Influence of field management practices, altitude and seasonality on abundance and dynamics of wasps in cucurbit agroecosystems

Despite the ongoing research on insects there is limited knowledge on how different farming practices influence wasp abundance and dynamics, especially in cucurbit agroecosystems in Africa. This study addresses this gap by examining the influence of farming practices on wasp abundance and dynamics in cucurbit farms in Morogoro region of Tanzania. A large-scale experimental design comprising twenty 45 m × 45 m plots across high- and low-altitude sites, with equal representation of agroecological and conventional systems was developed. Three cucurbit species were cultivated in each plot and wasps were sample using hand netting and yellow pan traps for eight consecutive weeks during both dry (May–July 2023) and wet (September–October 2023) seasons. Results revealed that the abundance of wasps was significantly influenced by seasonality (df = 1, F = 14.342, P = 0.0006) and altitude (df = 1, F = 17.501, P = 0.0002), while the dynamics of wasps were significantly affected by seasonality alone (df = 1, F = 4.605, P = 0.04). Farming practices (conventional versus agroecological) did not show any significant effects on either wasp abundance or dynamics (P > 0.05). Both the abundance and dynamics were positively correlated with temperature at low altitude and negatively at high altitude. These findings indicate that wasp populations are mainly influenced by complex interactions among altitude, seasonality, and weather variables, rather than by the type of farming practice. This emphasises the ecological importance of conserving diverse landscapes and integrating climate-sensitive strategies into agricultural planning. It also reinforces the need for evidence-based policies that promote landscape-level biodiversity conservation to maintain beneficial insects that are vital for crop production and ecosystem resilience.