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1

A method for studying social and reproductive behaviour of subterranean rodents in captivity

100%
Zenuto R. R., Vassallo A. I., Busch C.
Acta Theriologica
|
2001
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tom 46
|
nr 2
A methodology for studying the social and reproductive behaviour of solitary subterranean rodents under laboratory conditions is proposed. A first account of Ctenomys talarum (Thomas, 1898) behaviour is also provided with the aim of evaluating the proposed methodology and to advance presently unknown information on its social behaviour and mating system. The device is a seminatural enclosure, departing from traditional test cages with respect to increased: (1) size, (2) structural complexity, (3) social complexity, and (4) resemblance to natural conditions. It consists of artificial burrows each comprising 3.5 m of tunnel, a resource cage and a nest box, resembling the structural complexity described for C. talarum burrows. Burrows are connected to a common space, which allows social interaction among various individuals. Animals were observed in the seminatural enclosure - 3 females and 2 males, in accordance with sex ratios found in natural populations - for a period of 6 months. We obtained data related to reproductive and social behaviour: marking, aggression, vocalization, courtship and copulation, pregnancy, pup development, and parental care. The proposed system enables the collection of behavioural data as yet unavailable due to the secretive habits and aggressiveness that characterize this group of rodents, coupled with the difficulties associated with simulating subterranean conditions.
2

Strongyloides myopotami in ctenomyid rodents: Transition from semi-aquatic to subterranean life cycle

84%
Rossin M. A., Varela G., Timi J. T.
Acta Parasitologica
|
2009
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tom 54
|
nr 3
257-262
Strongyloides myopotami, a parasite of Myocastor coypus (nutria or coypu), was found during an extensive parasitological survey carried out on parasitic helminths of 5 species of subterranean rodents (tuco-tucos) belonging to the genus Ctenomys from Argentina and Uruguay. Strongyloides myopotami became known by causing “marsh itch” (also called “nutria itch” or “swimmer’s itch”), a severe rash caused by larvae that enter the skin in humans, and it is recognised as a zoonosis for people handling nutria fur. In the present study S. myopotami was found in 2 of the 5 examined species of Ctenomys (C. talarum from Argentina and C. pearsoni from Uruguay), both inhabiting the vicinity of water courses. Population descriptors of S. myopotami in C. talarum showed that a population of this parasite is well established in this rodent. The development of infective filariform larvae from eggs in the faeces of C. talarum and the prevalence of gravid parasitic females in this host can be considered as evidence of the establishment of a population of S. myopotami independent of the source population parasitizing M. coypus. Therefore, the presence of S. myopotami in these species of tuco-tucos indicates a change from a semi-aquatic to subterranean life cycle. Evidence that tuco-tucos are reservoirs for these nematodes and therefore may be a risk to human health in the areas studied is provided.
3

Female reproductive behaviour, ovarian hormones and vaginal cytology of the induced ovulator, Ctenomys talarum

84%
Fanjul M. S., Zenuto R. R.
Acta Theriologica
|
2012
|
tom 57
|
nr 1
In the present study, we evaluated whether reproductive condition affects female reproductive behaviour in the induced ovulator Ctenomys talarum. We also explored the effect of the interaction with a male on the reproductive condition of females. To evaluate this, we arranged mating trials and evaluated female reproductive behaviour. Reproductive status of females was evaluated using a combined approach of vaginal smears, urinary progesterone and oestradiol, and ovarian histology. Behaviours denoting attraction (‘male sniff’ and ‘mount attempts’) and mutual courtship behaviours (‘spin’ and copula) were correlated with vaginal cytology before and oestradiol and progesterone levels in urine 12 h after male–female encounter. After 24 h of the interaction, oestradiol levels and vaginal epithelization increased while progesterone levels decreased in soliciting females. C. talarum females’ reproductive behaviour was related to its physiological reproductive state and vaginal cytology. The kind of male interaction, whether couples copulated or remained indifferent affected the later status of females. Females are induced ovulators by mating but male presence and interaction also affected other components of their reproductive physiology such as ovarian hormones and vaginal cytology.
4

Parasitism underground: lice (Insecta: Phthiraptera) from Ctenomys talarum (Rodentia: Ctenomyidae) along its coastal distribution in Argentina

84%
Martino N. S., Romero M. D., Malizia A. I.
Acta Parasitologica
|
2015
|
tom 60
|
nr 1
5

A new species of Trichostrongylus [Nematoda, Trichostrongyloidea] parasitizing the subterranean rodent Ctenomys talarum [Rodentia, Octodontidae] from Mar de Cobo, Argentina

84%
Rossin M. A., Timi J. T., Malizia A. I.
Acta Parasitologica
|
2006
|
tom 51
|
nr 4
A new nematode species, Trichostrongylus duretteae sp. nov., found in the small intestine of Ctenomys talarum from Argentina is described. The new species more closely resembles T. suis lwanitsky, 1930 a parasite of Sus scrofa in the USSR. However, the new species can be distinguished by the morphology of male genital bursa: Rays 6 distant from rays 8 and a larger dorsal ray in relation to the length of rays 2 to 8. The present finding is the first record of the genus Trichostronglyus in rodents of the family Octodontidae.
6

Juvenile vocalizations of Ctenomys talarum [Rodentia: Octodontidae]

84%
Schleich C. E., Busch C.
Acta Theriologica
|
2002
|
tom 47
|
nr 1
We analysed the physical structure and functional interpretation of juvenile vocaliza­tions of Ctenomys talarum Thomas, 1898. Two sounds, one true vocalization (care- -elicitation call) and one mechanical sound (nursing sound) were recorded during the nestling period. Care-elicitation calls were emitted by isolated pups and caused the mother to respond by immediately approaching the pups to take care of them. This maternal response to the care-elicitation calls of C. talarum pups, together with the production of these vocalizations during the first weeks after birth, when pups depend exclusively on their mother to obtain food and maintain their body temperature, give preliminary support for the recent theory that care-elicitation cries are honest adver­tisements of offspring need.
7

Redescription and new host record of Paraspidodera uncinata [Rudolphi, 1819] [Nematoda, Aspidoderidae] from the South American subterranean rodent Ctenomys talarum [Rodentia, Octodontidae]

84%
Rossin M. A., Timi J. T., Malizia A. I.
Acta Parasitologica
|
2004
|
tom 49
|
nr 4
Paraspidodera uncinata (Rudolphi, 1819) (Nematoda, Aspidoderidae), a parasite of Neotropical caviids and octodontids, is redescribed based on specimens from the caecum and large intestine of the subterranean rodent Ctenomys talarum Thomas, 1898 (Octodontidae). During 2002, a total of 3,899 nematodes was recovered from eighty one specimens of C. talarum (prevalence 93.8%, mean abundance 51.3) from Mar de Cobo, Buenos Aires Province, Argentina (37°58'S, 57°34'W). In spite of the long list of records of P. uncinata published since its original description in 1819, descriptions available in the literature are scattered and incomplete. Therefore, a number of diagnostic morphological and morphometric features that were omitted in previous descriptions of this species, are given. These are: variability in number and position of caudal papillae in males, presence of caudal papillae in females, as well as descriptions and measurements of corpus, bulb, pharynx, lateral alae, deirids, nerve ring, vagina and uterus. Location of labial papillae and the vulva as well as the length of the left and right spicules are also provided.
8

Use of olfaction for sexual recognition in the subterranean rodent Ctenomys talarum

84%
Fanjul M. S., Zenuto R.R. Busch C.
Acta Theriologica
|
2003
|
tom 48
|
nr 1
The ability of the tuco-tuco Ctenomys talarum Thomas, 1898 to recognize sex by olfactory cues contained in urine, faeces and soiled shavings was tested by using preference tests. Nonbreeding tuco-tucos selected odours from opposite-sex rather than same-sex conspecifics. This pattern differed between sexes: females spent more time sniffing male than female odours for all scent sources whereas males did not show any difference in the time they spent investigating odours of each sex for each tested odour sources. Dissimilarities in odour selections between sexes may be attributed to a different combination of factors involved in olfactory interest for each sex. The function of gender cues recognition is discussed.
9

Female reproductive responses to photoperiod and male odours in the subterranean rodent Ctenomys talarum

67%
Fanjul M. S., Zenuto R. R.
Acta Theriologica
|
2008
|
tom 53
|
nr 1
The tuco-tucoCtenomys talarum Thomas, 1898 is a solitary subterranean rodent that breeds seasonally in coastal sand-dune grasslands from Argentina. We assessed whether short-day photoperiod determines the onset of reproduction by an increase in female’s receptivity and whether male odour interacts with photoperiod as a cue by producing a greater response in receptivity. Receptivity was measured by an increase in the percentage of vaginal epithelial cells, particularly cornified cells. Females were trapped during their non-reproductive season (summer-long days) and randomly assigned to different day-length experimental groups: constant summer (CS), early winter (EW), and natural (NA) photoperiod. We examined the vaginal epithelium using vaginal smears during the first experimental phase (120 days) to test the effect of photoperiod. In the second experimental phase (15 days), we presented the females with male-soiled shavings to test the effect of photoperiod and male odor.Ctenomys talarum females showed some evidence of reproductive responsiveness to photoperiodic cuing. The proportion of epithelial cells peaked earlier in females when winter day-length was advanced than in females under natural photoperiod. Contrary to that expected, male odours did not stimulate female receptivity. These results suggest that, while photoperiod may participate in regulating reproduction, the integration of other environmental and social factors, as well as the identification of bodily conditions that lead to differences in individual response needs further consideration.
10

Heterogeneity of heterochromatin in six species of Ctenomys [Rodentia: Octodontoidea: Ctenomyidae] from Argentina revealed by a combined analysis of C- and RE-banding

59%
Ipucha M. C., Gimenez M. D., Bidau C. J.
Acta Theriologica
|
2008
|
tom 53
|
nr 1
Exceptional chromosomal variability makesCtenomys an excellent model for evolutionary cytogenetic analysis. Six species belonging to three evolutionary lineages were studied by means of restriction endonuclease and C-chromosome banding. The resulting banding patterns were used for comparative analysis of heterochromatin distribution on chromosomes. This combined analysis allowed intra- and inter-specific heterochromatin variability to be detected, groups of species belonging to different lineages to be characterized, and phylogenetic relationships hypothesized from other data to be supported. The “ancestral group”,Ctenomys pundti andC. talarum, share three types of heterochromatin, the most abundant of which was also found in C. aff.C. opimus, suggesting that the latter species also belongs to the “ancestral group”. Additionally, within the subspeciesC. t. talarum, putative chromosomal rearrangements distinguishing two of the three chromosomal races were identified. Two species belong to an “eastern lineage”,C. osvaldoreigi andC. rosendopascuali, and share only one type of heterochromatin homogeneously distributed across their karyotypes.C. latro, the only analyzed species from the “chacoan” lineage, showed three types of heterochromatin, one of them being that which characterizes the “eastern lineage”.C. aff.C. opimus, because of its low heterochromatin content, is the most primitive karyotype of the genus yet described. The heterochromatin variability showed by these species, reflecting the evolutionary divergence toward different heterochromatin types, may have diverged since the origin of the genus. Heterochromatin amplification is proposed as a trend withinCtenomys, occurring independently of chromosomal change in diploid numbers.
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