The morphology of the immature stages of Metadonus vuillefroyanus (Capiomont, 1868) (Coleoptera, Curculionidae, Hyperini) and notes on its biology

Abstract

Last instar larva and pupa of Metadonus vuillefroyanus (Capiomont, 1868) (Curculionidae: Hyperini) are described and compared with known larvae of the other 43 hyperine taxa. The thorn-like setae located on distinct black protuberances on the larval body are characteristic features of the genus Metadonus and the subgenus Eririnomorphus of the genus Hypera. The biological singularity of this species was studied and described. The variable colouration of larvae has been confirmed in association with the variability of the host plant’s colouration at the studied localities. This species’ reported inability to spin cocoons has been disproven. A different type of cocoon with two layers, where the inner layer consists of proteins from Malpighian tubules while the outer layer contains soil particles, is described. This type of cocoon is unique compared with those known from other hyperines, which usually pupate on or above the ground and do not use substrate particles in building their cocoons.

Velcro-Like System Used to Fix a Protective Faecal Shield on Weevil Larvae

“…The ectophagous and ectophytic larvae are found in only a few groups, primarily most members of the subfamily Cyclominae [ 32 , 41 – 43 ] and the unclassified tribes Bagoini, Gonipterini and Hyperini [ 32 , 41 , 43 , 44 ]. These insects have all evolved strategies of physical or chemical defence against predators and parasitoids [ 45 – 48 ]. In Central Europe, in which this new defensive strategy in weevils was observed, ectophagous larvae, feeding on leaves or flowers, are currently found only in the following tribes: Bagoini, Cionini, Hyperini, Phytobiini and rarely Ceutorhynchini [ 32 , 36 , 49 ].…”

Revision of the genus Limobius, with the description of a new species (Coleoptera, Curculionidae, Hyperini)

“…Their only unique feature appears to be the specific meshed cocoon spun by the larvae from strands of protein secreted by the Malpighian tubules (Scherf 1964; Kenchington 1983), and ectophagous larvae (Oberprieler et al 2014a; Skuhrovec and Bogusch 2016). Petri (1901) was the last to define this group using ten morphological characters.…”

“…Hyperini currently comprises approximately 44 genera and 500 described species (Oberprieler et al 2014a). Skuhrovec (unpublished data, see Skuhrovec and Bogusch 2016) recently divided this tribe into three “operating” groups with different distributions: (1) the Palaearctic region (Hyperina) – the majority of the species (ca. 370) occur in the Palaearctic region, with far fewer species in the Nearctic (ca.…”

“…Skuhrovec (2005a, 2005b, 2006a, 2006b, 2007) and Skuhrovec and Bogusch (2016) studied the larvae of Donus Jekel, 1865, Hypera Germar, 1817 and Metadonus Capiomont, 1868, clarified (2008) the complex nomenclature of the large and important genera Brachypera Capiomont, 1868, Donus and Hypera , and revised (2012) the genus Metadonus . Alonso-Zarazaga and Lyal (2002) transferred the monobasic genus Herpes Bedel, 1874, previously classified in Brachycerinae or Rhythirrinini but in Thecesternini by Alonso-Zarazaga and Lyal (1999), to Hyperini.…”

“…Hence, Skuhrovec (2013a) and Oberprieler et al (2014a) did not accept these taxonomic changes. A detailed comparative study of all hyperine is necessary in context of taxa representing all genera / subgenera and also species groups because most characters of adults and also of immature stages are based only on the relatively well-studied genera (Oberprieler et al 2014a; Skuhrovec and Bogusch 2016). …”