Adult Postabdomen, Immature Stages and Biology of Euryommatus mariae Roger, 1856 (Coleoptera: Curculionidae: Conoderinae), a Legendary Weevil in Europe

SIMPLE SUMMARY: Euryommatus mariae is a legendary weevil species in Europe, first described in the 19th century and not collected through the 20th century. Though rediscovered in the 21st century at few localities in Poland, Austria, and Germany, it remains one of the rarest of European weevils, and its biology is unknown. We present the first descriptions of the larva and pupa of E. mariae, and confirm its saproxylic lifestyle. The differences and similarities between immatures of E. mariae and the genera Coryssomerus, Cylindrocopturus and Eulechriopus are discussed, and a list of larval characters common to all Conoderitae is given. The characters of adult postabdomen are described and illustrated for the first time for diagnostic purposes. Our study confirmed the unusual structure of the male endophallus, equipped with an extremely long ejaculatory duct enclosed in a peculiar fibrous conduit, not seen in other weevils. We hypothesize that the extraordinarily long and spiral spermathecal duct is the female’s evolutionary response to the male’s extremely long intromittent organ. ABSTRACT: The larva and pupa of the saproxylic Euryommatus mariae Roger, 1857, the weevil species extremely rare in Europe, are described from Poland. It was reared from galleries in dead branches of a fallen spruce Picea abies. The larval morphology is compared with available larval descriptions of other genera of the supertribe Conoderitae, namely, the Palaearctic Coryssomerus, and the Nearctic Cylindrocopturus and Eulechriopus. The specific characters of the male and female postabdomen are described and illustrated, expressing the peculiar structure of endophallus and spermathecal duct, not seen in any other weevil species. A hypothesis regarding the mechanics of mating in this species is proposed. Euryommatus mariae is recorded for the first time to occur in China.