PHYLOGENETICS OF SOCIAL-BEHAVIOR IN AUSTRALIAN GALL-FORMING THRIPS - EVIDENCE FROM MITOCHONDRIAL-DNA SEQUENCE, ADULT MORPHOLOGY AND BEHAVIOR, AND GALL MORPHOLOGY
Bj. Crespi et al., PHYLOGENETICS OF SOCIAL-BEHAVIOR IN AUSTRALIAN GALL-FORMING THRIPS - EVIDENCE FROM MITOCHONDRIAL-DNA SEQUENCE, ADULT MORPHOLOGY AND BEHAVIOR, AND GALL MORPHOLOGY, Molecular phylogenetics and evolution, 9(1), 1998, pp. 163-180
Six species of Australian gall-forming thrips (Insecta: Thysanoptera)
on Acacia exhibit soldier castes, individuals with reduced wings and e
nlarged forelegs that defend their gall against interspecific invaders
. We used data from two mitochondrial genes (cytochrome oxidase I and
16S rDNA), adult morphology and behavior, and gall morphology to infer
a phylogeny for Acacia gall-forming thrips with and without soldiers,
and we used this phylogeny to evaluate hypotheses concerning soldier
evolution. Phylogenies inferred from each data set analyzed separately
yielded large numbers of most-parsimonious trees and weak support for
most nodes. However, when analyzed together the data sets complemente
d and reinforced one another in such a way as to yield a well-resolved
phylogeny. Our phylogeny implies that soldiers originated once or twi
ce early in the history of this clade, that soldiers were lost once or
twice, and that soldiers evolved from winged dispersers rather than f
rom non-soldier within-gall reproductive offspring of foundresses. The
phylogeny also provides evidence for long-term morphological stasis,
an ancient split between eastern and western gall thrips species, and
a high degree of conservatism in host-plant affiliations. (C) 1998 Aca
demic Press.