Species richness and survival constraints of predatory ladybird beetles (Coleoptera: Coccinellidae): A review of abiotic and biotic mortality factors

Vallabh Mahadev Shete, Baswaraj Vishwanath Bhede — Thu, 15 Oct 2026 00:00:00 +0000

Objectives: To synthesize evidence on species richness of predatory ladybird beetles and the stage-specific abiotic, biotic and management-related factors that constrain their survival, recruitment and persistence in agroecosystems.

Methods: A critical narrative review was developed from foundational and recent literature on Coccinellidae richness, temperature and moisture effects, prey-dependent performance, cannibalism, intraguild predation, predators, parasitoids, pathogens and pesticide effects. Quantitative claims were retained when attributable to specific studies.

Results: Ladybird richness represents a regional species pool rather than guaranteed biological-control capacity. Temperature, moisture and rainfall can alter development, survival, activity and disease risk. Prey limitation can reduce growth and reproduction and intensify cannibalism and intraguild predation. Parasitoids, pathogens, external predators and pesticide exposure further reduce recruitment. Recent life-table evidence identifies the first larval instar as a major mortality bottleneck in several aphidophagous species.

Conclusions: Realized biological-control function depends on sequential survival from egg to reproductive adult, not on richness alone. Field life tables, multifactor experiments and region-specific demographic studies are needed to quantify interacting mortality processes and improve conservation and deployment of predatory Coccinellidae.

Diversity and seasonal abundance of harmful and beneficial true bugs (Hemiptera: Heteroptera) in Bt cotton

Vallabh Mahadev Shete, Baswaraj Vishwanath Bhede — Thu, 15 Oct 2026 00:00:00 +0000

Objectives: To document the diversity and relative abundance of harmful and beneficial true bugs and characterize their seasonal abundance and relationship with major weather parameters on unsprayed Bt cotton under the agro-climatic conditions of Marathwada, Maharashtra.

Methods: A field investigation was conducted during Kharif 2025-26 at the Experimental Farm, Department of Entomology, College of Agriculture, Vasantrao Naik Marathwada Krishi Vidyapeeth, Parbhani, Maharashtra, in unsprayed Rasi Swift BG-II (RCH-971 BG II) cotton. Diversity and seasonal abundance were assessed in two separate observation plots using five plants in each of four quadrats per plot; diversity was recorded fortnightly and seasonal abundance weekly. Pearson correlation coefficients were calculated between weekly bug abundance and weather parameters.

Results: Ten true-bug taxa belonging to six families were recorded. Of 1,689 individuals, Dysdercus cingulatus was most abundant (38.24%), followed by Oxycarenus hyalinipennis (23.68%); together they constituted 61.92% of the assemblage. Phytophagous taxa accounted for 80.46%, entomophagous taxa for 11.19% and the zoophytophagous Campylomma livida for 8.34%. Hill species richness, Margalef richness, Menhinick richness, Shannon-Wiener diversity, Pielou evenness and Simpson dominance were 10, 1.211, 0.243, 1.761, 0.765 and 0.229, respectively. Dysdercus cingulatus peaked at 13.75 bugs per plant in the 48th standard meteorological week, whereas O. hyalinipennis peaked at 15.75 bugs per plant in the 50th week. Late-season seed bugs showed significant negative associations with several weather variables, while N. viridula, Eocanthecona furcellata and C. livida were positively correlated with maximum temperature.

Conclusions: The true-bug community showed clear crop-stage-dependent succession. Monitoring should be intensified from boll opening onward for D. cingulatus and O. hyalinipennis while conserving beneficial heteropterans present earlier in the crop cycle.

Journal of Applied Entomologist

Species richness and survival constraints of predatory ladybird beetles (Coleoptera: Coccinellidae): A review of abiotic and biotic mortality factors

Diversity and seasonal abundance of harmful and beneficial true bugs (Hemiptera: Heteroptera) in Bt cotton