Seasonal dynamics of Elaeidobius Kamerunicus in allopatric populations: comparative analysis from indigenous mainland and introduced oil palm ecosystems in Uganda’s lake Victoria islands

Abstract

Oil palm (Elaeis guineensis L.), native to Africa but widely cultivated in Southeast Asia, isincreasingly grown in Uganda, and pollination efficiency is critical for fruit set and oilyield. The study assessed the population and sexual diversity of the primary pollinator,Elaeidobius kamerunicus FAUST, in introduced hybrid plantations in Kalangala andnatural stands in Bundibugyo. Pollinator weevils were sampled across both wet anddry seasons in 2022 and 2023, and data were analyzed using ANOVA and correlationtests in Minitab 17. Results revealed significant variation between sites, with higherpopulations in Kalangala (7,503 ± 8.682) compared to Bundibugyo (5,164 ± 5.829).Furthermore, females (6,636 ± 4.646) outnumbered males (6,032 ± 5.028), with a slightlyhigher concentration of females in the middle section of male inflorescences. Seasonaldifferences were evident, as the wet season supported slightly higher weevil popula-tions relative to the dry season. Correlation analysis indicated a weak negative relation-ship between weevil abundance and weather variables, suggesting that coolerconditions suppress population growth. Overall, Uganda provides favorable conditionsfor pollinator weevil multiplication, particularly under moist climatic regimes, whileextensive cold conditions limit population expansion. These findings highlight theimportance of pollinator dynamics in sustaining oil palm productivity in diverse agro-ecological regions.