INFLUENCE OF DISTURBANCE REGIMES ON FIG-WASP RELATIONSHIPS AND SYCONIAL CHARACTERISTICS OF Ficus tinctoria (MORACEAE) IN SOME SELECTED SITES OF KANDY AND MATALE DISTRICTS

Abstract

The fig–fig wasp interaction is an obligate mutualistic relationship. Ficus tinctoria (Moraceae) is a hemi-epiphytic dioecious fig tree species. The present study investigated the influence of vegetation disturbance regimes on the fig–fig wasp relationship and syconial characteristics of F. tinctoria across two study sites and was conducted from October 2024 to February 2025. Study sites were selected based on the difference of disturbance level in their vegetation after calculating the percentage vegetation cover. The study sites were the less disturbed Nattarampotha area which belongs to the Kandy District (Site 1) and the more disturbed urban core within Matale city (Site 2). Mature syconia were collected, their diameter measured, cut into two halves and reared until the complete wasp emergence. The number of galls and florets per syconia, pollinator fig wasps (PFWs) and non-pollinator fig wasps (NPFWs) were counted and recorded according to their sex. Percentage contribution of galls in the syconium for fig wasp production was higher in Site 1 (89.00%) than Site 2 (79.85%). Mean values of syconial diameter (DS), volume (VS) and number of florets per syconium (Fl/S) were comparatively higher at Site 2 (DS = 9.46 ± 0.40 mm; VS = 473.23 ± 63.67 mm3; Fl/S = 134.60 ± 21.6). The sex ratio of PFWs in Site 1 was 0.06 and in Site 2 was 0.30, indicating that Site 1 is more female-biased. The pollinator ratio of Site 1 (0.40) was significantly higher (p=2.14 × 10⁻⁸ ) than Site 2 (0.10). At site 1, there was a strong positive correlation between total non-pollinator fig wasps and pollinator male fig wasps (PMFWs) (r = 0.785) and between non pollinator male fig wasps and PMFWs (r = 0.824), whereas there was no strong correlation found at Site 2. Overall, Site 1 showed higher pollinator ratio, proportion of female wasps and wasp abundance within the syconia, indicating a stable mutualistic relationship. This study reveals the significant effects of disturbance on the relationship between F. tinctoria and its associated fig wasp species. The findings support the conclusion that increased disturbance negatively impacts syconial characteristics and fig–fig wasp relationships.