A team led by Dr. LUO Shixiao at South China Botanical Garden (SCBG) of the Chinese Academy of Sciences and Dr. CHEN Huayan at Sun Yat-sen University, discovered two new parasitoid species named Ismarus areolatus and Ismarus paradorsiger from the botanical garden.
Their study was published in the Journal of Hymenoptera Research.
The two new species belongs to a rare parasitoid family Ismaridae, which only has about 60 described species worldwide and less than 10 species from China.
Specie of Ismaridae are actually hyperparasitoids of Dryinida, which are parasitoids of Auchenorrhyncha (Hemiptera), such as leafhoppers, planthoppers and treehoppers.
According to previous studies, species of Ismaridae are likely to be found from wooded areas at higher elevations in warmer climatic zones and at low elevations in cooler climatic zones. However, the new species I. areolatus was found in SCBG and Yunkaishan Mountain, both of which are at low elevations in warmer climatic zone, suggesting that Ismarids might be able to adapt to wider ranges than previously thought.
Dryinidae are important natural enemies of leafhoppers in forestry and agriculture and some species have been successfully used in the biological control of leafhoppers. While Ismarids are hyperparasitoids of Dryinidae, and therefore may diminish the effectiveness of Dryinidae against leafhoppers.
"Understanding their adaptation to environment and climate can help reduce the negative effect of Ismarids on Dryinidae species in biological control programs," said Dr. CHEN.
A healthy ecosystem should include a stable composition of all kinds of organisms from different trophic levels. "The presence of Ismarids indicates a high diversity and abundance of Dryinidae in the botanical garden and Dryinidae species play a key role in keeping the leafhopper populations. Thus, Ismarids can be used as bioindicators to access the health of the ecosystem," said Dr. LUO.
Fig. 1 Ismarus areolatus Chen, 2021 (Image by CHEN Huayan)
Fig. 2 Ismarus paradorsiger Chen, 2021 (Image by CHEN Huayan)
Fig. 3 Left: leafhopper parasitized by Dryinidae; Right: nymphal planthopper parasitized by Dryinidae. Arrows showing the lava of Dryinidae. (Image by CHEN Huayan)
