Eduard Petitpierre

Cytogenetics, cytotaxonomy and chromosomal evolution of Chrysomelinae revisited (Coleoptera, Chrysomelidae)

Abstract Nearly 260 taxa and chromosomal races of subfamily Chrysomelinae have been chromosomally analyzed showing a wide range of diploid numbers from 2n = 12 to 2n = 50, and four types of male sex-chromosome systems. with the parachute-like ones Xyp and XYp clearly prevailing (79.0%), but with the XO well represented too (19.75%). The modal haploid number for chrysomelines is n = 12 (34.2%) although it is not probably the presumed most plesiomorph for the whole subfamily, because in tribe Timarchini the modal number is n = 10 (53.6%) and in subtribe Chrysomelina n = 17 (65.7%). Some well sampled genera, such as Timarcha, Chrysolina and Cyrtonus, are variable in diploid numbers, whereas others, like Chrysomela, Paropsisterna, Oreina and Leptinotarsa, are conservative and these differences are discussed. The main shifts in the chromosomal evolution of Chrysomelinae seems to be centric fissions and pericentric inversions but other changes as centric fusions are also clearly demonstrated. The biarmed chromosome shape is the prevalent condition, as found in most Coleoptera, although a fair number of species hold a few uniarmed chromosomes at least. A significant negative correlation between the haploid numbers and the asymmetry in size of karyotypes (r = -0.74) has been found from a large sample of 63 checked species of ten different genera. Therefore, the increases in haploid number are generally associated with a higher karyotype symmetry.

Updated checklist of Balearic leaf beetles (Coleoptera: Chrysomelidae)

The first updated checklist of Balearic leaf beetles (Chrysomelidae) since 1960 is presented here, evincing the presence of 118 species. This estimation is clearly lower than the 141 species reported in the only list available to date (Jolivet, 1953), and the dissimilarity is even more pronounced if we take into account that 22 new species have been added during this period. The possible explanations for these differences are discussed. The main island in the archipelago holds most of the species (Mallorca, 113 spp.), followed by Menorca (71 spp.), Eivissa (39 spp.) and Formentera (19 spp.). Thus, the Gymnesian islands (Mallorca and Menorca) are more species-rich than the Pityusic ones (Eivissa and Formentera). The number of species per island is significantly correlated with their respective areas not only for the Balearic but also for the much larger western Mediterranean islands of Corsica and Sardinia, and these abundances are not related with their nearness to the closest mainland. Among the different subfamilies and tribes, the Balearic flea-beetles (Alticinae) are clearly more prevalent whereas on the contrary, the Clytrini are less represented in comparison with the nearest mainland (Iberian Peninsula). The presented checklist includes four endemic species, Cryptocephalus majoricensis (Mallorca, Menorca and Formentera), C. tramuntanae (Mallorca), Cyrtonus majoricensis (Mallorca) and Timarcha balearica (Mallorca and Menorca). Furthermore, two adventitious species, Monoxia obesula and Epitrix hirtipennis of North American origin, have been reported for the first time in the Balearic Islands, in agreement with previous findings in other Mediterranean countries.

A chromosomal analysis of four species of Chilean Chrysomelinae (Coleoptera, Chrysomelidae).

Abstract Four species of Chilean leaf beetles in the subfamily Chrysomelinae have been cytogenetically analyzed, Blaptea elguetai Petitpierre, 2011, Henicotherus porteri Bréthes, 1929 and Jolivetia obscura (Philippi, 1864) show 2n = 28 chromosomes and a 13 + Xyp male meioformula, and Pataya nitida (Philippi, 1864) has the highest number of 2n = 38 chromosomes. The karyotype of Henicotherus porteri is made of mostly small meta/submetacentric chromosomes, and that of Jolivetia obscura displays striking procentric blocks of heterochromatin at pachytene autosomic bivalents using conventional staining. These findings are discussed in relation to previous cytogenetic data and current taxonomy of the subfamily.

Endophallus structure: a promising tool for cryptic species identification in Timarcha Samouelle, 1819 (Coleoptera: Chrysomelidae: Chrysomelinae)

Contrary to the subtle differences of habitus found between many species of Timarcha their internal sacs of male genitalia have shown a remarkable variation. Thirty-two Palaearctic taxa, mostly from the Iberian Peninsula, have been analyzed for this trait, which can be used for species diagnosis and also for establishing species groups of close relatedness in agreement mainly with genetic analyses. According with this trait, new synonymies and taxonomical changes are proposed: T. intermedia carmelenae Petitpierre, 2013 stat. nov., T. intermedia kiesenwetteri Kraatz, 1879 stat. nov., T. intermedia lugens Rosenhauer, 1856 stat. nov.; T. sinuatocollis monserratensis Bechyné, 1962 comb. nov.; T. piochardi Fairmaire, 1874 stat. nov.; T. tortosensis Bechyné, 1948 stat. nov.; T. perezii Fairmaire, 1884 syn. nov. and T. asturiensis Kraatz, 1879 syn. nov. = T. geniculata Germar, 1824. Furthermore, the endophalli of T. hummeli, T. carmelenae, T. kiesenwetteri, T. lugens, T. tenebricosa, T. parvicollis, T. insparsa, T. marginicollis, T. balearica, T. strangulata spp., T. calceata, T. scabripennis, T. espanoli, T. monticola, T. cyanescens, T. interstitialis, T. aurichalcea, T. oblongula, T. hispanica and T. granadensis are illustrated. One new species, T. aitanae sp. nov. is described.

A chromosomal analysis of three species of Timarcha (Coleoptera, Chrysomelidae, Chrysomelinae)

Abstract The karyotypes of three species of Timarcha Latreille, 1829 have been analysed. Timarcha (Metallotimarcha) metallica (Laicharting, 1781), has 18 + Xyp male meioformula and 2n = 38 chromosomes, similar to those found in the two species of subgenus Americanotimarcha Jolivet, 1948, in agreement with morphological and molecular phylogenetic grounds. Timarcha (Timarcha) carmelenae Petitpierre, 2013 displays 9 + Xyp and 2n = 20 chromosomes as in morphologically related Andalusian species, whereas Timarcha (Timarcha) parvicollis ssp. seidlitzi Kraatz, 1879 shows 11 + Xyp and 2n = 24 chromosomes, clearly differing from the previous species. These results are discussed in order to get an insight into the main trends of the chromosomal evolution in Timarcha.

New contributions to the molecular systematics and the evolution of host-plant associations in the genus Chrysolina (Coleoptera, Chrysomelidae, Chrysomelinae)

Abstract The taxonomic circumscription of the large and diverse leaf beetle genus Chrysolina Motschulsky is not clear, and its discrimination from the closely related genus Oreina Chevrolat has classically been controversial. In addition, the subgeneric arrangement of the species is unstable, and proposals segregating Chrysolina species into new genera have been recently suggested. In this context, the availability of a phylogenetic framework would provide the basis for a stable taxonomic system, but the existing phylogenies are based on few taxa and have low resolution. In the present study we perform a phylogenetic analysis based on mitochondrial (cox1 and rrnL) and nuclear (H3) DNA sequences from a sample of fifty-two Chrysolina species representing almost half of the subgeneric diversity of the group (thirty out of sixty-five subgenera) and most of the morphological, ecological and karyological variation in the genus. In addition, five Oreina species from two subgenera have also been analysed. The resulting phylogeny is used to evaluate some of the most relevant taxonomic hypotheses for Chrysolina, and also to reconstruct its ancestral host plant associations in a Bayesian framework. Our findings support the paraphyly of Chrysolina as currently defined due to the inclusion of Oreina, the monophyly of the Chrysolina (plus Oreina) species including the divergent Chrysolina (Polysticta) vigintimaculata (Clark, 1864), and enable inferences of deep-level evolutionary relationships among the studied subgenera. The plant family Lamiaceae is inferred as the ancestral host of the study group, whose evolution is characterized by continuous host-shifting among pre-existing host plant families. Some Chrysolina clades include mixtures of species with different levels of diet breadth, indicating that niche width has varied through time.