Opportunistic Feeding Research Articles

Using DNA metabarcoding and a novel canid-specific blocking oligonucleotide to investigate the composition of animal diets of raccoon dogs (Nyctereutes procyonoides) inhabiting the waterside area in Korea

The raccoon dog (Nyctereutes procyonoides) is known to be an opportunistic generalist who feeds on a wide variety of foods. Historically, their diet has been investigated by morphological observation of undigested remains in feces, requiring specialized knowledge such as osteology, zoology, and phytology. Here, we used DNA metabarcoding of vertebrate 12S rRNA gene and invertebrate 16S rRNA gene to investigate their fecal contents. Additionally, we developed a blocking oligonucleotide that specifically inhibits the amplification of the canid 12S rRNA gene. We confirmed that the blocking oligonucleotide selectively inhibit the amplification of raccoon dog's DNA without significantly changing the composition of the preys' DNA. We found that the main foods of raccoon dogs in our study area, the waterside of paddy fields in Korea, were fishes such as Cyprinidae and insects such as mole crickets, which makes sense given the Korean fauna and their well-known opportunistic feeding behaviors. As a method to conveniently and objectively investigate feeding habits of raccoon dogs, this study provided baseline information on DNA metabarcoding. By using DNA metabarcoding, it is expected that the diet habits and ecology of raccoon dogs will be better understood by future research.

Ecological Traits of Fish for Mercury Biomonitoring: Insights from Compound-Specific Nitrogen and Stable Mercury Isotopes.

We coupled compound-specific isotopic analyses of nitrogen (N) in amino acids (δ15NGlu, δ15NPhe) and mercury stable isotopes (δ202Hg, Δ199Hg) to quantify ecological traits governing the concentration, variability, and source of Hg in largemouth bass (LB) and pike gudgeon (PG) across four rivers, South Korea. PG displayed uniform Hg concentration (56-137 ng/g), trophic position (TPcorrected; 2.6-3.0, n = 9), and N isotopes in the source amino acid (δ15NPhe; 7-13‰), consistent with their specialist feeding on benthic insects. LB showed wide ranges in Hg concentration (45-693 ng/g), TPcorrected (2.8-3.8, n = 14), and δ15NPhe (1.3-16‰), reflecting their opportunistic feeding behavior. Hg sources assessed using Hg isotopes reveal low and uniform Δ199Hg in PG (0.20-0.49‰), similar to Δ199Hg reported in sediments. LB displayed site-specific δ202Hg (-0.61 to -0.04‰) and Δ199Hg (0.53-1.09‰). At the Yeongsan River, LB displayed elevated Δ199Hg and low δ15NPhe, consistent with Hg and N sourced from the atmosphere. LB at the Geum River displayed low Δ199Hg and high δ15NPhe, both similar to the isotope values of anthropogenic sources. Our results suggest that a specialist fish (PG) with consistent ecological traits and Hg concentration is an effective bioindicator species for Hg. When accounting for Hg sources, however, LB better captures site-specific Hg sources.

First record of Acromitus flagellatus (Maas, 1903) (Cnidaria: Scyphozoa) swarm from the world’s largest deltaic ecosystem, the Sundarbans, India

The present study describes the first record of Acromitus flagellatus (Maas, 1903) swarm from the east coast of India, Bay of Bengal. Specimens of A. flagellatus were collected from the estuarine waters of Saptamukhi river channel, of the Sundarbans deltaic region during February 2021. The exumbrella was 160 ± 40 mm in diameter, with oral arms measuring 115 ± 45 mm and possessing a single long flagellum at the distal end of each oral arm. A. flagellatus swarm had an abundance of 5200 ± 440 ind. m−3. Sea surface temperature and salinity in the study area were 25.3 ±0.7°C and 24.5 ± 0.5 ‰ respectively. Common phytoplankton species encountered were Biddulphia sinensis, Planktoniella blanda and P. sol; while microzooplankton comprised mostly of larval forms of invertebrate metazoans. Mesozooplankton species during A. flagellatus swarm were dominated by Centropages orsinii, Bestiolina similis, Subeucalanus subcrassus, Clytia simplex, Pleurobrachia globosa, Zonosagitta pulchra and Hyperia macrocephala. Our study points to the non-specific, opportunistic feeding pattern of A. flagellatus across different trophic levels, from phytoplankton to fish and will extend the distribution of A. flagellatus up to the Sundarbans delta of the Bay of Bengal.

Growth, reproduction, and feeding habits of striped bonito, Sarda orientalis, in the East China Sea

We evaluated the growth, reproduction, and feeding habits of striped bonito (Sarda orientalis) in the East China Sea. We collected a total of 289 specimens and determined their age from polished otoliths. The estimated growth function was FLt=586.98{1−exp[−0.76exp(t+0.33)]}, where FLt represents fork length (mm) at age t. Males reached spermiation in April through September, and females spawned in May through July. The main spawning periods for females were May and June. The smallest sexually mature female and male reached 445 and 436 mm in FL, respectively, and were both age 1. The principal prey species were jack mackerel (Trachurus japonicus), scad (genus Decapterus), and anchovy (Engraulis japonicus). The mean carbon and nitrogen stable isotope ratios of the striped bonito were −16.6‰ and 13.7‰, respectively. The relative contribution of prey species based on stable isotope ratios indicates that the striped bonito is an opportunistic feeder of small pelagic fishes. These biological and ecological data on the striped bonito will be of great importance for stock assessment and the development of ecosystem-based fisheries management schemes.

Decipher groundwater food web interactions by means of stable isotope and gut microbiome analyses

The traditional perception of groundwater food webs is that of short and poorly structured food chains extending to only few trophic levels. This is mainly attributed to the lack of light and the shortfall of substantial primary production as well as the shortage of dissolved organic carbon and nutrients. It is frequently argued that microbes form the basis of groundwater food webs. In reality, the obvious lack of comprehensive biofilms may point to detritus as the main common food source and an opportunistic and omnivorous feeding strategy with most groups and species. Also, the relative stability of groundwater environments may have led to low trait variability. However, recent research also contrasts the paradigm of poorly structured food chains against emerging convoluted mechanisms sustaining a great range of biotic diversity and functional complexity. In summary, understanding of the ecological and functional linkages among stygofaunal groups, and their interaction with the microbial community, is still in its infancy. Stygofauna sampled from three spots of a shallow alluvial aquifer in the vicinity of the Danube River in the city of Vienna, Austria, has been analyzed by means of bulk stable carbon and nitrogen isotope and gut microbiome analysis to disentangle food web interactions. Our preliminary data revealed the following pattern: plant material, terrestrial insects, and detritus show a narrow range in carbon (-32 to -25δ13C) and a wide range in nitrogen (-1.5 to 6.5 δ15N) isotope signatures. In terms of nitrogen isotope values, the next tropic level is represented by isopods and gastropods, followed by ostracods, oligochaetes and amphipods. The broader range of stygofauna in carbon isotope signatures indicate an additional food source; most probably microbes; gut microbiome analyses indicate differences with oligochaetes, gastropods, ostracodes, isopods and amphipodes, however, with a few individuals from the later three groups sharing a very similar gut microbiome; within the amphipods, there is obviously a difference in gut microbiome composition with species and sampling sites; carbon and nitrogen isotope signatures underline amphipod-species differences; microbiome diversity in all cases was less divers in the animal guts when compared to environmental water, sediment and detritus samples. plant material, terrestrial insects, and detritus show a narrow range in carbon (-32 to -25δ13C) and a wide range in nitrogen (-1.5 to 6.5 δ15N) isotope signatures. In terms of nitrogen isotope values, the next tropic level is represented by isopods and gastropods, followed by ostracods, oligochaetes and amphipods. The broader range of stygofauna in carbon isotope signatures indicate an additional food source; most probably microbes; gut microbiome analyses indicate differences with oligochaetes, gastropods, ostracodes, isopods and amphipodes, however, with a few individuals from the later three groups sharing a very similar gut microbiome; within the amphipods, there is obviously a difference in gut microbiome composition with species and sampling sites; carbon and nitrogen isotope signatures underline amphipod-species differences; microbiome diversity in all cases was less divers in the animal guts when compared to environmental water, sediment and detritus samples. Finally, we first collected evidence for anaerobic processes taking place in animal guts living in an oxic groundwater environment. In light of our data, putative groundwater food web interactions in the shallow alluvial aquifer are discussed.

Trunk picking from a truncating menu: Dry season forage selection by Asian elephant in a multi-use landscape.

Elephants show a strong selection towards areas with high foraging opportunities at the landscape level making top-down decisions by first selecting patch types within landscapes and finally species within them. Understanding forage selection in a multi-use landscape is critical for prioritising patches for habitat management, ensuring availability of selected forage, helping in minimizing pressure on food crops and subsequent negative interactions with people. We assessed dry season forage selection in a multi-use landscape of West Bengal state, India. Relative forage use and relative plant species availability ratio were calculated to assess forage selection in a multi-use landscape comprising of the forest, tea estates, agricultural land, and human settlement. Forage use was assessed using the opportunistic feeding trail observation method (150.01 km). Stratified random sampling was used to assess plant species availability using the quadrat method (123 plots of 0.1 ha each). Among 286 plant species recorded, 132 plant species were consumed by elephants. A majority (80.21%) of plant species were consumed more than the proportional availability thereby showing selective foraging during the dry season in the study area. From forest to semi-open forest and open forest, canopy layer tree density and the total number of species decreased whereas invasive species density increased. This indicates the high impact on the forage species availability for elephants and the requirement of appropriate habitat management strategies. The presence of 32.14% of the selected forage species in human-use landscape alone demands the development of conservation interventions. This is the first study to assess forage selection by elephants in a multi-use landscape and used to prioritise conservation and management strategies at a landscape level.

Food composition and feeding strategies of an invasive species, Carassius gibelio (Bloch, 1782) inhabiting a eutrophic lake in Middle Black Sea region

Diet composition and feeding features of the Prussian carp Carassius gibelio (Bloch, 1782) were studied by analysing the stomach content of 155 fish specimens sampled from Lake Ladik during November 2009-October 2010. Five of the specimens had empty stomachs. A total of 29 prey taxa belonging to eight major groups comprising aquatic insects, Copepoda, Cladocera, Rotifera, Bacillariopyhta, Chlorophyta, Cyanobacteria and fish eggs were identified in 150 full stomachs. Diet composition showed slight seasonal variation. Cladocera was the most important prey item in all seasons, with peak abndance in spring. Feeding intensity exhibited seasonal change and was maximum in summer. Summer and autumn diets of this species showed the highest similarity. The study indicated that the Prussian carp in Lake Ladik showed both omnivorous and opportunistic feeding habits, exhibiting specialised feeding strategy on Cladocera, while they showed generalised feeding strategy on most prey items. The wide dietary plasticity of invasive Prussian carp can help their population to expand rapidly in different aquatic ecosystems. Keywords: Alien species, Diet composition, Feeding habits, Lake Ladik, Prussian carp

Fish thieves: An alternative tactic of food capture in a Neotropical frugivorous species (Brycon falcatus)

AbstractFrugivorous fishes switch their diets seasonally in response to fluctuating food availability; a strategy that maximizes energy and nutrient intake and reduces competition for food. Kleptoparasitism is a form of competition that involves the stealing of already‐procured items, for which the host has invested energy in prey capture. We did not find previous studies on kleptoparasitism among Neotropical fish. Here we contribute the first record of kleptoparasitism among a frugivorous fish species. The matrinxã (Brycon falcatus) is a member of an iconic genus of broadly distributed frugivorous fishes. We made focal daylight underwater observations (by snorkeling) of frugivorous fish behavior in an Amazonian stream. Opportunistic feeding interactions between a school of juvenile matrinxã, (B. falcatus) and an individual of threespot leporinus (Leporinus friderici) were observed. The matrinxã stole the fruit that was captured in the substrate by the leporinus. Brycon falcatus usually lives between the middle of the water column to the surface of rivers and streams while Leporinus friderici occupies the lower portion of the water column and it actively forages close to the substrate. This suggests that stealing food from a benthic feeder is an opportunistic ecological interaction to take advantage of scarce resources during the period of food scarcity. This alternative technique of capturing fruits may be advantageous (i.e., save energy expenditures related to searching) for young matrinxã who do not eat fruit as frequently as adults. Our results reflect the trophic plasticity and foraging opportunism characteristic of most tropical freshwater fish. We believe that the hydrological period in which the observations were made, when a few trees were bearing fruit, can favor fruit stealing by Brycon falcatus.

Correction to: Powder Flow Feed Behavior in Synchronous Induction-Assisted Laser Deposition

Correction to: Powder Flow Feed Behavior in Synchronous Induction-Assisted Laser Deposition

Feeding ecology of the last European colobine monkey, Dolichopithecus ruscinensis

Currently, very little is known about the ecology of extinct Eurasian cercopithecids. Dietary information is crucial in understanding the ecological adaptations and diversity of extinct cercopithecids and the evolution of this family. For example, the colobine genus Dolichopithecus is represented by multiple large-bodied species that inhabited Eurasia during the Pliocene-Early Pleistocene. The available evidence, though limited, suggests semiterrestrial locomotion, which contrasts with most extant African and Asian colobines that exhibit morphological and physiological adaptations for arboreality and folivory. These differences raise questions regarding the dietary specialization of early colobine taxa and how/if that influenced their dispersion out of Africa and into Eurasia. To further our understanding of the ecology of Plio-Pleistocene cercopithecids, we characterized the dental capabilities and potential dietary adaptations of Dolichopithecus ruscinensis through dental topographic and enamel thickness analyses on an M1 from the locality of Serrat d'en Vacquer, Perpignan (France). We also assessed the feeding behavior of D. ruscinensis through dental microwear texture analysis on a broad sample of fossil molars from fossil sites in France, Greece, Bulgaria, and Romania. Dental topographic and enamel thickness analyses suggest that D. ruscinensis could efficiently process a wide range of foods. Results of the dental microwear texture analysis suggest that its diet ranged from folivory to the consumption of more mechanically challenging foods. Collectively, this suggests a more opportunistic feeding behavior for Dolichopithecus than characteristic of most extant colobines.

GUT CONTENT ANALYSIS OF ENDEMIC LARVIVOROUS FISH FROM SUSWA RIVER OF DOON VALLEY, DEHRADUN

Food is the basic prerequisite for growth, development, survival and existence of all organisms. Gut content analysis of fish provides an important insight into feeding patterns and quantitative assessment of feeding habits of fish. The objective of present study is to identify the endemic fish having larvivorous potential in natural condition by gut content analysis. Fish were collected from Suswa river, Doon valley by following the standard techniques of fishing during July 2018 to June 2019. The collected fishes were shorted and identified using standard identification keys and catalogues. Fish were dissected and gut content were examined microscopically and numerical methods was used by calculating percentage composition of food items in total contents of fish stomach. A total of 200 fish of 20 species belonging to 13 genera were dissected for gut content analysis. The contents were classified based on food types and fish were differentiated into herbivorous, omnivorous and carnivorous. Choices of food by fish were based on the availability of food at a particular habitat and the fish species showed omnivorosity habit of feeding. Further, feeding potential of fish were estimated based on the percentage composition of insect content only among animal content and categorized as voracious feeder, moderate feeder and opportunistic feeder.

Diet of the Indian fox (Vulpes bengalensis) in dry scrubland of north Gujarat, India

Indian fox Vulpes bengalensis, a mesocarnivore of the Indian subcontinent, is distributed widely in all kinds of habitats in India except the Western Ghats. The Indian fox prefers semi-arid landscapes with low rainfall where it is easy to hunt and dig dens and where the vegetation is mainly short grasslands or scrub, thorn thickets or dry deciduous forests. They mostly avoid dense forests, steep terrain, tall grasslands, and true deserts. The Indian fox is listed as of Least Concern (LC) by the IUCN and legally protected in India under schedule II of the Indian Wildlife Protection Act 1972. An opportunistic and omnivorous feeder, its diet includes insects, scorpions, centipedes, small rodents, monitor lizards and other reptiles, ground nesting birds, their eggs and fruit such as Ziziphus sp. (Rhamnaceae), Citrullus vulgaris (Cucurbitaceae), Azadirachta indica (Meliaceae), Mangifera indica (Anacardiaceae), Syzigium cumini (Myrtaceae), Melia azedarach (Meliaceae), and Ficus bengalensis (Moraceae). Some local shepherds have also reported seeing Indian foxes feed on the freshly voided pellets of sheep. Their presence and density in any area is closely related to the abundance of food.

Microplastics in the Deep: Comparing Dietary and Plastic Ingestion Data between Two Mediterranean Bathyal Opportunistic Feeder Species, Galeus melastomus, Rafinesque, 1810 and Coelorinchus caelorhincus (Risso, 1810), through Stomach Content Analysis

Marine plastic pollution is currently an issue of mounting concern around the world. Stomach content of marine fish has been increasingly used as a valid proxy for detecting the presence of such a pollutant in marine biota, both for coastal and deep-water environments. Although ingestion of microplastics has been reported in an increasing number of species, the patterns of ingestion still remain unclear, depending closely on the interaction between the species and types of microplastics involved. In this context, we analysed and compared the stomach contents of two bathyal dwelling opportunistic feeder species namely Galeus melastomus and Coelorinchus caelorhincus. In particular, we analysed microplastic items according to their dimension, morphology and colour, and diet’s variation with size obtained through prey identification. Both species showed a higher frequency of occurrence of the blue filament-like middle-sized microplastics (1.01–4.75 mm) compared with the other categories, although this pattern was much more marked in C. caelorhincus than in G. melastomus. The latter conversely showed a larger array of ingested plastic items in terms of shape and colour. Matching plastic ingestion with dietary data suggested potential predator confusion occurring in C. caelorhincus through active mis-selection of a defined type of microplastic instead of some particular family of polychaetes, which resemble in shape, size, and color to that type. Otherwise, G. melastomus appeared more prone to a random ingestion of a larger array of microplastic items because of a more generalistic and less selective feeding strategy. Although further validation is needed, stomach contents of the two species showed evidence strong enough to be considered as potential bioindicator species of microplastic pollution, as required by the Marine Strategy Framework Directive for monitoring this pollutant in the marine environment.

Forage fish as a predator: summer and autumn diet of Atlantic herring in Trinity Bay, Newfoundland

Atlantic herring (Clupea harengus; hereafter herring) is a forage fish that transfers energy from lower to higher trophic levels and sustains high-volume fisheries in the North Atlantic. This study aims to improve our understanding of the ecology of Newfoundland herring and its vulnerability to climate change by identifying key prey items and describing adult herring feeding strategies. We compared plankton assemblages to stomach content and stable isotope analyses from herring collected in Trinity Bay, Newfoundland, in late summer and autumn 2017–2019. Six distinct zooplankton communities were identified across all years, with a shift in community structure in September 2018. This shift coincided with a change from fresher, warmer waters (12–17 °C) to more saline, cooler waters (10.5 °C). The most frequently consumed prey items were amphipods (Themisto spp.) and calanoid copepods (primarily Calanus and Temora spp.). Fish eggs, larvae, and juveniles, primarily identified as capelin, were observed in stomach contents in all years. Fish contributed most to diets in 2017, which corresponded with the peak year for larval densities in Trinity Bay, suggesting that piscivory may increase at higher larval densities. Herring were opportunistic feeders, although some individuals exhibited selective feeding on copepods, amphipods, euphausiids, and the early life stages of fishes. Stable isotope analyses supported the finding that herring piscivory is prevalent in eastern Newfoundland. Given its adaptive feeding strategy and wide range of consumed prey, we conclude that adult Newfoundland herring is resilient to bottom-up changes observed in the environment.

The Beat Goes On: Humpback Whale Song Seasonality in Antarctic and South African Waters

Little is known of the movements and seasonal occurrence of humpback whales (Megaptera novaeangliae) of South Africa and the Antarctic, populations once brought to near extinction by historic commercial whaling. We investigated the seasonal occurrence and diel-vocalizing pattern of humpback whale songs off the west coast of South Africa (migration route and opportunistic feeding ground) and the Maud Rise, Antarctica (feeding ground), using passive acoustic monitoring data collected between early 2014 and early 2017. Data were collected using acoustic autonomous recorders deployed 200-300 m below the sea surface in waters 855, 1,118 and 4,400 m deep. Acoustic data were manually analyzed for humpback whale vocalizations. While non-song calls were never identified, humpback whale songs were detected from June through December in South African waters, with a peak in percentage of acoustic occurrence around September/October in the austral spring. In Antarctic waters, songs were detected from March through May and in July (with a peak occurrence in April) where acoustic occurrence of humpback whales was negatively correlated to distance to the sea ice extent. Humpback whales were more vocally active at night than in the day at all recording sites. Detection range modelling indicates that humpback whale vocalizations could be detected as far as 18 and 45 km from recorders in South African and Antarctic waters, respectively. This study provides a multi-year description of the offshore acoustic occurrence of humpback whales off the west coast of South Africa and Maud Rise, Antarctica, regions that should continue to be monitored to understand these recovering populations.

Blood meal profile and positivity rate with malaria parasites among different malaria vectors in Sudan

BackgroundMalaria is a life-threatening public health problem globally with particularly heavy burden in the sub-Saharan Africa including Sudan. The understanding of feeding preference of malaria vectors on different hosts is a major challenge for hindering the transmission cycle of malaria. In this study, blood meals taken by blood-fed Anopheles mosquitoes collected from the field in malaria endemic areas of Sudan were analysed for source of blood meal and malaria parasite presence.MethodsAnopheles mosquitoes were collected from different regions in Sudan: Khartoum state, Sennar state, Northern state, and El Gedarif state between September 2020 and February 2021. Anopheles mosquitoes were collected using the standard pyrethrum spray catch and back-pack aspirator. Mosquito samples were sorted and morphologically identified to species level using international identification keys. Morphologically identified mosquito species were also confirmed using PCR. Genomic DNA was extracted from mosquitoes for molecular identification of blood meal source and parasite detection. The presence of Plasmodium species DNA in each mosquito sample was investigated using semi-nested PCR. Frequency of each blood meal source, Anopheles mosquito vector, and malaria parasite detected was calculated. Positivity rate of each fed female Anopheles mosquito was calculated for each species.ResultsA total of 2132 Anopheles mosquitoes were collected. 571 (26.8%) were males and 1561 (73.2%) were females classified based on their abdominal status into 1048 (67.1%) gravid, 274 (17.6%) fed, and 239 (15.3%) unfed females. Among the blood fed Anopheles mosquitoes, 263 (96.0%) were morphologically identified and confirmed using PCR to Anopheles arabiensis, 9 (3.3%) to Anopheles stephensi, and 2 (0.7%) to Anopheles rufipes. Of 274 blood-fed An. arabiensis, 68 (25.9%) fed on mixed blood meals from human and cattle, 8 (3.0%) fed on cattle and goat, and 13 (4.8%) fed on human, cattle and goat. For single blood meal sources, 70 (26.6%) fed on human, 95 (36.1%) fed on cattle, 8 (3.0%) fed on goat, and 1 (0.4%) fed on dog. While An. rufipes and An. stephensi fed on dog (2; 0.75%) and cattle (9; 3.3%), respectively. Plasmodium parasite detection in the blood meals showed that 25/274 (9.1%) An. arabiensis meals were positive for Plasmodium vivax and 19/274 (6.9%) An. arabiensis meals were positive for Plasmodium falciparum. The rate of positivity of An. arabiensis with any Plasmodium species was 16.7%. However, the positivity rate with P. falciparum only was 7.2%, while P. vivax was 9.5%. Both An. rufipes and An. stephensi were having positivity rates of 0.0% each.ConclusionsThis study which was mainly on blood-fed Anopheles mosquitoes showed a diversity in the type of diet from human, cattle, and goat. Anopheles mosquitoes especially An. arabiensis in Sudan, are opportunistic blood feeders and can feed broadly on both human and cattle. The application of blood meal identification is not only important in malaria vector epidemiological surveillance but also is very useful in areas where arthropods exhibit zoophilic feeding behaviour for mammals.

Is Resource Utilization by Desert Fox (Vulpes vulpespusilla) in Thar Landscape an Indicative of its Opportunistic Feeding Behavior? – A Preliminary Insight

Opportunistic feeding behavior may absolve species survival entirely upon the resources available within its habitat. Present study assesses this assumption with respect to Desert fox found in Thar landscape in India. Density of selected food items that encompass dietary spectrum of this species was estimated in a given area and the biomass available for its consumption was calculated seasonally. Relative percentage of biomass available and biomass consumed was correlated, wherein preference was calculated using Ivlev’s Index. It is concluded that opportunistic feeding behavior is being exhibited by Desert fox especially in winter season, when resources are limited in terms of their availability. Also, it prefers scavenging on dead carcasses and fallen fruits rather than hunting.

The first Asian record of the mouse-deer Afrotragulus (Ruminantia, Tragulidae) reassess its evolutionary history and offers insights on the influence of body size on Afrotragulus diversification

ABSTRACT New fossils of the Miocene crown-tragulid Afrotragulus from Chinji and Dhok Pathan Formations of the Pakistan Siwaliks Group represent its first record out of Africa. This material from Babri Wala (ca. 12.6 Ma), Hasnot 6 (ca. 6.5 Ma) and Barnum Brown’s B 51 classic locality (ca. 13.7 Ma) constitutes three new species, Afrotragulus akhtari, A. moralesi and A. megalomilos. We reassess Afrotragulus ingroup phylogeny recovering two clades with African and Asian representatives. Our results reject the existence of a strictly African lineage in the genus. Body-size estimates show three tiny Afrotragulus with a size corresponding to the lower spectrum of extant Tragulus. However, both Afrotragulus lineages produced species larger than 10 kg. Previously considered very small tragulids, these new forms demonstrate that size range of Afrotragulus equals that of all living tragulids. The smallest forms could be frugivorous/browsers but A. megalomilos and A. moralesi could be opportunistic feeders, specially accounting for their highly derived dentition. These new Asian Afrotragulus extend the biochronological range of the genus from the lower Miocene to the late upper Miocene. Afrotragulus is surprisingly uncovered here as one of the longest-lived and most successful members of the Tragulidae, existing during ca. 13.5 million years (20–6.5 Ma).

Factors influencing the feeding habits of the ghost crab Ocypode quadrata (Fabricius, 1787) on subtropical sandy beaches

Studies on feeding habits are fundamental to characterising the trophic role that species play in an ecosystem. They also help to understand the dynamics of populations involved in ecological relationships. Among the existing populations on tropical and subtropical sandy beaches in the world, the ghost crab (Ocypode) is the most conspicuous invertebrate. Despite its wide distribution, there is arguable information on the trophic ecology of this crab. Our study thus aimed to characterize the diet of the Ocypode quadrata on three morphologically distinct beaches in southern Brazil. Considering such factors as environmental differences, seasons, sex, and ontogeny, we evaluated which of these would be responsible for differences in the crab's food composition and quantity of items consumed. In addition, we used the repletion index (RI) to check the presence of food resource throughout the year. The samples were collected monthly, from March 2017 to February 2018, on three subtropical beaches in southern Brazil. We performed the biometry of the crabs, which involved weighing and measuring the size of the individuals, followed by the weighing of the stomachs to calculate the repletion index. We examined the contents of 660 stomachs, which were grouped into major food categories. Feeding index (IAi) indicates that feeding patterns varied only between seasons, demonstrating that the availability of prey is reflected in the diet of the ghost crab. The most significant items in its diet were insects, unidentified organic matter, and crustaceans. The RI tended to increase as the sand temperature increased. An increase in daytime foraging activity during cold months in contrast to a greater night-time foraging during warmer months shows a plasticity in the time of foraging. Finally, we conclude that the variety of prey consumed suggests that the O. quadrata has mainly opportunistic detritivorous feeding habits, as well as other feeding modes.

113 Cannabidiol Supplementation and Physiological Response in Transported Horses

Abstract With traveling between competition use, breeding purposes, relocation to new owners; horses are the most transported animals of domesticated species. Transportation can lead to higher stress levels therefore impairing the immunological response. With an increase in stress, horses can experience illness, dehydration, abnormal feeding behavior, injuries, or negative stereotypic behaviors. Cannabidiol (CBD) supplementation has suggested the possibility in the reduction of anxiety and lessening impairment to immunity. The objective of this study was to determine if oral supplementation of CBD oil mediated physiological response to transportation. Six geldings were used in a switchback experimental design. Horses were housed in 11’x14’ stalls containing cameras to monitor feed and water intake and behavior. A control dose of olive oil (n = 4) or CBD oil (0.6 mg/kg BW; n = 3) was administered for five days. On day 7, horses were transported for three hours in groups of three. Variables measured included plasma cortisol, blood lactate, rectal temperature, and thermography imaging. Measurements were taken prior to transport, immediately following transport, and 24h post transportation. Horses underwent a 3-week washout period before returning to stalls. Control and treatment doses were switched between horses before repeating the experiment. Data were analyzed in R Studio© for analysis of variance (ANOVA). Findings were considered significant at P ≤ 0.05. There were no differences shown upon analysis in cortisol levels (P = 0.646), blood lactate levels (P = 0.560) or rectal body temperatures (P = 0.347). While oral supplementation of CBD oil may reduce stressors, further studies are needed to determine if CBD affects physiological response to transportation.