Distribution of the parasitic isopod Tachaea chinensis in China

Abstract

Tachaea chinensis Thielemann, 1910 (Isopoda: Corallanidae) is a branchial ectoparasite that attaches onto shrimps and prawns. However, the distribution of T. chinensis in China, especially its epidemiology, remains unclear. We determined the prevalence of T. chinensis on the ridgetail white prawn (Exopalaemon carinicauda Holthuis, 1950) in Jiangsu Province. Fifty ponds in 10 shrimp farms were assessed. Isopod species were identified by morphological features and mitochondrial 16S rRNA gene analysis. A literature review was performed to determine the geographical distribution of T. chinensis in China. Published data revealed that T. chinensis was geographically distributed throughout five provinces in China, including Liaoning, Tianjin, Henan, Hubei, and Guangxi. A total of 998 T. chinensis were collected from 50 ridgetail white prawn ponds in Yancheng City and Rudong County. Tachaea chinensis prevalence ranged from 0.98% to 4.42% in Yancheng City and 0.62% to 0.92% in Rudong County. This is the first study to investigate the geographical distribution of T. chinensis in China and determine the prevalence of T. chinensis on the ridgetail white prawn in Jiangsu Province. Overall, we provide available data that fill gaps in the epidemiology of T. chinensis.

Host selection and potential predation in the host-parasite interaction between the isopod Tachaea chinensis and freshwater host species

“…Therefore, T. chinensis isopod may demonstrate a high degree of flexibility with regard to host species and readily adapt to different hosts that provide adequate space for attachment. Previous studies from China and Japan have also come to similar conclusions ( Ota, 2019 ; Xu et al, 2019 ).…”

“…The ectoparasite Tachaea chinensis has been found infesting a broad range of host shrimps and prawns, including the three families Atyidae, Palaemonidae, and Penaeidae ( Xu et al, 2019 ; Nagasawa et al, 2018 ). The observed host–parasite associations may not necessarily correspond to low host specificity of the isopods because such interactions are greatly influenced by biotic and abiotic factors ( Nagel and Grutter, 2007 ).…”

“…Isopod prevalence may be partially governed by the locality and type of species found at a given location ( Nagasawa et al, 2018 ; Ota, 2019 ; Xu et al, 2019 ), which might explain the great variability in the selected host species in the single-host treatments. Therefore, T. chinensis isopod may demonstrate a high degree of flexibility with regard to host species and readily adapt to different hosts that provide adequate space for attachment.…”

“…In Japan, the isopod T. chinensis is found on various host species depending on the density of the host species at a given site, but they are frequently observed infesting the shrimp Palaemon paucidens De Hann, 1844, in the Honshu region in Japan's mainland ( Nagasawa et al, 2018 ). This isopod has also been found infesting the exotic shrimp Palaemon sinensis (Sollaud, 1911) in Japan ( Oonuki et al, 2010 ; Imai and Oonuki, 2014 ; Saito, 2017 , 2018 ; Saito et al, 2016 , 2019 ; Imai et al, 2021 ; Ogasawara et al, 2021 ), as well as P. sinensis in rice fields in China ( Xu et al, 2019 ). Other potential hosts include the prawn Macrobrachium nipponense (De Haan, 1849), the invasive crayfish Procambarus clarkii (Girard, 1852), and freshwater fishes occupying similar habitats.…”

“…Tachaea chinensis Thielemann, 1910 is an ectoparasitic isopod infesting freshwater shrimps and prawns in Japan, China, Vietnam, Thailand, and Malaysia ( Shiino, 1965 ; Nagasawa et al, 2018 ; Xu et al, 2019 , 2021 ; Nunomura and Shimomura, 2020 ). It exhibits a biphasic lifestyle– isopods in the manca stage and immature stage infest the host shrimps, whereas during the mature stages, they detach for reproductive proposes ( Ota, 2019 ).…”