Immature stages of Palearctic Mecinus species (Coleoptera, Curculionidae, Curculioninae): morphological characters diagnostic at genus and species levels

Abstract

The immature stages of ten Mecinus species are described for the first time and those of two other species are redescribed, adding important chaetotaxy characters that were missing from previous descriptions. These species belong to six of the nine assemblages of Mecinus species previously established according to a phylogenetic analysis. All these groupings are confirmed on the basis of several characters of mature larvae and pupae. Moreover, all the species show several characters that are useful for distinguishing them from each other, including cryptic species that previously had few differential characters. Some characters that may be useful for separating Mecinus from other genera in the tribe are suggested. To confirm the taxonomic identification of some larvae, the mtCOII gene was obtained and compared with sequences from identified adult specimens. The most important characters for separating the immature stages of the genera and species groups in Mecinus are the number of palpomeres of the labial palpi (1 or 2), the number of air tubes of the thoracic and abdominal spiracles (unicameral or bicameral), and the number of epipharyngeal setae. The species studied herein were compared with those known from other genera in the tribe Mecinini. Two keys, one to the described larvae and the other to the pupae, are provided. Detailed biological data, several of which are new, on some species are reported.

On the Affinities and Systematic Position of Lachnaeus Schoenherr and Rhinocyllus Germar in the Tribe Lixini (Coleoptera: Curculionidae: Lixinae) Based on the Morphological Characters of the Immature Stages

“…The complex of these new data have allowed us to support that (1) Lachnaeus and Rhinocyllus are two valid genera that are different from Larinus , (2) Rhinocyllini is not a tribe different from Lixini, and (3) the separation of Rhinocyllus into two subgenera is rational. Therefore, it seems obvious why it will be important to increase the exiguous number of species of this tribe with known immature stages in order to address other unresolved questions, as already shown in other tribes or subfamilies (see Otiorhynchinini [ 43 ], Cionini [ 44 ], Mecinini [ 45 , 46 ], Smicronychini [ 47 ], Tychiini [ 42 ] and Cossoninae [ 48 ]). It is clearly confirmed that a detailed description of immature stages is a very important component for a better understanding of generic taxonomy but also tribal taxonomic and phylogenetic relationships within Lixinae, as well as within other subfamilies (see above).…”

Morphology of immature stages, biology, and systematic position of the Violet seed weevil, Orobitis cyanea (Linnaeus, 1758) (Curculionidae, Conoderinae, Orobitiditae, Orobitidini)

“…The number of larval instars in weevils is correlated primarily with the body size of a species. Thus, small species (head width of the mature larva below ~ 0.65 mm) usually have only three larval instars (Dosdall et al 2007;Gosik et al 2020;Skuhrovec et al 2022), whereas larger species can have up to seven instars (Skuhrovec et al 2022).…”