蜡蚧轮枝菌分生孢子在不同虫态棕尾別麻蝇体表的附着能力及与寄主体表结构的关系

【目的】为解释蜡蚧轮枝菌Lecanicillium lecanii对棕尾别麻蝇Boettcherisca peregrina成虫、蛹和幼虫等 3种虫态的致病性差异，研究分析了蜡蚧轮枝菌L. lecanii分生孢子在3种虫态体表的附着能力及与寄主体表结构的关系。【方法】采用血球计数板计数法测量蜡蚧轮枝菌分生孢子在棕尾別麻蝇B. peregrina成虫、蛹和幼虫体表的附着数量，并利用扫描电子显微镜等显微技术观察供试虫体体壁外长物分布情况以及附着分生孢子情况。【结果】蜡蚧轮枝菌分生孢子在棕尾別麻蝇3种虫态上的附着数量差异显著(P=0.0001)，成虫附着孢子数量为(1.35±0.12)×10⁶个/头，而蛹和幼虫分别为(0.57±0.09)×10⁶个/头和(0.45±0.06)×10⁶个/头。成虫周身微毛上均有孢子附着；整个蛹体仅棘刺底部呈“绳索状”的褶皱处可发现有孢子的附着；幼虫的体表未发现有孢子的附着。【结论】蜡蚧轮枝菌分生孢子在棕尾別麻蝇成虫、蛹、幼虫体表的附着能力与寄主体表结构有密切关系，是蜡蚧轮枝菌对该虫不同虫态间存在致病差异的原因。

Adhesion capacity of Lecanicillium lecanii conidia on body surface of Boettcherisca peregrina (Diptera: Sarcophagidae) at different developmental stages and its relationship with surface structures of host body

【Aim】In order to explain the different pathogenicity of Lecanicillium lecanii to adults, pupae and larvae of Boettcherisca peregrina, the adhesion capacity of L. lecanii conidia on body surface of B. peregrina at the three developmental stages and its relationship with the surface structures of insect body were analyzed. 【Methods】The number of conidia adhered to the surface of adults, pupae and larvae of B. peregrina were measured by hemocytometer, and the distribution of outgrowths and conidia on the body surface were observed by scanning electron microscope (SEM) and other microscopies.【Results】 There was significant difference in the adhesion number of L. lecanii conidia on the surface of three developmental stages of B. peregrina (P=0.0001). The adhesion number of L. lecanii conidia was (1.35±0.12)×10⁶, (0.57±0.09)×10⁶ and (0.45±0.06)×10⁶ on each adult, pupa and larva, respectively. Many L. lecanii conidia adhered to microchaetae of adults. Only few L. lecanii conidia were found to adhere to "rope" folds on the bottom of the thorns in pupae. No adhered L. lecanii conidia on larvae were found. 【Conclusion】 The adhesion capacity of L. lecanii conidia is closely associated with the body surface structures of adults, pupae and larvae of B. peregrina, resulting in the different pathogenicity of L. lecanii to these different developmental stages of B. peregrina.