The common name 'long-horned bees' refers to genera in the tribe Eucerini (Apidae). These bees are so named because of the large antennae present on males. There are over 30 genera in the tribe, including Melissodes or long-horned bees, Peponapis and Xenoglossa or squash bees, and Svastra or sunflower bees. Bees in this tribe are found worldwide. Squash bees (Peponapis and Xenoglossa spp.) are important crop pollinators of the half billion dollar agricultural industry that produces Cucurbita spp., pumpkins, gourds, and squashes. Sunflower bees (Svastra and Diadasia spp. - Diadasia spp. are in the tribe Emphorini) are specialist bees that forage on particular plants, like crop sunflowers (Helianthus annuus).

Melissodes is a large genus of bees in the tribe Eucerini that tend to fly in the mornings and early afternoons. These bees are important pollinators of several crop and wild plants. They are primarily restricted to foraging on plants in the sunflower family (Asteraceae), specializing on asters, daisies, and sunflowers. In fact, sunflowers are quite dependent on cross-pollination by Melissodes spp., and they are one of the most important pollinators of crop sunflowers in California. However, these bees are also important pollinators of watermelon crops in California, and although cotton is generally considered to be a self-pollinating crop, Melissodes spp. do cross-pollinate it, leading to increased seed and lint yield of cotton. These bees are also commonly found on cosmos (Cosmos spp.), pincushion flower (Scabiosa spp.), coreopsis (Coreopsis spp.), and Peter's gold carpet (Bidens ferulifolia) and are one of the only effective bee pollinators of narrowpod sensitive pea (Chamaecrista keyensis) because they are able to buzz pollinate this species. These bees possess several characteristics - like gregarious nesting and restricted floral visitation - that make them good candidates to be managed for pollination services. However, no research has yet been conducted in this area.