Host-specific gene expression as a tool for introduction success in Naupactus parthenogenetic weevils.

Food resource access can mediate establishment success in invasive species, and generalist herbivorous insects are thought to rely on mechanisms of transcriptional plasticity to respond to dietary variation. While asexually reproducing invasives typically have low genetic variation, the twofold reproductive capacity of asexual organisms is a marked advantage for colonization. We studied host-related transcriptional acclimation in parthenogenetic, invasive, and polyphagous weevils: Naupactus cervinus and N. leucoloma. We analyzed patterns of gene expression in three gene categories that can mediate weevil-host plant interactions through identification of suitable host plants, short-term acclimation to host plant defenses, and long-term adaptation to host plant defenses and their pathogens. This approach employed comparative transcriptomic methods to investigate differentially expressed host detection, detoxification, immune defense genes, and pathway-level gene set enrichment. Our results show that weevil gene expression responses can be host plant-specific, and that elements of that response can be maintained in the offspring. Some host plant groups, such as legumes, appear to be more taxing as they elicit a complex gene expression response which is both strong in intensity and specific in identity. However, the weevil response to taxing host plants shares many differentially expressed genes with other stressful situations, such as host plant cultivation conditions and transition to novel host, suggesting that there is an evolutionarily favorable shared gene expression regime for responding to different types of stressful situations. Modulating gene expression in the absence of other avenues for phenotypic adaptation may be an important mechanism of successful colonization for these introduced insects.

Revision of the Pantomorus albosignatus species group (Coleoptera: Curculionidae: Entiminae) from Mexico and Central America.

Pantomorus albosignatus Boheman, 1840 (Entiminae: Naupactini), type species of the genus Pantomorus Schoenherr, 1840, is broadly distributed in Mexico, from Oaxaca and Veracruz to Chihuahua and Coahuila, and is probably related to P. parvulus Sharp 1891 (México: Oaxaca and Veracruz), P. andersoni sp. nov. (México: Guerrero), and P. crinitus (Boheman, 1840) (southern Mexico, El Salvador and Guatemala). The four species are small (5-8 mm), apterous, usually show a characteristic maculation and erect setae on the elytra, short antennae, vestigial to absent humeri, and well-developed, squamose corbels of the metatibiae, and are here referred to as the Pantomorus albosignatus species group. Our study was based on the examination of type material and about 500 specimens from different collections, and provides a dichotomous key, descriptions or redescriptions of the species, habitus photographs, line drawings of female and male genitalia, a map of distribution, new locality records and new plant associations. We propose that Pantomorus nobilis (Boheman 1840) is a new junior subjective synonym of P. crinitus (Boheman, 1840), and we designate lectotypes for the species Pantomorus albosignatus Boheman, P. parvulus Sharp, P. crinitus (Boheman), P. nobilis (Boheman) and P. affinis Sharp, 1891 (the latter is also a junior synonym of P. crinitus). Pantomorus albosignatus usually inhabits Acacia grasslands and cactus deserts of the Mexican Plateau, at higher elevations than remaining species; P. parvulus occurs in cloud forests and tropical deciduous forests of southern Mexico; P. crinitus in open oak pine forests, cloud forests and tropical deciduous forests of southern Mexico, Guatemala and El Salvador; and P. andersoni is endemic to the state of Guerrero, in Acacia-cactus woodlands.

Recognition of species groups of Naupactus Dejean (Coleoptera: Curculionidae) from Argentina and neighboring countries.

Naupactus Dejean is the most diverse genus of the tribe Naupactini (Curculionidae: Entiminae), with more than 200 species occurring in South America, of which about 40 range in Argentina and neighboring countries. The Argentinean species treated herein were classified into nine groups having different biogeographic patterns: (1) the groups of Naupactus xanthographus, N. delicatulus and N. auricinctus mainly occur in northeastern Argentina (Misiones province) and reach the highest species diversity in the Atlantic and Parana forests of Brazil; (2) the groups of N. hirtellus, N. cinereidorsum, N. rivulosus and N. tarsalis show the highest species diversity in the Chacoan biogeographic province and also occur in the Yungas, Espinal, Monte, Parana forest (Argentina) and Cerrado (Brazil); (3) the groups of N. leucoloma and N. purpureoviolaceus have the highest species diversity in the Pampean biogeographic province, being also present in adjoining areas, mainly Chaco, Espinal, Monte and Parana forest. We provide descriptions, a dichotomous key, habitus photographs and line drawings of genitalia for the identification of the nine species groups, and a list of the Argentinean species from each group, together with their abbreviated synonymies, updated geographic distributions (including six new country records and several state/province records) and host plant associations. We discuss the characters that allow the separation of the species groups in a geographic distribution context, and provide information on species reassigned to genera other than Naupactus; among these, we transferred N. cephalotes (Hustache) to the tribe Tanymecini, genus Eurymetopellus, establishing the new combination Eurymetopellus cephalotes.

New synonymies, new combinations and lectotype designations for weevils in the tribe Naupactini (Coleoptera: Curculionidae: Entiminae).

We examined the type material of 15 species of Naupactus Dejean and related genera (Curculionidae: Entiminae), most of them described by Alphonse Hustache (Museum National d'Histoire Naturelle, Paris) and Carl Boheman (Naturhistoriska Riksmuseet, Stockholm). The information associated with the types was compared with the original descriptions, and large series of specimens were examined in order to analyze the variation of each species throughout its range (sexual dimorphism, other kinds of polymorphism or geographic variation). Based on the results of this study we establish seven new combinations, one new placement and nine new synonymies, we make 21 lectotype designations and provide three new country and state records. Alceis curtus (Boh.), Lanterius leucophaeus (Boh.), L. sparsus (Boh.), L. sellatus (Boh.), Parapantomorus carinirostris (Hust.), Symmathetes signatus (Blanchard) and Teratopactus acerbus (Boh.) are new combinations and T. sulphureoviridis Hust. is a new placement. The following names are senior synonyms of those between parentheses: Lanterius inermis (Hust.) (syn. Macrostylus ocellatus Lanteri); Naupactus auricinctus Boh. (syn. N. ruficornis Boh.); N. bridgesii G.R. Waterhouse (syn. N. angulithorax Hust.); N. condecoratus Boh. (syn. N. bosqi Hust.); N. cyphoides (Heller) (syn. N. calamuchitanensis Hust., N. viridinitens Hust, N. viridulus Hust.); N. peregrinus (Buchanan) (syn. N. brevicrinitus Hust.); and Trichonaupactus densior Hust. (syn. T. rexus Hust.). For each species we provide the following information: synonyms, available data on type specimens (sex, body length, geographic location, kind of type, and repository), complete geographic distribution, pictures of types or specimens compared with types, an explanation about the reasons that justify the nomenclatural acts.

A tale of swinger insects: Signatures of past sexuality between divergent lineages of a parthenogenetic weevil revealed by ribosomal intraindividual variation.

Naupactus cervinus (Boheman) (Curculionidae, Naupactini) is a parthenogenetic weevil native to the Paranaense Forest which displays high levels of genetic variation. Two divergent clades were identified, one ranging in forest areas (Forest clade), and the other in open vegetation areas (Grassland clade). Both of them have individuals with high levels of heterozygosity in ribosomal sequences. Investigation of intraindividual variation in ITS1 sequences through cloning and posterior sequencing suggested that mating between both groups most likely occurred in the Paranaense Forest after a secondary contact, which led to fixed heterozygotes as a consequence of parthenogenesis. Otherwise, sexual segregation would have disrupted multilocus genotypes. Only a small number of heterozygous genotypes of all the possible combinations are found in nature. We propose the occurrence of a hybrid zone in the Paranaense Forest. The fact that it is one of the most important biodiversity hotspots of the world, together with its key role for investigating evolutionary processes, makes it worthy of conservation. This is the first genetic evidence of bisexuality in N. cervinus.

Out of the forest: past and present range expansion of a parthenogenetic weevil pest, or how to colonize the world successfully.

Previous research revealed complex diversification patterns in the parthenogenetic weevil Naupactus cervinus. To understand the origin of clonal diversity and successful spreading of this weevil, we investigated its geographic origin and possible dispersal routes and whether parthenogens can persist in habitats under unsuitable environmental conditions. This study is based on samples taken throughout a broad area of the species' range. We used both mitochondrial and nuclear markers and applied phylogenetic and network analyses to infer possible relationships between haplotypes. Bayesian phylogeographic analyses and ecological niche modeling were used to investigate the processes that shaped genetic diversity and enabled the colonization of new geographic areas. Southeastern Brazil emerges as the original distribution area of N. cervinus. We detected two range expansions, one along natural corridors during the Pleistocene and the other in countries outside South America during recent times. Isolation due to climate shifts during the early Pleistocene led to diversification in two divergent clades, which probably survived in different refugia of the Paranaense Forest and the Paraná River delta. The origin of the clonal diversity was probably a complex process including mutational diversification, hybridization, and secondary colonization. The establishment of N. cervinus in areas outside its native range may indicate adaptation to drier and cooler conditions. Parthenogenesis would be advantageous for the colonization of new environments by preventing the breakup of successful gene combinations. As in other insect pests, the present distribution of N. cervinus results from both its evolutionary history and its recent history related to human activities.

Taxonomic revision of the genus Stenocyphus Marshall (Coleoptera, Curculionidae) from Brazil.

Stenocyphus Marshall, 1922 (Entiminae, Naupactini) includes three species: the type species S. bituberosus (Gyllenhal, 1833), S. tuberculatus (Hustache, 1938), comb. n. herein transferred from Neoericydeus Hustache, 1938, and S. sextuberosus sp. n. The genus is endemic to the Atlantic forests of the states of Espirito Santo, Rio de Janeiro and São Paulo, Brazil andis mainly characterized by the presence of humped elytra bearing large conical tubercles on the intervals 5, or 3 and 5, or 3, 5 and 7. It shares some external morphological characters with Hadropus Schoenherr, 1826 and the Brazilian species of Cyrtomon Schoenherr 1823, but its phylogenetic position is uncertain. Herein we provide a diagnostic key to separate Stenocyphus from those genera, generic and species redescriptions or descriptions, a key to species, habitus photographs, line drawings of genitalia, and a discussion of the patterns of elytral tubercles in unrelated genera of Neotropical broad-nosed weevils.

Obrieniolus, a new monotypic genus of Naupactini (Coleoptera, Curculionidae, Entiminae) from the Peruvian Andes and its phylogenetic placement.

A new monotypic genus of Naupactini (Coleoptera: Curculionidae), Obrieniolus del Río is described based on the new species Obrieniolus robustus del Río, endemic to Peru. This genus is easily recognized by the black, denuded and shiny integument, with imbricate microsculpture and the rounded body, with short, cordiform and moderately convex elytra. According to a cladistic analysis based on 69 continuous and discrete morphological characters, the new genus is the sister taxon of a group formed by Amitrus Schoenherr, Trichocyphus Heller, Amphideritus Schoenherr, Asymmathetes Wibmer & O'Brien and Galapaganus Lanteri. The paper includes habitus photographs, line drawings of genitalia, mouthparts, and other external features of taxonomic value, and a dichotomous key to the genera of Naupactini distributed in the South American Transition Zone.

Mito-nuclear genetic comparison in a Wolbachia infected weevil: insights on reproductive mode, infection age and evolutionary forces shaping genetic variation.

BACKGROUND: Maternally inherited endosymbionts like Wolbachia pipientis are in linkage disequilibrium with the mtDNA of their hosts. Therefore, they can induce selective sweeps, decreasing genetic diversity over many generations. This sex ratio distorter, that is involved in the origin of parthenogenesis and other reproductive alterations, infects the parthenogenetic weevil Naupactus cervinus, a serious pest of ornamental and fruit plants. RESULTS: Molecular evolution analyses of mitochondrial (COI) and nuclear (ITS1) sequences from 309 individuals of Naupactus cervinus sampled over a broad range of its geographical distribution were carried out. Our results demonstrate lack of recombination in the nuclear fragment, non-random association between nuclear and mitochondrial genomes and the consequent coevolution of both genomes, being an indirect evidence of apomixis. This weevil is infected by a single Wolbachia strain, which could have caused a moderate bottleneck in the invaded population which survived the initial infection. CONCLUSIONS: Clonal reproduction and Wolbachia infection induce the coevolution of bacterial, mitochondrial and nuclear genomes. The time elapsed since the Wolbachia invasion would have erased the traces of the demographic crash in the mtDNA, being the nuclear genome the only one that retained the signal of the bottleneck. The amount of genetic change accumulated in the mtDNA and the high prevalence of Wolbachia in all populations of N. cervinus agree with the hypothesis of an ancient infection. Wolbachia probably had great influence in shaping the genetic diversity of N. cervinus. However, it would have not caused the extinction of males, since sexual and asexual infected lineages coexisted until recent times.

Diversity of boll weevil populations in South America: a phylogeographic approach.

A phylogeographic approach was conducted to assess the geographic structure and genetic variation in populations of the boll weevil Anthonomus grandis, which is the most harmful insect pest of cotton in the Americas. COI and COII mitochondrial gene sequences were analyzed to test a former hypothesis on the origin of the boll weevil in Argentina, Brazil and Paraguay, using samples from Mexico and USA as putative source populations. The analysis of variability suggests that populations from South American cotton fields and nearby disturbed areas form a phylogroup with a central haplotype herein called A, which is the most common and widespread in USA and South America. The population from Texas has the A haplotype as the most frequent and gathers in the same group as the South American populations associated with cotton. The sample from Tecomán (México) shows high values of within-nucleotide divergence, shares no haplotype in common with the South American samples, and forms a phylogroup separated by several mutational steps. The sample from Iguazú National Park (Misiones Province, Argentina) has similar characteristics, with highly divergent haplotypes forming a phylogroup closer to the samples from cotton fields, than to the Mexican group. We propose that in South America there are: populations with characteristics of recent invaders, which would be remnants of "bottlenecks" that occurred after single or multiple colonization events, probably from the United States, and ancient populations associated with native forests, partially isolated by events of historical fragmentation.

Chave de identificação, ocorrência e distribuição dos curculionídeos-das-raízes dos citros em São Paulo e Minas Gerais / Key for identification, ocurrence and distribution of citrus root weevils in São Paulo and Minas Gerais, Brazil

O objetivo deste trabalho foi efetuar a diagnose de quatro espécies de curculionídeos-das-raízes que ocorrem nos citros, fornecer uma chave para identificação de 14 espécies, além de estudar sua ocorrência e distribuição na área citrícola dos estados de São Paulo e Minas Gerais. As quatro espécies são registradas pela primeira vez causando danos em citros pertencem ao gênero Naupactus Dejean (Curculionidae; Entiminae; Naupactini): N. bellus Boheman, N. cinerosus Boheman, N. decorus (Fabricius) e N. virens Boheman. Das 14 espécies listadas na chave, onze pertencem ao gênero Naupactus [N. ambiguus Boheman, N. bellus, N. cervinus Boheman, N. cinerosus; N. curtus Boheman, N. decorus, N. navicularis Boheman, N. rivulosus (Olivier), N. tarsalis Boheman, N. versatilis Hustache e N. virens; uma ao gênero Teratopactus Heller (T. nodicollis (Boheman)]; uma ao gênero Parapantomorus Emden [P. fluctuosus (Boheman)] e uma ao gênero Symmathetes (S. kollari Schoenherr). Os curculionídeos-das-raízes foram encontrados em todas as regiões citrícolas dos estados de São Paulo e Minas Gerais sendo a região centro-sul do estado de São Paulo a que apresentou maior número de espécies. N. tarsalis, N. versatilis e P. fluctuosus ocorreram em maior número de municípios.

The objective of this paper is to bring about a diagnosis of four species of root weevils, recorded for the first time causing damage in citrus grooves of the states of São Paulo and Minas Gerais, Brazil. A key for the identification of 14 species harmful for citrus in these states is provided as well as a study on their occurrence and distribution. The four species treated in this paper belong to the genus Naupactus Dejean (Curculionidae: Entiminae: Naupactini): N. bellus Boheman, N. cinerosus Boheman; N. decorus (Fabricius) and N. virens Boheman. Among the 14 species included in the key, eleven belong to Naupactus [N. ambiguus Boheman, N. bellus Boheman, N. cervinus Boheman, N. cinerosus Boheman; N. curtus Boheman, N. decorus (Fabricius), N. navicularis Boheman, N. rivulosus (Olivier), N. tarsalis Boheman, N. versatilis Hustache and N. virens (Boheman); one to Teratopactus Heller (T. nodicollis (Boheman)]; one to Parapantomorus Emden [P. fluctuosus (Boheman)] and one to Symmathetes (S. kollari Schoenherr). The citrus root weevils occur in all citrus grooves of São Paulo and Minas Gerais, and the species diversity is higher in the center-south area of São Paulo. N. tarsalis, N. versatilis and P. fluctuosus are present in the highest number of localities.

Phylogeny of the Pantomorus-Naupactus complex based on morphological and molecular data (Coleoptera: Curculionidae).

The Pantomorus-Naupactus complex is a Neotropical group of broad-nosed weevils (Coleoptera: Curculionidae) including several parthenogenetic species usually assigned to the genera Naupactus Dejean, Pantomorus Schoenherr, Asynonychus Crotch, Aramigus Horn, Eurymetopus Schoenherr and Graphognathus Buchanan. Sixteen species were studied to test hypotheses on the monophyly of these genera, and on the origin of the parthenogenetic lineages. A matrix of 30 morphological characters and 999 positions of the Cytochrome Oxidase I gene, was analyzed with separate partitions and simultaneously, under equal and implied weights, and with different transversion/transitions costs. The ILD test indicates that the incongruence between the molecular and morphological data is not significant. Under equal weights, the molecular data resulted in a single tree and morphology in 34 trees; under implied weights morphology gave a different tree, and under TV:TS ≥ 4:1 molecular and combined analyses resulted in the same optimal tree. According to the latter, Naupactus includes Graphognathus, and is thus paraphyletic and basal regarding remaining genera, Pantomorus is polyphyletic and includes Aramigus and Asynonychus, and Eurymetopus is monophyletic. The species in which apomictic parthenogenesis has been verified (Aramigus tessellatus, Asynonychus cervinus and Graphognathus lecuoloma), belong to different clades of the Pantomorus-Naupactus complex, with basal sexual relatives.

Weevils Injurious for Roots of Citrus in São Paulo State, Brazil / Curculionídeos que Atacam as Raízes dos Citros no Estado de São Paulo

São registradas dez espécies de Entiminae, Naupactini que ocorrem em Citrus no estado de São Paulo, Brasil. A maioria das espécies pertence ao gênero Naupactus Dejean, sendo: N. rivulosus (Olivier), N. tarsalis Boheman, N. curtus Boheman, N. navicularis Boheman, N. versatilis Hustache, N. ambiguus Boheman, e N. cervinus Boheman; uma espécie do gênero Teratopactus, T. nodicollis (Boheman); uma do gênero Parapantomorus, P. fluctuosus (Boheman); e uma de Symmathetes (gênero revalidado), Symmathetes kollari Schoenherr. As larvas vivem no solo alimentando-se das raízes dos citros, causando danos mais importantes que os adultos que consomem as folhas das plantas. O objetivo deste trabalho é fornecer uma chave, com o diagnóstico e fotografias dos adultos, para sua identificação. Também são apresentadas informações sobre a distribuição geográfica das espécies, associação com outras plantas e discutidos aspectos relevantes da sua biologia, com ênfase à oviposição.

Ten species of broad nosed weevils belonging to Entiminae, Naupactini, are recorded as harmful for roots of citrus in São Paulo state, Brazil. Most species belong to Naupactus Dejean, N. rivulosus (Olivier), N. tarsalis Boheman, N. curtus Boheman, N. navicularis Boheman, N. versatilis Hustache, N. ambiguus Boheman, and N. cervinus Boheman; one species was assigned to Teratopactus Heller, T. nodicollis (Boheman); one to Parapantomorus, P. fluctuosus Schoenherr (Boheman) and one to Symmathetes Schoenherr (a genus herein reinstated), S. kollari Schoenherr. Larvae live in soil and bore on roots of the trees, causing more damages than adults, that feed on leaves. The main goal of this paper is to provide a key, diagnosis and habitus photographs of the species, in order to facilitate their identification. We also provide information on their geographic range in Brazil and previous plant associations, and we discuss some relevant biological features, especially those related to oviposition habits.