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; approximately 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.

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Rhinocyllus conicus, a weevil introduced for biological control of exotic weeds, has had major nontarget ecological effects on native thistles. Some practitioners have argued that this is an isolated case. We report, however, that another Eurasian weevil (Larinus planus), currently being distributed in North America for the control of Canada thistle (Cirsium arvense), is significantly reducing seed production by a native thistle (Tracy's thistle, Cirsium undulatum var. tracyi) in Colorado. In 1999 we discovered L. planus feeding in flower heads of Tracy's thistle near a 1992-1993 biocontrol release site. Of the heads collected, 74% had evidence of L. planus, and these heads produced only 1.1 viable seeds on average, compared with 45.9 in heads without this weevil. In 2000 we investigated whether L. planus feeding persisted on Tracy's thistle and whether this feeding affected seed production significantly. Feeding by L. planus occurred on 80% of the plants and in 76% of all the main heads of Tracy's thistle. Flower heads with L. planus averaged 1.4 viable seeds, compared with 44.5 in uninfested heads. Feeding by L. planus decreased the average number of viable seeds produced per plant by over 51%. In contrast, L. planus had less effect on its targeted exotic host, Canada thistle than it did on Tracy's thistle. The high-frequency and high-level feeding of L. planus on the native species, coupled with the lack of evidence of its effectively limiting the seed production or density of Canada thistle suggest that the deliberate distribution of this weevil entails a high risk-to-benefit ratio and should be discontinued. Our findings challenge the general assumption that biological control with exotic insects is consistent with conservation goals of weed management in natural areas. Effective, a priori quantitative evaluation of the potential effects on both target and nontarget species and better regulatory oversight are required. ResumenEfectos Ecológicos Inesperados de la Distribución del Gorgojo Exótico, Larinus planus (F.), para el Control Biológico del Cardo de Canadá: Rhinocyllus conicus, un gorgojo introducido para el control de hierbas exóticas, ha tenido importantes efectos ecológicos en cardos nativos. Sin embargo, algunos profesionales han argumentado que este es un caso aislado. Reportamos que otro gorgojo eurasiático (Larinus planus), que actualmente está siendo distribuido en Norte América para el control del Cardo de Canadá (Cirsium arvense), esta reduciendo significativamente la producción de semillas de un cardo nativo (Cirsium undulatum var. tracyi) en Colorado. En 1999 descubrimos a L. planus alimentándose de flores de C. undulatum cerca de un sitio de liberación de biocontrol en 1992-1993. De las flores recolectadas, el 74 % tenía evidencia de L. planus y estas flores produjeron solo 1.1 semillas viables en promedio, en comparcaión con 45.9 en flores sin este gorgojo. En 2000 investigamos si persistía la alimentación de L. planus en el cardo nativo y si esto afectaba la producción de semilla...

Diversity and Seasonality in Tropical Panama as Deduced from Light-Trap Catches (Coleoptera: Curculionoidea). Smithsonian Contributions to Zoology, number 590, 79 pages, 9 tables, 27 figures, 1998.-Weevils were collected with light traps at seven localities in the Republic of Panama, varying in altitude from sea level to 2200 m, in climate from sharply seasonal to virtually nonseasonal, and in habitat from natural tropical forest to areas strongly disturbed by humans. Although only an estimated 25-40 percent of the species of weevils present in an area were attracted to light, a total of 2086 species was nonetheless obtained in the traps. On Barro Colorado Island (BCI), the canopy trap caught more individuals but fewer species than the trap near the ground. Species richness (alpha-diversity) varied greatly between sites, BCI being the richest and the high-altitude site of Guadalupe Arriba being the poorest. Using the logseries as an arbitrary but useful basis for comparison, there were too many rare species and too few species of intermediate abundances at all sites. Between-site (beta-) diversity was also large, with one-third to two-thirds of the species at each site being only observed at that site, whereas species occurring at four or more sites were very rare. Descriptors of seasonal patterns are proposed that were borrowed from circular statistics, such as Mean Vector and Mean Week. The former indicates the degree of seasonality, i.e., the concentration of the individuals in a year, which ranges in value from zero (uniform distribution) to unity (all individuals occurring at the same time), whereas the latter indicates the circular mean of the seasonal distribution. These were used in conjunction with other seasonality measures, such as Peak Week, which is the mode of the seasonal distribution. For all six sites with at least one year of data, these measures were calculated for each year for all species with at least 10 individuals in that year. A very rich variation in seasonal patterns was observed among species, ranging from species with very short seasons to species occurring year-round, sometimes without any clear seasonal peaks. At the climatically seasonal sites and at one less seasonal site, most species exhibited their maximum abundance at the beginning of the rainy season. However, at all sites some species were active or even had their mean or maximum abundance at any time of the year. Most species demonstrated very similar seasonal patterns in successive years, apart from shifts of a few weeks related to the actual beginning of the rainy season, but there were some clear exceptions. Similarly, for most species that occurred at more than one site in reasonable numbers the seasonal patterns were rather similar in those different sites in spite of differences in habitat, seasonality, or altitude. However, there were a number of species with spectacular differences in seasonal patterns at different sites. In some cases such differences could partly be attributed to differences between the sites, in ...

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Two major lineages of beetles inhabit cycad cones in the New World: weevils (Curculionoidea) in the subtribe Allocorynina, including the genera Notorhopalotria Tang and O'Brien, Parallocorynus Voss, Protocorynus O'Brien and Tang and Rhopalotria Chevrolat, and beetles in the family Erotylidae, including the genus Pharaxonotha Reitter. Analysis of the 16S ribosomal RNA (rRNA) mitochondrial gene as well as cladistic analysis of morphological characters of the weevils indicate four major radiations, with a probable origin on the cycad genus Dioon Lindl. and comparatively recent host shifts onto Zamia L. Analysis of the 16S rRNA gene for erotylid beetles indicates that an undescribed genus restricted to New World Ceratozamia Brongn. is the most early-diverging clade, and this lineage is sister to a large radiation of the genus Pharaxonotha onto Zamia, with apparent host shifts onto Dioon and Ceratozamia. Analysis of beetles are in accord with current models of continental drift in the Caribbean basin, support some proposed species groupings of cycads, but not others, and suggest that pollinator type may impact population genetic structure in their host cycads.

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