Insect Prey Foraging Strategies in C allicebus oenanthe in Northern P eru

Titi monkeys (genus C allicebus ) are small‐bodied platyrrhines that supplement their predominantly frugivorous diet with variable amounts of leaves, seeds, and/or arthropod prey. Notable interspecific variation in the amount of insect prey in the diet has been observed in C allicebus , ranging from 0% to 20%. In this study, I investigate the degree and type of prey foraging in a little‐known species, C allicebus oenanthe inhabiting a fragmented, secondary forest on the foothills of the A ndes in northern P eru. I present data on prey type, prey search and capture techniques, substrate/vegetation use, foraging height, prey capture efficiency, and seasonal variation of insect prey foraging in one group of C . oenanthe observed from January to August 2005. Insect prey accounted for 22% of the diet, the highest amount reported for any C allicebus species to date, and insects from at least six different orders were included. C . oenanthe was mainly an investigative forager of hidden prey, manipulating easy‐to‐open substrates such as rolled up leaves, and hunted ant swarms and larger insects opportunistically. Insect foraging was predominant during the dry season (26%) and decreased during the wet season (13%). The study group foraged mostly in the understory (2–6 m) within vine‐laden shrubs and trees, which may conform to an anti‐predator strategy of crypticity. Overall the group had an 83% insect capture success rate. These data suggest that insect prey is an important part of the diet of C . oenanthe and may be especially notable during periods of resource scarcity. This study adds to the knowledge concerning insect prey foraging in C allicebus , which can have an important role in defining ecological strategies in the selection of secondary protein food resources within a given ecosystem. Am. J. Primatol. 74:450‐461, 2012. © 2012 Wiley Periodicals, Inc.