Host Breadth, Organic-Resource Associations, and Quantitative Variation in Pupal Parasitism by Brachymeria podagrica (Fabricius, 1787) (Hymenoptera: Chalcididae) in Brazil

Brachymeria podagrica (Fabricius, 1787) (Hymenoptera: Chalcididae) is a parasitoid associated with several Diptera developing in decomposing organic resources. This study integrated records from eight experimental investigations conducted in Brazil to evaluate host breadth, organic-resource associations, and quantitative variation in pupal parasitism by B. podagrica. Records identified only as Brachymeria sp., duplicated observations, capture-only data, and records in which parasitoid emergence could not be reliably related to parasitized host pupae were excluded from the principal quantitative comparisons. The retained datasets included calliphorid, muscid, and sarcophagid hosts associated with bovine kidney, bovine liver, chicken viscera, fish, and human feces. For Peckia chrysostoma, parasitism differed markedly among five organic resources, ranging from 2.3% in fish to 34.6% in bovine liver (χ² = 164.20; df = 4; P < 0.0001). Comparisons among hosts in chicken viscera produced contrasting results. In the Itumbiara dataset, parasitism differed significantly among three hosts (χ² = 9.58; df = 2; P = 0.0083), whereas no significant difference was detected among three hosts in the forest dataset (χ² = 0.07; df = 2; P = 0.966). These results demonstrate broad host use by B. podagrica but also substantial variation in realized parasitism among host–resource systems. Host identity alone does not explain this variation; organic resource and local experimental context are also important. The findings reinforce the ecological flexibility of B. podagrica while showing that natural parasitism should not be interpreted automatically as evidence of effective population-level biological control.