The ecology and evolution of the Monito del monte, a relict species from
the southern South America temperate forests
Abstract
The arboreal marsupial Monito del Monte (genus Dromiciops, with two
recognized species) is a paradigmatic mammal. It is the sole living
representative of the order Microbiotheria, the ancestor lineage of
Australian marsupials. Also, this marsupial is the unique frugivorous
mammal in the temperate rainforest, being the main seed disperser of
several endemic plants of this ecosystem, thus acting as keystone
species. Dromiciops is also one of the few hibernating mammals in South
America, spending half of the year in a physiological dormancy where
metabolism is reduced to 10% of normal levels. This capacity to reduce
energy expenditure in winter contrasts with the enormous energy turnover
rate they experience in spring and summer. The unique life-history
strategies of this living Microbiotheria, characterized by an
alternation of life in the slow and fast lanes, putatively represent
ancestral traits that permitted these cold-adapted mammals to survive in
this environment. Here we describe the ecological role of this
emblematic marsupial, summarizing the ecophysiology of hibernation and
sociality, actualized phylogeographic relationships, reproductive cycle,
trophic relationships, mutualisms, conservation and threats. This
marsupial shows high densities, despite presenting slow reproductive
rates, a paradox that is explained by the unique characteristics of its
three-dimensional habitat. We finally suggest immediate actions to
protect these locally abundant but globally threatened species.