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1.
Neuroscience Bulletin ; (6): 817-831, 2023.
Article in English | WPRIM | ID: wpr-982451

ABSTRACT

Predatory hunting is an important type of innate behavior evolutionarily conserved across the animal kingdom. It is typically composed of a set of sequential actions, including prey search, pursuit, attack, and consumption. This behavior is subject to control by the nervous system. Early studies used toads as a model to probe the neuroethology of hunting, which led to the proposal of a sensory-triggered release mechanism for hunting actions. More recent studies have used genetically-trackable zebrafish and rodents and have made breakthrough discoveries in the neuroethology and neurocircuits underlying this behavior. Here, we review the sophisticated neurocircuitry involved in hunting and summarize the detailed mechanism for the circuitry to encode various aspects of hunting neuroethology, including sensory processing, sensorimotor transformation, motivation, and sequential encoding of hunting actions. We also discuss the overlapping brain circuits for hunting and feeding and point out the limitations of current studies. We propose that hunting is an ideal behavioral paradigm in which to study the neuroethology of motivated behaviors, which may shed new light on epidemic disorders, including binge-eating, obesity, and obsessive-compulsive disorders.


Subject(s)
Animals , Zebrafish , Hunting , Predatory Behavior/physiology , Neurons/physiology , Motivation
2.
Acta amaz ; Acta amaz;49(2): 114-117, abr. - jun. 2019. ilus
Article in English | LILACS, VETINDEX | ID: biblio-1119153

ABSTRACT

The post-fledging period is of paramount importance for raptors, since this is when a juvenile develops its hunting skills and gains the abilities required in adulthood and independence through dispersal. Little is known however, about this stage in the lives of raptors such as harpy eagles, Harpia harpyja. Between March 2016 and July 2017, we recorded three predation attempts on groups of primates by a wild juvenile harpy eagle in southwestern Brazilian Amazonia, including the first predation of an adult squirrel monkey, Saimiri ustus. These sequential records give insights into the gradual development of hunting skills during the post-fledging period, similar to what has been reported for other birds of prey. We hypothesize that a link between developing flight skills, decreasing parental food provisioning and increasingly successful captures triggers adulthood and independence in harpy eagles. (AU)


O período pós-emplumagem é de suma importância para os rapinantes, pois é quando um jovem desenvolve a habilidade de caça necessária na idade adulta e a independência por meio da dispersão. Entretanto, pouco se sabe sobre esse estágio na vida de rapinantes como o gavião-real, Harpia harpyja. Entre março 2016 e julho 2017, três tentativas de predação sobre grupos de primatas por um gavião-real juvenil foram registradas no sudoeste da Amazônia brasileira, incluindo a primeira predação de um macaco-de-cheiro adulto, Saimiri ustus. Estes registros sequenciais indicam um desenvolvimento gradual da habilidade de caça ao longo do período de pós-emplumagem, de forma similar ao relatado para outros rapinantes. Hipotetizamos que a associação entre o desenvolvimento da habilidade de voo, diminuição do provisionamento pelos pais e aumento da taxa de capturas bem-sucedidas promove a maturidade e independência no gavião-real.(AU)


Subject(s)
Animals , Predatory Behavior/physiology , Hawks/physiology , Hunting , Brazil , Amazonian Ecosystem , Raptors/physiology
3.
Acta amaz ; Acta amaz;49(1): 24-27, jan. - mar. 2019. ilus
Article in English | LILACS, VETINDEX | ID: biblio-1119182

ABSTRACT

We report an observation of predation by an Amazon tree boa, Corallus hortulanus, on an American fruit-eating bat, Artibeus sp., in an area of seasonal forest close to a small stream in the northern Brazilian Amazon. While bats appear to be one of the main food items of C. hortulanus, our observation is only the fourth such event to be recorded in the Brazilian Amazon. The Artibeus sp. individual was observed making distress (agony) calls continuously over a period of three hours, much longer than recorded on previous observations. Records of this type are important to further our knowledge on bat predators, and the defensive behavior of bats. (AU)


Nós relatamos uma observação de predação por uma serpente Corallus hortulanus sobre um morcego do gênero Artibeus em uma área de floresta estacional perto de um córrego, no norte da Amazônia brasileira. Enquanto os morcegos parecem ser um dos principais itens alimentares de C. hortulanus, a nossa observação representa somente o quarto relato para a Amazônia brasileira. O indivíduo de Artibeus sp. foi observado vocalizando com chamados de distress (agonia) durante um período de três horas, o que representa uma duração muito maior do que o reportado em registros anteriores. Registros deste tipo são extremamente importantes para aumentar o nosso conhecimento sobre os predadores de morcegos e sobre o comportamento de defesa dos morcegos.(AU)


Subject(s)
Animals , Predatory Behavior/physiology , Chiroptera/physiology , Boidae/physiology , Behavior, Animal , Brazil , Amazonian Ecosystem
4.
Braz. j. biol ; Braz. j. biol;78(3): 556-563, Aug. 2018. tab, graf
Article in English | LILACS | ID: biblio-951585

ABSTRACT

Abstract We used miniaturized GPS loggers and site observations to access foraging patterns and nest behaviour of the White-tailed Tropicbird Phaethon lepturus (WTTB), an endangered species at its South Atlantic breeding colony. Dual foraging pattern was observed with alternation between long and short foraging trips. Birds responsible for nest attendance engaged in short foraging trips with mean distance from colony of 25 ± 17 km, total distance covered of 79 ± 65 km and mean duration of 4.02 ± 5.28 hours. Birds flew by dawn and returned before dusk while partners were at sea for long foraging trips that ranged from four to 11 days, with mean maximum distance from colony of 105 ± 47.48 km. Chicks were usually left alone for hours and chick predation by Land Crab Johngartia lagostroma, egg consumption by Goniopsis cruentata and intra-specific competition are suspected to be responsible for high chick mortality rates.


Resumo Utilizamos aparelhos de GPS miniaturizados e observações de campo para determinar padrões de forrageio e comportamento em ninho da espécie ameaçada Rabos-de-palha-de-bico-laranja Phaethon lepturus em sua colônia reprodutiva do Atlântico Sul. Padrão dual de forrageio foi observado, com alternância entre viagens longas e curtas. Aves responsáveis por cuidado parental efetuaram viagens curtas de forrageio com em média 25 ± 17 km de distância da colônia, distância total percorrida média de 79 ± 65 km e duração média de 4.02 ± 5.28 horas. As aves saíram da colônia entre o amanhecer e o entardecer, enquanto seus parceiros estavam em alto-mar em viagens longas de quatro a 11 dias de duração, com média de distância máxima da colônia de 105 ± 47.48 km. Filhotes foram constantemente deixados sozinhos por várias horas, e predação por Johngartia lagostroma, consumo de ovos por Goniopsis cruentata e competição intra-específica possivelmente foram responsáveis por sua morte.


Subject(s)
Animals , Predatory Behavior/physiology , Birds/physiology , Oceans and Seas , Brazil , Breeding , Endangered Species
5.
An. acad. bras. ciênc ; 90(1): 373-383, Mar. 2018. tab, graf
Article in English | LILACS | ID: biblio-886881

ABSTRACT

ABSTRACT The intercropping is an important cultural practice commonly used in pest management. It is based on the principle that increased plant diversity in the agro-ecosystem can lead to reductions of pest populations in the crop. The current study aimed to assess the impact the colored fiber cotton-cowpea intercropped systems on Aphis gossypii and Aphis craccivora and on their predator Cycloneda sanguinea and the losses and the dispersion behavior of these aphids and their predator in these cropping systems. The experiment had a randomized block experimental design with two bioassays and four treatments. The number of apterous and alate aphids (A. gossypii) per cotton plant was 1.46 and 1.73 or 1.97 and 2.19 times highest in the solid cotton system than that found in the cotton-cowpea intercropped systems (S1) and (S2), respectively. On the other hand, the cotton-cowpea intercropped systems (S1 and S2) reduced, respectively, in 43% and 31% the number of apterousA. gossypiiper cotton plant compared to the control. Implementing cotton-cowpea intercropped system in the S1 scheme reduced A. gossypii infestation, favored the multiplication of C. sanguinea, and allowed obtaining heavier open bolls.


Subject(s)
Animals , Aphids/physiology , Predatory Behavior/physiology , Coleoptera/physiology , Crops, Agricultural/parasitology , Gossypium/parasitology , Vigna/parasitology , Biological Assay , Pest Control, Biological , Analysis of Variance , Statistics, Nonparametric , Animal Distribution
6.
An. acad. bras. ciênc ; 90(1): 179-183, Mar. 2018. tab, graf
Article in English | LILACS | ID: biblio-886895

ABSTRACT

ABSTRACT Coenosia attenuata Stein (1903) is a predatory fly that is commonly found in greenhouses and open fields preying on whiteflies, leafminers, psocopterans and other insects. The species is widespread in the Old World and its distribution has expanded in recent times to Neotropical countries including Chile, Colombia, Costa Rica, Ecuador and Peru. We report here for the first time the presence of C. attenuata in Brazil, occurring in different sites in the State of Ceará (Northeastern Brazil). Expansion of the distribution range of this muscid to the eastern parts of South America opens up the possibility of applying the beneficial predator as a biological control agent for protected crops of the region.


Subject(s)
Animals , Predatory Behavior/physiology , Muscidae/physiology , Pest Control, Biological , Crops, Agricultural/parasitology , Brazil , Introduced Species , Animal Distribution
7.
Rev. biol. trop ; Rev. biol. trop;65(1): 117-125, Jan.-Mar. 2017. tab, ilus
Article in Spanish | LILACS | ID: biblio-897530

ABSTRACT

ResumenEl primer avistamiento del pez león en el Parque Nacional "Cayos de San Felipe" en el 2009 podría amenazar la diversidad de sus ecosistemas marinos y la capacidad de brindar servicios. Para analizar la incidencia de la invasión del pez león en el área, se realizó un muestreo anual entre 2013 y 2015. La abundancia y la talla del pez león se estudió en manglares a través de censos visuales en diez transectos de 30x2 m/estación y en arrecifes (15 y 25 m de profundidad) con estéreo video en seis transectos de 50x2 m/estación. En arrecifes también se estimó incidencia de posibles competidores y depredadores nativos. En los tres años de estudio, la densidad promedio del pez león varió entre 0.0-1.3 indiv./100 m2 por estación de muestreo y no fue significativamente diferente entre hábitats (mangle - 0.6 indiv./100 m2, arrecifes a 15 m - 0.4 indiv./100 m2 y arrecifes a 25 m - 0.3 indiv./100 m2). La densidad de pez león fue igual o menor que la de competidores e igual o mayor que la de depredadores en ambas profundidades. La densidad del pez león en manglares y arrecifes a 25 m se mantuvo temporalmente estable, mientras que en arrecifes a 15 m disminuyó. Se observó que el incremento temporal de la abundancia de competidores y la densidad de depredadores no cambió durante el monitoreo. La talla del pez león varió entre 5 y 39 cm, siendo su promedio en manglares (12.6 cm) menor que en arrecifes (25.2 cm) y no mostró variaciones entre años. La talla de pez león en arrecifes fue más alta que la de competidores y menor que la de depredadores. Los resultados mostraron que en el parque: 1) los manglares son zonas de cría del pez león, 2) la incidencia del pez león en arrecifes no es tan alta como en otras áreas de Cuba y el Caribe y 3) la abundancia del pez león en arrecifes tendió a disminuir en el tiempo sin intervención de acciones extractivas o presencia de abundancia alta de meros nativos de tallas grandes. Considerando los resultados, se hacen recomendaciones para continuar el monitoreo e investigar los efectos del pez león y los factores que estan regulando su incidencia en el parque.


Abstract:The first lionfish sighting at the National Park "Cayos de San Felipe" was in 2009 and could be a threat to its marine ecosystem diversity and their capacity to generate services. To analyze the incidence of the lionfish invasion in the area, an annual sampling was conducted between 2013 and 2015. Lionfish abundance and size was investigated on mangroves through visual census on ten transects of 30x2 m/station, and on coral reefs (15 and 25 m deep) with stereo video on six transects of 50x2 m/station. Additionally, incidence of potential native competitors and predators on coral reefs were also estimated. Over the three years, the average density of lionfish varied between 0.0-1.3 indiv./100 m2 per sample stations and it was not significantly different among habitats (mangroves with 0.6 indiv./100 m2, reefs at 15 m - 0.4 indiv./100 m2 and reef at 25 m with 0.3 indiv./100 m2). Lionfish's density was equal to or lower than competitors' density, and was equal to or higher than predator's density in both depths. While lionfish density on mangroves and on reefs at 25 m remained temporally stable, it decreased on reefs at 15 m. Temporary increase in the competitor's density was observed and the predator´s density did not change during the monitored time. Lionfish size varied between 5 and 39 cm; the average fish size from mangroves (12.6 cm) was consistently lower than from reefs (25.2 cm) and showed no variations among years. Lionfish size in reefs was higher than competitor's size and lower than that of predator. Results showed that in the park: 1) mangroves represent lionfish nursery areas; 2) incidence of reef lionfish was not as high as in other areas of Cuba and the Caribbean; and 3) lionfish abundance in reefs tended to decrease over the years, without the intervention of extractive activities or high abundance of large size native groupers. In this sense, recommendations are made to continue monitoring and to investigate lionfish effects and factors that are regulating its incidence in the park. Rev. Biol. Trop. 65 (1): 117-125. Epub 2017 March 01.


Subject(s)
Animals , Perciformes/physiology , Introduced Species/statistics & numerical data , Animal Distribution/physiology , Predatory Behavior/physiology , Time Factors , Population Dynamics , Analysis of Variance , Population Density , Statistics, Nonparametric , Cuba , Wetlands , Coral Reefs , Spatio-Temporal Analysis
8.
Rev. biol. trop ; Rev. biol. trop;65(1): 267-277, Jan.-Mar. 2017. tab, ilus
Article in English | LILACS | ID: biblio-897540

ABSTRACT

Abstract:Predators can influence a variety of prey traits, including behavior. Traits such as boldness, activity rate, and tendency to explore can all be shaped by predation risk. Our study examines the effects of predation on these behaviors by considering a natural system in which two sister species of livebearing fishes, Brachyrhaphis roseni and B. terrabensis, experience divergent predation environments. In February of 2013, we collected fish in the Río Chiriquí Nuevo drainage, Chiriquí, Panama, and conducted behavioral assays. Using open-field behavioral assays, we evaluated both juveniles and adults, and males and females, to determine if there were differences in behavior between ontogenetic stages or between sexes. We assessed boldness as 'time to emerge' from a shelter into a novel environment, and subsequently measured activity and exploration within that novel environment. We predicted that B. roseni (a species that co-occurs with predators) would be more bold, more active, and more prone to explore, than B. terrabensis (a species that does not co-occur with predators). In total, we tested 17 juveniles, 21 adult males, and 20 adult females of B. roseni, and 19 juveniles, 19 adult males, and 18 adult females of B. terrabensis. We collected all animals from streams in Chiriquí, Panama in February 2013, and tested them following a short acclimation period to laboratory conditions. As predicted, we found that predation environment was associated with several differences in behavior. Both adult and juvenile B. roseni were more active and more prone to explore than B. terrabensis. However, we found no differences in boldness in either adults or juveniles. We also found a significant interaction between 'sex' and 'species' as predictors of boldness and exploration, indicating that predation environment can affect behaviors of males and females differently in each species. Our work demonstrates the importance of considering sex and life history stage when evaluating the evolution of behavior. Rev. Biol. Trop. 65 (1): 267-277. Epub 2017 March 01.


ResumenLos depredadores pueden influenciar una variedad de rasgos de la presa, incluyendo el comportamiento. Los rasgos tales como la audacia, nivel de actividad, y la tendencia a explorar; pueden ser moldeados por el riesgo de depredación. Nuestro estudio examina los efectos de la depredación en el comportamiento al considerar un sistema natural en el que dos especies hermanas de peces vivíparos, Brachyrhaphis roseni y B. terrabensis, se presentan en ambientes de depredación divergente. En febrero 2013, recolectamos peces en el drenaje del Río Chiriquí Nuevo, Chiriquí, Panamá y llevamos a cabo ensayos de comportamiento. Al usar ensayos de comportamiento en campo abierto, se evaluó el comportamiento en juveniles y adultos, machos y hembras, para determinar si los patrones de divergencia diferían entre las etapas ontogenéticas o entre sexos. Se evaluó la audacia como "tiempo en salir" de un refugio a un ambiente nuevo, y posteriormente se midió la actividad y la exploración dentro de ese nuevo ambiente. Nosotros predijimos que B. roseni (una especie que se presenta con los depredadores) sería más audaz, activa y propensa a explorar que B. terrabensis (una especie que no se presenta con los depredadores). En total, probamos 17 jóvenes, 21 machos adultos, y 20 hembras adultas de B. roseni, y 19 jóvenes, 19 machos adultos, y 18 hembras adultas de B. terrabensis. Recogimos todos los animales en Chiriquí, Panamá en Febrero 2013, y los probamos después de un corto período de aclimatación a las condiciones de laboratorio. Como se predijo, se encontró que la depredación ambiental se asoció con varias diferencias en el comportamiento. Tanto adultos y jóvenes de B. roseni eran más activos y más propensos a explorar que B. terrabensis. Sin embargo, no se encontraron diferencias en la audacia en adultos o menores. También se encontró una interacción significativa entre "sexo" y "especie" como predictores de la audacia y la exploración, lo que indica que la depredación puede afectar el comportamiento de los machos y hembras de manera diferente en cada especie. Nuestro estudio demuestra la importancia de considerar el sexo y la etapa del ciclo de vida al evaluar la evolución del comportamiento.


Subject(s)
Animals , Male , Female , Predatory Behavior/physiology , Poecilia/physiology , Ecosystem , Reference Values , Species Specificity , Time Factors , Sex Factors , Analysis of Variance , Age Factors
9.
Neotrop. ichthyol ; 15(2): e160036, 2017. graf
Article in English | LILACS, VETINDEX | ID: biblio-841891

ABSTRACT

The recognition of chemical information indicating the presence of a predator is very important for prey survival. In this study we tested antipredator behavioral response of juvenile silver catfish (Rhamdia quelen) against predator odor released by two different potential predators, Hoplias malabaricus and the snake Helicops infrataeniatus, and alarm cues and disturbance cues released by conspecifics and by non-predator species, Megaleporinus obtusidens and Astyanax lacustris. We used juvenile catfish that were naive to predators. The trials consisted of a 10-min prestimulus and a 10-min post-stimulus observation period. The behavioral response displayed by silver catfish exposed to alarm cues comprised a decrease in shelter use and an increase in locomotion, and also a longer latency period before feeding. Our results showed that juvenile silver catfish can perceive chemical cues released by predators, heterospecifics and conspecifics.(AU)


O reconhecimento das informações químicas indicando a presença de predadores é muito importante para a sobrevivência da presa. Neste estudo foi testada a resposta comportamental anti-predação de juvenis de jundiás (Rhamdia quelen) a substâncias liberadas por dois predadores potenciais, Hoplias malabaricus e a cobra Helicops infrataeniatus, e substâncias de alarme liberadas por conspecíficos e pelas espécies não predadoras Megaleporinus obtusidens e Astyanax lacustris. Foram usados juvenis de jundiá que não possuíam nenhum contato prévio com predadores. Os testes consistiram em observações de períodos de 10 minutos pré estímulo e 10 minutos pós estímulo. As respostas comportamentais apresentadas pelos jundiás expostos às substâncias de alarme consistiram em diminuição no uso do abrigo, aumento na locomoção e também um longo período de latência antes de ingerir o alimento. Os resultados demonstram que juvenis de jundiá percebem substâncias químicas liberadas por predadores, heterospecíficos e conspecíficos.(AU)


Subject(s)
Animals , Predatory Behavior/physiology , Catfishes/classification , Metabolic Side Effects of Drugs and Substances
10.
Braz. j. biol ; Braz. j. biol;76(2): 495-499, Apr.-June 2016. tab
Article in English | LILACS | ID: lil-781409

ABSTRACT

Abstract Stiretrus decastigmus (Herrich-Schaeffer) (Hemiptera: Pentatomidae) is an important predator of the insect pest Microtheca ochroloma Stal (Coleoptera: Chrysomelidae). The present study investigated the pre-imaginal development of S. decastigmus at different temperatures. The temperatures were: 20, 25, and 30 °C, with a relative humidity of 70 ± 10% and a photofase of 12 h, and the nymphs were fed larvae of M. ochroloma. We evaluated the duration and viability of the egg and nymphal stages, the duration of each instar, and the predation potential. The incubation time decreased with increasing temperature, and the viability was highest at 25 °C. The duration of the nymphal stage was inversely proportional to the temperature, ranging from 18 days at 30 °C to 40.6 days at 20 °C. The highest S. decastigmus predation rates were found at 20 °C (90.4 larvae) and 30 °C (72.5 larvae). S. decastigmus showed the highest viability and lowest consumption of larvae of M. ochroloma at 25 °C.


Resumo Stiretrus decastigmus (Herrich-Schaeffer) (Hemiptera: Pentatomidae) é um importante predador do inseto-praga Microtheca ochroloma Stal (Coleoptera: Chrysomelidae). O objetivo deste trabalho foi estudar o desenvolvimento pré-imaginal de S. decastigmus em diferentes temperaturas. Foram utilizadas as temperaturas de 20, 25, e 30 °C, umidade relativa do ar de 70 ± 10% e fotofase de 12 h, sendo as ninfas alimentadas com larvas de M. ochroloma. Foram avaliados a duração e viabilidade dos estágios de ovo e ninfa, a duração de cada instar e o potencial de predação. O período de incubação diminuiu com o aumento da temperatura e apresentou maior viabilidade a 25 °C. A duração do estágio ninfal foi inversamente proporcional a temperatura com 18 dias a 30 °C e 40,6 dias a 20 °C. A maior taxa de predação de S. decastigmus foi encontrada a 20 °C (90,4 larvas) e 30 °C (72,5 larvas). S. decastigmus teve maior viabilidade e menor consumo de larvas de M. ochroloma a 25 °C.


Subject(s)
Animals , Predatory Behavior/physiology , Temperature , Coleoptera/physiology , Pest Control, Biological/methods , Heteroptera/growth & development , Time Factors , Brazil , Ecosystem , Ecological and Environmental Phenomena , Larva/growth & development
11.
Rev. biol. trop ; Rev. biol. trop;63(3): 815-825, jul.-sep. 2015. tab, ilus
Article in English | LILACS | ID: lil-778086

ABSTRACT

Little is known about the effects of jaguars on the population of marine turtles nesting in Tortuguero National Park, Costa Rica. This study assessed jaguar predation impact on three species of marine turtles (Chelonia mydas, Dermochelys coriáceaand Eretmochelys imbricata)that nest in Tortuguero beach. Jaguar predation data was obtained by using two methodologies, literature review (historical records prior the year 2005) and weekly surveys along the 29 km stretch of beach during the period 2005-2013. Our results indicated that jaguar predation has increased from one marine turtle in 1981 to 198 in 2013. Jaguars consumed annually an average of 120 (SD= 45) and 2 (SD= 3) green turtles and leatherbacks in Tortuguero beach, respectively. Based on our results we concluded that jaguars do not represent a threat to the population of green turtles that nest in Tortuguero beach, and it is not the main cause for population decline for leatherbacks and hawksbills. Future research should focus on continuing to monitor this predator-prey relationship as well as the factors that influence it so the proper management decisions can be taken.


Existe poco conocimiento sobre el impacto que tienen los jaguares sobre las tortugas marinas que anidan en el Parque Nacional Tortuguero, Costa Rica. Este estudio evaluó el impacto de la depredación de jaguar sobre tres especies de tortugas marinas (Chelonia mydas, Dermo-chelys coriáceay Eretmochelys imbricata)que anidan en Tortuguero. Los reportes de depredación fueron obtenidos empleando dos metodologías, revisión literaria (eventos registrados antes del 2005) y monitoreos semanales a lo largo de la playa (durante el periodo 2005-2013). La depredación del jaguar se ha incrementado de una tortuga en 1981 a 198 tortugas en 2013. Asimismo, los jaguares consumieron anualmente un promedio de 120 (SD= 45) y 2 (SD= 3) tortugas verdes y tortugas baula en Tortugue-ro, respectivamente. Nuestros resultados indican que los jaguares no representan una amenaza para la población de tortugas verdes que anida en Tortuguero, y no son la causa principal de la disminución poblacional de la tortuga baula y carey. No obstante, se recomienda continuar con el monitoreo con el fin de entender cómo esta interacción depredador-presa evolucionará en el futuro.


Subject(s)
Animals , Panthera/physiology , Predatory Behavior/physiology , Turtles/physiology , Costa Rica , Environmental Monitoring , Nesting Behavior , Population Density , Turtles/classification
12.
Braz. j. biol ; Braz. j. biol;75(2): 347-351, 05/2015. graf
Article in English | LILACS | ID: lil-749698

ABSTRACT

This paper evaluates the post-dispersal artificial seed predation rates in two areas of the southeastern Amazon forest-savanna boundary, central Brazil. We conducted the survey in a disturbance regime controlled research site to verify if exists an edge effect in these rates and if the disturbance (in this case annual fire and no fire) affects seed predation. We placed 800 peanuts seeds in each area at regular distance intervals from the fragment`s edge. Data were analyzed by a likelihood ratio model selection in generalized linear models (GLM). The complete model (with effects from edge distance and site and its interaction) was significative (F3=4.43; p=0.005). Seeds had a larger predation rates in fragment’s interior in both areas, but in the controlled area (no disturbance) this effect was less linear. This suggests an edge effect for post-dispersal seed predation, and that disturbances might alter these effects. Even if we exclude the site effect (grouping both areas together) there is still a strong edge effect on seed predation rates (F3=32.679; p>0.001). We did not verify predator’s species in this study; however, the presence of several species of ants was extremely common in the seeds. The detection of an edge effect in only a short survey time suggests that there is heterogeneity in predation rates and that this variation might affect plant recruitment in fragmented areas of the Amazon forest. Henceforth, this seed predation should be taken in consideration in reforestation projects, where the main source of plants species is from seed distribution.


Este artigo avaliou a predação de sementes pós-dispersão em duas áreas da borda entre a Amazônia e o Cerrado, no Brasil central. O experimento foi realizado em uma área de estudos controlados, no qual foi verificada a existência de um efeito de borda na predação de sementes e se a existência de distúrbio (área sujeita a fogo anual e área controle) afeta estes valores. Foram colocadas 800 sementes de amendoim em cada uma das duas áreas em distância regulares da borda do fragmento. Os dados obtidos foram analisados através de seleção de modelos por verossimilhança em modelos lineares generalizados (GLM). O modelo completo (com efeitos da distância da borda e da área amostrada com suas interações) foi significativo (F3=4,43; p=0,005). As sementes apresentaram uma maior taxa de predação no interior do fragmento em relação a sua borda em ambas as áreas, mas na área controle (sem distúrbio), o efeito foi menos linear. Isto sugere que existe um efeito de borda para a predação de sementes, e que distúrbios podem alterar estes efeitos. Mesmo se o efeito das áreas for removido (considerando ambas as áreas em conjunto), o efeito de borda sobre a predação de sementes persiste (F3=32,679; p>0,001). Não foram verificadas diretamente as espécies de predadores neste estudo, no entanto a presença de algumas espécies de formigas nas sementes foi extremamente comum. A detecção deste efeito de borda em um espaço de tempo curto sugere que existe uma heterogeneidade nas taxas de predação e que esta variação pode afetar o recrutamento vegetal em áreas fragmentadas da floresta amazônica. Portanto, este efeito sobre a predação de sementes deve ser levado em consideração em projetos de reflorestamento, nos quais a principal fonte de espécies vegetais seja através da distribuição de sementes.


Subject(s)
Animals , Ants/physiology , Forests , Predatory Behavior/physiology , Seed Dispersal/physiology , Brazil
13.
Rev. biol. trop ; Rev. biol. trop;62(4): 1459-1467, oct.-dic. 2014. graf, tab
Article in Spanish | LILACS | ID: lil-753703

ABSTRACT

Attacks by big cats on livestock are one of the major causes of human-felid conflicts and, therefore, an important factor in the conservation of these species. It has been argued that a reduction in natural prey abundance promotes attacks on domestic species, but few studies have tested this statement, and some have delivered contradictory results. We investigated whether the occurrence of attacks to livestock by jaguar and puma relates to the abundance and richness of their natural prey. In the rainy season 2009, we tracked potential prey species counting signs of presence along linear transects in 14 non-attacked cattle farms (control) and in 14 attacked cattle farms in NW Costa Rica. There was a negative relationship between the occurrence of attacks and both species richness (p=0.0014) and abundance (p=0.0012) of natural prey. Our results support the establishment of actions to promote support and recovery of natural prey, in order to diminish attacks on livestock, while maintaining jaguar and puma populations. Rev. Biol. Trop. 62 (4): 1459-1467. Epub 2014 December 01.


Los ataques de grandes felinos al ganado son una de las principales causas de conflicto entre humanos y felinos, siendo por ello un tema prioritario para la conservación de estas especies. Se ha argumentado que la reducción en abundancia de presas naturales incrementa la ocurrencia de ataques a las especies domésticas. Sin embargo son pocos los estudios que han evaluado esta afirmación, algunos con resultados contradictorios. Nosotros investigamos cómo la ocurrencia de ataques al ganado, por parte de puma o jaguar, se relaciona con la abundancia y la riqueza de sus presas naturales. Muestreamos las presas potenciales contando los rastros de presencia a lo largo de transectos lineales en 14 fincas sin ataques (control) y en 14 fincas con ataques en el Noroeste de Costa Rica durante la temporada lluviosa de 2009. Encontramos una relación negativa entre la ocurrencia de ataques al ganado y la riqueza (p=0.0014) y abundancia (p=0.0012) de presas naturales. Nuestros resultados respaldan la aplicación de medidas que promuevan el mantenimiento y recuperación de las presas naturales como medida para reducir los ataques al ganado y conservar las poblaciones de puma y jaguar.


Subject(s)
Animals , Cattle , Panthera/physiology , Predatory Behavior/physiology , Puma/physiology , Costa Rica , Population Density
15.
Braz. j. biol ; Braz. j. biol;74(4): 977-982, 11/2014. graf
Article in English | LILACS | ID: lil-732327

ABSTRACT

A type of locomotor behavior observed in animals with rigid bodies, that can be found in many animals with exoskeletons, shells, or other forms of body armor, to change direction, is the turning behavior. Aquatic floated-turning behavior among rigid bodies animals have been studied in whirligig beetles, boxfish, and more recently in freshwater turtle, Chrysemys picta. In the laboratory we observed a different kind of turning movement that consists in an underwater turning movement during foraging, wherein the animal pivoted its body, using one of the hindlimbs as the fixed-point support in the substratum. We describe, analyze and quantify this movement during foraging in Hydromedusa maximiliani, using observations made in the laboratory. We studied 3 adult specimens (2 males, 1 female) and 2 non-sexed juveniles of H. maximiliani. They were kept individually in an aquarium filled with water and small fish. They were filmed, in dorsal view, at 30 frames per second. Sequences were analyzed frame by frame and points were marked on limbs and shell to enable analysis of variation in limb flexion and extension, as well as rotation movements. While foraging, turtles frequently turned their bodies, using one hind leg as the pivot point. This underwater turning movement, in addition to slow movements with the neck stretched, or staying nearly immobile and scanning the surroundings with lateral movements of the neck (in arcs up to 180°), and fast attacks of neck, may increase prey capture rates.


Um tipo de comportamento locomotor observado em animais com corpo rígido, que pode ser encontrado em muitos animais com exoesqueleto, conchas, ou outras formas de armaduras, para mudar de direção, é o girar o corpo num plano horizontal (Turning performance). O movimento de girar o corpo flutuando na água (Aquatic floated-turning performance) entre animais de corpo rígido tem sido estudado em besouros, peixe-caixa, e mais recente na tartaruga de água doce, Chrysemys picta. No laboratório nós observamos um tipo diferente de giro que consiste em um giro subaquático, não flutuando na água, durante o forrageio, onde o animal pivota seu corpo, usando uma das patas traseiras como um ponto fixo de suporte no substrato. Nós descrevemos, analisamos e quantificamos esse movimento durante o forrageio de Hydromedusa maximiliani, usando observações feitas em laboratório. Nós analisamos três adultos (2 machos, 1 fêmea) e dois juvenis não sexados. Eles foram mantidos individualmente em um aquário preenchido água e pequenos peixes. Eles foram filmados, em vista dorsal, a 30 imagens por segundo. As sequencias foram analisadas quadro a quadro, e pontos foram marcados nos membros e no casco para permitir analisar variações angulares durante a flexão e extensão, bem como movimentos de rotação. Os membros fizeram movimentos sequencias durante o movimento de giro, mantendo sempre um dos membros posteriores como ponto fixo. Esta estratégia de forrageio associada com movimentos lentos e pescoço esticado, ou permanecer praticamente imóveis apenas observando o ambiente através de movimentos laterais do pescoço, descrevendo trajetórias em um ângulo de 180°, e ataques rápidos com o pescoço, talvez aumente seu potencial na captura de presas.


Subject(s)
Animals , Female , Male , Movement/physiology , Predatory Behavior/physiology , Turtles/physiology , Fishes , Fresh Water
16.
Braz. j. biol ; Braz. j. biol;74(3): 632-641, 8/2014. tab, graf
Article in English | LILACS | ID: lil-723866

ABSTRACT

We studied the diet of the ocelot and puma during the years 2007 and 2008 at the Feliciano Miguel Abdala Reserve, in Minas Gerais, south-eastern Brazil. We collected 49 faecal samples (scats) from cats, and identified the species of cat from 23 of them by the analysis of the microstructure patterns of hairs found in their faeces: 17 scats of the puma (Puma concolor) and six of the ocelot (Leopardus pardalis). In the puma scats, we identified three species of primates (Brachyteles hypoxanthus, Alouatta guariba and Sapajus nigritus), the remains of which were found in eight of 17 collected (47.1%), representing 26.7% of items consumed. For the ocelot, we detected capuchin monkey (S. nigritus) remains in three of the six scats (50%), accounting for 18.7% of items consumed by ocelot. We were unable to identify the cat species in the remaining 26 faecal samples, but we were able to analyse the food items present. Primates were found in five of these 26 faeces (19.2%) and represented 10.2% of the items found. Although the sample size is limited, our results indicate a relatively high consumption of primates by felines. We believe that this high predation may be the result of the high local density of primates as well as the greater exposure to the risks of predation in fragmented landscapes, which tends to increase the incidence of the primates using the ground.


Nós estudamos a dieta de jaguatiricas e onças-pardas entre os anos de 2007 e 2008 na Reserva Feliciano Miguel Abdala, em Minas Gerais, sudeste do Brasil. Nós coletamos 49 amostras fecais de felinos, em 23 das quais foi possível a identificação do predador através da análise do padrão microestrutural dos seus pelos encontrados nas fezes, sendo 17 fezes de onça-parda (Puma concolor) e seis de jaguatirica (Leopardus pardalis). Nas amostras de onça-parda nós identificamos três espécies de primatas (Brachyteles hypoxanthus, Alouatta guariba e Sapajus nigritus), cujas partes não digeridas foram encontradas em oito das 17 fezes coletadas, representando 26,7% dos itens consumidos por onças-pardas. Para jaguatirica, nós detectamos macacos-prego (S. nigritus) em três de seis fezes, o que correspondeu a 18,7% dos itens consumidos. Para as 26 amostras fecais restantes, cuja identificação do predador não foi possível, nós analisamos os itens alimentares presentes. Restos de primatas foram identificados em cinco dessas fezes (19,3%), representando 10,2% dos itens encontrados. Apesar do tamanho da amostra ser limitado, nossos resultados indicam uma taxa relativamente alta de consumo de primatas por felinos. Nós acreditamos que essa alta taxa de predação pode ser resultado da grande densidade local de primatas, bem como do aumento do risco de predação em paisagens fragmentadas, o que tende a aumentar a incidência do uso do chão por parte dos primatas.


Subject(s)
Animals , Felidae/physiology , Feeding Behavior/physiology , Predatory Behavior/physiology , Brazil , Feces , Forests , Felidae/classification , Puma/physiology
17.
Braz. j. biol ; Braz. j. biol;74(3): 656-658, 8/2014.
Article in English | LILACS | ID: lil-723885

ABSTRACT

Microtheca spp. (Coleoptera: Chrysomelidae) are insect pests primarily related to Brassicaceae crops. In the State of Rio Grande do Sul (RS), southern Brazil, they are found on forage turnip, Raphanus sativus L. var. oleiferus Metzg., which is commonly grown during fall/winter seasons. This work reports the predation of Microtheca spp. larvae by Toxomerus duplicatus Wiedemann, 1830 (Diptera: Syrphidae) larvae, on forage turnip crop, in Santa Maria, RS. This register provides new information about Microtheca spp. natural enemies in Brazil, which might be a new option for integrate pest management of these species.


Microtheca spp. (Coleoptera: Chrysomelidae) são insetos-praga relacionados principalmente às culturas da família Brassicaceae. No Estado do Rio Grande do Sul (RS), no sul do Brasil, são encontrados no nabo forrageiro, Raphanus sativus L. var. oleiferus Metzg, comumente cultivado no outono/inverno. Este trabalho relata a predação de larvas de Microtheca spp. por larvas de Toxomerus duplicatus Wiedemann, 1830 (Diptera: Syrphidae), em nabo forrageiro, em Santa Maria, RS. Este registro oferece nova informação sobre os inimigos naturais de Microtheca spp. no Brasil os quais podem ser uma nova opção para o manejo integrado dessas espécies.


Subject(s)
Animals , Coleoptera/physiology , Brassica napus/parasitology , Diptera/classification , Predatory Behavior/physiology , Brazil , Coleoptera/classification , Larva , Pest Control, Biological , Seasons
19.
Braz. j. biol ; Braz. j. biol;73(2): 245-252, maio 2013. tab, graf
Article in English | LILACS | ID: lil-679998

ABSTRACT

The snail kite (Rostrhamus sociabilis) is widely distributed in the American continent. Its specialised diet consists mostly of the gastropod mollusk Pomacea sp and its foraging strategy probably varies depending on the season, prey availability, and climate factors, which can be reflected in its semi-nomad behaviour. This study was aimed at examining the hunting strategy of the snail kite, and its association with climate factors and habitat heterogeneity. Direct observations of birds between January 2010 and March 2011 in southernmost Brazil revealed that hunting was still the predominant foraging strategy (79% of records) to capture mollusks. Despite morphological specialisations to extract mollusks from the shells, the handling time (average = 92.4 s) was twice as much the time between prey search and capture (average = 55 s). The increase in the number of mollusks ingested apparently occurs when the resting time on perches or any other substrates near the hunting sites decreases between successive unsuccessful attempts. The correlation between the number of consumed preys and the climatic variables examined was low. Regarding habitat heterogeneity, our findings suggest that birds forage preferentially in marshes with low vegetation, which may increase the access to mollusks. The hunting efficiency of the snail kite was high (76 % successful attempts) compared to those of other birds of prey.


O gavião-caramujeiro (Rostrhamus sociabilis) possui ampla distribuição no continente americano e apresenta dieta especializada no molusco gastrópode Pomacea sp. Possivelmente, a estratégia de forrageio da espécie responde às variações sazonais na disponibilidade de presas, bem como aos fatores climáticos, o que pode refletir em seu comportamento seminômade. O objetivo desse estudo foi avaliar a estratégia de caça do gavião-caramujeiro, buscando suas associações quanto aos aspectos climáticos e à heterogeneidade do habitat. Observações diretas das aves, feitas entre janeiro de 2010 e março de 2011 no extremo sul brasileiro, revelaram que, para a captura dos moluscos, as aves usaram predominantemente a estratégia de caça do tipo still hunting (79% dos registros). Apesar de apresentar especializações morfológicas para a extração dos moluscos da concha, a avaliação do tempo empregado na manipulação (média = 92,4 s) foi quase o dobro do desprendido entre a procura e a captura (média = 55 s) das presas. Aparentemente, o aumento no número de moluscos ingeridos ocorre por meio de redução no tempo de repouso entre sucessivas investidas de captura mal sucedidas, tal como pelo uso de poleiros ou quaisquer outros substratos próximos aos locais de captura. O número de presas consumidas apresenta baixa relação com as variáveis climáticas testadas. Quanto à heterogeneidade do habitat, os dados sugerem que as aves forrageiam preferencialmente em banhados com cobertura vegetal rasteira, o que poderia aumentar a acessibilidade aos moluscos. O gavião-caramujeiro apresentou alta taxa de eficiência de caça (76% das investidas tiveram êxito), revelando a eficiência da estratégia de caça desta ave quando comparada a outras aves de rapina.


Subject(s)
Animals , Falconiformes/physiology , Feeding Behavior/physiology , Predatory Behavior/physiology , Snails , Brazil , Falconiformes/classification , Seasons , Wetlands
20.
Braz. j. biol ; Braz. j. biol;73(2): 419-424, maio 2013. tab
Article in English | LILACS | ID: lil-680001

ABSTRACT

Eriopis connexa (Germar) (Coleoptera: Coccinellidae) occurs in several countries of South America and its mass rearing is important for biological control programmes. This work evaluated biological aspects of E. connexa larva fed on eggs of Anagasta kuehniella (Zeller) (Lepidoptera: Pyralidae) and Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) frozen for one day, fresh eggs of Diatraea saccharalis (Fabricius) (Lepidoptera: Pyralidae), S. frugiperda newly-hatched caterpillars, nymphs of Rhopalosiphum maidis (Fitch) and Schizaphis graminum (Rondani) (Hemiptera: Aphididae). Duration of larva, pupa and larva to adult stages differed among prey offered, whereas the prepupa stage was similar. Larva, pupa, prepupa and larva to adult viabilities were equal or major of 87.5% in all prey, except for larva fed on newly-hatched larvae of S. frugiperda. Eriopis connexa has good adaptation to different prey corroborating its polyphagous feeding habit, which evidences the potential of this natural enemy for controlling corn and sorghum pests.


Eriopis connexa (Germar) (Coleoptera: Coccinellidae) ocorre em vários países da América do Sul e sua criação massal é importante para programas de controle biológico. Este trabalho avaliou os aspectos biológicos de larvas de E. connexa alimentadas com ovos de Anagasta kuehniella (Zeller) (Lepidoptera: Pyralidae) e de Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) congelados por um dia, ovos frescos de Diatraea saccharalis (Fabricius) (Lepidoptera: Pyralidae), lagartas de S. frugiperda recém-eclodidas, ninfas de Rhopalosiphum maidis (Fitch) e Schizaphis graminum (Rondani) (Hemiptera: Aphididae). A duração da fase larval, pupal e de larva a adulto diferiu entre as presas oferecidas; entretanto, a fase de pré-pupa foi semelhante. A viabilidade larval, pré-pupal, pupal e de adultos foi maior ou igual a 87,5% em todas as presas, com exceção para larvas alimentadas com lagartas recém-eclodidas de S. frugiperda. Eriopis connexa tem boa adaptação a diferentes presas, corroborando seu hábito alimentar polífago, o que evidencia o potencial desse inimigo natural para o controle de pragas de milho e sorgo.


Subject(s)
Animals , Coleoptera/physiology , Predatory Behavior/physiology , Sorghum/parasitology , Zea mays/parasitology , Coleoptera/classification
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