Risk assessment of non-target effects caused by releasing two exotic phytoseiid mites in Japan: can an indigenous phytoseiid mite become IG prey?
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Two exotic phytoseiid mites, Neoseiulus cucumeris and Amblyseius swirskii, are commercially available in Japan for the control of thrips and other pest insects. As part of a risk assessment of the non-target effects of releasing these two species, we investigated intraguild predation (IGP) between these exotic phytoseiid mites and an indigenous phytoseiid mite Gynaeseius liturivorus, which is promising as an indigenous natural enemy for the control of thrips in Japan. To understand IGP relations between the exotic and indigenous phytoseiid mites after use of the exotic mites for biological control, we investigated IGP between them in the absence of their shared prey. When an IG prey was offered to an IG predator, both exotic and indigenous females consumed the IG prey at all immature stages (egg, larva, protonymph, deutonymph), especially at its larval stages. The propensity for IGP in a no-choice test was measured by the survival time of IG prey corrected using the survival time of thrips offered to the IG predator. There was no significant difference in the propensity for IGP between N. cucumeris and G. liturivorus, but the propensity was significantly higher in A. swirskii than G. liturivorus. The propensity for IGP in a choice test was measured by the prey choice of the IG predator when a conspecific and a heterospecific larva were offered simultaneously as IG prey. Both exotic females consumed the heterospecific larva only. The indigenous female preferentially consumed the heterospecific larva when the heterospecific larva was N. cucumeris, but consumed the conspecific larva when the heterospecific larva was A. swirskii. We concluded that further investigation would be necessary for the exotic mites’ risk assessment, since the propensity for IGP of the two exotic females was similar to or higher than that of the indigenous female in both the no-choice and choice tests.
KeywordsIntraguild predation Intra-specific predation Risk assessment Gynaeseius liturivorus Neoseiulus cucumeris Amblyseius swirskii
We thank Drs. M. Mochizuki (National Institute of Fruit Tree Sciences, Japan), N. Hinomoto (National Institute of Agrobiological Sciences), and M. Momoshita (Arysta LifeScience Corporation, Japan) for providing G. liturivorus, F. occidentalis, N. cucumeris and A. swirskii and valuable advice on them. We thank Dr. K. Komi (Kôchi Agriculture Research Center) for valuable advice on G. liturivorus. We also thank Ms. K. Furukawa for her assistance in setting up the experiments. This study was partly supported by a subsidy from the Japan Society for the Promotion of Science for Young Scientists (no. 21-1045).
- Babendreier D, Bigler F, Kuhlmann U (2006) Current status and constraints in the assessment of non-target effects. In: Bigler F, Babendreier D, Kuhlmann U (eds) Environmental impact of invertebrates for biological control of arthropods: methods and risk assessment. CABI Publishing, Oxon, pp 1–14CrossRefGoogle Scholar
- Kuhlmann U, Schaffner U, Mason PG (2006) Selection of non-target species for host specificity testing. In: Bigler F, Babendreier D, Kuhlmann U (eds) Environmental impact of invertebrates for biological control of arthropods, methods and risk assessment. CABI Publishing, Oxon, pp 15–37CrossRefGoogle Scholar
- Mochizuki A (2010) Invasive insects: problem and risk assessment. Extension bulletins, FFTC for the Asian and Pacific Region, Taipei. http://www.agnet.org/library/eb/616/
- Mochizuki A, Naka H, Hamasaki K, Mitsunaga T (2006) Larval cannibalism and intraguild predation between the introduced green lacewing, Chrysoperla carnea, and the indigenous trash-carrying green lacewing, Mallada desjardinsi (Neuroptera: Chrysopidae), as a case study of potential nontarget effect assessment. Environ Entomol 35:1298–1303CrossRefGoogle Scholar
- Murai T, Ishii T (1982) Simple rearing method for flower thrips (Thysanoptera: Thripidae) on pollens. Jpn J Appl Entomol Zool 26:149–154 (in Japanese with English summary)Google Scholar
- Sabelis MW, van Rijn PCJ (1997) Predation by insects and mites. In: Lewis T (ed) Thrips as crop pests. CAB International, London, pp 259–354Google Scholar
- Schausberger P, Croft BA (1999) Predation on and discrimination between con- and heterospecific eggs among specialist and generalist phytoseiid mites (Acari: Phytoseiidae). Environ Entomol 28:523–528Google Scholar
- van Rijn PCJ, Burgio G, Thomas MB (2005) Impact of intraspecific and intraguild predation on predator invasion and coexistence: can exotic ladybeetles displace native species? In: Hoddle MS (ed) Second international symposium on biological control of arthropods. USDA Forest Service Publication, Morgantown, pp 38–47Google Scholar