Fig. 1: Bacterial diet modulates killing behavior in P. pacificus.

a Eurystomatous (Eu) and stenostomatous (St) mouth forms. Eu worms are capable of predation and have a wide mouth with two teeth, whereas St worms feed on bacteria and have a narrower mouth with one tooth. b A predatory P. pacificus adult biting a C. elegans larvae. c Corpse assay of P. pacificus predators fed upon C. elegans larvae following growth on a variety of bacteria from Pristionchus-associated environments; five predators are fed prey for 2 h for each assay. N = 5 replicates for each assay. d Bite assay after growth on either an E. coli OP50 or Novosphingobium L76 diet to assess the effect on P. pacificus surplus-killing behavior. Numbers of bites, successful bites and feeding was quantified during a 10 min interval while fed upon C. elegans larvae. e Corpse assay of P. pacificus fed with E. coli OP50, Novosphingobium L76 or of E. coli OP50 with Novosphingobium L76 supernatant. N = 10 replicates for each assay for d and e. f Corpse assays of P. pacificus previously fed with a mixture of Novosphingobium L76 and E. coli OP50 at 1/10, 1/100, and 1/1000 concentrations. Low concentrations of Novosphingobium L76 in the diet is sufficient to influence killing behavior. Bacteria were spotted to NGM without peptone to prevent bacterial growth. N = 10 replicates for each assay.