Regular inbreeding by sib-mating is one of the most successful ecological strategies in the bark beetle family Scolytinae. Within this family, the many species (119) in Coccotrypes are found breeding in an exceptional variety of untraditional woody tissues different from bark and phloem. Species delineation by morphological criteria is extremely difficult, however, as in most other inbreeding groups of beetles, perhaps due to the unusual evolutionary dynamics characterizing sib-mating organisms. Hence, we here performed a phylogenetic analysis using molecular data in conjunction with morphological data to better understand morphological and ecological evolution in this sib-mating group. We used partial DNA sequences from the nuclear gene EF-alpha and the mitochondrial genes 12S and CO1 to elucidate patterns of morphological evolution, haplotype variation, and evolutionary pathways in resource use. Sequence variation was high among species and far above that expected at the species level (e.g., 19% for CO1 within Coccotrypes advena). The tendency for exhaustive sequence variation at deeper nodes resulted in ambiguous reconstructions of the deepest splits. However, all results suggested that species with the broadest diets were clustered in a single derived position-another piece of evidence against specialization as a derived evolutionary feature. (C) 2002 Elsevier Science (USA). All rights reserved.

The weevil subfamily Scolytinae includes at least seven groups of regularly sib-mating species with extremely female-biased offspring sex ratios. The enigmatic SE-Asian bark beetle genus Ozopemon (25 spp.) belong to the most diversified clade (>1400 spp.) of such ancient inbreeding lineages. While males of all sib-mating scolytines are flightless, and are usually dwarfed versions of their larger sisters, the existence of males in Ozopemon has been a controversial issue. Some strangely modified male beetles, with fully developed aedeagus, strongly flattened pronotum and bead, and 10-segmented larviform abdomen, were first described as males of O.brownei, but were later assigned to the Histeridae. With the new evidence provided here, based on DNA sequence data from mitochondrial and nuclear gene partitions, and examination of genitalic characters, we re-assign these males, as well as males for two more species, to Ozopemon. Neoteny evolved close to the origin of sib-mating and possibly haplodiploidy, but the transition to neoteny occurred separately from all other inbreeding dryocoetine and xyleborine beetles. The neotenic development of these males is the first known example in Coleoptera, and several remarkable morphological modifications demonstrate an ontogenetic transformation series from female to males of different species. We discuss possible scenarios for the evolution of neoteny, precocity and fighting characteristics in these male beetles, in the light of W. D. Hamilton's 'ideal biofacies' of extreme inbreeding. (C) 2002 The Linnean Society of London.

The main goals of this study were to provide a robust phylogeny for the families of the superfamily Curculionoidea, to discover relationships and major natural groups within the family Curculionidae, and to clarify the evolution of larval habits and host-plant associations in weevils to analyze their role in weevil diversification. Phylogenetic relationships among the weevils (Curculionoidea) were inferred from analysis of nucleotide sequences of 18S ribosomal DNA (rDNA; 2, 000 bases) and 115 morphological characters of larval and adult stages. A worldwide sample of 100 species was compiled to maximize representation of weevil morphological and ecological diversity. All families and the main subfamilies of Curculionoidea were represented. The family Curculionidae sensu lato was represented by about 80 species in 30 "subfamilies" of traditional classifications. Phylogenetic reconstruction was accomplished by parsimony analysis of separate and combined molecular and morphological data matrices and Bayesian analysis of the molecular data; tree topology support was evaluated. Results of the combined analysis of 18S rDNA and morphological data indicate that monophyly of and relationships among each of the weevil families are well supported with the topology (( Nemonychidae, Anthribidae) (Belidae (Attelabidae (Caridae (Brentidae, Curculionidae))))). Within the clade Curculionidae sensu lato, the basal positions are occupied by mostly monocot-associated taxa with the primitive type of male genitalia followed by the Curculionidae sensu stricto, which is made up of groups with the derived type of male genitalia. High support values were found for the monophyly of some distinct curculionid groups such as Dryophthorinae (several tribes represented) and Platypodinae (Tesserocerini plus Platypodini), among others. However, the subfamilial relationships in Curculionidae are unresolved or weakly supported. The phylogeny estimate based on combined 18S rDNA and morphological data suggests that diversification in weevils was accompanied by niche shifts in host-plant associations and larval habits. Pronounced conservatism is evident in larval feeding habits, particularly in the host tissue consumed. Multiple shifts to use of angiosperms in Curculionoidea were identified, each time associated with increases in weevil diversity and subsequent shifts back to gymnosperms, particularly in the Curculionidae.