Inferring larval taxonomy and morphology in Maladera species (Coleoptera: Scarabaeidae: Sericini) using DNA taxonomy tools

Based on a comparative molecular study of scarab chafers we matched adult and larval instars to identify and describe unknown larvae of Sericini. Here, we use for the first time a two‐fold DNA taxonomy approach based on: (i) mitochondrial and nuclear DNA markers of a local sample (from Nepal) of adults and larvae, in combination with character and tree‐based species delimitation methods; and (ii) a global search of cytochrome c oxidase subunit I (cox1) sequences with GenBank data. In the latter analysis we used a sequence of a specimen that resulted in the first analysis conspecific with the larvae of Maladera affinis (Blanchard) as the query sequence in GenBank, and checked in a minimum evolution tree whether larva–adult matches from the local approach were altered through interference with other taxa of the worldwide database. Both approaches unambiguously identified the unknown larvae as belonging to M. affinis and Maladera cardoni (Brenske). Based on this robust framework of taxonomic identification we could associate names to the larval morphology of the third larval instar of these two Nepalese Maladera species, which are both known for their economical importance in agriculture. They are described here in detail and are compared with known related taxa, especially with Maladera castanea (Arrow).     

Speciation in sexually deceptive orchids: pollinator-driven selection maintains discrete odour phenotypes in hybridizing species

Ophrys orchids mimic the female sex pheromones of their pollinator species to attract males for pollination. Reproductive isolation in Ophrys is based on the selective attraction of only a single pollinator species. A change of floral odour can result in the attraction of a new pollinator species that acts as an isolation barrier towards other sympatrically occurring Ophrys species. Ophrys lupercalis, Ophrys bilunulata, and Ophrys fabrella grow sympatrically and bloom consecutively on Majorca and are pollinated by three species of Andrena. We investigated variation of phenotypic and genotypic flower traits, aiming to study the role of the floral odour for reproductive isolation and speciation. Using chemical and electrophysiology (gas chromatography coupled with an electroantennographic detector) methods, we show that the three Ophrys species use the same odour compounds for pollinator attraction, but in different proportions. A comparison of the floral odour bouquets in a multivariate analysis revealed a clear grouping of plants from the same species, although with an overlap between species. A comparison of the same plants using molecular markers gave a contrasting result. Although O. lupercalis and O. fabrella were genetically well separated, plants of O. bilunulata did not form a distinct group but were similar to either O. lupercalis or O. fabrella. Our data indicate gene flow and hybridization to occur between O. bilunulata and O. lupercalis as well as between O. bilunulata and O. fabrella. All plants of O. bilunulata, despite having different genotypes, showed a very similar floral odour. This reflects a strong selective pressure by the pollinating males. The overlap of genotypes of O. bilunulata and O. fabrella supports our hypothesis that O. fabrella diverged from O. bilunulata by scent variation and the attraction of a new pollinator species, Andrena fabrella. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98 , 439–451.     

Molecular phylogeny of Abyssocladia (Cladorhizidae: Poecilosclerida) and Phelloderma (Phellodermidae: Poecilosclerida) suggests a diversification of chelae microscleres in cladorhizid sponges

Vargas, S., Erpenbeck, D., Göcke, C., Hall, K. A., Hooper, J. N. A., Janussen, D. & Wörheide, G. (2012) Molecular phylogeny of Abyssocladia (Cladorhizidae: Poecilosclerida) and Phelloderma (Phellodermidae: Poecilosclerida) suggests a diversification of chelae microscleres in cladorhizid sponges. —Zoologica Scripta, 42, 106–116. The taxonomic placement of Abyssocladia Lévi, 1964 (Poecilosclerida) is controversial, having been assigned at various times to three different families (Mycalidae, Cladorhizidae and Phellodermidae) in two different suborders (Mycalina and Myxillina, respectively), since its inception in 1964. It shares the general body plan with the carnivorous sponge family Cladorhizidae (Mycalina), including the lack of an aquiferous system. Nevertheless, it also has chela spicules apparently identical to those in Phelloderma Ridley & Dendy 1886 (Phellodermidae, Myxillina). The ongoing debate on the position of Abyssocladia ultimately reduces to a discussion on the use of chelae morphology to infer phylogenetic relationships within Poecilosclerida. Here, we infer the phylogenetic relationships of the genera Phelloderma and Abyssocladia using two independent molecular markers (28S rDNA and COI), showing that Abyssocladia is not closely related to Phelloderma and belongs in Cladorhizidae. We suggest that despite their complexity, chelae morphology can evolve independently in different poecilosclerid lineages and as such might be potentially misleading as indicator of the phylogenetic history of the group. We also provide the first phylogenetic analysis of the carnivorous sponge family Cladorhizidae and give first insights into the evolution of this feeding mode in Poecilosclerida and, more generally, in Porifera.