Nomad bee

The genus Nomada, commonly known as nomad bees, belongs to the order Hymenoptera and the family Apidae. These insects are classified as kleptoparasites rather than direct plant pests, as they do not feed on crops but instead parasitize the nests of other solitary bee species that provide essential pollination services.

The biological strategy of Nomada involves a specialized life cycle. Adult females do not construct their own nests or provision cells with pollen. Instead, they stealthily enter the nests of ground-nesting bees, primarily from the genus Andrena, and deposit their eggs. The hatched Nomada larva consumes the host's food stores and often kills the host larva, effectively reducing the next generation of pollinators.

Their life cycle is strictly synchronized with the phenology of their specific hosts. They typically overwinter as adults in soil crevices or hollow plant stems. During the spring, they emerge to search for host nesting sites. While they visit flowers for nectar, their role in pollination is marginal compared to the impact they have on host suppression.

Their economic significance lies in the reduction of pollinator density in agricultural landscapes. By successfully parasitizing dominant wild bee populations, Nomada can indirectly impact the fruit set and seed production of crops that rely on insect pollination, thereby serving as a limiting factor in natural pollination efficiency.

Management strategies focus on protecting and boosting populations of the host bees to ensure a resilient pollinator community. Recommended agronomic practices include:

• Implementing integrated pest management (IPM) to avoid chemical exposure during bloom.
• Preserving non-tilled soil patches which are critical for the nesting of ground-nesting bees.
• Enhancing landscape diversity with flowering field margins to support the nutritional needs of pollinators.