title: Ecological allometries and niche use dynamics across Komodo dragon ontogeny.
abstract: Ontogenetic allometries in ecological habits and niche use are key responses by which individuals maximize lifetime fitness. Moreover, such allometries have significant implications for how individuals influence population and community dynamics. Here, we examined how body size variation in Komodo dragons (Varanus komodoensis) influenced ecological allometries in their: (1) prey size preference, (2) daily movement rates, (3) home range area, and (4) subsequent niche use across ontogeny. With increased body mass, Komodo dragons increased prey size with a dramatic switch from small (≤10 kg) to large prey (≥50 kg) in lizards heavier than 20 kg. Rates of foraging movement were described by a non-linear concave down response with lizard increasing hourly movement rates up until ∼20 kg body mass before decreasing daily movement suggesting reduced foraging effort in larger lizards. In contrast, home range area exhibited a sigmoid response with increased body mass. Intrapopulation ecological niche use and overlap were also strongly structured by body size. Thus, ontogenetic allometries suggest Komodo dragon's transition from a highly active foraging mode exploiting small prey through to a less active sit and wait feeding strategy focused on killing large ungulates. Further, our results suggest that as body size increases across ontogeny, the Komodo dragon exhibited marked ontogenetic niche shifts that enabled it to function as an entire vertebrate predator guild by exploiting prey across multiple trophic levels.
authors.affiliation: Komodo Survival Program, Denpasar, Bali, Indonesia.
authors.forename: Deni
authors.initials: D
authors.lastname: Purwandana
authors.affiliation: Komodo Survival Program, Denpasar, Bali, Indonesia.
authors.forename: Achmad
authors.initials: A
authors.lastname: Ariefiandy
authors.affiliation: Komodo Survival Program, Denpasar, Bali, Indonesia.
authors.forename: M Jeri
authors.initials: MJ
authors.lastname: Imansyah
authors.affiliation: Komodo National Park, Labuan Bajo, Flores, Indonesia.
authors.forename: Aganto
authors.initials: A
authors.lastname: Seno
authors.affiliation: Department Biology, University of Florence, Sesto Fiorentino, 50019, Florence, Italy.
authors.forename: Claudio
authors.initials: C
authors.lastname: Ciofi
authors.affiliation: Centre for Ecosystem Science, School of Biological, Earth and Environmental Sciences, University of New South Wales, Kensington, NSW, Australia.
authors.forename: Mike
authors.initials: M
authors.lastname: Letnic
authors.affiliation: Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Waurn Ponds, Victoria, Australia. t.jessop@deakin.edu.au.
authors.forename: Tim S
authors.initials: TS
authors.lastname: Jessop
mesh_terms: D063147:Animal Distribution / Q000502:physiology; D000818:Animals; D049628:Body Size; D017753:Ecosystem; D005260:Female; D020387:Food Chain; D008116:Lizards / Q000254:growth & development / Q000502:physiology*; D008297:Male; D009043:Motor Activity / Q000502:physiology; D011235:Predatory Behavior / Q000502:physiology
keywords: Body size; Individual ecological strategies; Intrapopulation variation; Predator; Resource use