Filling the gaps in ecology of tropical tiger beetles (Coleoptera: Cicindelidae): first quantitative data of sexual dimorphism in semi-arboreal Therates from the Philippine biodiversity hotspot.

Background: Sexual dimorphism, driven by sexual selection, leads to varied morphological distinctions in male and female insects, providing insights into selection pressures across species. However, research on the morphometric variability within specific taxa of tiger beetles (Coleoptera: Cicindelidae), particularly arboreal and semi-arboreal species, remains very limited. Methods: We investigate sexual dimorphism in six semi-arboreal Therates tiger beetle taxa from the Philippines, focusing on morphological traits. We employed morphometric measurements and multivariate analyses to reveal patterns of sexual dimorphism between sexes within the taxa. Results: Our results indicate significant sexual dimorphism in elytra width, with females consistently displaying broader elytra, potentially enhancing fecundity. Notable sexual size dimorphism was observed in Therates fulvipennis bidentatus and T. coracinus coracinus, suggesting heightened sexual selection pressures on male body size. Ecological factors, mating behavior, and female mate choice might contribute to the observed morphological variation. These findings emphasize the need for further studies to comprehend mating dynamics, mate choice, and ecological influences on morphological variations in semi-arboreal and arboreal tiger beetles.

Tiger beetles (Coleoptera, Cicindelidae) of Northern Mindanao region (Philippines): checklist, distributional maps, and habitats.

The knowledge about tiger beetle fauna of the Northern Mindanao region (Philippines) is summarized based on literature data and new records. Thirty species classified in ten genera (Tricondyla, Neocollyris, Protocollyris, Therates, Prothyma, Heptodonta, Thopeutica, Lophyra, Calomera, and Cylindera) were documented from the area (56% of tiger beetle fauna of Mindanao and 21% of Philippine species). Twelve species were noted from Northern Mindanao region for the first time, including five taxa, Neocollyris speciosa, Calomera angulata, Cylindera minuta, Lophyra striolata tenuiscripta, and Thopeutica virginea, not recorded from Mindanao before. Distribution maps for all recorded species and the first photographs of habitats for some species in Mindanao and/or in the Philippines are provided. Eight species (27% of recorded fauna) were noted from riverine habitats while 18 tiger beetles (60%) were typical forest taxa; in the case of four species, their habitats in Northern Mindanao region are not known.