From nest to parasite: investigating the biology and host–parasite dynamics of Hoplitis laevifrons and Chrysis rufitarsis

Hoplitis laevifrons (Morawitz) is a groundnesting solitary bee species of the subgenus Pentadentosmia, with limited knowledge regarding its nesting biology, floral preferences, and parasitoids associations. This study investigates the nesting behaviour and host–parasite dynamics of H. laevifrons and its brood parasite Chrysis rufitarsis Brullè, through observations at nesting aggregations in central Italy. Nest structure, brood cell morphology, and floral resource preferences were documented, with pollen analyses confirming oligolecty for Fabaceae. The presence of C. rufitarsis at H. laevifrons nests is published for the first time, and molecular analyses revealed the occurrence of multiple bee-attributed pathogens, especially deformed wing virus (DWV) and Nosema ceranae, in both host and parasite populations. These findings provide new insights into the nesting ecology of H. laevifrons and its brood parasite C. rufitarsis, particularly regarding pathogen transmission within wild bee communities, and highlight the need for further research on this wild bee species.

光滑额切叶蜂（Hoplitis laevifrons (Morawitz)）是隶属于五齿切叶蜂亚属（Pentadentosmia）的营地下筑巢独居蜂类，目前学界对其筑巢生物学、花卉偏好及寄生生物关联的研究仍较为匮乏。本研究通过在意大利中部筑巢集群开展的野外观测，探究了光滑额切叶蜂及其育性寄生蜂红足青蜂（Chrysis rufitarsis Brullè）的筑巢行为与宿主-寄生物动态关系。研究记录了该蜂的巢穴结构、育幼房形态与花卉资源偏好，并通过花粉分析证实其为豆科（Fabaceae）专性采粉蜂。本研究首次报道了红足青蜂在光滑额切叶蜂巢穴中的寄生现象，分子分析结果显示，宿主与寄生蜂种群中均检出多种蜂源病原体，其中以变形翼病毒（deformed wing virus, DWV）与东方蜜蜂微孢子虫（Nosema ceranae）最为常见。上述研究结果为光滑额切叶蜂及其育性寄生蜂红足青蜂的筑巢生态学，尤其是野生蜂群落内的病原体传播途径，提供了全新的研究视角，同时凸显了针对该野生蜂类开展后续研究的必要性。