Does cross-mating affect behavioral asymmetries and mating success of khapra beetle (Trogoderma granarium) strains?

Herein, sexual interactions and left-right asymmetries in brain and behavior (lateralization) of Czech and Turkish strains of Trogoderma granarium Everts (Coleoptera: Dermestidae) were investigated, assessing courtship and mating dynamics within each strain and in all possible cross mating combinations. Trogoderma granarium species identity was confirmed by DNA sequencing, using three mitochondrial DNA genes, Cytochrome Oxidase I (COI), large subunit ribosomal RNA (16S), and Cytochrome b (CYTb). The selected genetic markers were also used to examine any intraspecific variations between the two strains analyzed. The aligned COI and 16S DNA sequences obtained revealed several polymor- phisms, when both inter-and intra-strains analyzed. In behavioral experiments, more males of the Czech strain performed left-biased approaches (53%) than right-biased approaches (42%), with 20% of left-biased males and 13% of right-biased males using the right foreleg to explore females, achieving 18% and 10% successful copulations, respectively. Males of the Turkish strain exhibited right-(50%) or left-biased approaches (45%), with 17% of right-biased males and 21% of left biased males exploring females with the left foreleg, resulting in 15% and 20% mating success, respectively. During cross mating of strains, all possible combinations exhibited a population-level left-biased approach to the potential mates and a right-biased exploration of females with foreleg, leading to high successful copulations. Significant differences were noted in the duration of copulation of Turkish males interacting with females of the same strain (backside males 122.3 s, left biased males 72.0 s, and right-biased males 68.6 s). Overall, this research firstly sheds light on how cross-mating among strains can affect courtship, mating success and laterality in a key beetle pest