Home range variability, spatial aggregation, and excursions of Akodon azarae and Oligoryzomys flavescens in Pampean agroecosystems

2020 ◽  
Vol 15 (5) ◽  
pp. 401-415
Author(s):  
Irene GOROSITO ◽  
Ailén BENÍTEZ ◽  
Maria BUSCH
2012 ◽  
Vol 62 (4) ◽  
pp. 381-396 ◽  
Author(s):  
Florencia Bonatto ◽  
Daniela Gomez ◽  
Andrea Steinmann ◽  
José Priotto

Patterns of space use and sexual dimorphism are frequently used to infer mating systems. We examined body size and home range size and intra- and intersexual overlap degree in order to elucidate mating strategy of Akodon azarae males. We studied spacing patterns using 113 and 129 home ranges established by males and females, respectively, in four 0.25 ha enclosures during the breeding season. Significant differences between sexes in home range size and overlap degree were found. Male home ranges were always larger than those of females. We observed exclusive space use among males and among females. Considering only those males that shared their home ranges with females, average intersexual overlap value was about 50%. Males mainly overlap their home ranges with home ranges of two or three females. Significant differences in body size were found between males and females, with males being larger. We concluded that space use and sexual dimorphism in this species is consistent with patterns characteristic of polygynous rodents, and we propose a polygynous system in A. azarae.


Behaviour ◽  
1995 ◽  
Vol 132 (11-12) ◽  
pp. 811-820 ◽  
Author(s):  
David N. Bilenca ◽  
Fernando O. Kravetz ◽  
Gerardo R. Cueto

AbstractWe studied the social interactions between Akodon azarae and Calomys laucha, and between A. azarae and Oligoryzomys flavescens, by means of experimental confrontations under laboratory conditions. Trials were carried out after two treatments: in the first one ('food' treatment), the animals were offered food ad libitum permanently, whereas in the other ('fast' treatment), the animals were previously submitted to fasting for 30 hours. The largest species- A. azarae - dominated the other two species, being dominant in 69.6% of the aggressive interactions in which a clear dominant/subordinate relationship was detected (N = 79). During the 'fast' treatment, A. azarae fed longer than C. laucha and O. flavescens, and it was the only species which significantly increased its feeding time with respect to 'food' treatment. There were higher frequencies of aggressive interactions in A. azarae - C. laucha trials than in A. azarae - O. flavescens trials. Comparisons of the behavioural variables between C. laucha and O. flavescens during their respective confrontations with A. azarae showed that C. laucha had significantly higher median values of freezing and walking behaviours, whereas O. flavescens showed a higher frequency of alertness. Species differences found in the laboratory support the interpretation that A. azarae is usually dominant over C. laucha and O. flavescens, and that A. azarae has the priority of access to food sources in situations of food shortage (winter) by means of its social dominance over the other two species. We suggest that the differences in the behavioural reactions of the subordinate species when meeting the dominant one may help to explain the different scales of spatial segregation that C. laucha and O. flavescens maintain with A. azarae in the field.


2017 ◽  
Vol 22 (12) ◽  
pp. 2057 ◽  
Author(s):  
Thais Michel ◽  
Ugo Souza ◽  
Bruno DallAgnol ◽  
Anelise Webster ◽  
Felipe Peters ◽  
...  

Among the 251 described species of ticks from the genus Ixodes, only eight were previously reported in Brazil, Ixodes amarali, Ixodes aragaoi, Ixodes auritulus, Ixodes fuscipes, Ixodes loricatus, Ixodes luciae, Ixodes paranaensis and Ixodes schulzei. Of those species, I. loricatus is considered commonly found, whereas I. auritulus and I. aragaoi were registered just one time in Rio Grande do Sul (RS) state, Southern Brazil. This paper aims to update the Ixodes species occurring in RS through the investigation of the ixodofauna of small rodents. Data from 314 wild rodents were analyzed from nine municipalities of Pampa biome and five from the Atlantic Rainforest in RS. Rodents belonging to the following species were infested by Ixodes spp. ticks: Akodon azarae, Akodon montensis, Akodon paranaensis, Akodon reigi, Calomys laucha, Delomys dorsalis, Deltamys kempi, Holochilus brasiliensis, Oligoryzomys flavescens, Oligoryzomys nigripes, Oxymycterus nasutus, Scapteromys tumidus (Cricetidae) and Cavia aperea (Caviidae). The tick identification was performed based on morphological dichotomous keys, their updates and by molecular techniques. Considering the ticks from the rodents and those collected directly from the environment, 34 specimens of Ixodes spp. were collected. Our results improved to five the list of Ixodes species that occur in RS: I. loricatus, I. auritulus, I. aragaoi, I. fuscipes and I. longiscutatus. Moreover, the finding of I. longiscutatus increases to nine the number of Ixodes species in Brazil. The occurrence of two species of the Ixodes ricinus complex (I. aragaoi and I. fuscipes) highlights the potential impact of Ixodes spp. ticks on public health.


Check List ◽  
2012 ◽  
Vol 8 (1) ◽  
pp. 130 ◽  
Author(s):  
Fernando J. Fernández ◽  
Fabricio Idoeta ◽  
César García-Esponda ◽  
Joaquín D. Carrera ◽  
Germán J. Moreira ◽  
...  

We studied small mammal assemblages recovered from owl pellets collected at 11 locations throughout the Argentina’s Pampean Region. We identified 21 species, including two marsupials, one bat, and 18 rodents. From the analysis of this dataset, we could distinguish three main groups of small mammals that currently inhabit the Pampean Region: 1) a group of taxa related to Pampean agroecosystems (Calomys spp., Akodon azarae, and Oligoryzomys flavescens); 2) a group of Brazilian species (Cavia aperea, Oxymycterus rufus, Necromys lasiurus, Necromys obscurus, Holochilus brasiliensis, and Monodelphis dimidiata); and 3) a group including species from Patagonia, Espinal and Monte phytogeographic provinces (Microcavia australis, Oligoryzomys longicaudatus, Eligmodontia typus, Graomys griseoflavus, and Akodon molinae). In addition, we documented the first record of a species of the large-bodied group of Calomys in Buenos Aires province, expanding its distribution ca. 420 km southward.


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