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1

Foraging behaviour of the Brazilian squirrel Sciurus aestuans [Rodentia, Sciuridae]

100%
Alvarenga C. A., Talamoni S. A.
Acta Theriologica
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2006
|
tom 51
|
nr 1
69-74
We describe the foraging behaviour of the Brazilian squirrelSciurus aestuans Linnaeus, 1776 in a natural free-living population, in an area with a high concentration of palm fruitsSyagrus romanzoffiana (Chamisso) Glassman. Our objective was to investigate if the abundance ofS. romanzoffiana fruits, an important food item for squirrels, temporally influenced the foraging behaviour of this population. The observations were carried out over an eight-month (April–November 2001) period. Fruiting phenology ofS. romanzoffiana was also monitored. The most consumed food item for this period was the fruit ofS. romanzoffiana (70%), followed by foods of human origin (14%). The percentage of time spent feeding increased in September, and the time spent travelling declined in September, October and November, when females were observed showing evidence of reproductive activity. At the same timeS. romanzoffiana fruits become available. The consumption of human items illustrates the opportunistic feeding habit of these squirrels, but variations in foraging behaviour detected probably were more strongly related to availability ofS. romanzoffiana fruits.
2

New data on the life history and occurrence of spiny rats Trinomys moojeni [Rodentia: Echimyidae], in southeastern Brazil

100%
Cordeiro J. D. A., Talamoni S. A.
Acta Theriologica
|
2006
|
tom 51
|
nr 2
163-168
We present new data on the life history and a new locality of occurrence ofTrinomys moojeni (Pessôaet al., 1992). The study was conducted in a region considered to be a transition zone between the Cerrado and the Atlantic Forest biomes in Minas Gérais, Brazil. Animals were sampled by the capturemark-recapture (CMR) methods between January 2001 and January 2002. Fifteen males and 34 females were captured and a total of 29 individuals were studied. Seasonal variation in the numbers ofT. moojeni males and females captured was observed; no sexual dimorphism was recorded. There was no evidence for the existence of a defined mating season. During the year, females remained in the vicinity of the study area while males dispersed over longer distances as evidenced by the fewer number of males captured. This suggests that females are more territorial.
3

Reproductive dynamics of the nectarivorous Geoffroy's tailless bat Anoura geoffroyi (Glossophaginae) in a highland Neotropical Area of Brazil, with evidence of a mating period

81%
Farias T. O., Talamoni S. A., Godinho H. P.
Acta Chiropterologica
|
2018
|
tom 20
|
nr 1
This study investigated the reproductive dynamics of a colony of Geoffroy's tailless bat (Anoura geoffroyi), an important pollinating bat, in a highland area of Southeastern Brazil. The colony was monitored each month from November 2014 to December 2015 with 154 males and 117 females captured. Testicular and ovarian histological data from 31 adult males and 22 adult females were obtained. Body condition index of male and female, and gonadosomatic index, epididymis-somatic index and Sertoli cell efficiency were analyzed. Females with spermatozoa in uterine crypts, embryos in oviducts, gravid uteri, and pregnant females were registered during the rainy season (November-March) and into the beginning of the following dry season (April), indicating asynchrony of births. The ovaries showed all types of ovarian follicles, and a polarized ovary cortex was found, differing from the organization pattern of most mammals. The testes showed continuous spermatic activity, but testicular parameters analyzed showed significantly higher values during the rainy season. A shorter mating period during the beginning of this season was detected, when values of the gonadosomatic and epididymis-somatic indexes, and Sertoli cell efficiency showed more pronounced differences in relation to the remaining period of study. Unlike polyestry known for some Neotropical phyllostomids, the reproductive cycle of A. geoffroyi was characterized as seasonal monoestrous, with the main reproductive events occurring during the rainy season, as the best time for females to reproduce, but with offspring recruitment occurring predominantly during the dry season, a period with fewer food resources.
4

Sertoli cell efficiency of the Neotropical bats Anoura geoffroyi, Artibeus lituratus and Myotis levis (Mammalia: Chiroptera)

81%
Viana P. I. M., Farias T. O., Talamoni S. A., Godinho H. P.
Acta Chiropterologica
|
2018
|
tom 20
|
nr 2
Sertoli cells play an essential role in spermatogenesis, being determinant of male reproduction capability. In this study we determined and compared the Sertoli cell efficiency (SCE), i.e. the ratio of the number of round spermatids to the number of Sertoli cells, of three species of Neotropical chiropterans, Anoura geoffroyi, Artibeus lituratus and Myotis levis, and additionally we tested for correlations between SCE, the combined mass of the testes and epididymides (CMTE), and the body condition index (BCI), considering that both BCI and testis mass can influence gonadal function of males. For SCE determination, the number of round spermatids and Sertoli cells present in stage 1 of the cycle of the seminiferous epithelium were counted. The Sertoli cell efficiency (mean ± 1 SD) was 4 ± 2.4 for A. geoffroyi, 4 ± 1.0 for A. lituratus and 6 ± 2.0 for M. levis. No significant variation was observed in SCE among the species, but A. lituratus exhibited a statistically significant correlation between CMTE and BCI. Anoura geoffroyi and M. levis exhibited significant positive correlations between SCE and CMTE, but not between SCE and BCI. Previous studies have shown that, unlike A. lituratus, A. geoffroyi and M. levis are subject to strong mating pressures, leading us to hypothesize that these findings may be related to differential mating pressures between species.
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