Digesta retention time in the Galapagos tortoise (Chelonoidis nigra)
2011 (English)In: Comparative Biochemistry and Physiology A, ISSN 1095-6433, E-ISSN 1531-4332, Vol. 160, no 4, 493-497 p.Article in journal (Refereed) Published
The retention time of food in the digestive tract of animals has important implications for digestive physiology. Retention time impacts digestive efficiency and among herbivores affects plant-animal interactions including herbivory and seed dispersal. Poorly studied yet iconic Galapagos tortoises are large-bodied generalist herbivores and ecosystem engineers which migrate seasonally. Potentially variable digesta retention times due to strong seasonal and attitudinal temperature gradients may influence tortoise seed dispersal abilities and rates of herbivory. We fed captive adult tortoises living in semi-natural conditions on Galapagos with inert particles and seeds from locally available fruits to determine whether seed size and ambient temperature influenced retention time. Median retention time varied from 6 to 28 days, with a mode of 12 days. Seed size had no effect on any of our measures of retention time, but ambient temperature was inversely correlated with retention times. Long retention time facilitates long distance seed dispersal by Galapagos tortoises, which may improve effectiveness. The effect of temperature, which may double from hot lowlands to cold highlands through the seasonal cycle, on tortoise digesta retention time will strongly influence seed dispersal efficiency and may influence patterns of food selection and migration in this species.
Place, publisher, year, edition, pages
2011. Vol. 160, no 4, 493-497 p.
Galapagos tortoise, Digesta retention, Seed dispersal, Herbivory, Digestive ecology
IdentifiersURN: urn:nbn:se:uu:diva-162443DOI: 10.1016/j.cbpa.2011.08.008ISI: 000296122800008OAI: oai:DiVA.org:uu-162443DiVA: diva2:460906