Diversity and distribution of crab spiders (Araneae: Thomisidae) at Allahabad University Campus, Prayagraj

Crab spiders (family Thomisidae), particularly the genus Thomisus Walckenaer, 1805, are known for their cryptic coloration and ambush predation strategy, often utilizing flowers as hunting grounds. Despite their global diversity, local populations, like those within the Indian subcontinent are often under-documented. This study was conducted over a two-year period (2023-2025), explored the presence and ecology of Thomisidae on the science campus of the University of Allahabad, Prayagraj. Using direct visual encounter surveys and opportunistic sampling across diverse seasonal flowering plants (Tagetes, Dahlia), a total of 168 specimens were collected and documented. Identification was performed based on morphological characteristics, eye arrangement and standard taxonomic literature. The survey recorded 10 species belonging to 4 genera (Thomisus, Camaricus, Mastira, and Misumena), with Thomisus spectabilis emerging as the most abundant taxon. The diversity indices indicate a healthy and relatively even distribution (Shanon index H’=2.1809; Simpson’s Index 1-D = 0.8861) among the observed species with a strong microhabitat preference for host plants in the Asteraceae family. The findings highlight the importance of managed green spaces in the university campuses, particularly those free from pesticides and rich in floral resources, in supporting the populations of these ecologically significant predators.