Seasonal Changes in Feeding Ecology and Activity Patterns of Two Sympatric Mouse Lemur Species, the Gray Mouse Lemur (Microcebus murinus) and the Golden-brown Mouse Lemur (M. ravelobensis), in Northwestern Madagascar

Abstract

Because closely related species are likely to be ecologically similar owing to common ancestry, they should show some degree of differentiation in order to coexist. We studied 2 morphologically similar congeneric species, the golden-brown mouse lemur (Microcebus ravelobensis) and the gray mouse lemur (M. murinus). These species are found in partial sympatry in the dry deciduous forest in northwestern Madagascar. We investigated whether 1) feeding niche differentiation and/or 2) a reduction in locomotor activity during periods of food shortage, which might reflect an energy saving strategy, can explain the coexistence of these 2 lemur species. To obtain feeding and behavioral data, we conducted focal observations of 11 female Microcebus murinus and 9 female M. ravelobensis during 11 months from 2007 to 2008 and collected fecal samples for 6 mo. We monitored the phenology of 272 plant specimens and trapped arthropods to determine food availability. Results Int J Primatol (2011) 32:566-586 revealed interspecific differences in 1) relative proportion of consumed food resources, resulting in a merely partial dietary overlap, and in 2) relative importance of seasonally varying food resources throughout the year. In addition, females of Microcebus murinus showed a reduction in locomotor activity during the early dry season, which might reflect an energy-saving strategy and might further reduce potential competition with M. ravelobensis over limited food resources. To conclude, a combination of interspecific feeding niche differentiation and differences in locomotor activity appears to facilitate the coexistence of Microcebus murinus and M. ravelobensis.

Edge Effects on Morphometrics and Body Mass in Two Sympatric Species of Mouse Lemurs in Madagascar

“…Microcebus spp. in general and M. ravelobensis in particular rely heavily on insects and their larval secretions for their diet [Dammhahn and Kappeler, 2010;Thorén et al, 2011], which occur in greater abundance near the forest edge at other dry forest sites in Madagascar [Corbin and Schmid, 1995]. The edge abundance model was developed to predict edge effects on animal abundance .…”

“…M. ravelobensis is listed by the IUCN as endangered and eats primarily insect secretions (i.e. sugary secretion produced by flatid leaf bug nymphs) and arthropods whereas M. murinus (IUCN Red List criteria of Least Concern) consumes relatively more gum and fruit [Thorén et al, 2011]. Partial dietary overlap occurs during times of peak fruit availability (February to April).…”

Habitat Separation of Sympatric Microcebus spp. in the Dry Spiny Forest of South-Eastern Madagascar

“…In the case of mouse lemurs, species separation and coexistence of similar species has been linked to different habitat components Rendigs et al, 2003;Rakotondravony and Radespiel, 2009;Thorén et al, 2011b]. The evolutionary benefit of one type of habitat utilization over the other remains enigmatic.…”

“…These congeneric mouse lemur species differ in habitat utilization [Rendigs et al, 2003;Schwab and Ganzhorn, 2004;Dammhahn and Kappeler, 2008a, b;Génin, 2008;Rakotondravony and Radespiel, 2009;Rakotondranary et al, 2011a], food composition [Radespiel et al, 2006;Kappeler, 2008a, b, 2010;Rakotondranary et al, 2011b;Thorén et al, 2011b] and activity patterns [Thorén et al, 2011b]. Different habitat utilization might be due to different competitive potential of two sympatric species, such as in Ampijoroa where M. murinus outcompete M. ravelobensis [Thorén et al, 2011a].…”

First Insights into the Social Organisation of Goodman’s Mouse Lemur (Microcebus lehilahytsara) – Testing Predictions from Socio-Ecological Hypotheses in the Masoala Hall of Zurich Zoo

“…Since mouse lemurs also occur throughout the eastern Malagasy rain forests and these species differ strongly in their ecology, it is of special interest to know whether the model can also explain the social organisation of rain forest species. Due to a lesser degree of rainfall seasonality in rain forests [Randrianambinina et al, 2003], food abundance should not vary to the extent known in dry forests [Dammhahn and Kappeler, 2008;Thorén et al, 2011]. Instead, thermoregulation could play at least a similar role, since highland rain forest habitats can reach very low minimum temperatures during the austral winter.…”