Phylogeny of Meloini blister beetles (Coleoptera, Meloidae) and patterns of island colonization in the Western Palaearctic

Abstract

Flightless, phoretic insects of the tribe Meloini include several widespread species able to inhabit both mainland and oceanic and continental islands. Relationships between phoretic and non‐phoretic species of Meloini are unclear, precluding broad evolutionary and biogeographic analyses within the group. We provide a robust molecular phylogenetic framework for Meloini, with finer sampling in the Western Palaearctic, by analysing two nuclear (Wg, 18S) and two mtDNA (cox1, 16S) gene fragments of 24 species representing eight subgenera of Meloe and Physomeloe. Our phylogenetic analyses revealed that Meloe, as currently recognized, is paraphyletic. Our phylogenetic hypothesis clarifies several controversial relationships within the group. We provide a new taxonomic framework that better reflects the evolutionary relationships of the group by raising to genus all previously considered subgenera: Afromeloe Schmidt, 1913, Alveomeloe Pripisnova, 1987, Chiromeloe Reitter, 1911, Desertimeloe Kaszab, 1964, Eurymeloe Reitter, 1911, Lampromeloe Reitter, 1911, Lasiomeloe Reitter, 1911, Listromeloe Reitter, 1911, Meloegonius Reitter, 1911, Mesomeloe Reitter, 1911, Meloenellus Reitter, 1911, Micromeloe Reitter, 1911, Taphromeloe Reitter, 1911 and Treiodous Dugès, 1869; while Anchomeloe Iablokoff‐Khnzorian, 1983, is recovered as subgenus of Meloe. In addition, we conducted an extensive intraspecific sampling for four phoretic taxa (Meloe proscarabaeus, Meloe autumnalis, Eurymeloe mediterraneus and Eurymeloe tuccia) and used mtDNA phylogeographic analyses to unveil patterns of overseas dispersal. Our phylogeographic analyses revealed a high level of geographically unstructured haplotype diversity within taxa, suggesting that transmarine dispersal events have occurred multiple times along the evolutionary history of phoretic species of blister beetles. Larval phoresy may explain the existence of idiosyncratic biogeographic and phylogeographic patterns in these flightless organisms.

Multigene phylogeny of blister beetles (Coleoptera, Meloidae) reveals extensive polyphyly of the tribe Lyttini and allows redefining its boundaries

“…The Meloini, as previously defined (Bologna & Pinto, 2001; Sánchez‐Vialas et al, 2021), is supported. Its close relationship to Trichomeloe (lineage III, Figure 3) suggests the reinclusion of the genus in the tribe warrants consideration.…”

Proctodeal extrusion as a defensive behavioral response in blister beetles (Coleoptera: Meloidae)

“…Two independent sets of phylogenetic hypotheses were used to identify the relationships between the studied taxa. A first set, from Bologna et al (2008) and Sánchez-Vialas et al (2021), which included a wide range of genera within the subfamily Meloinae, was used to identify the relationship between Physomeloe and Berberomeloe. A second set, from Sánchez- Vialas et al (2020), which included all species of Berberomeloe, was used to identify the relationship between B. comunero and B. majalis.…”

“…Berberomeloe and Physomeloe are phylogenetically unrelated taxa (Bologna et al 2008;Sánchez-Vialas et al 2021). Given the phylogenetic position of these genera, proctodeal extrusion may represent a homoplastic response elicited only in Physomeloe and Berberomeloe, or alternatively, a generalized trait that has been overlooked in all other genera of the subfamily.…”

Mitogenomics and hidden‐trait models reveal the role of phoresy and host shifts in the diversification of parasitoid blister beetles (Coleoptera: Meloidae)

“…In phoretic species, first instar larvae climb to flowers and latch to a passing bee to reach its nest (Figure 1 ; Hafernik & Saul‐Gershenz, 2000 ); in nonphoretic species, larvae wander along the ground, actively searching for bee nests (Figure 1 ) or grasshoppers’ egg‐pods (Figure 2 ). All Nemognathinae genera are phoretic bee‐parasitoids (with the probable exception of Stenodera ; Bologna et al, 2002 ; Bologna & Di Giulio, 2011 ), whereas some tribes of Meloinae that are bee‐parasitoids (e.g., Meloini) include both phoretic ( Meloe , Lampromeloe , Eurymeloe , etc,) and nonphoretic ( Physomeloe ) genera (Sánchez‐Vialas et al, 2021 ). Bologna and collaborators (Bologna et al, 2008 ; Bologna & Pinto, 2001 ) suggested that phoresy evolved at least two times independently in the bee‐parasitoid Meloinae.…”