Department of Environmental Science, Policy and Management, University of California, 137 Mulford Hall, #3114, Berkeley, CA 94720-3114, USA.
J Chem Ecol. 2010 Jul;36(7):751-8. doi: 10.1007/s10886-010-9812-4. Epub 2010 Jun 17.
Social insects maintain colony cohesion by recognizing and, if necessary, discriminating against conspecifics that are not part of the colony. This recognition ability is encoded by a complex mixture of cuticular hydrocarbons (CHCs), although it is largely unclear how social insects interpret such a multifaceted signal. CHC profiles often contain several series of homologous hydrocarbons, possessing the same methyl branch position but differing in chain length (e.g., 15-methyl-pentatriacontane, 15-methyl-heptatriacontane, 15-methyl-nonatriacontane). Recent studies have revealed that within species these homologs can occur in correlated concentrations. In such cases, single compounds may convey the same information as the homologs. In this study, we used behavioral bioassays to explore how social insects perceive and interpret different hydrocarbons. We tested the aggressive response of Argentine ants, Linepithema humile, toward nest-mate CHC profiles that were augmented with one of eight synthetic hydrocarbons that differed in branch position, chain length, or both. We found that Argentine ants showed similar levels of aggression toward nest-mate CHC profiles augmented with compounds that had the same branch position but differed in chain length. Conversely, Argentine ants displayed different levels of aggression toward nest-mate CHC profiles augmented with compounds that had different branch positions but the same chain length. While this was true in almost all cases, one CHC we tested elicited a greater aggressive response than its homologs. Interestingly, this was the only compound that did not occur naturally in correlated concentrations with its homologs in CHC profiles. Combined, these data suggest that CHCs of a homologous series elicit the same aggressive response because they convey the same information, rather than Argentine ants being unable to discriminate between different homologs. This study contributes to our understanding of the chemical basis of nestmate recognition by showing that, similar to spoken language, the chemical language of social insects contains "synonyms," chemicals that differ in structure, but not meaning.
社会性昆虫通过识别并在必要时区分不属于群体的同种个体来维持群体凝聚力。这种识别能力由复杂的表皮碳氢化合物(CHC)混合物编码,但很大程度上不清楚社会性昆虫如何解释这种多方面的信号。CHC 图谱通常包含几个同源碳氢化合物系列,它们具有相同的甲基分支位置,但链长不同(例如,15-甲基-五十烷、15-甲基-七十烷、15-甲基-九十烷)。最近的研究表明,在同种内,这些同系物可能以相关浓度存在。在这种情况下,单个化合物可能传达与同系物相同的信息。在这项研究中,我们使用行为生物测定法来探索社会性昆虫如何感知和解释不同的碳氢化合物。我们测试了阿根廷蚂蚁(Linepithema humile)对巢穴伙伴 CHC 图谱的攻击性反应,这些图谱通过添加八种合成碳氢化合物中的一种进行了增强,这些化合物在分支位置、链长或两者上有所不同。我们发现,阿根廷蚂蚁对巢穴伙伴 CHC 图谱的增强反应水平相似,这些图谱增强了具有相同分支位置但链长不同的化合物。相反,阿根廷蚂蚁对巢穴伙伴 CHC 图谱的增强反应水平不同,这些图谱增强了具有不同分支位置但链长相同的化合物。虽然在几乎所有情况下都是如此,但我们测试的一种 CHC 化合物比其同系物产生更大的攻击性反应。有趣的是,这是唯一一种在 CHC 图谱中与其同系物没有相关浓度的化合物。这些数据表明,同一系列的 CHC 化合物引发相同的攻击性反应,因为它们传达相同的信息,而不是阿根廷蚂蚁无法区分不同的同系物。这项研究通过表明,类似于口语,社会性昆虫的化学语言包含“同义词”,即结构不同但含义相同的化学物质,从而有助于我们理解巢内识别的化学基础。