Evolution of host
Sonoma State University
Results and conclusions (Page 3
- A robust tree indicated that
Phratora is a monophyletic group and that
morphologically similar species are especially closely
- The use of host plant salicylates to
produce a salicylaldehyde larval secretion evolved along
the lineage leading to P.
- Our reconstruction of host plant
preference suggests that evolutionary history constrains
host plant use but that radical changes in host plant use
are possible after specialization.
- The topology of the tree
remained identical, regardless of whether
parsimony or maximum-likelihood methods were
- Bootstrap values were very
high for most nodes in the tree.
- The phylogenetic tree showed
clearly is a monophyletic group.
- Species that are
morphologically similar tend to cluster together
in the tree (e.g. the North American
aklaviki and the
- The willow-feeding
belong to different species.
Phylogenetic tree based on maximum
parsimony analysis of the nucleotide sequence.
- Closely related beetles tend
to use related or chemically similar host plant
- There was a trend towards
increasing specialization in Phratora,
because the basal species, P. vitellinae, had the broadest diet.
- Specialized species are
still capable of making a shift among host
families (from willows in the Salicaceae to
birch in the Betulaceae)
- There was no evidence in
favor of the Predation Hypothesis, because the
species that uses host salicylates for its
larval secretion, P.
vitellinae, has the
broadest diet breadth (see also
pages on Natural enemies and herbivore host
Biology | Sonoma State
January 23, 1999 NER