松天牛小首螨的研究Ⅲ.携播特性

Research on Paracarophenax alternatus Ⅲ. Phoretic Characteristics by Monochamus alternatus Adults

【目的】松天牛小首螨是新发现对松材线虫传播媒介松褐天牛卵具有寄生致死作用的微型携播螨类,研究阐明该螨的携播特性可为深入理解其生境适应性、评价其应用潜能和建立科学的野外应用方法提供依据。【方法】通过室内饲养、行为观察、模拟试验和野外诱捕调查,研究松天牛小首螨在松褐天牛成虫体表的分布规律,在松褐天牛成虫取食、产卵和共饲养等过程中的携播规律以及林间松褐天牛成虫携带松天牛小首螨的情况。【结果】松天牛小首螨以雌成螨为携播螨态,主动转移聚集在松褐天牛成虫体腹面沟缝处,雌、雄天牛均以后胸腹面携螨数量显著最多。在携螨天牛取食过程中,1 h内每头雌、雄天牛分别平均传播3.0、2.9头松天牛小首螨到松枝上。在携螨松褐天牛雌成虫产卵过程中,平均每产1粒卵可传播6.5头松天牛小首螨到天牛产卵部位。松天牛小首螨可在不同松褐天牛成虫个体间相互传播,当携螨天牛与未携螨天牛共饲养2天后,平均每头携螨天牛可传播39.3头松天牛小首螨到未携螨天牛体上,传播率为8.1%,共饲养10天后则每头携螨天牛可传播192.2头松天牛小首螨,传播率达38.5%。在不同天牛共饲养组合中,携螨雄天牛向未携螨雌天牛传播松天牛小首螨的数量和传播率均显著最高。在松天牛小首螨自然栖息林分内的松褐天牛成虫携螨率为55.0%,其中雌、雄天牛的携螨率分别为61.6%和39.2%,雌天牛显著高于雄天牛,平均每头雌、雄天牛分别携螨291.4、247.3头,二者间无显著差异。【结论】松天牛小首螨以雌成螨附着在松褐天牛成虫体腹面,通过在不同天牛成虫个体间传播、天牛的取食和产卵等行为传播扩散和繁殖扩张种群。该螨的这一携播特性既是其种群生境适应性的体现,也说明其具有较强的生物防治应用潜能。在未来林间应用中,可通过在松褐天牛成虫活动区或松褐天牛卵高密度部位释放松天牛小首螨,利用该螨的携播特性发挥其生物防治效能。

【Objective】 Paracarophenax alternatus is a newly found miniature phoretic mite that has parasitic and lethal effects on the eggs of Monochamus alternatus, a main vector of pine wood nematode in China. This study aims to further understand the mite’s habitat adaptability by investigating its phoretic characteristics by M. alternatus adults, and to evaluate its application potential in order to provide an important basis for establishing scientific filed application technique. 【Method】 The indoor breeding, behavior observation, simulation experiment and field trapping investigation were conducted to study the distribution of the mites on the body surface of M. alternatus adults, the transmitting law during M. alternatus adults feeding, oviposition and co-breeding, and the amount of the mites carried by the M. alternatus adults trapped in the field. 【Result】 The female adult mites were taken as phoretic state, P. alternatus actively transferred and aggregated in the ventral grooves of M. alternatus adults, and the number of mites carried by both male and female M. alternatus adults on the metathorax was the most. During the feeding process, each female and male M. alternatus adult transmitted an average of 3.0 and 2.9 P. alternatus to the pine branches in 1 hour, respectively. During the process of ovipositon, an average of 6.5 P. alternatus were able to be transmitted to the egg-laying site per egg laid. The mites were able to be transmitted from one to another of M. alternatus adult. An average 39.3 P. alternatus individuals were transmitted from mites-carrying M. alternatus to non mites-carrying M. alternatus, and after 2 days of co-breeding, the transmitted percentage was 8.1%. After 10 days of co-breeding, the transmitted number and percentage increased to 192.2 and 38.5%, respectively. In different feeding combinations, the transmitted number and percentage were the highest in the M. alternatus gender combination from mites-carrying M. alternatus males to non mites-carrying M. alternatus females. In the inhabited forest of P. alternatus, the mites-carrying percentage of M. alternatus adults is 55.0%, of which 39.2% were male and 61.6% were female, and the latter was significantly higher than the former. A single M. alternatus male adult carried an average of 247.3 mites, and a single female adult carried an average of 291.4 mites. There was no significant difference between these two. 【Conclusion】 P. alternatus can actively aggregate on the M. alternatus adults, be transferred among different individuals, and then accelerate diffusion and expansion of populations through feeding, oviposition and other living activities of M. alternatus adults. The phoresy characteristics of the mite do not only reflect P. alternatus’ population habitat adaptability, but also show its strong a bio-control potential. In the future field practices, it is recommended to release high-density P. alternatus population in the activity area of M. alternatus adults or eggs, using its phoresy characteristics to exert its biological control effect.