Jason B. Shaw


Adams, Rick A. (Rick Alan)

Committee Member

Mackessy, Stephen P.

Committee Member

Thomas, Mark

Committee Member

Gilliam, David


Biological Science


University of Northern Colorado

Type of Resources


Place of Publication

Greeley (Colo.)


University of Northern Colorado

Date Created





232 pages

Digital Origin

Born digital


Differences in developmental patterns important to diversification are produced through heritable variation of the onset/offset and timing of juvenile growth. As the size and shape of an organism changes during ontogeny, morphological, and behavioral components must adjust to accommodate proper function. This study explored the ontogenetic pathways of two closely related Phyllostomids differing in flight ability, body size, life history strategies, and developmental state at birth. We hypothesized that Artibeus jamaicensis and Carollia perspicillata will show ontogenetic differences that account for the diversification of morphological, body size, and behavioral patterns. Comparisons between the two species‟ flight development, growth rates, and morphometrics were made from day 1 to adult size (AJ n = 45, CP n = 25). Forearm length, mass, wing area, and wingspan were measured on a daily basis. Flight behavior was compared with juveniles being dropped from a 1 meter high roost from day 1 post-partum. Logistic growth equations were used to compare growth rates of all measured parameters and t-tests (p < 0.001) showed significant differences between the species of all measured variables. Muscle development in the pectoralis major was iv significantly different with A. jamaicensis having significantly more slow-twitch fibers. There were significant differences between the day of first flap (t-test, p = 0.01) and flight (t-test, p < 0.0001) with C. perspicillata achieving flight at 22 days and A. jamaicensis achieving flight 33 days post-partum. C. perspicillata was shown to be significantly more maneuverable than A. jamaicensis. Our data suggest that growth trends are significantly different with the more altricial A. jamaicensis developing faster than the more precocial C. perspicillata. Ontogenetic comparisons are important proxies when determining evolutionary diversification of closely related species. Data can be combined with phylogenetic information, providing possible mechanisms as to what factors could have influenced the divergence of closely related species.

Degree type


Degree Name




Local Identifiers


Rights Statement

Copyright is held by author.