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Scramble or contest competition over food in solitarily foraging mouse lemurs ( Microcebus spp.): New insights from stable isotopes
Author(s) -
Dammhahn Melanie,
Kappeler Peter M.
Publication year - 2010
Publication title -
american journal of physical anthropology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.146
H-Index - 119
eISSN - 1096-8644
pISSN - 0002-9483
DOI - 10.1002/ajpa.21129
Subject(s) - scramble competition , biology , competition (biology) , foraging , niche , ecology , torpor , trophic level , zoology , seasonality , thermoregulation
The relationships between resource distribution, type of competition, and consequences for social organization have been formalized in the socioecological model (SEM) which predicts that ecological factors are the main determinants of female distribution. We tested this basic prediction in two solitary primates ( Microcebus berthae and M. murinus ) which differ in female association patterns. Using stable nitrogen and carbon isotope data of hair samples and food sources we quantified inter‐specific differences in diet. δ 13 C in M. berthae reflected a diet composed mainly of insect secretions. Higher within‐species as well as seasonal variation in δ 13 C of M. murinus indicated a wider trophic niche including plant and animal source food. Constantly elevated δ 15 N in M. murinus most likely reflected extended torpor during the lean season. This energy‐saving strategy together with a wider, more opportunistic feeding niche might reduce female competition in this species, facilitating smaller female ranges, and a higher association potential. In contrast, δ 15 N fluctuated seasonally in M. berthae , most likely indicating varying amounts of arthropod food in the diet. Intense scramble competition over small and seasonally limited resources might lead to female spatial avoidance and a reduced association potential in M. berthae . Thus, differences in female association patterns between these two solitary foragers are due to different types of competition and overall intensities of intra‐specific competition. Am J Phys Anthropol, 2010. © 2009 Wiley‐Liss, Inc.