Sequence comparisons of the internal transcribed spacer region of ribosomal genes support close relationships between parasitic ants and their respective host species (Hymenoptera: Formicidae)

Abstract

SummaryA fragment of the internal transcribed spacer (ITS-l) adjacent to the 5.8S rRNA gene of 20 myrmicine ant species was sequenced. Sequence comparisons were carried out between 11 species of the tribe Leptothoracini, five species of the tribe Tetramoriini, three species of the tribe Solenopsidini and one species of the tribe Myrmicini. Additionally, the formicine ant Camponotus ligniperda (tribe Camponotini) was analyzed as an outgroup species. Among all investigated species, the fragment had a variable length of =230-380 bp with only a few conserved sequence elements. The sequences of this fragment were perfectly identical within four palearctic populations of Leptothorax acervorum indicating that intraspecifie variation is rather low. Within the species of Tetramoriini (including Anergates atratulus) 94 A. atratulus has as yet been uncertain, however, sequence comparison of the ITS-1 fragment leads to the conclusion that A. atratulus rather belongs to the tribe Tetramoriini than to the Solenopsidini.

Phylogenetic relationships among social parasites and their hosts in the ant tribe Tetramoriini (Hymenoptera: Formicidae)

“…Evolutionary rates of the enzyme loci appear very high compared to their Tetramorium hosts. This is particularly surprising in light of the low di vergence of ITS-1 sequences in this group (Baur et al, 1996). A number of studies have shown that rates of mo lecular evolution vary considerably among hosts and parasites belonging to different taxonomic groups (e.g.…”

“…6). First, two shared-derived base substitutions in the ITS-1 and 5.8S rRNA sequences have been reported by Baur et al (1996). Secondly, both Anergates and Teleutomyrmex have developed a very similar form of workerless parasit ism including manifold adaptations, such as physogastry, reduced mouthparts and specialized males (Kutter, 1969;Bolton, 1976).…”

“…Recently, some progress has been made toward under standing the evolutionary history of the Tetramoriini (Sanetra et al, 1994;Baur et al, 1996), but a thorough phylogenetic analysis has not been presented so far. A se vere problem in the use of the genera Tetramorium and Strongylognaihus for phylogenetic studies is the lack of comprehensive taxonomical revisions.…”

“…Ward, 1989;Bourke & Franks, 1991). Since the enormous spread of molecular methods, a number of studies have further revealed that social parasites often fall into monophyletic groups which are closely attached to their host species' groups (Choud hary et al, 1994;Baur et al, 1995Baur et al, , 1996Pedersen, 1996;Lowe & Crozier, 1997). Thus, the application of Emery's rule in the strict sense, that is each parasite is the sister species of its respective host, appears confined to a num ber of inquilines scattered through various groups of ants (Holldobler & Wilson, 1990;Buschinger, 1990).…”

Cloning and sequencing of wsp encoding gene fragments reveals a diversity of co-infecting Wolbachia strains in Acromyrmex leafcutter ants

“…For example, it could explain how the social parasite A. insinuator could have evolved from its host, A. echinatior (Bekkevold and Boomsma, 2000;Schultz et al, 1998) by sympatric speciation. The close phylogenetic affiliation of ant social parasites and their hosts (Schultz et al, 1998) is known as ÔEmeryÕs ruleÕ (Baur et al, 1995(Baur et al, , 1996Buschinger, 1986) and while sympatric speciation is often invoked to explain this pattern (Baur et al, 1995(Baur et al, , 1996Buschinger, 1986), it hard to see how it could arise in the absence of a clear mechanism. Incompatibility between multiple Wolbachia types within a population could provide such a mechanism (Hurst and Schilthuizen, 1998;Stouthamer et al, 1999;Werren, 1998).…”