Description of the immature stages of Larinus vulpes and notes on its biology (Coleoptera, Curculionidae, Lixinae)

Abstract

Mature larva and pupa of Larinus vulpes (Olivier, 1807) (Curculionidae: Lixinae: Lixini) are morphologically described for the first time and compared with known larvae and pupae of other Larinus species. Very high counts of larval body setae (pronotum with more than 25 setae and postdorsum on meso- and metathorax and also on abdominal segments I–VII with more than 12 setae) are characteristic features of the nominotypical subgenus Larinus. The biology of the species was studied in Ukraine. Echinops ruthenicus and E. sphaerocephalus were identified as host plants of both larvae and adults of this weevil based on the present research in Ukraine, which shows probably oligophagous. Overwintering beetles emerged at the end of May or earlier, then feeding and mating on the host plants. The highest level of adult activity was observed at the end of June. Larvae were endophagous within the flower heads. In July and August, the larvae pupated within inflorescences in a pupation cell. Adults exited the cells at the end of August and did not hibernate on the host plants. Sometimes, larvae and imagines of a new generation were found outside the flower heads in chambers constructed on the stems.

Cleonis pigra (Scopoli, 1763) (Coleoptera: Curculionidae: Lixinae): Morphological Re-Description of the Immature Stages, Keys, Tribal Comparisons and Biology

“…The mature larvae of the subfamily Lixinae were characterized by three diagnostic features [44]: the increased number of pds (1) on the meso- and metathorax and (2) abdominal segments I–VII, and (3) the increased number of setae on the epipharyngeal lining ( als ); i.e., more than the most frequent number of setae in weevils (for details, see [11]). These differential features of mature larvae were confirmed in all known descriptions from the tribe Cleonini [9,10,11,27,43], and all known species from the Lixini tribe fit this diagnosis (genus Larinus [45,46,47,48]; Lixus species [27,45,49,50,51,52,53,54,55]; and Rhinocyllus conicus [37]).…”

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

“…X reduced to four anal lobes of unequal size, dorsal one by far the largest, ventral one very small". These different traits of mature larvae of Lixini have been confirmed in several descriptions concerning the genus Larinus [3,22,[32][33][34][35][36][37][38] and the genus Lixus [20,21,24,31,33,34,[39][40][41] but there were also more exceptions [21,22] than those presented in Gosik and Wanat [31]. All Larinus species differ from Lixus species, mainly by their (1) U-shaped premental sclerite (vs. Lixus species with a trident-shaped premental sclerite), (2) abdominal segments I-VII with three folds (vs. four folds), and (3) pupae with distinct urogomphi (vs. indistinct).…”

“…All Larinus species differ from Lixus species, mainly by their (1) U-shaped premental sclerite (vs. Lixus species with a trident-shaped premental sclerite), (2) abdominal segments I–VII with three folds (vs. four folds), and (3) pupae with distinct urogomphi (vs. indistinct). However, an exception is represented by most species of the nominotypic subgenus of the genus Larinus , whose chaetotaxy on the body is markedly different [ 22 ]. Skuhrovec et al [ 22 ] also identified the morphological features of larvae and pupae, which significantly distinguish the subgenus Larinus from the other subgenera, Phyllonomeus Gistel, 1856 and Larinomesius .…”

“…However, an exception is represented by most species of the nominotypic subgenus of the genus Larinus , whose chaetotaxy on the body is markedly different [ 22 ]. Skuhrovec et al [ 22 ] also identified the morphological features of larvae and pupae, which significantly distinguish the subgenus Larinus from the other subgenera, Phyllonomeus Gistel, 1856 and Larinomesius .…”

“…It is well known that the study of the morphology of the immature stages can be of much help in the generic taxonomic relationships within weevil subfamilies and tribes; this seems true also for Lixinae, as recent descriptions of several species of the main genera Lixus and Larinus have shown [ 20 , 21 , 22 ].…”