Akodon subfuscus

Geographic Range

Puno grass mice ( Akodon subfuscus ) are distributed in Southern Peru, Bolivia, and both the eastern and western Andean slopes located in the Southern Hemisphere. In Peru they can be located in the Cusco, Apurimac, Arequipa, Ayacucho, and Puno regions, while in Bolivia they can be found in the La Paz region.

The subspecies A. subfuscus subfuscus is found in the eastern Andean slopes and northern Altiplano, while the subspecies A. subfuscus arequipae is found in the western Andean slopes and western Altiplano.

• Biogeographic Regions
• neotropical neotropical
  • native native

Habitat

Puno grass mice can live in completely treeless grassland areas to forests such as Polylepis woodlands. They are frequently found in bunchgrasses and grass clumps, places that contain large rocks, and stone walls surrounding farmland. This habitat is humid and prone to freezing temperatures at night in higher elevations. The Puno grass mice live at an elevational range of 2000 m to 3500 m, but can found as low as 1900 m and as high as 4500 m.

• Habitat Regions
• terrestrial terrestrial

• Terrestrial Biomes
• savanna or grassland savanna or grassland
• forest forest

• Other Habitat Features
• agricultural agricultural

Physical Description

Puno grass mice are classified within a group of closely-related Akodon species, which are described as being small and brown, with faint hair stripes on their back. This species group is often referred to as A. boliviensis , which may cause confusion because A. boliviensis is also the name of a species within this group. For clarity, the species group will be referred as the boliviensis group in this account.

Members of the boliviensis group also have yellow around their eyes, small round ears covered in agouti or black hair, and small white hair located on their chin. These rodents have both plantigrade forefeet and hindfeet, which also may have small white hair tufts. Akodon subfuscus itself compared to other members of the boliviensis group has a lining of darker fur varying from a dusky-olive color to grayish brown, and a slightly fuzzy tail which is about 75-81% of the length of their body, averaging at about 68.2 mm. The average total body length of Puno grass mice fall around 159.6 mm. Body mass of A. subfuscus is not available, but a close relative Akodon azarae has an average body mass of 19 g. Teeth of A. subfuscus wear down quickly and easily, but are fairly large in comparison to other members of the boliviensis group. Their mandibular toothrow length averages at about 3.74 mm, and the third upper molar is noted as being small and oval shaped.

In some populations of A. subfuscus , sexual dimorphism is present, but only slightly. Male rodents on average tend to have 1-2% larger skulls than females, but the difference is only significant in A. subfuscus from Arequipa, Peru. It's noted that skulls of members in the boliviensis group increase in length as they age.

Two subspecies of A. subfuscus are recognized, being A. subfuscus subfuscus and A. subfuscus arequipae . Subspecies A. subfuscus arequipae is noted as being smaller, having a thinner mesopterygoid fossa in the skull, and having a duller fur coloring than A. subfuscus subfuscus . The tail length of A. subfuscus subfuscus is on average 75% of their body length, while the tail length of A. subfuscus arequipae is about 81% of their body length.

• Other Physical Features
• endothermic endothermic
• homoiothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• male larger

Reproduction

Information on the mating systems of A. subfuscus is not available, but other Akodon species such as Akodon azarae are mentioned as being polygynous, with males mating with more than one female. Outside of reproductive season, male and female A. azarae mates may occupy the same nest, but during reproductive season will distance themselves or become aggressive. Males will also show aggression against other males when females are present.

• Mating System
• polygynous polygynous

There is no information on the breeding season of A. subfuscus . There is however a close relative, Akodon boliviensis was found to start reproductive activity during the Southern Hemisphere's late winter months (July and August), with all mice being reproductively active during the spring (September, October, and November). Another close relative, Akodon polopi were most likely to be found pregnant during November and December.

Information on the gestation of A. subfuscus is not available, but a related species A. azarae has a gestation period of 22-23 days. Furthermore, they can produce about 3 litters in their lifetime with an average 4.6 pups per litter. Young A. azarae are weaned 14-15 days old and reach sexual maturity at 60 days old. Interestingly, when females of A. boliviensis were observed, those that were lactating had a slightly redder fur tint than rodents that were not.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• fertilization fertilization
• viviparous viviparous

There is no data on parental care for A. subfuscus . The parental investment in a closely related Akodon group A. azarae find that only female A. azarae care for young. Female A. azarae will lick and groom and give milk to their pups, and will start weaning them when they are 15 days old.

• Parental Investment
• female parental care female parental care

Lifespan/Longevity

Puno grass mice live about 1-2 years in the wild. There is no information on lifespan in captivity for A. subfuscus , but another member of the Akodon species A. azarae had an average laboratory lifespan of 8-10 months for both males and females, with the highest on record for males being 40 months and females being 28 months.

Behavior

There is no specific data on Akodon subfuscus in regards to behavior or activity, but other Akodon species such as A. azarae have been observed to build and occupy nests on the surface and burrows underground. Different Akodon species have times that they are active. While A. azarae can be nocturnal or diurnal, other Akodon species may specialize in being only nocturnal, only diurnal, or crepuscular.

There is no specific data on A. subfuscus in regards to interaction with others of the same species, but the related A. azarae can socially tolerate other mice around them, and may even share nesting sites as long as it is not breeding season. Once breeding season hits, A. azarae become aggressive towards each other.

• Key Behaviors
• terricolous
• fossorial fossorial
• diurnal diurnal
• nocturnal nocturnal
• motile motile
• territorial territorial
• social social

Home Range

There is no data specifically on A. subfuscus , but males of a related species A. azarae are known to have wider home ranges than females, and may overlap their territory with females while avoiding other male territories. Female A. azarae were found to have home ranges between 36 m^2 and 317.4 m^2, while males had home ranges between 67.2 m^2 and 499 m^2, the largeness depending on how many overlapping female mice were present in the territory.

Communication and Perception

There is no specific information on how Akodon subfuscus communicates, but rodents in general perceive the world with sight, smell, touch, and sound. Often rodents are found to have poor eyesight, but an excellent sense of smell and hearing which they use to communicate chemically and vocally. A related species to Puno grass mice, Akodon azarae can communicate using chemical scents to indicate presence or territory.

• Communication Channels
• acoustic acoustic
• chemical chemical

• Other Communication Modes
• scent marks scent marks

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

The diet of Puno grass mice is primarily insectivorous, but their full diet consists of both arthropods (adult and larvae) and various plants. Puno grass mice are seen to have seasonal variation in food choice, with plants becoming more frequently eaten during the dry season (May to September), consuming the seeds and other plant parts containing vascular plant tissue.

• Primary Diet
• carnivore carnivore
  • insectivore insectivore
• herbivore herbivore
  • folivore folivore
  • granivore granivore
  • lignivore

• Animal Foods
• insects

• Plant Foods
• leaves
• roots and tubers
• wood, bark, or stems
• seeds, grains, and nuts

Predation

While there is no data on predation specifically for A. subfuscus , a closely related species A. boliviensis has been listed as being prey for Culpeo Foxes. Other species in Akodon such as Akodon longipilis , Akodon olivaceus and Akodon azarae are known to face predation by birds of prey such as owls.

Ecosystem Roles

While there is no specific information regarding the roles of A. subfuscus , members of Akodon are prey for different types of predators, and contribute to predation on arthropods and various plants. Furthermore, A. boliviensis is a closely associated species that helps the life cycle of parasitic Trypanosoma cruzi by consuming a carrier bug called Triatoma infestans .

Economic Importance for Humans: Positive

Akodon subfuscus and other Akodon species have no data indicating a positive economic importance.

Economic Importance for Humans: Negative

There is no data indicating Akodon subfuscus has a negative economic importance for this species, however a closely related species A. boliviensis is a known transmitter of Trypanosoma cruzi . The parasite T. cruzi causes Chagas disease in humans, which can result in death. Another closely related species, A. Azarae is considered one of many pest rodents in farmlands.

• Negative Impacts
• injures humans
  • carries human disease
• crop pest

Conservation Status

The Puno grass mouse is listed by the IUCN as Least Concern, and its range inhabits several areas that are under protection. Currently it is facing no threats, and is considered a stable population due to its wide distribution.

Other Comments

Akodon subfuscus is classified within a group of closely related species often referred to as A. boliviensis , otherwise called the boliviensis group. This group consists of the species A. boliviensis as well as the other Akodon species A. subfuscus , A. lutescens , A. spegazzinii , A. kofordi , A. polopi , A. fumeus and A. juninensis .

Additional Links

Encyclopedia of Life

Contributors

Gidget Boe (author), University of Washington, Laura Prugh (editor), University of Washington, Tanya Dewey (editor), University of Michigan-Ann Arbor.

References

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