Assaying Predatory Feeding Behaviors in <em>Pristionchus</em> and Other Nematodes

Abstract

This protocol provides multiple methods for the analysis and quantification of predatory feeding behaviors in nematodes. Many nematode species including Pristionchus pacificus display complex behaviors, the most striking of which is the predation of other nematode larvae. However, as these behaviors are absent in the model organism Caenorhabditis elegans, they have thus far only recently been described in detail along with the development of reliable behavioral assays 1 . These predatory behaviors are dependent upon phenotypically plastic but fixed mouth morphs making the correct identification and categorization of these animals essential. In P. pacificus there are two mouth types, the stenostomatous and eurystomatous morphs 2 , with only the wide mouthed eurystomatous containing an extra tooth and being capable of killing other nematode larvae. Through the isolation of an abundance of size matched prey larvae and subsequent exposure to predatory nematodes, assays including both "corpse assays" and "bite assays" on correctly identified mouth morph nematodes are possible. These assays provide a means to rapidly quantify predation success rates and provide a detailed behavioral analysis of individual nematodes engaged in predatory feeding activities. In addition, with the use of a high-speed camera, visualization of changes in pharyngeal activity including tooth and pumping dynamics are also possible.

Serotonin Drives Predatory Feeding Behavior via Synchronous Feeding Rhythms in the Nematode Pristionchus pacificus

“…The “corpse assay” was performed as previously described ( Wilecki et al 2015 ; Lightfoot et al 2016 ). To collect young larvae as prey, freshly starved plates of C. elegans ( N2 ) were washed with M9 buffer and larvae were filtered twice with 20 µm Nylon Net Filters (Millipore, NY2004700).…”

“…The “biting assay” was performed as previously described by Wilecki et al (2015) and Lightfoot et al (2016) . In short, young larvae were collected as mentioned in the previous section.…”

“…Pumping and tooth movement were observed as previously described by Wilecki et al (2015) and Lightfoot et al (2016) . Worms were transferred to 35 mm NGM assay plates with E. coli OP50 or plates full with young larvae of C. elegans ( N2 ).…”

Succession and dynamics of Pristionchus nematodes and their microbiome during decomposition of Oryctes borbonicus on La Réunion Island

“…To study predation by P. pacificus nematodes, the corpse assay was performed as previously described (Wilecki et al, 2015;Lightfoot et al, 2016b). In brief, five P. pacificus nematodes were used as predators on approximately 1,000 prey J1 larvae.…”

Two independent sulfation processes regulate mouth-form plasticity in the nematodePristionchus pacificus

“…The dimorphism is associated with predatory feeding behavior, as Eu worms have the extraordinary ability to prey on other nematodes including Caenorhabditis elegans (Fig. 1C), whereas St worms are strictly bacteriovorous (Serobyan et al, 2014;Wilecki et al, 2015;Lightfoot et al, 2016). P. pacificus is amenable to the genetic analysis of mouth-form plasticity for several reasons (Sommer et al, 2017).…”