Vidak Lakušić

This study examined the impact of environmental variables on distributional patterns of 12 riffle beetle species (Coleoptera: Elmidae) in the Serbian streams and rivers. During six-year period (2019-2024), a total of 68 waterbodies of the Serbian streams and rivers from that riffle beetles were included (of total 226 running waterbodies covered by water status monitoring). During Regular National Annual Water Monitoring Programmes of the SEPA (Serbian Environmental Protection Agency), riffle beetle sampling was carried out simultaneously with aquatic macroinvertebrate samples in line with the AQEM protocol (multi-habitat sampling). Among all environmental variables analyzed, a total of 16 variables most important for aquatic macroinvertebrate community in general, and species' stream/river longitudinal distribution, were selected. Canonical Correspondence Analysis (CCA) revealed that the most significant parameters for each riffle beetle species depending on the species-specific ecological preference, and on the other hand, with regard to aquatic beetle species longitudinal distribution, the species' distributional patterns only corresponded with the RCC (River Continuum Concept) principle in larger Serbian rivers. It is concluded that limited riffle beetle species distribution in small and medium submountain and mountain streams/rivers is primarily affected by local water quality conditions and species-specific microhabitat preference rather the principle proposed by the RCC.

The study present data on morphological plasticity of the riffle beetle species, Elmis maugetii (Coleoptera: Elmidae) in the Balkan Peninsula. In general, morphological plasticity of the riffle beetles explains that identification of imagoes is difficult due to many species expressed high morphological variability influenced by environmental conditions. For the purposes of this study, riffle beetle samples were sampled in 2014-2017 period from four Balkans' countries: Serbia, Bosnia and Herzegovina, North Macedonia and Greece. Species morphological variability are related to body shape, pronotum structure, abdomen length/width and size, and it can vary considerably among beetle populations. Determining morphological plasticity, shaped by genetically-based species characters as well as ability of organism to alter its physical structure in response to environmental conditions, is inherently complex. Such complexity stems from distinguishing species' ecological responses from genetic variation in the light of spatio-temporal and environmental context. The present study specifically discussed ecophenotypic and morphometric plasticity of Elmis maugetii among investigated localities (different population ecophenotypes) assumpting that water discharge, water temperature, dissolved oxygen concentration in water, HYMO (hydromorphological) characteristics, are strongly associated with the riffle beetle species morphological plasticity.

This study presents the first faunistic records of blister beetles (Coleoptera, Meloidae) from north-western Saudi Arabia, specifically Hejaz mountains and north Tihama, expanding the known distribution range of the species within the country. Field surveys were conducted between 2022 and 2024, aiming to cover different seasons. These observations contribute to the knowledge of the diversity of meloid fauna of the country and underscoring the importance of continued faunistic exploration in north-western Saudi Arabia, a region that remains relatively under-surveyed in terms of meloid diversity. Three species ( Hycleus borchmannianus , Hycleus trizonatus , Mylabris filicornis ) and one genus ( Sitaris ) are recorded for the first time in Saudi Arabia. Besides that, this work also provides the first description of the male morphology and genitalia of Mylabris desertica Bologna, 2007.