Functional Correlation between Floral Style Length and Ovipositor Length in Ficus benghalensis – Eupristina masoni Mutualism across South India

Abstract

The present study aimed to quantify the functional relationship between floral style length (stigma + style) in Ficus benghalensis and the ovipositor length of its obligate pollinator Eupristina masoni across ecologically distinct populations in South India. A total of Twenty-five receptive-phase flowers and 25 emerging female pollinating wasps were measured per site. Floral style length was recorded under a stereomicroscope, while ovipositor length was measured using an ocular micrometer. Summary statistics, Pearson’s correlations, ANOVA, and mismatch analyses were performed. Floral style length (mean = 1.76 mm) exceeded ovipositor length (mean = 1.50 mm) in most flowers, with only 38.5% of flowers having style length ≤ ovipositor length. Individual-level correlation between style and ovipositor length was statistically significant but modest (r = 0.313, P < .001), whereas site-level mean traits were strongly correlated (r = 0.817, P < .001). Both traits varied significantly among populations, with ovipositors showing lower within-site variation compared to floral styles. The Ficus benghalensis–Eupristina masoni mutualism exhibits strong but imperfect morphological matching. Geographic covariation suggests coevolution and local adaptation, but the consistent floral advantage (styles deeper than ovipositors) indicates an evolutionary balance favouring increased seed production over wasp brood success.