Meeting Abstract

19.2  Jan. 5  The consequences of olfaction for predation in a natural stream habitat FERRER, R. P.*; ZIMMER, R. K.; University of California, Los Angeles rferrer@ucla.edu

Despite significant advances in understanding the olfactory basis for predatory behavior in laboratory environments, little is known about the sense of smell in natural aquatic habitats. The California newt (Taricha torosa) inhabits mountain streams and feeds on, primarily, insects and other invertebrates. Here, we investigated the role of olfaction in determining newt foraging success. Time/activity budgets were established for individuals as they moved undisturbed in natural stream pools. Newts foraged selectively, emphasizing search for prey in leaf litter, as opposed to cobble or sand. Notably, leaf litter harbored significantly higher densities of potential invertebrate prey. To explore the role of olfaction in prey selection, newts were captured by hand, stomach contents flushed completely, noses blocked non-destructively with an inert silicon gel, and animals tagged and released. As a control, newts were treated identically, except that gel was placed on the forehead prior to tag and release. After 48 h, treatment and control animals were re-captured and their stomach contents flushed and examined. Newts with blocked noses consumed significantly less prey than their control counterparts. In fact, treatment animals hardly ate at all (mean of <1 prey/item per individual). Thus, it has yet to be determined if a sense of smell is critical for newts in finding prey, or in selecting leaf litter microhabitats that provide food-enriched environments. Combined, our results show that even animals like newts, widely believed to rely on vision and ambush predation, may use olfaction as a critical component of an integrated sensory strategy for resource acquisition.