Life Span Changes of Coffee White Stem Borers, Xylotrechus quadripes (Coleoptera: Cerambycidae) in Response to Directed Homosexual and Heterosexual Interactions
Prashant Mangalgikar *
Department of Agricultural Entomology, University of Agricultural Sciences, Bengaluru, 560065, India and Department of Agricultural Entomology, College of Horticulture, Bidar, University of Horticultural Sciences, Bagalakote, 585403, India.
Karumuru Raja Madhura Bhanu
Bio-Control Research Laboratories, A Division of Pest Control (India) Pvt. Ltd., Bengaluru, 561203, India and UPL Pvt. Ltd., Mumbai, India.
Vasuki Belavadi
Department of Agricultural Entomology, University of Agricultural Sciences, Bengaluru, 560065, India.
Shashank Pathour
Department of Agricultural Entomology, University of Agricultural Sciences, Bengaluru, 560065, India. and Indian Agricultural Research Institute, Delhi, 577117, India.
Chandrashekharaiah Muniyappa
Department of Agricultural Entomology, University of Agricultural Sciences, Bengaluru, 560065, India and Basic Tasar Silkworm Seed Organization - Central Silk Board, Bilaspur, 495112, India.
Byrappa Ammagarahalli
Department of Crop and Forest Sciences, University of Lleida, Av. Alcalde Rovira Roure 191, 25198 Lleida, Spain and Gaiagen Technologies Pvt. Ltd., Formerly Pest Control (India) Pvt. Ltd., Bengaluru, 562163, India.
*Author to whom correspondence should be addressed.
Abstract
Our study on coffee white stem borers, Xylotrechus quadripes investigated the influence of different sex-based clustering factors on beetle survivorship and life spans. Our experiments involved various groups, including individually isolated virgin males, individually isolated virgin females, groups of only males, groups of only females, and mixed-sex groups. First, survivorship reached 100% within the initial 15 days for all groups except for isolated virgin males. In contrast, the survivorship rates of both groups involving only virgin females and only virgin males ranged from 80% to 90% compared to the maximum survival duration. Notably, in scenarios with males in groups or mixed-gender groups, survival dropped to zero percent after 45 days. Our study also highlighted the comparable costs incurred by males engaging in both homosexual and heterosexual interactions. Males interacting with females and other males exhibited similar survival curves, displaying shorter median life spans compared to isolated virgin males, suggesting that both courting and mounting behaviors, regardless of the recipient's sex, might affect the life span of males. Furthermore, our research revealed that female-female interactions, while less costly than male-male interactions, still reduced survival periods in only the female group. These findings highlight the cost possibly associated with same-sex interactions and shed light on the dynamics of mating behaviors in this beetle. In conclusion, our findings underscore the significance of studying behavioral and life history traits in different environmental contexts. Social circumstances and ecological factors significantly influence sexual differences in lifespan and highlight the complexity of the interplay between reproductive strategies and survival rates in Xylotrechus quadripes.
Keywords: Coffee white stem borer, survival, coffee, behaviour