Colorado State University Extension, Grand Junction, CO.
Department of Entomology, North Carolina State University, Raleigh, NC.
J Econ Entomol. 2020 Feb 8;113(1):230-238. doi: 10.1093/jee/toz297.
Two invasive drosophilids, Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) and Zaprionus indianus (Gupta) (Diptera: Drosophilidae) are expanding their geographic distribution and cohabiting grape production in the Mid-Atlantic. The ecological and economic impact of these two species within vineyards is currently unknown. Zaprionus indianus was presumably not capable of ovipositing directly into grapes because they lack a serrated ovipositor and may use D. suzukii oviposition punctures for depositing their own eggs. Therefore, an interspecific larval competition assay was performed at varying larval densities using commercial medium and four commonly grown wine grapes in Virginia to investigate the impact Z. indianus larvae may have on the mortality and developmental parameters of D. suzukii larvae. Zaprionus indianus did not affect D. suzukii mortality or development parameters even at high interspecific densities when reared in commercial medium, but it did cause higher D. suzukii mortality within grapes. Mortality was also influenced by the variety of grape in which the larvae were reared, with smaller grapes having the highest D. suzukii mortality. Presence of Z. indianus also increased development time to pupariation and adult emergence for most interspecific competition levels compared with the intraspecific D. suzukii controls. Pupal volume was marginally affected at the highest interspecific larval densities. This laboratory study suggests that competition from Z. indianus and grape variety can limit D. suzukii numbers, and the implications on D. suzukii pest management be further verified in the field.
两种入侵的果蝇，铃木氏果蝇（Drosophila suzukii）（双翅目：果蝇科）和印度实蝇（Zaprionus indianus）（双翅目：果蝇科）正在扩大其地理分布范围，并共同栖息在大西洋中部的葡萄产区。这两个物种在葡萄园中的生态和经济影响目前尚不清楚。印度实蝇大概不能直接将卵产入葡萄中，因为它们缺乏锯齿状的产卵器，并且可能会利用铃木氏果蝇的产卵孔来产卵。因此，在不同的幼虫密度下，使用商业培养基和弗吉尼亚州四种常见的酿酒葡萄进行了种间幼虫竞争测定，以研究印度实蝇幼虫可能对铃木氏果蝇幼虫的死亡率和发育参数产生的影响。即使在商业培养基中以高种间密度饲养，印度实蝇也不会影响铃木氏果蝇的死亡率或发育参数，但它确实会导致葡萄中铃木氏果蝇的死亡率更高。死亡率还受到幼虫饲养的葡萄品种的影响，较小的葡萄的铃木氏果蝇死亡率最高。与铃木氏果蝇的种内对照相比，印度实蝇的存在也会使大多数种间竞争水平的化蛹和成虫出现时间延长。在最高的种间幼虫密度下，蛹体积受到轻微影响。这项实验室研究表明，印度实蝇和葡萄品种的竞争可以限制铃木氏果蝇的数量，并且这种影响需要在田间进一步验证。
