Akodon montensis
montane akodont

Akodon montensis is found in the northeastern portion of Argentina, along the southeastern coast of Brazil, and throughout eastern Paraguay. (Pardinas, et al., 2008)

Akodon montensis is found in both temperate and tropical habitats. Within these habitats it occupies evergreen, semi-deciduous, and riparian gallery forests. It is also found in grassland and coastal biomes and in open areas. Furthermore, it occurs in agricultural fields, gardens, and young secondary growth. Generally, the species prefers areas with ground cover and leaf litter. Akodon montensis can be found at elevations of 800 m, but is more common at elevations of 900 m or higher. (Couto and Talamoni, 2005; Couto and Talamoni, 2005; Jordao, et al., 2010; Pardinas, et al., 2008)

Akodon montensis is a small rodent with a heavy body that is often described as closely resembling a vole. Young differ from adults only in size, and males (45 g) are slightly larger than females (40 g). Adult mass ranges from 19 to 57 g, with a mean of 42 g. Total length of Akodon montensis ranges from 90 to 136 mm, with hind feet ranging from 17 to 28 mm long, ears ranging from 11 to 21 mm long, and tails ranging from 32 to 98 mm long. Although its basal metabolic rate is unknown, the basal metabolic rate for other members of Akodon is typically around 46 mL of oxygen per hour. Dorsal pelage of A. montensis is auburn and fades to lighter tan on the sides. The venter is either reddish grey or reddish tan with a slight orange hew. It has tan feet and a sparsely haired tail. Akodon montensis looks similar to Akodon cursor, however, A. montensis is smaller than A. cursor. (Bozinovic, 1992; Goncalves, et al., 2007; Redford and Eisenberg, 1989; Wienke and Yahnke, 2007)

Reproductive behavior of Akodon montensis has not been extensively studied, and the mating system that best characterizes this species is currently unknown.

Reproductive efforts of male Akodon montensis occurs via a four-stage process. First, recrudescence of spermatogenesis occurs, followed by the act of mating. These two stages take place between October and February (the wet season). The third stage, regression of activity and spermatogenesis, and the fourth stage, rest, take place from March to July (the dry season). If the immediate environment and weather are favorable, mating can take place year round. Typically, females have two litters but may have more if environmental conditions are favorable. Litter size ranges from 3 to 10 offspring, with an average litter size of 5. On average, gestation lasts 23 days, and offspring are typically weaned within 15 days. Males achieve sexual maturity in 32 to 37 days while females achieve sexual maturity between 35 and 91 days. Sexual maturity is most often reached between October and March. No information on birth mass is available, but average birth mass of other members of Akodon (e.g., Akodon lindberghi and Akodon azarae) ranges from 1.97 g to 3.10 g. No information is available concerning time to independence. Reproductively active and fertile females can be found in the wild with XY chromosomes. (Couto and Talamoni, 2005; De Conto and Cerqueira, 2007; Nowalk, 1991; Suarez, et al., 2004; Wienke and Yahnke, 2007)

Information on parental investment specific to Akodon montensis is not available. However, in most mammals care of the young (e.g., provisioning and protecting) is performed by the mother from the time of fertilization until independence. (Dewey, 2011; Higdon, 2004)

No specific information is available pertaining to the lifespan of Akodon montensis, aside from observations that they have a short life expectancy and quick population turnover . One member of Akodon, Akodon azarae, has a maximum lifespan of 18 months but typically lives one year or less. (Higdon, 2004; Kittlein, 2008; Wienke and Yahnke, 2007)

Akodon montensis is solitary, with most intraspecific interactions occurring during mating season. It is nocturnal and spends much of its time in leaf litter, where it creates tunnels to travel through and nest in. (Jordao, et al., 2010; Puttker, et al., 2008; Wienke and Yahnke, 2007)

The home range of Akodon montensis is relatively small, with individuals occupying 36 m^2 on average. Home ranges never exceed 100 m^2 and do not vary in size between genders or seasons. (Jordao, et al., 2010; Wienke and Yahnke, 2007)

There is no information available on intraspecific communication in Akodon montensis. Its close relative, Akodon cursor uses olfactory cues to inform conspecifics about reproductive availability and territorial boundaries. (Higdon, 2004; Higdon, 2004)

Akodon montensis is omnivorous. Its diet consists of fungi, plant matter, and invertebrates (e.g., insects and spiders) and does not vary in relation to season. Studies indicate that A. montensis prefers foraging on the seeds and mesocarp of Leandra panifilamentosa, Myrceugenia cucullata, Rubus sellowii and Berberis laurina. Similar to other small mammals, A. montensis caches food. (Talamoni, et al., 2008; Vieira, et al., 2006)

Aside from barn owls, little information is available on the major predators of Akodon montensis. Although not documented, it is likely that mammalian carnivores, snakes, and large birds also prey on Akodon montensis. The brownish pelage of Akodon montensis helps it blend in with leaf litter and avoid predators. (Higdon, 2004; Jordao, et al., 2010; Pardinas, et al., 2004)

Akodon montensis preys on a variety of small insects including beetles, moths, flies, and other arthropods. Although limited information is available concerning is major predators, it is likely an important prey item for many large birds and carnivores. In addition, it is a host to numerous species of parasitic protists in the genus Besnoitia and a variety of nematodes. It is also a known carrier of hantavirus. Finally, Akodon montensis may play an important role in the seed dispersal of certain plant species as it is known to cache seeds throughout its home range. (Goodin, et al., 2009; Grisard, et al., 1997; Jordao, et al., 2010; Puttker, et al., 2008; Wienke and Yahnke, 2007)

There are no known positive effects of Akodon montensis on humans. However, it may help control insect pest populations throughout its native range.

Akodon montensis poses two main problems for humans. First, it is a known vector for hantaviruses. When transmitted to humans this virus can cause hantavirus pulmonary syndrome which can be fatal. Secondly, some members of the genus Akodon have a significant impact on agriculture by foraging on crops (e.g., rice, maize, peanuts, and cereal crops), resulting in a 10% to 90% decrease in crop yield. (Goodin, et al., 2009; Stenseth, et al., 2003)

Although Akodon montensis is thought to be decreasing in abundance, it is currently listed as a species of least concern by the IUCN Red List of Threatened Species. (Pardinas, et al., 2008)

Akodon montensis was formerly considered a subspecies of Akodon cursor. It has recently been promoted to species level based on several factors, including occupying a different elevational habitat then Akodon cursor and having a different karyotype (2n=24 for Akodon montensis, 2n=14/15 for Akodon cursor). Akodon montensis does not have a gall bladder but Akodon cursor does. Due to this recent change in classification, it is often difficult to determine if the study results apply to Akodon cursor or Akodon montensis. (Wienke and Yahnke, 2007)