Nesting biology and phenology of a new Andean Colletes (Colletidae: Colletinae) from Colombia, with the description of a new parasitoid species of Grotea (Ichneumonidae: Labeninae)

High-Andean ecosystems harbor poorly known bee communities, and basic aspects of their taxonomy, nesting biology, and trophic interactions remain largely undocumented. Here we describe two new species associated with trap-nest surveys conducted between September 2024 and December 2025 across two habitat types representing contrasting restoration stages in Tocancipá, Cundinamarca, Colombia: Colletes paulae n. sp. (Apidae: Colletidae), a new cellophane bee from the high Andes, and Grotea colletiphaga n. sp. (Ichneumonidae: Labeninae), a parasitoid wasp reared from its brood cells. We document, for the first time, the nesting biology, phenology, and ecological interactions of C. paulae . Nests consisted of a linear series of brood cells lined with a characteristic cellophane-like polyester secretion and provisioned with a liquid pollen–nectar mixture, sealed by a vestibular cell and a closing plug. Nesting activity occurred year-round, with a marked seasonal peak in October–November. Although nest architecture was largely consistent across habitats, nests in conserved areas contained significantly more brood cells than those in restoration areas, indicating that habitat quality directly influences reproductive investment. Brood survival differed markedly between habitats and was strongly driven by parasitoidism, with parasitoidism rates being substantially higher in conserved habitats — a pattern suggesting that parasitoid assemblages may function as indicators of ecosystem integrity. The association between G. colletiphaga and C. paulae represents the first confirmed host–parasitoid interaction between the genera Grotea and Colletes . Collectively, our results expand knowledge of Andean bee diversity, uncover a previously unknown trophic interaction, and demonstrate that trap-nest methods are powerful tools for simultaneously resolving taxonomy and revealing ecological processes in understudied solitary bee communities.