Exploring the abundance and diversity of hymenopteran PARASITOIDS IN PADDY Fields cultivated with beneficial plant, Turnera trioniflora SIMS

Abstract

Beneficial insects such as hymenopteran parasitoids play a crucial role in pest population control and reducing the use of pesticides in paddy fields. To maintain sustainable parasitoid populations in the field, a sufficient nectar source is required, which can be provided by beneficial plants such as Turnera plants. However, studies on the abundance and diversity of hymenopteran parasitoids in paddy fields cultivated with Turnera plants are scarce. Hence, this study aimed to identify the families of hymenopteran parasitoids and determine their abundance and diversity in paddy fields cultivated with beneficial plant, Turnera trioniflora in Besut, Terengganu, Malaysia. Two paddy fields of 1 ha/field were selected, where one plot was cultivated with T. trioniflora (Plot A) and the other without T. trioniflora (Plot B). Three Malaise traps were randomly placed in each plot and insect samples were collected weekly during paddy off-season (Season 1: March-May 2021) and paddy main-season (Season 2: September-November 2021), and all samples were brought to the laboratory for identification. The study successfully identified 120 hymenopteran parasitoids comprising six families, namely Ichneumonidae, Braconidae, Chalcididae, Scelionidae, Torymidae, and Bethylidae, with the most abundant families being Ichneumonidae (72 individuals) and Braconidae (35 individuals). A significant difference (P<0.05) of hymenopteran parasitoid abundance was observed between different families in Season 1 but not in Season 2. The hymenopteran parasitoid abundance in Plot A was recorded as 73% higher than that in Plot B for both seasons. The diversity of hymenopteran parasitoids in Plot A was also higher than that in Plot B for both seasons. The study concludes that the abundance and diversity of hymenopteran parasitoids were higher in paddy plots cultivated with T. trioniflora, indicating the beneficial effects of T. trioniflora on the hymenopteran parasitoid’s populations. These findings suggest that the presence of T. trioniflora in paddy fields may contribute to a more abundant and diverse family of hymenopteran parasitoids that may help improve paddy field pest management strategies.