Sebastiano Barbagallo

Molecular phylogeny and systematic in the genus Brachycaudus (Homoptera: Aphididae): insights from a combined analysis of nuclear and mitochondrial genes

Phylogenetic relationships among members of the Aphid genus Brachycaudus (Homoptera: Aphididae) were inferred from partial sequences of mitochondrial cytochrome B oxidase (CytB), two partial fragments of mitochondrial cytochrome C oxidase subunit I (COI) and the internal transcribed spacer II (ITS2) of ribosomal DNA. Twenty‐nine species, with several specimens per species, were included, representing all the historically recognized species‐groups and subgenera used in the genus except the monospecific subgenus Mordvilkomemor. Results indicate that the genus Brachycaudus is a well‐supported monophyletic group. While our results validate the monophyly of subgenera Thuleaphis, Appelia and Brachycaudus s. str., they reveal two discrepancies in the classical taxonomy. First, the monotypic subgenus Nevskyaphis does not appear valid. Second, the traditionally defined Acaudus subgenus is not monophyletic. On the other hand, our phylogenetic trees corroborate Andreevs recent definition of Acaudus and Brachycaudina. However, they clearly show that the subgenera Prunaphis, Nevskyaphis and Scrophulaphis as defined by this author do not form monophyletic groups. Our results also highlight a highly supported clade that has not been discussed by previous authors; this clade could form a new subgenus, the subgenus Nevskyaphis. Finally, our study shows that molecular data and morphology meet the same limits in delimiting species groups and species themselves. Species groups in which taxonomic treatment is difficult are polytomous. Furthermore, except for one node clustering Brachycaudus s. str. and Appelia, intersubgeneric relationships remain poorly resolved even when several genes are added to the phylogenetic analysis. These results, together with previous studies in other aphid groups suggest that diversification might have been a rapid process in aphids.

Semipersistent transmission of viruses by vectors with special emphasis on citrus tristeza virus.

Semipersistent viruses (SPV) have received less attention than either nonpersistent (NPV) (94, 95) or persistent viruses (PV) (129). The group of SPV includes some of the most economically important diseases in cultivated crops: viz., citrus tristeza virus (CTV) in citrus fruits, beet yellows virus (BYV) in beets, maize chlorotic dwarf virus (MCDV) in maize and rice tungro virus (RTV) in rice.

ADDITIONS TO THE KNOWLEDGE OF THE APHID FAUNA IN THE VENETO REGION NORTH EASTERN ITALY (HEMIPTERA APHIDOIDEA)

An updated checklist of aphids detected in Veneto region (NE Italian peninsula) is reported. This list follows a previous one published in 1994, where 130 aphid species were checked for the same regional area. At present, our available data refer, as a whole, to the presence of 332 species, distributed into 106 genera. Six of the species reported are new records for the Italian aphid fauna. For each of the listed taxa short informative notes are given on their previous records (if any) in current literature and/or their collecting data (i.e. host plant species, localities and dates for each of the available samples). In addition, and whenever useful, more extensive faunistic information is given on a few of the most relevant species listed. Short accounts are added, at the end, on the regional biogeographical pattern of the listed aphid species as a whole.

Macrosiphoniella remaudierei, a new species of aphid on Helichrysum in Iran (Hemiptera, Aphididae)

Abstract A new species of aphid, belonging to the genus Macrosiphoniella Del Guercio, 1911, is described using three samples collected in Iran on Helichrysum armenium (Asteraceae, Inuleae) by the late Prof. G. Remaudière. Both apterous and alate viviparous females of the new taxon, Macrosiphoniella remaudierei sp. n., are described and compared to corresponding morphs of the closely allied Macrosiphoniella aetnensis and to other congeneric aphid species on Helichrysum in the Palaearctic region. Type specimens are now stored in the Muséum national d’Histoire naturelle in Paris.