Keyword: feeding habits

Eating like a girl: sex differences in the diet of the lesser grison (Galictis cuja) in southern Brazil

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The lesser grison is a hypercarnivore mustelid that is widespread in South America, inhabiting a large variety of habitats, including steppes, deserts, grasslands, forests, and swamps. However, there are few scientific data on the ecology of the species. In our study, we investigate the feeding habits of the Galictis cuja in the Brazilian Pampas by analyzing the stomach contents of road-killed individuals collected from 2013 to 2023. We identify a high consumption of mammals found in 80% of the samples, comprising 75% of the prey  consumed. Amphibians, reptiles, and birds are consumed in smaller proportions. Regarding mammals, only rodents were consumed, among which Cavia sp., Holochilus brasiliensis, and Rattus sp. stand out, corresponding to 62% of biomass intake. Although there was no sexual difference in the prey consumed, we found a difference in predation rate, with males consuming more Rattus and females consuming more Cavia. As a result, males are consuming prey that is proportionally smaller (equivalent to 1/6 of their own weight) than that of females (1/3 of their own weight). This is contrary to what is expected due to the sexual dimorphism of the species; in other mustelids, males consume the larger prey.

Comendo como uma menina: diferenças sexuais na dieta do furão (Galictis cuja) no sul do Brasil. O furão-pequeno é um mustelídeo hipercarnívoro amplamente distribuído na América do Sul, ocorrendo em uma variedade de habitats, incluindo estepes, desertos, campos, florestas e áreas úmidas. Todavia, há poucos dados científicos sobre a ecologia da espécie. Nesse estudo investigamos os hábitos alimentares de Galictis cuja na região do Pampa brasileiro, pela análise de conteúdo estomacais de indivíduos encontrados atropelados entre os anos de 2013 e 2023. Identificamos um alto consumo de mamíferos, encontrados em 80% das amostras e compreendendo 75% das presas consumidas. Anfíbios, répteis e aves são consumidos em baixas proporções. No que se refere aos mamíferos, apenas roedores foram encontrados, dentre os quais Cavia sp., Holochilus brasiliensis e Rattus sp. se destacam, correspondendo a 62% da biomassa ingerida. Apesar de não terem sido encontradas diferenças nas presas consumidas por machos e fêmeas, foram encontradas diferenças nos padrões de predação, com machos consumindo mais Rattus e fêmeas consumindo mais Cavia. Como resultado, machos consomem presas proporcionalmente menores (equivalentes a 1/6 de seu peso) do que as fêmeas (com presas equivalentes a 1/3 de seu peso). Isso é contrário ao esperado dado o dimorfismo sexual de tamanho existente nessa espécie e ao observado em outros mustelídeos, em que os machos consomem presas maiores.

Graphical abstract for the article “Eating like a girl: sex differences in the diet of the lesser grison (Galictis cuja) in southern Brazil” (B.M. Rodrigues et al., 2024)

Dietary variation and reproductive status of Mormoops megalophylla (Chiroptera: Mormoopidae) in a cave of Northeastern Andes from Colombia

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Dietary studies of insectivorous bats are critical for a comprehensive analysis of their ecological role in pest control. Several factors including seasonality, reproductive status and sex may influence dietary specialization. However, data on insectivorous bat diet are scarce, especially in Mormoopidae family. Here, we analyzed the dietary variation of Mormoops megalophylla (Peters, 1864) between sexes, reproductive states and climatic seasons in Macaregua cave, located in Northeastern Andes of Colombia. We collected fecal samples and vaginal smears from 377 individuals. We assess differences between sexes in the frequency of insect consumption and we estimate dietary breadth in reproductive and non-reproductive bats. Mormoops megalophylla has a highly specialized diet, selecting primarily for Lepidoptera insects. There were no differences between sexes, but wider dietary breadth was found in reproductive bats in comparison to non-reproductive bats. Probably, the specialization on Lepidoptera insects is explained by the high amounts of caloric energy that these insects can offer. It was remarkable the upward trend in Lepidoptera consumption from reproductive bats during the wet season, when moths are available. By contrast, non-reproductive bats increased Lepidoptera consumption in the dry season, possibly to prepare for the next reproductive events. The analysis of diet over time suggests variations between climatic seasons and reproductive states; that is, when bats are reproductively active, they increase the amount of Lepidoptera consumption in the wet season to supply their energy requirements during reproduction. These results provide key information about the ecology of M. megalophylla in the northern part of its South American distribution.

Variación en la dieta y estado reproductivo de Mormoops megalophylla (Chiroptera: Mormoopidae) en una cueva del noreste de los Andes de Colombia. Los estudios de dieta en murciélagos insectívoros son fundamentales para un análisis exhaustivo de su papel en el control de plagas. Varios factores como la estacionalidad, el estado reproductivo y el sexo, pueden incidir en la especialización de la dieta. Sin embargo, información sobre la dieta en murciélagos insectívoros es escasa, especialmente en la familia Mormoopidae. Analizamos la variación en la dieta de Mormoops megalophylla (Peters, 1864) entre sexos, estados reproductivos y estaciones climáticas en la cueva Macaregua, en los Andes nororientales colombianos. Recolectamos muestras fecales y citologías vaginales de 377 individuos. Evaluamos las diferencias entre sexos en la frecuencia del consumo de insectos y estimamos la amplitud de dieta en murciélagos reproductivos y no reproductivos. Mormoops megalophylla presenta una dieta especializada en lepidópteros. No hubo diferencias entre sexos, pero hubo mayor amplitud de dieta en murciélagos reproductivos en comparación con los no reproductivos. La especialización en lepidópteros se puede explicar por las altas cantidades de energía que proveen estos insectos. Fue notable el incremento en el consumo de lepidópteros en murciélagos reproductivos durante la estación húmeda, que es cuando hay más polillas. Contrariamente, murciélagos no reproductivos aumentaron el consumo de lepidópteros en la estación seca, como preparación para futuros eventos reproductivos. El análisis de la dieta en el tiempo sugiere variaciones entre estaciones climáticas y estados reproductivos; individuos reproductivos consumen más lepidópteros en época húmeda supliendo sus requerimientos energéticos durante la reproducción. Estos resultados proporcionan información clave de la ecología de M. megalophylla en el norte de su distribución sudamericana.

Dieta del jabalí (Sus scrofa), invasor biológico reciente del Parque Nacional Puyehue, sur de Chile

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Se identifican los ítems-presas y categorías tróficas representados en los contenidos estomacales de una muestra estival-otoñal (2013) de siete estómagos de jabalíes silvestres cazados en el Parque Nacional Puyehue, sur de Chile. La dieta del jabalí incluyó plantas, animales y hongos, siendo en general similar a la previamente documentada para dos áreas silvestres del sur de Chile. Este invasor biológico reciente en el área de estudio se caracteriza como generalista y oportunista, con potenciales impactos negativos sobre la fauna y la flora que deben ser prontamente evaluados.

Diet of the wild boar (Sus scrofa), a recent biological invader of Puyehue National Park, southern Chile. We identified the prey items and trophic categories represented in the contents of a summer-autumn (2013) sample of seven stomachs from wild boars hunted in the interior of Puyehue National Park, southern Chile. The diet included plants, animals and fungi, generally similar to previous reports from two other southern Chilean wilderness areas. This recent biological invader in the study area is characterized as an opportunistic generalist and has potential negative impacts on the fauna and flora that should be promptly evaluated.

Hábitos alimentarios del puma (Puma concolor) e incidencia de la depredación en la mortandad de guanacos (Lama guanicoe) en el noreste de la Patagonia

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En la Patagonia, las relaciones funcionales entre el puma y sus presas nativas se han modificado como consecuencia de la introducción de especies exóticas. Estudiamos los hábitos alimentarios de Puma concolor en el nordeste del Chubut durante un período de 3 años y encontramos que: (1) el guanaco, Lama guanicoe, fue la presa más importante en su dieta; (2) ante una reducción sustancial en la abundancia de ovinos, el puma respondió con una ampliación de su nicho trófico mediante la incorporación de presas de menor tamaño; y (3)  la depredación por pumas fue la principal causa de muerte de guanacos.

Feeding habits of the puma (Puma concolor) and the incidence of predation on guanaco (Lama guanicoe) mortality in northeastern Patagonia. In Patagonia, the functional relationships between pumas and their native prey species have been modified as a result of the introduction of exotics. We studied the feeding habits of Puma concolor in northeastern Chubut province during 3 years and found that (1) the native guanaco, Lama guanicoe, was the most important prey in the diet of pumas; (2) pumas expanded their trophic niche by incorporating smaller prey species to their diets after a substantial reduction in the abundance of the introduced sheep; and (3) puma predation was the main cause of guanaco mortality.

Nuevos registros de Eumops dabbenei (Chiroptera: Molossidae) en Argentina: ampliación de la distribución y comentarios sobre su ecología

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Se citan dos nuevos registros de Eumops dabbenei para Argentina. El primero corresponde a un ejemplar incorrectamente identificado (como E. perotis) depositado en el Museo Argentino de Ciencias Naturales colectado en la localidad de Unquillo, que representa el primer registro para la provincia de Córdoba. El segundo proviene del Parque Nacional Copo, provincia de Santiago del Estero, donde se detectó un refugio de E. dabbenei en un árbol, lo que permitió obtener datos reproductivos, dietarios, composición aproximada y de características del refugio de la especie.

New records of Eumops dabbenei (Chiroptera: Molossidae) from Argentina: distribution extension and comments about its ecology. We report two new records of Eumops dabbenei for Argentina. The first record corresponds to a misidentified specimen (originally E. perotis) deposited at the Museo Argentino de Ciencias Naturales, collected in Unquillo (Córdoba province), and represents the first record for this province. The second record, from Copo National Park, Santiago del Estero province, was observed in its roost tree where additional data about reproduction, diet, composition of the colony and roost characteristics were obtained.

Adaptaciones morfológicas de la lengua de Desmodus rotundus rotundus (Chiroptera: Phyllostomidae) en función de la alimentación

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Morphological adaptations of the tongue of Desmodus rotundus (Chiroptera: Phyllostomidae) related with their feeding habits. An analysis of the external morphology and histomorphology of the tongue, as well as an histochemical analysis of the glands of Desmodus rotundus, are here presented with the purpose of establishing a correlation between these structures and the feeding habits of this species. In the lingual surface they have the typical filiform papillae modified to different degrees of keratinization, and there are fungiform-like papillae in less amount. The intrinsic musculature and the presence of lynphocitary infiltration are described; the presence of important nervous packages was observed.

Dieta del ciervo de los pantanos, Blastocerus dichotomus, en la Reserva del Iberá, Corrientes, Argentina

El presente trabajo tuvo como objetivo estudiar la dieta del ciervo de los pantanos y los aspectos nutricionales de las especies vegetales más utilizadas. Se realizaron inventarios florísticos y se detectaron las principales especies utilizadas por el ciervo de los pantanos a lo largo del año. Además, se realizaron observaciones del comportamiento alimentario. En el laboratorio se efectuó el análisis químico de siete especies, incluyendo la determinación de humedad y materia seca, proteína bruta, fibra bruta, fósforo, calcio y magnesio. Los valores obtenidos indicarían ciertas carencias minerales en la dieta, especialmente de fósforo y calcio, en algunas categorías de la población.

Diet of the Marsh Deer, Blastocerus dichotomus, at lberá reserve, Corrientes, Argentina. The present study on the marsh deer’s diet was carried out at lberá Natural Reserve. The nutritional quality of the botanical species most commonly used by this cervid has also been investigated. Botanical inventories were made and the main species in the deer’s year round diet were detected. In addition, observations of the deer’s behavior were made during different seasons of the year. Twenty-two species were identified as components of the marsh deer’s diet in the lberá lake area; 72.7% are herbs, 18.1% are shrubs and 9% are subfruits. Of these 22 species, 14 probably constitute the “base” of the diet. The feeding activity of the deer varies with the season of the year according to the weather. Chemical analyses performed on seven plant species induded the determination of water content and the remaining dry residue, total protein, total fiber, phosphorus, calcium and magnesium. The different laboratory values obtained for the 7 selected species were compared with different ruminants (Odocoileus spp.) and cattle. The results indícate the lack of certain minerals in the diet of some individuals, especially phosphorus and calcium. The importance of the aquatic habitats in the marsh deer’s feeding habits is mentioned.