DOI: 10.3897/zoologia.38.e63231

Authors: Carlos A. Contreras-Díaz, Leroy Soria-Díaz, Yuriana Gómez-Ortiz, Rogelio Carrera-Treviño, Claudia C. Astudillo-Sánchez, Julio C. Chacón-Hernández, Luis F. Martínez-García

Abstract: Jaguars, Panthera onca (Linnaeus, 1758), and pumas, Puma concolor (Linnaeus, 1771) are the largest felids in the neotropics. Both can overlap in niche axes (time, space and prey), and are therefore potentially competing species. Segregation mechanisms presented by a low overlap in one of these axes of niche can facilitate the coexistence. Our aim was to analyze jaguar and puma temporal and spatial overlap for understanding their segregation mechanisms. Between 2015 and 2017, twenty-six camera trap stations were located in five habitat types of El Cielo Biosphere Reserve (ECBR) in northeastern Mexico. Temporal activity was analyzed using circular statistics and time overlap analysis. Spatial overlap was calculated with the Pianka index and a selectivity habitat analysis. Our results showed that jaguars and pumas were nocturnal and that the temporal overlap was high (∆4 = 0.77). We found an intermediate spatial overlap (Pianka index = 0.61). Jaguars were more selective and preferred the deciduous forest. In comparison, pumas preferred oak-pine forest, but also used oak and deciduous forest. Our results indicate that spatial segregation best explains the coexistence of jaguars and pumas in our study area, probably due to both habitat diversity in the reserve and the generalist habits of the puma.

HTML

XML

PDF

DOI: 10.3897/zoologia.37.e47223

Authors: Rafael C. R. Souza, Paulo S. Pompeu

Abstract: The high diversity of freshwater fish species reflects a great morphological plasticity. Understanding the relationship between swimming capacity, morphology and habitat use may be important to predict the chances of finding a species at an anthropized environment. The swimming capacity and morphological aspects of two sympatric species of Characidium, and for which spatial segregation in different hydraulic habitats is known, were compared in this study. Twenty-one individuals of Characidium fasciatum Reinhardt, 1867 and 23 individuals of Characidium cf. zebra Eigenmann, 1909 were captured and used for the evaluation of the swimming capacity and ecomorphological attributes. The swimming capacity of each species was obtained by measuring critical and relative velocities. A total of 12 ecomorphological attributes correlated with habitat use and swimming characteristics were also compared. The Mann-Whitney mean test showed that the swimming capacity of C. fasciatum was greater than that of C. cf. zebra, and the standard length of the individuals explained 12.42% of the variation in their capacity to withstand water flow. Both species were morphologically distinct in the relative length of the caudal peduncle, ventral flattening index and the relative area of the pectoral fin. The relative area of the pectoral fin alone accounted for 16.71% of the differences in the ability to resist the water flow and which were not explained by body length. Our results showed that two species differed in the ecomorphological space and in their swimming capacity, supporting the hypothesis that the greater the hydrodynamism, the better a fish is able to withstand the water flow, and that this capacity is correlated with the morphological characteristics linked to the swimming activity of the fish.

HTML

XML

PDF

DOI: 10.3897/zoologia.37.e56795

Authors: Roberto Leonan M. Novaes, Fernanda M. Alves, Renan F. Souza, Rafael S. Laurindo, Ricardo Moratelli

Abstract: Amblyomma Koch, 1844 is distributed worldwide, with ca. 130 species currently recognized. These ticks are vectors of pathogens to animals and humans, including the causative agent of the New World Rocky Mountain spotted fever. Species of the Amblyomma parasitize a wide range of organisms, especially medium and large terrestrial mammals. Here we report for the first time the association of Myotis lavali Moratelli, Peracchi, Dias & Oliveira, 2011, Noctilio albiventris Desmarest, 1818 and Noctilio leporinus (Linnaeus, 1758) as hosts for Amblyomma sculptum Berlese, 1888. The ticks were originally identified as Amblyomma cajennense (Fabricius, 1787), in 2011. However, a later taxonomic review indicated that the species of the A. cajennense complex occurring in the Caatinga is A. sculptum. We also discuss the ecoepidemiological implications of this association.

HTML

XML

PDF

DOI: 10.3897/zoologia.37.e37716

Authors: Leonardo Fernandes França, Victória Helen Figueiredo-Paixão, Thales Afonso Duarte-Silva, Kamila Barbosa dos Santos

Abstract: Rainfall in tropical semi-arid areas may act as a reliable cue for timing bird reproduction, since it precedes future food supply. With this in mind, we set-up a study to test the reproductive response of insectivorous bird to arthropod abundance and rainfall patterns. Sampling occurred in a seasonally dry Neotropical forest, in north-eastern Brazil, between October, 2015 and October 2016, at 14-day intervals. We used brood patch to assess reproductive periodicity of insectivorous birds (eight species, 475 captures, 121 patch records). We sampled arthropods to quantify abundance, using biomass and number of individuals (1755 individuals, 15 Orders). Rainfall temporal distribution was analyzed using daily precipitation data. We used a cross-correlation function to test for correlation and time-lags between the covariates under study. Both the number of reproductively-active birds and arthropod abundance were higher in time periods close to the rainy season. Increase in arthropod biomass in the aerial stratum preceded the period of greatest rainfall by one (14 days, r = 0.44) to three sampling periods (0.47). In contrast, the highest proportion of individuals with brood patches occurred after the main rainfall peak, with the strongest relationship occurring after two (0.52) to four (0.50) time lags. Finally, the proportion of individuals with brood patches was positively correlated with aerial stratum arthropod biomass when five time lags were considered (0.55). Our results support the hypothesis of a temporal process involving rainfall, arthropods and reproduction of insectivorous birds in the wet/dry tropics. However, rainfall did not appear to act as a cue for the timing of reproduction, since records indicated higher arthropod biomass before the main rainfall peak. At least occasionally in the study area, insectivorous bird reproduction peaks after food abundance.

HTML

XML

PDF

DOI: 10.3897/zoologia.35.e24446

Authors: Mauricio Lang dos Santos, Valéria Marques Lemos, João P. Vieira

Abstract: We report on the interaction between common bottlenose dolphins, Tursiops truncatus (Montagu, 1821) and cast net fishermen in southern coast of Brazil. The fishery was monitored in the mouth of the Tramandaí River Estuary to investigate the seasonality of catches and their relationships with a set of variables: presence/absence and number of bottlenose dolphins, fishing area, temperature, salinity, wind and water flow direction in the channel. The mullet, Mugil liza Valenciennes, 1836 is the target species and was the dominant fish in the catches (77% of total catch; 50% in frequency; 0.2 ind. x f-1). The use of GLM models helped to reveal that the number of the bottlenose dolphins, time of year (months) and spatial variation of fishing activity were the main factors explaining the presence and abundance of mullet in the fishermen’s catches. The presences of bottlenose dolphins in the fishing area raise the probability of fishermen catch larger number of mullets with smaller fishing effort. However, the size of the mullet is influenced basically by seasonality. The mullets are the “currency” of bottlenose dolphins and fishermen interaction. There are reasons for concern about the sustainability of the southern Brazilian M. liza stock, once the decrease of this fishing resource can lead this rare and traditional fishery to the extinction.

HTML

XML

PDF

DOI: 10.3897/zoologia.35.e20583

Authors: Carolina Scultori, Wesley R. Silva

Abstract: Neotropical bats are recognized as effective seed dispersers, especially of small-seeded pioneer plants during early stages of forest regeneration. There had been few reports on the ecology of the bat Pygoderma bilabiatum (Wagner, 1843), which appears to be mainly frugivorous and to undertake vertical migrations in Brazil. Our analyzes of fecal samples of P. bilabiatum specimens captured in mist nets and direct observations of their feeding behavior on Citharexylum solanaceum Cham. fruits in a mosaic of restored forests and forest fragments in southeastern Brazil constitute one of the few records of consumption of large-seeded fruits by P. bilabiatum, and indicate that it may be an important disperser for large-seeded plants. We found evidence that the temporal availability of those fruits may influence the movement ecology of those bats.

HTML

XML

PDF

DOI: 10.3897/zoologia.35.e14678

Authors: Laís Ribeiro-Silva, Daniel Fernandes Perrella, Carlos H. Biagolini-Jr, Paulo V.Q. Zima, Augusto J. Piratelli, Marcelo N. Schlindwein, Pedro M. Galetti-Jr, Mercival R. Francisco

Abstract: Identification of the predators of bird nests is essential to test ecological and evolutionary hypotheses and to make practical management decisions. A variety of nest monitoring devices have been proposed but many remain difficult to set up in the field. The aim of this study was to test camera traps as a potential tool to study predation of natural nests in a tropical rainforest environment. Specifically, we registered the predators, assessed their size range, and we compared the use of one and two cameras per nest. Of 122 nests from 24 bird species, 45 (37%) were depredated, and the cameras recorded the predator species in 29 of the total of depredated nests (64%). We identified predators in eight of 16 depredated nests (50%) in which we used one camera trap per nest, and we identified predators in 21 of 29 depredated nests (72%) when we used two camera traps per nest. The predators included six species of birds and six species of mammals, with body masses varying from 20 g to 16.5 kg. Causes for 10 of the 16 detection failures were identified and are discussed. These results suggest that camera traps are viable tools to investigate nest predation in a tropical rainforest area.

HTML

XML

PDF