The effect of insecticides on bees has gained great attention, however, there are few studies that explore this issue on Neotropical bees. Bombus atratus is a neotropical species broadly distributed in Colombia and is considered an important pollinator of both Andean ecosystems and agroecosystems. However, as for many wild bees species, the effect of insecticides on B. atratus is unknow. In this study we determined the acute median lethal dose (LD50) of commercial formulations of insecticides Imidacloprid, Spinosad and Thiocyclam hydrogen oxalate, widely used in Colombia to control several pests of important crops. The LD50 was carried out by oral and contact routes, following and modifying the EPPO and OECD guidelines to perform LD50 on A. mellifera. We evaluated five doses for each route and insecticide, in a total of 25 medium-size workers for each dose by duplicate. Mortality was registered at 24, 48 and 72 hours after the experiment; and data were analyzed with the Probit regression model. For Imidacloprid, contacts and oral LD50 were 0.048 µg/bee and 0.010 µg/bee, respectively. For Thiocyclam hydrogen oxalate, topical and oral LD50 were 0.244 µg/bee and 0.056 µg/bee, respectively. For Spinosad, the oral LD50 corresponded to 0.28 µg/bee; it was not possible to establish the LD50 for the contact route. The Hazard Quotient (HQ) and Index of Relative Toxicity indicated that all three active ingredients are highly toxic. We discussed the risk of the insecticides use on B. atratus, considering their chemical nature.

Bombus pauloensis Friese is a promising managed bumblebee that can pollinate crops in South America. Highbush blueberry (Vaccinium corymbosum L.) is a recently introduced and economically promising crop cultivated in open fields or greenhouses in Colombia. Although this crop is known to be pollinator-dependent, the efficiency of local pollinators in this geographic area has yet to be established. This study aimed to establish the pollination effectiveness and foraging behavior of B. pauloensis in two of the most common cultivars of highbush blueberries planted in a high Andean region of Colombia. We hand-reared and located B. pauloensis colonies in two different plantations of Sharpblue (open field) and Biloxi (greenhouse) cultivars. The time spent per flower and the number of flowers visited per minute of 300 foragers were registered to characterize the foraging behavior in both cultivars. Pollen analysis was performed once from corbicular loads, larvae, larval cells, and colony feces to identify the pollen sources collected by colonies located in the Sharpblue crop. Analysis of fruit quality was performed to establish the effect of B. pauloensis pollination. Foragers visited blueberry flowers with a corolla aperture of more than 3mm in both cultivars but spent more time visiting Biloxi than Sharpblue flowers. B. pauloensis pollination reduced the ripening time and increased the fresh and dry weight and the number of true seeds in both cultivars. Our results provide evidence that B. pauloensis pollination can improve the fruit quality in the blueberry cultivars evaluated here in Colombia, making it an efficient native pollinator for a promising commercial species.

Bombus atratus es considerada una especie promisoria para ser implementada en programas de poliniza­ción de cultivos de tomate en Colombia. El método de cría utilizado para la producción de colonias era una adaptación del descrito para B. terrestris, Sin embargo, B. atratus difiere en el comportamiento de alimenta­ción de las larvas (alimentación directa por bolsillo “pocket maker” vs. por regurgitación “pollen storer” en B.terrestris). Este trabajo describe de forma detallada el desarrollo de dos colonias criadas bajo dos condicio­nes de alimentación diferentes: a) cría cerrada, con ofrecimiento de néctar y polen por parte del asistente de laboratorio en la base de la caja de cría, semejante a la metodología descrita para B. terrestris (colonia cautiva – CC), b) cría cerrada hasta alcanzar diez obreras y con forrajeo externo a partir de ese momento (colonia forra­jera - CF). La colonia CC produjo un total de 110 adultos (obreras+machos). El tiempo promedio de desarrollo para las obreras fue de 32,9±7.9 y para los machos 35,7±9,1 días. La mortalidad de larvas fue elevada (70%). CF produjo 107 celdas de huevo de las que se generaron 344 obreras+machos. El tiempo promedio de desarrollo de las obreras fue 29,5±5.1 y de los machos 30±6.8 días. La mortalidad en el estado larval fue baja. En CF dos reinas silvestres tomaron el control de la colonia en momentos diferentes de su desarrollo. Los resultados del presente trabajo mostraron que la alimentación por regurgitación afecta la supervivencia de las larvas y por consiguiente el crecimiento y desarrollo de las colonias. Lo anterior permitió el desarrollo de técnicas combi­nadas de alimentación que permiten la cría de colonias de B. atratus en condiciones controladas.

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.