Varied Feeding Habits Research Articles

Pervasive Microplastic Ingestion by Commercial Fish Species from a Natural Lagoon Environment

Microplastics have emerged as a significant global environmental concern in the recent decade. The aim of this study was to elucidate microplastic contamination of commercial fish species in a natural lagoon environment. Microplastic contamination was examined in the gastrointestinal tracts and gills of 157 commercial fish from 18 species with varying feeding habits in a vital and sensitive lagoon ecosystem, which connects to the Indian ocean. Microplastics were extracted using digestion, followed by stereomicroscopic inspection using Nile Red stain, and identified via μ-FTIR analysis. Over half of studied fishes ingested microplastics (54.14%). Filaments (50%) and blue items (43%) were the most commonly ingested. Of all the fish species, Eubleekeria splendens had the highest average concentration of microplastics in GIT (1.41 ± 2.52 items/g w.w. tissues), although no statistically significant difference in amount of ingested microplastics (items/g w.w. tissues) was observed among species. The highest concentrations of inhaled microplastics were recorded in Sillago vincenti (1.38 ± 1.30 items/g w.w. tissues). The majority of the extracted microplastics (33%) belonged in the size class 500–1500 μm with rayon, polyethylene terephthalate, and polypropylene as the primary polymers. This study found no correlation between microplastic ingestion and fish species and feeding habits, but a positive correlation with fish size was observed. These findings reveal widespread microplastic contamination in edible fish, posing potential risks to commercially important species due to increasing pollution in lagoon ecosystems.

Lingual adaptations of the Tarentola annularis with new insights into its papillary system adaptations: Ultrastructure, histochemistry, and immunohistochemical observations

Our research aims to conduct a comprehensive ultrastructural, histochemical, and immunohistochemical examination of Tarentola annularis' tongue, utilizing various techniques such as light, scanning electron microscopy, and morphometric analysis. The complex papillary system consisted of four conical subtypes and one filiform type. The apex carried three conical subtypes (elongated, quadrilateral, and round); the midtongue carried two papillary types (quadrilateral conical and rectangular pointed filiform); and the hindtongue carried two conical subtypes (quadrilateral and elongated serrated). The dorsal papillary surface carried little taste pores on the foretongue and taste buds on the midtongue. The foretongue had a slightly stratum corneum that spread to coat the papillae, while the mid- and hindtongue did not. The glands are absent from the foretongue but are found in the interpapillary spaces of the mid- and hindtongue. Histochemical analysis reveals the presence of collagen fibers in the muscle bundles and the papillary core. The midtongue glands exhibited a strong reaction to AB and PAS, while the hindtongue showed moderate AB positivity and strong positive PAS. The cytokeratin expression in the foretongue papilla was positive, whereas the papillae in other regions were negative. The Tarentola annularis exhibits distinctive lingual structural characteristics due to its varied feeding habits influenced by available food particles.

Effects of different fertilization patterns on the dietary composition of Procambarus clarkii in a rice-crayfish coculture system

As an omnivorous species, crayfish (Procambarus clarkii) have varying feeding habits in different environments. However, little is known about the diet of crayfish under different fertilization patterns in rice-crayfish cocultures. In this study, we investigated the effect of fertilization on the growth performance, dietary composition and isotopic niche of crayfish in a rice-crayfish coculture system. Four experimental treatments were established: no fertilizer (CK), slow-release fertilizer (HS), crayfish rice fertilizer (XD) and compound fertilizer (FH). The results showed that HS and FH could significantly promote crayfish growth, and the growth of crayfish treated with HS was the best. Fertilization patterns had significant effects on the dietary composition of crayfish. The food source of unfertilized crayfish was relatively balanced. However, in the HS, XD and FH treatments, particulate organic matter increased with contribution rates of 34.04%, 56.89% and 42.86%, respectively. In addition, the artificial feed intake of crayfish in the FH group was the lowest. The isotopic niche revealed that crayfish in the HS group significantly increased in the direction of the δ15N axis. Based on routine economic indicators, slow-release fertilizer was suitable for the rice-crayfish coculture system. These findings could provide scientific guidance for the selection of fertilization modes in rice-crayfish coculture systems and the exploration of healthy crayfish culture models.

Trait–environment relationships in Amazon stream fish assemblages

AbstractStudies of trait–environment relationships provide important tools for the prediction of the response of biological communities to environmental alterations. The Amazon basin presents enormous potential for the development of research on this type of relationship, given the diversity of both its fish fauna and the aquatic ecosystems this fauna inhabits. The present study investigated the association between local environmental variables and the functional traits of fish in 54 streams of six major Amazonian basins. We identified the relationship between the characteristics of the streams (channel morphology, channel habitat units, riparian vegetation cover, large woody fragments and instream cover for aquatic organisms) and fish traits related to locomotion, habitat use and feeding behaviour. The fish fauna of the broader, deeper and more slowly flowing streams was dominated by nektobenthic species that exploit autochthonous resources such as fish and invertebrates. In narrow, fast‐flowing streams, by contrast, there was a predominance of benthic fishes with varying feeding habits, including periphytivorous and invertivorous species. Narrow, shady streams were inhabited by nektonic species adapted for the exploitation of resources from the marginal vegetation. The results of this study contribute to the understanding of the association between the functional structure of fish assemblages and local environmental variables in Amazonian streams. We hope that these findings will stimulate further research into the natural variation in stream fish assemblages that will ensure the development of more effective management strategies that better protect these important aquatic ecosystems.

Diversity of mites in blackberry genotypes in Pelotas, Rio Grande do Sul, Brazil

ABSTRACT: Blackberry is part of the small-fruit group and the blackberry cultivation area is expanding as an important option for small farmers using the agroecological production system. Mites are prominent among the world’s major crop pests, as they can affect plants from growth to fruiting. The objective of this study was to evaluate the occurrence of phytophagous and predatory mites in different blackberry genotypes in the municipality of Pelotas, RS, Brazil. This study was carried out in the period Nov. 2015 - Oct. 2016, totaling 14 samples. A total of 11,158 mites were collected [phytophagous (5940) and predatory (323) mites, and those with varied feeding habits (4895)], which were distributed in 8 families. The species Neotetranychus asper (Feres & Flechtmann, 2000), Diptacus rubuscolum (Trinidad, Duarte & Navia, 2018), and Acalitus orthomerus (Keifer, 1951) had highest occurrence. According to the faunistic classification, the N. asper phytophagous species is predominant in genotypes 128 and 178; whereas, D. rubuscolum is predominant in genotype 132. Monitoring of these genotypes is recommended to detect possible damage to the crop.

The phyllostomid bat (Mammalia, Chiroptera) assemblage in a fragmented landscape in Midwestern Brazil

ABSTRACT Bats are the second largest order of mammals, with varying feeding habits and great ecological significance. Anthropization has several important effects on animal communities and the Brazilian Cerrado, a Neotropical savannah, has been severely affected by human activity. The objective of this study was to evaluate phyllostomid bat assemblage distributions in the different landscape formations of a modified savannah. Using mist nets, we performed 36 sampling nights between 2015 and 2016. The sampling effort was 23,328 m².h and was equally distributed over three landscape formations: a large fragment, riparian forest, and small fragments. We compared capture rates, richness, diversity, similarity, and feeding guilds for the three formations. We captured 418 bats of 12 species belonging to the family Phyllostomidae. The most abundant species was Artibeus planirostris (Spix, 1823) (n = 126). We found no significant differences in capture rate or diversity between the areas, but there were differences in feeding guild representation. Frugivores species were the most abundant in the three areas. No gleaning insectivore or carnivore species were captured in the small fragments, and the large fragment contained no hematophages. The large fragment and the small fragments had the greatest similarity whereas the riparian forest and small fragments had the least similarity.

Genome wide identification of taste receptor genes in common carp (Cyprinus carpio) and phylogenetic analysis in teleost

Taste receptors (TRs) are seven trans-membrane G protein-coupled receptors as well as the interface between internal and external milieus, which playing pivotal roles in nutrient identification and acquisition. To better understand the scope and function of tr gene family in common carp, one of the most economic and important breeding fish species, which has undergone an additional round of whole genome duplication (WGD), we characterized 13 tr gene homologues including eight type I and five type II taste receptor genes from common carp genome, which were more than any other teleosts. Phylogenetic and syntenic analysis revealed the evolution dynamics of tr gene family, which was highly conserved, though gene duplication and gene loss do exist recently. Furthermore, the motif and dN/dS analyses indicated that these receptors were under different negative selection pressure. Additionally, the gene expression divergences were observed in 12 health tissues of common carp, with a relatively high level in barbel and head kidney, demonstrating tissue-specific expression of tr genes in the tetraploidized genome. The overarching goals of this study were to identify the abundance of tr genes in common carp, compare the gene divergence among species with varied feeding habits and provide genomic resources for future studies on teleost taste sensation.

Influence of season, environment and feeding habits on the enzymatic activity of peptidase and β-glucosidase in the gastrointestinal tract of two Siluriformes fishes (Teleostei)

The enzymatic activities involved in the digestion of proteins and carbohydrates were compared among three organs of the digestive track of two Siluriformes fish species, and between two areas: a reservoir, and an area downriver of it. Our aim was to test the hypothesis that the digestive organs of species with varied feeding habits have different enzymatic activities, and that the enzymatic activity differs among seasons and environmental conditions. The iliophagous/herbivorous species Hypostomus auroguttatus Kner, 1854 had higher trypsin-like, chymotrypsin-like peptidase and β-glucosidase activity in the intestine when compared with the omnivorous species Pimelodus maculatus Lacepède, 1803, whereas the latter had more hepatic trypsin-like activity than the former. The peak of activity of the three enzymes in H. auroguttatus was recorded in the winter and spring. On the other hand, P. maculatus tended to have the more prominent peptidase and β-glucosidase activity in the summer, and the smallest in the winter. The intestine of H. auroguttatus had higher enzymatic (trypsin, chymotrypsin and β-glucosidase) activity than the stomach and the liver. For P. maculatus, the highest β-glucosidase activity was found in the liver. The enzymatic activity of H. aurogutattus did not differ between lotic and lentic systems, whereas P. maculatus had comparatively higher stomach and hepatic trypsin levels and hepatic chymotrypsin-like activities in the reservoir than down in the river. These findings indicate that, in H. auroguttatus, most digestive activity occurs in the intestine, which is long and adapted for the digestion of bottom-river vegetable matter and detritus. The seasons and the type of the system (lentic vs. lotic) seem to affect the enzymatic activity for these two species differently, a likely consequence of their different lifestyles.

The oral apparatus of tadpoles of Rana dalmatina, Bombina variegata, Bufo bufo, and Bufo viridis ( Anura)

The morphology and development of the larval oral apparatus of Rana dalmatina, Bombina variegata, Bufo bufo, and Bufo viridis are described and compared using scanning electron microscopy. The species show different arrangements of the mouthparts. The small oral apparatus of R. dalmatina larvae has three labial tooth rows on the upper labium, while there are four tooth rows on the lower labium with a medial gap in row proximal to the mouth. The margins of the oral apparatus are defined by papillae that encircle the lower labium. B. variegata tadpoles have two upper labial tooth rows and three lower labial tooth rows that are uninterrupted, unlike the ones of R. dalmatina. The mouth is encircled by papillae that are larger than those of R. dalmatina. The oral discs of tadpoles of both B. bufo and B. viridis are similar. They are defined by two upper labial tooth rows (the second of which is interrupted by a medial gap) and by three lower tooth rows that differ in lengths in the two Bufo species. Both species develop papillae on the mouth angles and in two rows on the upper labium. Some morphological differences among the oral discs of R. dalmatina, B. variegata, B. bufo, and B. viridis tadpoles can be attributed to phylogenetic differences, but most can be related to their varying feeding habits and/or to their dietary specializations.

Mite diversity on plants of different families found in the Brazilian Atlantic Forest

This work reports the occurrence of mites predominantly predatory, phytophagous and with varied feeding habits on plants of the Atlantic Forest vegetation type of the State of São Paulo. The objective was to estimate the possible role of the Atlantic Forest vegetation as reservoir of these groups of mites which are also found on plants of agricultural importance. Samples were taken from 187 plant species belonging to 73 families in three vegetation types of the Atlantic Forest from February of 2001 to October of 2002. A total of 2,887 mites belonging to 163 morpho-species of 16 families were collected. Mite diversity was high, especially of predatory mites; these corresponded to 1,562 specimens of 92 morpho-species. Within this group, Phytoseiidae comprised 71% of the specimens and 62% of the morpho-species. Phytophagous mites comprised 836 specimens of 36 morpho-species. Within this group, Tenuipalpidae comprised the larger proportion of specimens (61%) whereas Tetranychidae corresponded to the larger proportion of morpho-species (64%). Mites with varied feeding habits corresponded to 491 specimens of 36 morpho-species. In this group, the larger proportion of specimens (52%) consisted of Ascidae and the larger proportion of morpho-species (42%) consisted of Tydeinae (family Tydeidae). High abundance and high morpho-species richness of mites of predominantly predatory, phytophagous and variable feeding habits were observed on 17, five and nine plant species, respectively. The results obtained suggest the importance of plants of the studied vegetation as reservoirs of predatory mites.

Organochlorine and mercury contamination of little terns ( Sterna albifrons) breeding at the western Baltic Sea, 1978–96

Between 1978 and 1996, egg and chick samples of little terns ( Sterna albifrons) breeding at different colony sites along the eastern coast of Schleswig-Holstein, Germany, were annually gathered by chance in the framework of a long-term ringing programme. Analyses of polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT), hexachlorobenzene (HCB), hexachlorocyclohexane (HCHs), and mercury were carried out on eggs, chicks, and down (only mercury). In all matrices, pollutant concentrations decreased over the 19-year period. The mixture compositions of ΣPCB, ΣDDT, and ΣHCH changed during the previous decades indicating decreasing releases of PCB mixtures, DDT, and technical HCH mixtures. The pollutant concentrations currently found in the tern eggs are compared with those of other bird species from other Baltic Sea subregions, suggesting a relatively low pollution of the Belt Sea. The temporal trends in contamination are related to international measurements and conventions on bans of pollutants. Since individually known females were recaptured up to three times, inter-individual variation in pollutant burdens could be studied. Remarkable variation among individuals as well as between breeding seasons were found that were not explainable by general temporal trends. Influences of individually and seasonally varying feeding habits on this phenomenon are discussed. Compositions of individual PCB mixtures varied in relation to total PCB concentrations found in eggs suggesting a concentration-dependent metabolization of PCBs as with other species. Amounts of particular organochlorines varied between matrices possibly indicating metabolization of low chlorinated PCBs, β-HCH, and HCB during embryogenesis. In mercury, body detoxification via down is assumed. As indicated by eggshell parameters (thickness and index) being not related to organochlorine concentrations and being similar to that found in historical studies, respectively, effects of recent organochlorine contamination on eggshell thickness seem to be improbable. In conclusion, influences of contamination on declining little tern stocks observed in Germany are discussed. Negative influences of contamination in the 1960s and 1970s are assumed to be probable.

Form of the trilobite digestive system: alimentary structures in Pterocephalia

Three types of alimentary canals (=midgut) occur in the Annelida and non-trilobite Arthropoda: 1) a sagittal tube with metamerically paired diverticula related to the number of somites; 2) a tube that is constricted slightly between somites; and 3) a simple tubular gut that may taper slightly backwards to the anus. At least two of these three types (1 and 3) occur in the Trilobita. Pterocephalia and Olenoides share the first type with the probable sister taxon to the Trilobita, Naraoia (Nectaspida), and this is probably the plesiomorphic condition for the class. Varying feeding habits may well have made this character homoplastic within each of these groups. The preservation of parts of the alimentary tract in specimens of Upper Cambrian Pterocephalia n. sp. (McKay Group, British Columbia) was probably a function of taphonomic and/or very early diagenetic changes that resulted from the type of food preferred by that trilobite. Other trilobites from the same beds do not have their soft parts preserved. The alimentary structures are preserved in a different fashion from, apparently unattached to, and an order of magnitude larger than genal caeca that occur in this taxon. Thus, genal caeca are regarded as imprints of circulatory rather than alimentary structures.Energy dispersive analysis of a fragment of preserved alimentary tract of Pterocephalia n. sp. showed the presence of Ca, Si, Al, Fe, P, K, Na, and Cl. These alimentary tracts are composed of a complex mixture of minerals that probably includes clays, detrital quartz, carbonates, phosphates, and oxides or hydroxides. The structure of these dark fillings is microcrystalline. The presence of detrital minerals as part of this mixture would suggest that this trilobite was a deposit feeder.

Palm-fruit cracking behavior of wild black-capped capuchin (Cebus apella)

While some reports that capuchins crack nuts or hard-shelled fruit to eat have already been presented, it has been unknown whether such behavior is only one of the varied feeding habits of capuchins or if it is also a behavior adaptive to their habitats, a behavior which requires the use of hands and mastering of skill related to tool-using behavior. On a border of La Macarena National Park in Colombia, the authors minutely observed the feeding behavior of the black-capped capuchin, in which the monkey skillfully fed on the albumen of the fruit of cumare, a kind of cocoid palm-fruit, using two different methods, according to the degree of ripeness of the fruit. The characteristic behavior developed by the black-capped capuchin while eating the fruit of cumare could be fixed as one of the higher level adaptive behaviors of the animal to his habitat.

Bird Mortality Following DDT Spray for Dutch Elm Disease

Avian populations in Hanover, N. H., a town that has sprayed its elms with DDT for many years in an attempt to control Dutch elm disease, were compared with those in Norwich, Vt., a town 1 mile (1.6 km) west of Hanover that has never sprayed. Hanover applied 109 lb DDT/acre (2.1 kg/hectare) in April 1963, then used Methoxychlor in April 1964. Population surveys were taken regularly during spring and early summer of these years, dead birds were collected in both towns, and 106 birds were analyzed for DDT, DDE, and DDD. Severe mortality of both resident and migrant birds occurred in Hanover during spring 1963, and the evidence implicates DDT as its cause. Robin loss was estimated at 70% of the resident population, or 350 to 400 individuals, but mortality among other species of widely varied feeding habits was also substantial. Feeding habits suggest that some birds acquired the toxicant by eating living insects carrying DDT, presenting the paradox of survival of the intended DDT victims, and death, instead, of insectivorous birds. Organ and whole bird analyses are presented and criteria for establishing cause of death are discussed. Most of the DDT had been converted to DDE and DDD, and residues were found in all organs analyzed. Robin mortality was reduced, but not eliminated following Methoxychlor application in 1964; these losses were believed caused by residual DDT in the soil. There was no evidence DDT poisoning among other species in 1964, though the dead birds collected were not analyzed.

The Histological Anatomy of the Oesophagus of Physaloptera varani Parona, 1889

Recently the study of nemic oesophagi has attained considerable importance because they have proved to be of great systematic value. They present a remarkable diversity of form, structure and function, perhaps due to the different and varied feeding habits of different species. However, in every case, the oesophagus has certain characters common to all nematodes. It is a syncytial structure as no cell walls are present in it. Its lumen is triradiate and has a cuticular lining, one of the rays of the lumen being always directed ventrally. The ends of the rays of the lumen are connected with muscle fibres known as marginal fibres while the muscles connecting their sides are known as radial fibres. Each of the three sectors of the oeso-