Detection of Insect Pathogen Serratia marcescens in Protaetia brevitarsis seulensis (Kolbe) from Korea

Abstract

Protaetia brevitarsis seulensis (Kolbe) is widely used in Korea, as a protein-rich, alternate, functional food with pharmacological benefits. In addition to anti-oxidant properties, the larvae of P. b. seulensis also show positive effects against hepatic disorder and diabetes; therefore, P. b. seulensis larvae are being reared on a large scale in Korea. We evaluated reared larvae of P. b. seulensis from Gyeong-gi in Korea. Using 16SrRNA PCR, electro-microscopy, and bioassay techniques, we found that the larvae harbored Spo-1, a bacterium identified as the insect pathogen Serratia marcescens. Therefore, we highlight the use of this insect as an alternate food and the need for its sanitary rearing conditions, as contamination may affect public health. IntroductionThe white-spotted flower chafer, Protaetia brevitarsis seulensis, is an insect that belongs to Coleoptera species (Coleoptera: Scarabaeidae). Its life cycle includes the embryo, larva, pupa, and imago stages, of which the larval stage is the longest, where the insect feeds and stores energy for the rest of its life cycle. In Asian countries, P. brevitarsis seulensis larvae are generally known to be pharmacologically effective and used as medicine (Suh et al., 2010). Several reports suggest that P. brevitarsis extract in Lewis' methanol has antioxidant (Suh et al., 2010), anti-hepatofibrosis, and anti-diabetic properties (Miyanoshita et al., 1996). In addition, scientific reports highlight that, based on the composition of P. brevitarsis seulensis larvae, they can be used as a functional health food. Thus, it is essential to verify that the rearing conditions for P. brevitarsis seulensis larvae are sanitary and safe for consumption as food. On the other hand, Serratia marcescens is a bacterial pathogen, found in soil (Grimont and Grimont, 2006), water (Ajithkumar, 2003;Grimont and Grimont, 2006), and plant material (Grimont and Grimont, 2006). It is also known by alternate names such as Bacillus sphingidis (White, G.F., 1923) and Bacillus asepticus (Burnside, 1928) when it does not show its characteristic red pigment but rather grows as white colonies. S. marcescens and Serratia sp. generally are known to be fatal pathogens of several insect species (Orthoptera, Coleoptera, Hymenoptera, Lepidoptera, and Diptera) once they enter the hemocoel (Tanada et al., 1993

Comparing the mortality of Protaetia brevitarsis seulensis (Coleoptera: Cetoniidae) caused by entomopathogenic bacteria and Serratia marcescens (Enterobacteriales: Enterobacteriaceae)

“…seulensis larvae via hemolymph injection of S. marcescens (Kwak et al 2014), but showed 0% mortality when 3 We observed mortality after 4 wk when insect sawdust was treated with Sm together with Bt and Pp, which are known to its mortality rate after 4 wk was 95.23%, which was 42.85% higher than the Pp treatment alone. Since mortality is maximal when P. popilliae and S. marcescens are detected together in a breeding environment or in sawdust, the results of this study can be utilized in the prevention and diagnosis of such cases.…”

“…Bombyx mori (Lepidoptera: Bombycidae), P. b. seulensis (Coleoptera: Cetoniidae), and Rhagoletis pomonella (Diptera: Tephritidae) (Ishii et al 2014;Kwak et al 2014;Lauzon C. R. 2003). Moreover, S. marcescens is also considered to be an opportunistic pathogen and can cause antibioticresistant hospital-acquired infections (Murdoch et al 2011).…”

“…Some of these cases involved insects that are used as traditional medicines with proven efficacy (Chung et al 2013a;Chung et al 2013b;Kwon et al 2013). The distribution and sales of certain edible insects have accelerated the industrialization of insects; however, the mass breeding of insects has also caused an increase in diseases (Kwak et al 2014;Lee et al 2015). Accordingly, increased monitoring has been initiated for diseases occurring in farms of Protaetia brevitarsis seulensis (Coleoptera: Cetoniidae), an edible insect that is mass-reared in Korea, as well as the Japanese rhinoceros beetle Allomyrina dichotoma (Coleoptera: Scarabaeidae), and diseases with a high incidence were identified.…”

Soil Application of Metarhizium anisopliae JEF-314 Granules to Control, Flower Chafer Beetle, Protaetia brevitarsis seulensis

“…We showed that this isolate is highly virulent to the beetle larvae and inhibits the insect egg hatching in laboratory experimental conditions. Larval stages are the longest of the insect life cycle, where the insect feeds on various sources of decaying cellulose, including roots of grass and weed, rice straw and Oakwood [13]. The subterranean habitats of the white grubs, make them difficult to control since applied insecticides have to move into the soil.…”

“…This species is widely distributed in Korea, Japan, China, Taiwan and some parts of Europe [11,12]. Its life cycle comprises the embryo, larva, pupa, and imago stages, of which the larval stage is the longest and is the stage when the insect feeds and stores energy for the rest of the life cycle [13]. Depending on habitat conditions, adults can be observed in Korea from May to October with greatest abundance in July.…”