Impact of Flowering Plant Heterogeneity on Enhancing Population Abundance of Arthropod Predators and Pollinators

Plant inflorescence is not only the source of nectar and pollen to attract beneficial arthropods but also acts as the major tool for conservation of biodiversity in an agro-ecosystem. The present study aimed to quantify the ecosystem service value of arthropod predators and pollinators through enhanced plant biodiversity and mass flowering. The experiment consisted of a direct comparison between wheat monoculture crop versus wheat crop embedded with one strip each of three floral crops [singhra (Raphanus raphanistrum L.), coriander (Coriandrum sativum L.) and linseed (Linum usitatissimum L.)]. Thirty beneficial insect species including pollinators and predators belonging to 14 families from six arthropod orders were recorded in the strip planted field. Dominant pollinators' activity increased linearly with the blooming of R. raphanistrum, L. usitatissimum and C. sativum, while predator populations were directly proportional to aphid populations. The maximum foraging activity of dominant pollinators was recorded during afternoon hours (1200hr) than in the morning and evening hours. Flower initiation, duration of blooming, uniformity of flowering and flower morphometric variation directly affected the population activity of pollinators, where predator occurrences were dependent on the abundance and activity of herbivores, Rhopalosiphum padi (bird cherry-oat aphid) and Sitobion avenae (grain aphid), on wheat. Both pollinator and predator population dynamics positively correlated with ambient temperature, whereas the relative humidity and rainfall negatively impacted beneficial arthropod activities. Therefore, the selection and appropriate mix of suitable crops as intercrop, border, cover or bunker crops will provide an opportunity for enhanced habitat diversity thereby increasing pollinator and predator activities and lowering the risk of pest-induced yield losses.