Asian Journal of Agriculture and Allied Sciences

Aims: This study aimed to evaluate the functional role of Cosmos (Cosmos caudatus Kunth) refugia in supporting agroecosystem balance through the provision of ecological services, particularly the conservation of natural enemies and the suppression of pest populations in cayenne pepper (Capsicum frutescens L.).

Study Design: The study employed quantitative descriptive analysis, followed by a two-sample t-test assuming unequal variances, to compare diversity, evenness, and dominance indices between the treatments.

Place and Duration of Study: Field activities were conducted in Lolu Village, Sigi Biromaru Subdistrict, Sigi Regency, Central Sulawesi, from October 2024 to March 2025.

Methodology: Two treatments were compared: cayenne pepper plots with Cosmos refugia and plots without refugia (control). Arthropod sampling was performed weekly for 10 weeks (14 to 77 days after planting [DAP]) using yellow traps, pitfall traps, and hand collection. Data analysis focused on functional-role composition. The arthropod diversity index was determined using the Shannon–Wiener formula; the arthropod evenness index was calculated using the Pielou formula and the modified Ludwig and Reynolds formula; and the arthropod dominance index was calculated using the modified Simpson formula.

Results: Refugia plots contained 2,350 individuals from 36 families, whereas control plots contained 1,997 individuals from 26 families. Predators represented 26.9% (631 individuals) of arthropods in refugia plots compared with 3.8% (76 individuals) in plots without refugia. Parasitoid groups (Ichneumonidae, Tachinidae, and Tiphiidae) were detected exclusively in refugia plots. Pollinator abundance increased from 0.5% (10 individuals) to 6.4% (151 individuals) in the presence of refugia, whereas the pest proportion decreased from 93.6% to 60.4%. The mean diversity index was significantly higher in refugia plots (2.525) than in control plots (2.122) (p = 0.009), while the dominance index was significantly lower in refugia plots (0.107) than in control plots (0.148) (p = 0.012). These findings indicate that cosmos refugia support beneficial arthropod populations and the conservation of natural enemies, thereby contributing to agroecosystem balance.

Conclusion: Cayenne pepper plots with Cosmos refugia supported higher proportions of predators (26.9%) and parasitoids (3.9%) than plots without refugia (3.8% predators and 0% parasitoids). Parasitoid groups (Ichneumonidae, Tachinidae, and Tiphiidae) were found exclusively in refugia plots, indicating a role for refugia in providing nectar resources for adult parasitoids. The presence of Cosmos refugia was associated with a lower pest proportion (60.4% versus 93.6% without refugia). Pollinator populations were also higher in refugia plots (6.4% versus 0.5%), particularly among Halictidae, Nymphalidae, and Stratiomyidae. Overall, the observed community composition and ecological indices indicate that Cosmos refugia can support ecosystem services related to biological control, pollination, and nutrient cycling in cayenne pepper cropping systems.