This book explores the critical role of dipterans (flies) in global food production, plant reproduction, and ecological services. It highlights the diversity of pollinating dipterans worldwide, with a focus on their importance in India. Chapters cover key pollinator groups such as syrphid flies (hoverflies), thick-headed flies, bees (honeybees, bumblebees, solitary bees), and butterflies, explaining their impact on plant health and reproduction. Special attention is given to non-syrphid dipterans, which are vital in high-altitude and subarctic regions where bee populations are limited. The book also examines threats like climate change, habitat loss, land-use changes, and invasive species, along with recent research on insect immunity and antiviral defenses in honeybees. It is a valuable resource for researchers, academicians, and anyone interested in pollinators and their conservation.