meal. Pigs came from a backcross population between Large White (LW, heat sensitive) and Creole (CR, heat tolerant) pigs. The same 10 F1 LW × CR boars (sire families [SF]) were mated with related LW sows in each environment. Feeding behaviour was recorded for a total of 1,296 pigs (n = 634 pigs for TEMP and n = 662 pigs for TROP) between 11 and 23 weeks of age. Growth performance and thermoregulatory responses (rectal and skin temperatures) were also measured. Results show that TROP conditions affect feeding behaviour traits: animals had more meals per day but these meals were smaller both in duration and in size, resulting in lower daily feed intake and less time eating per day. Significant SF by environment (GxE) interactions were found for all feeding behaviour traits. When SF were distributed into robust and sensitive groups (previously defined according to performance and thermoregulatory traits), results showed group by environment interactions for all feeding traits, except meal frequency. Moreover, a significant difference in feeding rate between robust and sensitive group was detected in TEMP, suggesting that feeding rate may be a good candidate to evaluate heat tolerance.

Nutritional analysis of oat for food, feed and fodder quality traits under semi-arid Indian environment

Kumar, N., Rana, M., Singh, S. and Ahmed, S. 2022. Nutritional analysis of oat for food, feed and fodder quality traits under semi-arid Indian environment. Animal Nutrition and Feed Technology, 22: 575–588.

A multispecies TAC approach to achieving long-term sustainability in multispecies mixed fisheries

Abstract The management of mixed fisheries is complicated by the biological and technical interactions among fish species. We tested a multispecies total allowable catch approach to managing mixed fisheries while accounting for the interactions and changes within fish community. A multispecies size–spectrum model was developed to simulate the dynamic of fish community in North Yellow Sea, China. Three scenarios were evaluated: (1) business-as-usual (BAU); (2) Single-species TAC (SSTAC); and (3) Multispecies TAC (MSTAC, assigning an aggregated total TAC to a selected group of species). Our results showed that BAU reduced biomass of target species to a substantially low level, SSTAC led to loss of fishing opportunity by involving “choke species” with discard ban, while MSTAC had a potential for maintaining long-term yields and community structure. We demonstrated the ecological effects of varying levels of MSTACs on the target and non-target species. Species’ responses to MSTAC were stronger when the species had similar feeding and habitat traits to the target species, implying intense competition. Particularly, a 20% decrease in MSTAC could cause an average 17% decline in the biomass of other species through biological interactions in the long-term. MSTAC could be a promising approach to achieving long-term sustainability in data deficient fisheries.

Continental‐scale shifts in termite diversity and nesting and feeding strategies

Typically, termites are treated as a single guild, which ignores important internal diversity, including diverse feeding and nesting traits. These termite traits are crucial for both ecosystem‐level fluxes and trophic webs, with implications for vertebrate species. Despite their ecological importance, the large‐scale distribution of termite feeding and nesting traits and the relationship with termite diversity is largely unknown. We investigated whether functional diversity, species richness and feeding (wood, litter, grass and dung) and nesting trait (aboveground mound, belowground nest, inside tree or outside tree nest) distributions of termites were climatically controlled. To address this gap, we assembled a continental‐scale database of termite traits and occurrence in Australia and modelled termite nesting and feeding traits in response to macroclimate. Functional richness and evenness increased primarily with temperature. Australia showed multiple hotspots of termite diversity with each hotspot showing a distinct guild composition. The large‐scale distribution of nesting traits showed that aboveground nesting species were the most common nesting guild in the dry and wet tropics, while belowground nesting dominated in seasonally cold arid environments, demonstrating a strong climatic control on nesting strategy. Given their large biomass and many interactions with other species, the macroecology of termite traits may be especially important in predicting shifts in other species' distributions at continental and global scales.

Individual variation in feeding morphology, not diet, can facilitate the success of generalist species in urban ecosystems.

Generalist species dominate urban ecosystems. The success of urban generalists is often related to a plastic diet and feeding traits that allow them to take advantage of a variety of food resources provided by humans in cities. The classification of a species as a generalist is commonly based on mean estimates of diet‐ and feeding‐related traits. However, there is increasing evidence that a generalist population can consist of individual specialists. In such cases, estimates based on mean can hide important individual variation that can explain trophic ecology and the success of urban dwellers. Here, we focus on guppies, Poecilia reticulata, a widespread alien fish species which has invaded both urban and non‐urban systems, to explore the effect of urbanization on individual diet and feeding morphology (cranium shape). Our results show that guppies in urban and non‐urban populations are not individual specialists, having a similar generalist diet despite the high population density. However, there is important individual variation in cranium shape which allow urban guppies to feed more efficiently on highly nutritious food. Our data suggest that individual variation in feeding efficiency can be a critical overlooked trait that facilitates the success of urban generalists.

Presence and Characterization of Microplastics in Coastal Fish around the Eastern Coast of Thailand

Marine microplastic has been in the limelight recently. This study aimed to describe microplastic types ingested by 274 fish from Thailand’s eastern coast in 2020 and to compare the microplastic content among different feeding traits. The microplastics in the gastrointestinal tracts and gills were extracted, analyzed, and identified using FT-IR spectroscopy. Approximately 13.14% of the total specimen ingested microplastics, with an average of 0.14 items per individual. The detection frequency of microplastics was relatively high compared with other regions in Thailand but relatively low compared to global standards. Of the microplastic contaminated specimens, 56.41% had at least one piece of microplastic in their gastrointestinal tract. Pelagic (14.47%) species were found to have ingested more microplastics than the demersal (12.63%) group. Dominant aspects found included PET (as in polymers), fiber (as in shape), and black (as in color). However, microplastic numbers fluctuated with the size, weight, and feeding behavior of fish. This result suggested that the pelagic has a higher exposure risk and microplastic ingestion in relatively small quantities in a range of fish species. Our results indicated that the occurrence of microplastics in fish is not influenced by organism habitat or trophic level, although the characteristics of pelagic fish might significantly increase the chance of exposure to microplastics in pelagic species.