Oral Presentation- Symposium 12th International Mammalogical Congress

Plant odour and visual cues as proximate attractors to food patches (#274)

Adrian M Shrader 1 , Peter B Banks 2 , Clare McArthur 2
  1. University of KwaZulu-Natal, Scottsville, KWAZULU-NATAL, South Africa
  2. School of Biological Sciences, University of Sydney, Sydney, NSW, Australia

Key foraging decisions herbivores make are where to go and what to eat. Yet, we know very little about the cues herbivores use to make these decisions, nor the scale at which these cues are used. By detecting high quality food from afar, herbivores could forage more efficiently. To explore this, we tested the use of plant cues by two generalist browsers, African elephants and (Australian) swamp wallabies. Semi-domesticated elephants were able to locate preferred plants within feeding stations, and between patches using only olfactory cues. Elephants could also detect and select tiny food rewards through odour alone despite background odour from unpreferred plants. In the absence of visual cues, free ranging swamp wallabies relied on odour to locate high quality Eucalyptus seedlings. Moreover, time to discovery was related to odour cue size (i.e. number of leaves). When leaf odour was suppressed in whole seedlings yet visual cues intact, seedling detection at night was severely compromised. Though, suppression of visual cues with odour intact had a smaller impact, delaying discovery compared to whole intact seedlings, but not restricting nocturnal detection by wallabies. We conclude that leaf odour plays a critical role in the foraging efficiency of these mammalian herbivores. Moreover, the use of cues to detect plants may provide insight into food quality. As such, we suggest that these cues, in particular the role of leaf odour, should be explored in other plant-mammalian herbivore systems.