A new gregarine species (Eugregarinida: Gregarinidae) was previously reported from daikon leaf beetle, Phaedon brassicae at Daegwallyeong in Korea. Here, we found another novel gregarine species from the striped flea beetle, Phyllotreta striolata (Coleoptera: Chrysomelidae). This paper describes the morphological and molecular-biological characteristics of Gregarine species associated to P. brassicae and P. striolata. The size and body shape at mature trophozoite stage were the main diagnostic characteristics of those species. Gregarines from P. brassicae were bigger size (100um) with square shaped body while Gregarines from P. striolata were slightly smaller size (80um) with egg shaped body. Based on the partial 18S rDNA sequence, gregarine species from P. striolata was grouped in eugregarine and also this new gregarine showed 85% homology that of the reported Gregarina sp. from P. brassicae. However, gut dissection result showed that each species had own gregarine parasite species association. These results were identical in local populations from three surveyed locations. There was positive relationship between infection rates and elevation for gregarine related to P. striolata. Therefore, we suggested that the gregarines and their coleopteran hosts have species-specific interaction via co-evolution.

A new gregarine parasite (Apicomplexa: Protozoa) was observed in the population of the striped cabbage flea-beetle, Phyllotreta striolata (Coleoptera: Chrysomelidae) in Hoengseong-gun. Gregarines are well known species-specific parasites of various Arthropoda. Based on 954bp of 18S rDNA sequence, this gregarine species was grouped in eugregarine and also this new gregarine showed 85% homology that of the reported Gregarina sp. from daikon leaf beetle, Phaedon brassicae (FJ481523). These two coleopteran hosts were generally found coexist in highland cabbage fields. However, after gut dissection (n>50), each species confirmed has their own gregarine parasite species. These results were identical in surveyed three local populations (Pyeongchang-gun, Hoengseong-gun and Inje-gun). Therefore, we suggested that the gregarines and their coleopteran hosts has species specific interaction via co-evolution.

A gregarine parasite (Apicomplexa: Protozoa) was observed in the population of daikon leaf beetle, Phaedon brassicae Baly, (Coleoptera: Chrysomelidae) in Daegwallyeong. Gregarines are well known species-specific parasites of various Arthropoda. Based on 1.727kb of 18S rDNA sequence (FJ481523), this gregarine species was grouped in eugregarine and 5.258kb of full length rDNA replicon was cloned. We also observed interaction of tropozoite or gamonto of gregarine and epithelium of host midgut using scanning electron microscope. Although development of the infected host delayed half day in every larval stage, there was no significant difference in the development of daikon leaf beetle whether it is infected or not. Therefore, this gregarine parasite is not promising candidate for bio-insecticide in daikon leaf beetle.

Gregarine parasite (Apicomplexa: Protozoa) was observed in the population of daikon leaf beetle, Phaedon brassicae Baly (Coleoptera: Chrysomelidae) in Daegwallyeong. Morphological features of the gregarine in gut of P. brassicae have been studied by light microscope and scanning electron microscope with particular attention to the relationship between the epimerite and the host epithelium. On the average of mature trophozoite length and width are 100 and 40㎛, respectively. Based on 1.727kb of 18S rDNA sequence, this gregarine grouped in eugregarine.