Mogren Christina L, Walton William E, Parker David R, Trumble John T
Department of Entomology, University of California Riverside, Riverside, California, United States of America.
PLoS One. 2013 Jun 27;8(6):e67817. doi: 10.1371/journal.pone.0067817. Print 2013.
The movement of energy and nutrients from aquatic to terrestrial ecosystems can be substantial, and emergent aquatic insects can serve as biovectors not only for nutrients, but also for contaminants present in the aquatic environment. The terrestrial predators Tenodera aridifolia sinensis (Mantodea: Mantidae) and Tidarren haemorrhoidale (Araneae: Theridiidae) and the aquatic predator Buenoa scimitra (Hemiptera: Notonectidae) were chosen to evaluate the efficacy of arsenic transfer between aquatic and terrestrial environments. Culex tarsalis larvae were reared in either control water or water containing 1000 µg l(-1) arsenic. Adults that emerged from the control and arsenic treatments were fed to the terrestrial predators, and fourth instar larvae were fed to the aquatic predator reared in control or arsenic contaminated water. Tenodera a. sinensis fed arsenic-treated Cx. tarsalis accumulated 658±130 ng g(-1) of arsenic. There was no significant difference between control and arsenic-fed T. haemorrhoidale (range 142-290 ng g(-1)). Buenoa scimitra accumulated 5120±406 ng g(-1) of arsenic when exposed to arsenic-fed Cx. tarsalis and reared in water containing 1000 µg l(-1) arsenic. There was no significant difference between controls or arsenic-fed B. scimitra that were not exposed to water-borne arsenic, indicating that for this species environmental exposure was more important in accumulation than strictly dietary arsenic. These results indicate that transfer to terrestrial predators may play an important role in arsenic cycling, which would be particularly true during periods of mass emergence of potential insect biovectors. Trophic transfer within the aquatic environment may still occur with secondary predation, or in predators with different feeding strategies.
能量和营养物质从水生生态系统向陆地生态系统的转移量可能很大，而且水生昆虫不仅可以作为营养物质的生物载体，还可以作为水生环境中污染物的生物载体。选择陆生捕食者中华大刀螳（螳螂目：螳科）和痔突肥腹蛛（蜘蛛目：球蛛科）以及水生捕食者弯尾姬蝽（半翅目：仰蝽科）来评估砷在水生和陆地环境之间转移的效率。致倦库蚊幼虫分别在对照水或含1000微克/升砷的水中饲养。从对照处理和砷处理中羽化出的成虫喂食给陆生捕食者，四龄幼虫喂食给饲养在对照水或砷污染水中的水生捕食者。取食经砷处理的致倦库蚊的中华大刀螳积累了658±130纳克/克的砷。取食砷的肥腹蛛与对照之间没有显著差异（范围为142 - 290纳克/克）。当暴露于取食砷的致倦库蚊并饲养在含1000微克/升砷的水中时，弯尾姬蝽积累了5120±406纳克/克的砷。未暴露于水体砷中的对照或取食砷的弯尾姬蝽之间没有显著差异，这表明对于该物种而言，环境暴露在积累方面比严格的饮食砷更为重要。这些结果表明，向陆生捕食者的转移可能在砷循环中起重要作用，在潜在昆虫生物载体大量羽化期间尤其如此。在水生环境中，营养转移仍可能通过二次捕食或不同摄食策略的捕食者发生。
