Full length articleIdentification of egg parasitoids of rice leafhoppers and planthoppers (Hemiptera: Cicadellidae and Delphacidae) of economic importance in Taiwan, part 2: Trichogrammatidae (Hymenoptera)
Graphical abstract
Lectotype female of Japania andoi (=Paracentrobia (Brachistella) bicolor) (left); lectotype slide of Japania andoi (middle); and Pseudoligosita nephotetticum male (right). Photos by Serguei Vladimirovich Triapitsyn and Junsuke Yamasako.
Introduction
Trichogrammatidae (Hymenoptera: Chalcidoidea) is a family whose members are egg parasitoids of various insects; as such, several genera and species are important as natural enemies of agricultural pests, including rice leafhoppers and planthoppers (Hemiptera: Cicadellidae and Delphacidae) in Asia (Triapitsyn, 2013, Triapitsyn et al., 2018).
In Taiwan, Lin, 1974, Miura et al., 1981 reported on some egg parasitoids of rice leafhoppers and planthoppers. Of these, the important survey of Lin (1974) was the most comprehensive, covering the entire island, and also indicating percent parasitism of eggs of some of the pest species and identifying three trichogrammatid species (some determined only to genus) of egg parasitoids and providing a key to them. However, many of his identifications are now outdated, and some of them also indicated incorrect host associations. Later, Chu and Hirashima (1981) summarized the earlier Taiwanese literature on the natural enemies of rice leafhoppers and planthoppers, while Hirashima (1981) provided information on their survey in Taiwan conducted by the Japanese entomologists in the late 1970s. Unfortunately, almost no voucher specimens from these earlier studies in Taiwan could be found in the museum collections there or in Japan (Triapitsyn, 2018), so our survey had to begin from scratch and rely almost exclusively on the freshly collected and identified specimens, as well as on the critical taxonomic analysis of the previously published such records presented by the same author.
The first part of the current survey dealt with identification of the genera and species of Mymaridae (Hymenoptera) which are egg parasitoids of rice leafhoppers and planthoppers in Taiwan (Triapitsyn et al., 2020).
Because there are no reliable species determination keys currently available for any of the genera involved for the Oriental region, detailed illustrations (digital images) are provided to facilitate identification of the egg parasitoids treated herein. However, the generic keys (both in Chinese and English) and the relevant species keys (only in Chinese) for the Trichogrammatidae of China, as well as line drawings in Lin (1994) can be useful to identify the genera and at least some of the species included in this review.
Section snippets
Rearing
During 2016–2018, egg parasitoids of selected species of rice pests belonging to the Auchenorrhyncha, i.e., Maiestas dorsalis (Motschulsky) (zig-zag leafhopper) and Nephotettix cincticeps (Uhler) (green rice leafhopper) (Cicadellidae), as well as Laodelphax striatella (Fallén) (small brown planthopper), Nilaparvata lugens (Stål) (brown planthopper), and Sogatella furcifera (Horváth) (whitebacked planthopper) (Delphacidae), were reared in Chiayi, Hsinchu, Taitung, and Yunlin counties as well as
Confirmed (by rearing using sentinel eggs exposed in rice fields) trichogrammatid egg parasitoids of rice leafhoppers and planthoppers in Taiwan
Oligosita ?japonica Yashiro, 1979 (Fig. 1-4, Fig. 5-7)
?Oligosita sp. B: Lin, 1974: 94–98 (recorded from Pingtung; key, illustration of a fore wing, descriptive notes, host association).
?Oligosita sp.: Lin, 1981: 441 (in part, one of the two species common in rice fields in Taiwan).
Oligosita japonica Yashiro, 1979: 196 (key), 199–200. Type locality: Hatakeda, Ouji (Ōji), Nara Prefecture, Honshu Island, Japan. Holotype female (on slide, EUMJ), not examined.
Oligosita japonica Yashiro: Lin, 1994:
An excluded (although earlier reported as such) trichogrammatid which is not an egg parasitoid of rice leafhoppers in Taiwan
Lathromeroidea sp. (L. ?silvarum Nowicki, 1936) (Figs. 33–34)
Lathromeroidea sp.: Lin, 1981: 431 (rather abundant in Taiwan on grass).
Lathromeroidea nigra Girault: Lin, 1994: 106–107 (misidentification; redescription, illustrations, distribution).
Lathromeroidea silvarum Nowicki: Fursov, 2005: 166–169 (redescription, distribution, hosts, biology, behavior, illustrations; incorrectly indicated as described in 1937).
Material examined. Taiwan, Taichung, Wufeng, TARI, 24°01′52.4″N 120°41′34.2″E,
Discussion
Initially, plants containing parasitized eggs of rice leafhoppers and planthoppers were held in the emergence cages only for two weeks. Later (in fall of 2018), this period was extended for at least one month because the life cycle of the trichogrammatids attacking eggs of rice leafhoppers and planthoppers takes longer than that of the mymarids parasitizing eggs of the same hosts, as shown for Paracentrobia andoi by Miura (1990), who indicated its developmental period from egg to adult
Acknowledgements
We thank Mr. Vladimir V. Berezovskiy (UCRC) for mounting specimens, Dr. Charng-Pei Lee (TARI) for assistance with field surveys, Ms. Mei-Jung Tseng and Ms. Shiou-Ping Hsu (TARI) for collecting and help in processing Malaise, yellow pan trap, and reared samples, Dr. Chi-Feng Lee (TARI) and Dr. Gennaro Viggiani (DEZA) for providing access to the respective collections of Trichogrammatidae, Dr. Junsuke Yamasako (Insect Systematics Unit, Division of Informatics and Inventory, Institute for
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2023, Journal of Asia-Pacific EntomologyIdentification of egg parasitoids of rice leafhoppers and planthoppers (Hemiptera: Cicadellidae and Delphacidae) of economic importance in Taiwan, part 1: Mymaridae (Hymenoptera)
2021, Journal of Asia-Pacific EntomologyCitation Excerpt :It was a particularly dominant parasitoid of Nilaparvata lugens eggs while rarely attacking eggs of Nephotettix cincticeps (Figs. 23–24). In the same study but for the Trichogrammatidae (Triapitsyn et al., 2020), Pseudoligosita nephotetticum (Mani) was shown to be the most common egg parasitoid of the same two leafhopper and three planthopper pests of rice in Taiwan, albeit in much smaller overall numbers than A. incarnatus. Contrary to the earlier reports by Lin (1974) and Chu and Hirashima (1981), Gonatocerus aegyptiacus and Mymar taprobanicum seem to be parasitizing only eggs of Cicadellidae and not of any Delphacidae, not discriminating between eggs of Maiestas dorsalis and Nephotettix cincticeps in the conventional rice field (Fig. 24).