The Nematode Pristionchus pacificus (Nematoda: Diplogastridae) Is Associated with the Oriental Beetle Exomala orientalis (Coleoptera: Scarabaeidae) in Japan

Abstract

Pristionchus pacificus has been developed as a nematode satellite organism in evolutionary developmental biology. Detailed studies of vulva development revealed multiple differences in genetic and molecular control in P. pacificus compared to the model organism Caenorhabditis elegans. To place evolutionary developmental biology in a comprehensive evolutionary context, such studies have to be complemented with ecology. In recent field studies in western Europe and eastern North America we found 11 Pristionchus species that are closely associated with scarab beetles and the Colorado potato beetle. However, P. pacificus was not commonly found in association with scarab beetles in these studies. Here, we describe the results of a similar survey of scarab beetles in Japan. Pristionchus pacificus was the most common Pristionchus species on scarab beetles in Japan, with 40 out of 43 (93%) isolates. The other Pristionchus isolates represent three novel species, which we refer to as Pristionchus sp. 11, Pristionchus sp. 14, and Pristionchus sp. 15. Thirty-seven of the established P. pacificus strains were found on the oriental beetle Exomala orientalis. Laboratory studies with the sex pheromone (Z)-7-tetradecen-2-one of the oriental beetle revealed that P. pacificus shows strong olfactory attraction to the beetle's sex pheromone, which provides a potential mechanism for the recognition and interaction of P. pacificus and E. orientalis. Together, this study identifies P. pacificus as the most common Pristionchus nematode in field studies in Japan, identifies E. orientalis as an important host species, and provides the basis for the ecology of P. pacificus.

Host-finding behaviour in the nematodePristionchus pacificus

“…Steinernema species, both cruiser and ambusher, respond strongly to volatile cues [66]. Our experiments show that Pristionchus species first have the ability to recognize and move towards host-associated volatiles by chemotaxis, which typically applies to a cruiser strategy [22,64]. Second, P. pacificus show nictation behaviour that applies to a typical ambusher behaviour as well.…”

“…Pristionchus pacificus, a satellite model nematode for evolutionary and developmental studies, is known to live in association with scarab beetles in nature [21,22].…”

Opposing Forces of A/T-Biased Mutations and G/C-Biased Gene Conversions Shape the Genome of the Nematode Pristionchus pacificus

“…Potential support for a role of oxidative stress comes from the known ecosystem of P. pacificus and related nematodes. Unlike C. elegans, Pristionchus lives in tight association with scarab beetles in a necromenic interaction (Herrmann et al 2007(Herrmann et al , 2010. Nematodes rest on the living beetle in the dauer stage (Weller et al 2010) and resume development on the beetle carcass only to feed on all types of microbes (McGaughran et al 2013).…”

Molecular and morphological characterization of Pristionchus pacificus (Nematoda: Rhabditida: Neodiplogastridae), a new record of an entomophilic nematode from Iran

“…Some differences between P. pacificus and C. elegans with respect to the development of the vulva, the gonad and the buccal cavity, have contributed to this species being an ideal satellite organism in comparative studies with C. elegans (Rudel et al 2005;Hong & Sommer 2006;Herrmann et al 2007;Zauner et al 2007;Click et al 2009). Morgan et al (2012) mentioned that the complex effects of environmental, ecological and geological factors can influence local adaptation and genotypic evolution in P. pacificus.…”

“…This species is a satellite model nematode which used in evolutionary and developmental studies like another model species, Caeonorhabditis elegans (Maupas, 1900) (Rudel et al 2005;Hong & Sommer 2006;Herrmann et al 2007;Zauner et al 2007;Click et al 2009). P. pacificus has worldwide distribution and by now, more than 150 isolates have been recovered from soil and scarab beetles in different continents Rae et al 2008;Kanzaki et al 2011).…”