Investigation of the Nesting Biology and Natural Enemies of Megachile and Anthidiellum (Hymenoptera: Megachilidae) Species Associated with Pistachio (Pistacia Vera L.) Trees

Pistachio is one of Türkiye’s most important crops and constitutes a significant source of income for the producers. Leafcutter bees are essential contributors to the pollination of both wild and cultivated plants. This study was conducted to obtain information about the nesting biology of individuals belonging to the genera Megachile and Anthidiellum, which nest in pistachio trees by cutting leaves, causing damage by nesting in cavities in tree trunks, and nesting on shoots in the provinces of Adıyaman, Gaziantep, Kahramanmaraş, and Malatya between 2022 and 2024. To identify species belonging to the genera Megachile and Anthidiellum, specimens were collected from pistachio trees in Adıyaman, Gaziantep, Kahramanmaraş, and Malatya between February and September, either using a sweep net or by directly removing the nests. It has been determined that some individuals of Megachile species generally prefer the trunks of old pistachio trees for nesting, while other species utilize the sticky properties of the leaf pulp obtained by cutting and chewing pistachio leaves to create nests in the soil, using it to glue other plant leaves together and to fill small gaps with a thin layer. Furthermore, it has been found that species in the genus Anthidiellum prefer nesting in pistachio shoots. Damage caused by Megachile albisecta and Megachile doriae significantly decreased with increasing plant age, with the highest damage observed in young seedlings and minimal damage in mature trees. The parasitoid Anthrax anthrax (Schrank, 1781) (Diptera: Bombyliidae) was identified for the first time in this study on Megachile apicalis.