GULF OF GUINEA ISLANDS' BIODIVERSITY
NETWORK
ANALYSIS OF ASYMMETRIES IN THE
AFRICAN FRUIT BATS Eidolon helvum AND Rousettus
egyptiacus (MAMMALIA: MEGACHIROPTERA) FROM THE ISLANDS OF THE GULF OF
GUINEA. I. VARIANCE AND SIZE COMPONENTS OF BILATERAL VARIATION.
JAVIER JUSTE1,2, CELIA LÓPEZ-GONZÁLEZ,3 AND
RICHARD E. STRAUSS 3
1.
Estación Biológica de Doñana
(CSIC), Sevilla, 41080, Spain,
2.
Departamento de Bioquímica
y Biología Molecular IV. Facultad de Veterinaria,
Universidad Complutense de Madrid, Madrid 28040, Spain.
3.
Department of Biological
Sciences, Texas Tech University, Lubbock, TX 79409-3131, USA
Abstract
A set of cranial characters was examined in the fruit bats Rousettus
egyptiacus and Eidolon
helvum to compare trends and relative importance of major components of
bilateral morphometric variation, and their relationship with character size.
Using two-way, sides-by-individuals ANOVA, four components of variation were
estimated for each bilateral variable: individual variation (I), directional
asymmetry (DA), non-directional asymmetry (NDA), and measurement error (E).
Both species exhibit similar major trends of variation in asymmetry
across characters, as shown by principal component analysis, using variance
components as variables. Degree of
interspecific congruence among characters was confirmed by a two-way ANOVA with
species and variance components as fixed factors. Congruence
of asymmetry patterns between species suggests that the concept of population
asymmetry parameter (PAP) could be extended to higher hierarchies.
PAP’s above the species level may result from common mechanisms or
similar developmental constraints acting on species’ buffering capacities and
morphological integration processes.
Key words: Asymmetry, variance components, three-dimensional
coordinates, Eidolon helvum, Rousettus
egyptiacus, fruit bats, Gulf of Guinea.