Abstract：
Pygidial gland secretions are used as repellent defensive allomones in ground beetles. We provide the first precise data on the chemical composition and antimicrobial potency of the secretion of the blue ground beetle, as well as on the morphology of its pygidial glands. The latter structures were not previously studied chemoecologically and morphologically, and we hypothesized that their secretion may have some antimicrobial action, as is the case with certain Carabus species. Gas chromatography-mass spectrometry (GC-MS) was used to identify methacrylic and angelic acids as dominant chemicals in the secretion from individuals of three populations of the blue ground beetle in Serbia. We tested its secretion against selected strains of medically important microorganisms. The secretion exibits antimicrobial action against certain bacterial species and all tested micromycetes. The most significant antifungal effect of the secretion was against Penicillium ochrochloron, which is more sensitive to the secretion than to commercial antifungal drugs ketoconazole and bifonazole. Bifonazole achieved minimum inhibitory concentrations against Trichoderma viride at more than three times higher value than did the secretion, indicating a significant antifungal effect of the secretion against this micromycete as well. Additionally, we tested commercially available standards of two dominant chemicals in the secretion to investigate their interaction and antimicrobial role in the secretion. Finally, we describe all glandular morpho-functional units of the blue ground beetle. Our results suggest that the secretion of the blue ground beetle may serve not only defensive but also antimicrobial functions, which likely aid the survival of this beetle in the microbial-rich forest litter habitat.
摘要：
甲状腺肿腺分泌物被用作地面甲虫的驱避性防御性allomones。我们提供有关蓝地甲虫分泌物的化学成分和抗菌效力的第一个精确数据，以及其肾盂腺的形态。后者的结构以前没有在化学生态学和形态学上进行过研究，我们假设它们的分泌可能有一些抗菌作用，就像某些Carabus物种一样。气相色谱-质谱（GC-MS）用于鉴定甲基丙烯酸和当归酸是塞尔维亚三个蓝底甲虫种群个体分泌物中的主要化学物质。我们针对医学上重要的微生物的选定菌株测试了其分泌。分泌物对某些细菌物种和所有测试的微霉菌具有抗微生物作用。分泌的最显著的抗真菌作用是对抗产氯青霉菌，比商业抗真菌药物酮康唑和联苯苄唑对分泌更敏感。联苯苄唑对绿色木霉的最低抑制浓度比分泌物高三倍以上，表明分泌物对这种微生物也具有显着的抗真菌作用。此外,我们测试了分泌物中两种主要化学物质的市售标准品，以研究它们在分泌物中的相互作用和抗菌作用。最后,我们描述了蓝色甲虫的所有腺体形态功能单元。我们的结果表明，蓝地甲虫的分泌不仅可以起到防御作用，还可以起到抗菌作用。这可能有助于这种甲虫在富含微生物的森林凋落物栖息地中的生存。
