Ulitzka M.R.1*, Evdokarova T.G.2, Burnasheva A.P.2 2026. Morphological reduction and dispersal polymorphism in Baliothrips dispar (Haliday, 1836) (Insecta: Thysanoptera: Thripidae), with a redescription of forma sibirica // Russian Entomol. J. Vol.35. No.3: 343–352 [in English].
1 Thrips-iD, Straßburger Straße 37A, 77652 Offenburg, Germany.
2 Institute for Biological Problems of Cryolithozone SB RAS, Lenin Avenue 41, Yakutsk 677000 Russia.
* Corresponding author
Manfred R. Ulitzka: manfred.ulitzka@thysanoptera.de ORCID: https://orcid.org/0000-0002-2639-4867
Taisia G. Evdokarova: evdokarova@mail.ru
Albina P. Burnasheva: a_burnasheva@mail.ru
doi: 10.15298/rusentj.35.3.07
ABSTRACT. The Holarctic thrips Baliothrips dispar (Haliday, 1836) exhibits considerable intraspecific morphological variability that has not been adequately documented. Females assigned to forma sibirica differ from European populations by a consistent reduction of wings and associated thoracic structures, including the metascutellum and abdominal tergal ctenidia, complicating identification. Material from Yakutia and Magadan reveals intermediate female forms linking this morphotype with typical European populations. In males, geographic variation is expressed in wing morphology, with exclusively micropterous males in the Palaearctic, whereas hemi- and macropterous males are so far known only from the Nearctic. Variation in the sense cone on antennal segment III, including specimens with a reduced mesal tine of a forked cone, suggests a possible morphological transition between forked and simple states. These observations are interpreted within the framework of dispersal polymorphism and indicate a continuum of dispersal strategies across the species’ range, with populations of forma sibirica representing the extreme endpoint of dispersal reduction.
KEY WORDS: wing polymorphism, sense cones, ctenidia, geographic variation.