Abstract
Several shifts from ancestral conifer feeding to angiosperm feeding have been implicated in the unparalleled diversification of beetle species. The single largest angiosperm-feeding beetle clade occurs in the weevils, and comprises the family Curculionidae and relatives. Most authorities confidently place the bark beetles (Scolytidae) within this radiation of angiosperm feeders. However, some clues indicate that the association between conifers and some scolytids, particularly in the tribe Tomicini, is a very ancient one. For instance, several fragments of Gondwanaland (South America, New Caledonia, Australia and New Guinea) harbour endemic Tomicini specialized on members of the formerly widespread and abundant conifer family Araucariaceae. As a first step towards resolving this seeming paradox, we present a phylogenetic analysis of the beetle family Scolytidae with particularly intensive sampling of conifer-feeding Tomicini and allies. We sequenced and analysed elongation factor 1alpha and nuclear rDNAs 18S and 28S for 45 taxa, using members of the weevil family Cossoninae as an out-group. Our results indicate that conifer feeding is the ancestral host association of scolytids, and that the most basal lineages of scolytids feed on Aramucaria. If scolytids are indeed nested within a great angiosperm-feeding clade, as many authorities have held, then a reversion to conifer feeding in ancestral scolytids appears to have occurred in the Mesozoic, when Araucaria still formed a major component of the woody flora.
Full Text
The Full Text of this article is available as a PDF (233.9 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Ashworth P. J., Harrison R. A., Miller N. G., Plummer J. M., Watson P. F. Survival of ram spermatozoa at high dilution: protective effect of simple constituents of culture media as compared with seminal plasma. Reprod Fertil Dev. 1994;6(2):173–180. doi: 10.1071/rd9940173. [DOI] [PubMed] [Google Scholar]
- Dowton M., Austin A. D. Phylogenetic relationships among the microgastroid wasps (Hymenoptera: braconidae): combined analysis of 16S and 28S rDNA genes and morphological data. Mol Phylogenet Evol. 1998 Dec;10(3):354–366. doi: 10.1006/mpev.1998.0533. [DOI] [PubMed] [Google Scholar]
- Farrell BD. "Inordinate Fondness" explained: why are there So many beetles? . Science. 1998 Jul 24;281(5376):555–559. doi: 10.1126/science.281.5376.555. [DOI] [PubMed] [Google Scholar]
- Labandeira C. C., Dilcher D. L., Davis D. R., Wagner D. L. Ninety-seven million years of angiosperm-insect association: paleobiological insights into the meaning of coevolution. Proc Natl Acad Sci U S A. 1994 Dec 6;91(25):12278–12282. doi: 10.1073/pnas.91.25.12278. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Larson A. The comparison of morphological and molecular data in phylogenetic systematics. EXS. 1994;69:371–390. doi: 10.1007/978-3-0348-7527-1_22. [DOI] [PubMed] [Google Scholar]
- Michot B., Bachellerie J. P. Comparisons of large subunit rRNAs reveal some eukaryote-specific elements of secondary structure. Biochimie. 1987 Jan;69(1):11–23. doi: 10.1016/0300-9084(87)90267-7. [DOI] [PubMed] [Google Scholar]
- Savard L., Li P., Strauss S. H., Chase M. W., Michaud M., Bousquet J. Chloroplast and nuclear gene sequences indicate late Pennsylvanian time for the last common ancestor of extant seed plants. Proc Natl Acad Sci U S A. 1994 May 24;91(11):5163–5167. doi: 10.1073/pnas.91.11.5163. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sunnucks P., Hales D. F. Numerous transposed sequences of mitochondrial cytochrome oxidase I-II in aphids of the genus Sitobion (Hemiptera: Aphididae). Mol Biol Evol. 1996 Mar;13(3):510–524. doi: 10.1093/oxfordjournals.molbev.a025612. [DOI] [PubMed] [Google Scholar]
- Whiting M. F., Carpenter J. C., Wheeler Q. D., Wheeler W. C. The Strepsiptera problem: phylogeny of the holometabolous insect orders inferred from 18S and 28S ribosomal DNA sequences and morphology. Syst Biol. 1997 Mar;46(1):1–68. doi: 10.1093/sysbio/46.1.1. [DOI] [PubMed] [Google Scholar]