Sann, C.; Wemheuer, F.; Beaurepaire, A.; Daniel, R.; Erler, S.; Vidal, S. Preliminary Investigation of Species Diversity of Rice Hopper Parasitoids in Southeast Asia. Insects2018, 9, 19.
Sann, C.; Wemheuer, F.; Beaurepaire, A.; Daniel, R.; Erler, S.; Vidal, S. Preliminary Investigation of Species Diversity of Rice Hopper Parasitoids in Southeast Asia. Insects 2018, 9, 19.
On-going intensification of rice production systems in Southeast Asia is causing devastating yield losses each year due to rice hoppers. Continuing development of immunity to resistant rice varieties and pesticide application further complicate this problem. Hence, there is a high demand for biological control agents. Egg parasitoid wasps are among the most important natural enemies of rice hoppers such as Nilaparvata lugens and Nephotettix spp. However, our knowledge on their diversity is still very limited due to their small size and the lack of available morphological information. Classifying these parasitoids is the first step to properly understand their role in the rice agroecosystem. We used traditional morphological identification as well as DNA sequencing of COI and 28S genes to investigate the diversity of four important hopper egg parasitoid genera in the Philippines. Parasitoids of the genera Anagrus spp., Oligosita spp., Gonatocerus spp. and Paracentrobia spp. were collected in eight study landscapes located in Luzon. We found discrepancies between the morphological and the molecular analysis. Morphological and molecular results were only valid for Paracentrobia spp. Anagrus spp. and Gonatocerus spp. showed more genetic diversity, than expected after the morphological analysis, indicating cryptic species. The sequences for Oligosita spp. revealed less variation than expected. This is the first study on molecular diversity of rice parasitoids in the Philippines. More research combining morphological, behavioural and genetic methods as well as the establishment of a comprehensive DNA database is urgently needed to assess the performance and suitability of these organisms as biocontrol agents.
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