Critical Resource Limitation and the Properties of Deadwood that Influence Aye-aye (Daubentonia madagascariensis) Extractive Foraging
Open Access
- Author:
- Thompson, Katharine Et
- Area of Honors:
- Anthropology
- Degree:
- Bachelor of Arts
- Document Type:
- Thesis
- Thesis Supervisors:
- George H Perry, Thesis Supervisor
Timothy Michael Ryan, Thesis Honors Advisor
Sarah Barbara Mcclure, Faculty Reader - Keywords:
- Daubentonia madagascariensis
conversation
Madagascar
lemur
endangered - Abstract:
- The aye-aye (Daubentonia madagascariensis) is an endangered nocturnal lemur with adaptations for accessing structurally defended foods, including continuously-growing incisors, an elongated, flexible middle finger, and an advanced auditory system. In some seasons, ~90% of the aye-aye's diet consists of two structurally defended resources: (i) the larvae of wood boring insects, extracted after the aye-aye gnaws through decomposing bark (deadwood), and (ii) the seeds of Canarium spp. trees. Aye-ayes have massive individual home ranges (~120-215 ha for males and 30-40 ha for females) possibly due to the limited resource availability. Identification of the limiting dietary factor(s) is critical for our understanding of aye-aye behavioral ecology and future efforts to conserve this flagship species of Madagascar. To investigate whether aye-ayes equally accessed all deadwood resources within their range, I surveyed two 100 x 100 m forest plots, both within the known territories of two GPS collared aye-aye individuals (one male, one female) at Sangasanga, Kianjavato, Madagascar. Within the plots only two out of the total of 152 deadwood specimens (1.3%) were accessed by the aye-ayes. To test whether any structural or spatial variables explain aye-aye deadwood foraging preferences, I recorded tree species, height, diameter at breast height position in relation to Canarium resources, and images of the internal tree composition and density using a 3D acoustic tomograph for each accessed and un-accessed deadwood resource. No significant preferences for tree species, diameter or height were detected. Either a different major aye-aye food resource, such as Canarium, may be the critical limiting resource, or the internal structural properties of the deadwood might impact net nutritional gain from extractive foraging. Indeed, results from the acoustic analysis indicated a preference for trees with better ability to communicate sound, and thus higher densities, from 4cm towards the center of the specimen. This area may be important as a sounding board in the tap-foraging process to accurately identify potential grub-containing cavities in the outer 1-3 cm of the trees