Chelbi I, Zhioua E, Shocket M, Hamilton J G C
Unit of Vector Ecology, Institut Pasteur de Tunis, 13 Place Pasteur, 1002, Tunis, Tunisia.
Lancaster Environment Centre, Faculty of Science and Technology, Lancaster University, Lancashire, UK.
bioRxiv. 2025 May 7:2025.05.01.651664. doi: 10.1101/2025.05.01.651664.
is a vector of , the etiologic agent of zoonotic cutaneous leishmaniasis, a disfiguring and debilitating disease. In this study, we identified fatty acids found on the exterior of eggs laid by female that could be potential oviposition pheromones. We tested the effect of different treatments on 1) the number of eggs laid and 2) the spatial distribution of eggs laid. The treatments included three quantities of eggs (80, 160 and 320), hexane extracts of 160 eggs, 160 eggs after being washed with hexane to remove any pheromones, and three concentrations (1ng, 10ng and 100ng) of synthetic versions of three fatty acids that we identified as being present on egg exteriors. The saturated fatty acids dodecanoic (C12) and tetradecanoic (C14) acid, identified by GC/MS analysis, were abundant in hexane extracts of both eggs and gravid females but were present in only trace amounts in males. Hexadecanoic and hexadecenoic (C16) acids were abundant on eggs, gravid females and males. A negative binomial GLM found that significantly more eggs were oviposited by gravid females in response to 80 eggs (=0.0255), 160 eggs (<0.001), 320 eggs (<0.001) and the hexane extract of 160 eggs (<0.001). Eggs washed in hexane were not more attractive than a control (=0.591). The number of eggs laid was increased by all three concentrations of hexadecanoic acid (<0.001), 10ng and 100ng of tetradecanoic acid (<0.001), and 1ng and 10ng of dodecanoic acid (<0.001). The spatial response of oviposition (the proportion of eggs laid on the test vs. control side of the oviposition pot) was weaker than the response of total eggs laid. A beta GLM found that gravid females laid a significantly higher proportion of eggs near 160 eggs (=0.004) and significantly lower proportion of eggs near 100ng of dodecanoic acid (=0.016). Bootstrapping and permutation tests also suggested significant attractive effects of 320 eggs, egg extract, and 1ng and 10 ng of hexadecenoic acid. These results suggest that hexadecanoic acid is the oviposition pheromone, of from Tunisia because its presence increases both the number of eggs laid and attracts oviposition over the small spatial scales of the assay. Studies by others have shown that dodecanoic acid is the oviposition pheromone of from Turkey. In this study, dodecanoic acid increased the number of eggs laid but either did not change their spatial distribution or was repulsive at the highest concentration. The observed difference may be related to the different geographical origins of the sand flies used in this study.
是动物源性皮肤利什曼病的病原体,是一种会导致毁容和使人衰弱的疾病。在本研究中,我们鉴定了雌性 所产卵的外部发现的脂肪酸,这些脂肪酸可能是潜在的产卵信息素。我们测试了不同处理对1)产卵数量和2)产卵空间分布的影响。处理包括三种卵数量(80、160和320)、160个卵的己烷提取物、用己烷洗涤以去除任何信息素后的160个卵,以及我们鉴定出存在于卵外部的三种脂肪酸的三种浓度(1ng、10ng和100ng)的合成版本。通过气相色谱/质谱分析鉴定出的饱和脂肪酸十二烷酸(C12)和十四烷酸(C14)在卵和妊娠雌性的己烷提取物中含量丰富,但在雄性中仅微量存在。十六烷酸和十六碳烯酸(C16)在卵、妊娠雌性和雄性中含量丰富。负二项广义线性模型发现,妊娠雌性对80个卵(=0.0255)、160个卵(<0.001)、320个卵(<0.001)和160个卵的己烷提取物(<0.001)的反应显著产更多卵。用己烷洗涤的卵不比对照更具吸引力(=0.591)。所有三种浓度的十六烷酸(<0.001)、10ng和100ng的十四烷酸(<0.001)以及1ng和10ng的十二烷酸(<0.001)都增加了产卵数量。产卵的空间反应(在产卵盆的测试侧与对照侧产卵的比例)比总产卵量的反应弱。贝塔广义线性模型发现,妊娠雌性在160个卵附近产的卵比例显著更高(=0.004),在100ng十二烷酸附近产的卵比例显著更低(=0.016)。自举法和置换检验也表明320个卵、卵提取物以及1ng和10ng十六碳烯酸有显著的吸引作用。这些结果表明,十六烷酸是突尼斯 的产卵信息素,因为它的存在增加了产卵数量,并在测定的小空间尺度上吸引产卵。其他人的研究表明,十二烷酸是土耳其 的产卵信息素。在本研究中,十二烷酸增加了产卵数量,但要么没有改变它们的空间分布,要么在最高浓度时具有排斥性。观察到的差异可能与本研究中使用的白蛉的不同地理来源有关。
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