Henrard, A.,  Van den Neucker, T.,  Smitz, N.,  Deneve, S.,  Soors, J.,  Lock, K.,  Vanderheyden, A. & Jocqué, R. 2026. ‘Hidden travelers: introduced synanthropic arachnids dispersing through European botanical glasshouses’. 14th International Conference on Biological Invasions. Book of abstracts. Brussels.

Conference abstract

Botanical glasshouses provide stable, humid microclimates that facilitate the establishment and persistence of non-native arthropods, acting as nodes in continental dispersal networks linked to plant trade. Among arthropods, arachnids remain underrepresented in invasion biology, despite increasing evidence that synanthropic taxa can establish viable populations and spread between institutions. Here, we document a set of synanthropic arachnid taxa currently spreading among European glasshouse systems, focusing on four lineages representing distinct introduction and taxonomic stages. First, we expand the known distribution of a recently reported introduced species, Stenochrus portoricensis Chamberlin, 1922 (Schizomida: Hubbardiidae), with new records from Meise Botanic Garden (Belgium), indicating continued inter-institutional spread. Second, we document a putative other schizomid species tentatively assigned to the genus Zomus, discovered in the Ghent Botanical Garden (Belgium). Third, we report two undocumented spider species of the Ochyroceratidae family that have also been sighted in the Meise Botanic Garden, putatively from the Theotima and Speocera genera. The three last mentioned could represent rare cases of species being formally described from out of their native range, and whose systematic placements remain under investigation. Sampling combined targeted microhabitat surveys (leaf litter, understory vegetation, artificial substrates) with morphological examination and molecular analyses (using four to six DNA fragments) to assess phylogenetic affinities. These results highlight the role of glasshouse networks as potential reservoirs of cryptic arachnid diversity and as active corridors for biological invasions. Moreover, the detection of possible undescribed taxa highlights the extent to which invasion processes may involve species that remain taxonomically uncharacterized. This underscores the need for integrative taxonomic frameworks combining morphology and molecular data, alongside coordinated monitoring efforts across botanical institutions.