Rhopalapion

Distinguished from related genera by combination of elongate body, elongate antennal club, and pronounced sexual dimorphism in rostrum length. Formerly assigned species now placed in Pseudaspidapion and Harpapion based on revised taxonomy. Within the genus, R. longirostre and R. celatum separated by geographic distribution and subtle morphological differences; R. celatum occurs in the Turanian Region (Turkey through Central Asia), while R. longirostre has much broader distribution.

Heliophilic and xerothermophilous; occurs in pastures, meadows, roadsides, ruderal communities, and gardens. Recorded at elevations up to 2150 m above sea level in mountain regions. Patchy distribution within residential areas indicates anthropogenic influence on habitat occupancy.

Genus native to central Asia and adjacent regions. R. longirostre: native to central Asia; since 1960s expanded to Middle East, Mediterranean region, across Europe (except Scandinavia) to British Isles; introduced to North America with east-to-west spread. R. celatum: Turkey, Armenia, Azerbaijan, Syria, Iraq, Iran, Uzbekistan, Kyrgyzstan, Kazakhstan; type locality in Fars Province, Iran.

Adults of R. longirostre active March through November, potentially year-round in favorable conditions. Oviposition occurs May through July. Whole developmental period from egg to adult lasts 7–10 weeks, with pupation lasting 2–6 weeks depending on weather. Different generations may coexist during a single season.

Strictly associated with Malvaceae genus Alcea. Larvae consume seeds inside pericarps of Alcea species. Adults feed on host plant tissues.

• Alcea digitata - hostlarval development
• Alcea dissecta - hostlarval development
• Alcea rosea - hostprimary host; larval development in fruits
• Alcea setosa - hostlarval development

Females oviposit in holes bored in flower buds. First instar larva hatches after 3–4 days, migrates to ovary, enters a single pericarp, consumes seed and forms a chamber. Larva bores escape hole sealed with protective secretion. Pupation occurs inside pericarp. Adults overwinter under plant remains close to host plant.

Efficient, active fliers, especially females. Development occurs inside Alcea pericarps with intraspecific competition for single seeds. Sympatric development with caterpillars of Pexicopia malvella (hollyhock seed moth) in hollyhock fruit creates competitive interaction.

Specialized seed predator of Alcea species. Competition with Pexicopia malvella acts as pathogenic factor limiting R. longirostre population numbers. Rapid range expansion serves as documented case study of insect response to climate change.

R. longirostre regarded as pest of ornamental hollyhock plants in some countries. Anthropogenic dispersal facilitated through horticultural trade of host plants.

• Pseudaspidapion leptorostreFormerly assigned to Rhopalapion; distinguished by revised generic placement based on morphological characters
• Harpapion coelestipenneFormerly assigned to Rhopalapion; distinguished by revised generic placement based on morphological characters
• Pexicopia malvellaNot a weevil but hollyhock seed moth; competes for same development niche in Alcea fruits, limiting Rhopalapion numbers

• weevil
• brentid
• Malvaceae
• Alcea
• seed predator
• range expansion
• climate change
• sexual dimorphism
• pest

• BugGuide
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Taxonomic revision of the genus Rhopalapion Schilsky, 1906 (Coleoptera, Apionidae) with description of Rhopalapion celatum n. sp. from the Turanian Region
• Quelques observations sur la biologie de Rhopalapion longirostre (Olivier) (Coleoptera, Curculionidae, Apioninae)
• Immature Stages and Breeding Behaviour of the Hollyhock Weevil–Rhopalapion longirostre (Olivier 1807) (Coleoptera, Brentidae, Apioninae)