Fig 1.
P. pacificus dauer formation and natural variation.
(A) P. pacificus life cycle. (B) The scarab beetles Exomala orientalis (left) and Oryctes borbonicus (right) are two natural hosts of P. pacificus in Japan and La Réunion Island, respectively. (C) Natural variation in dauer longevity and fitness as measured by brood size after recovery from cold storage (data from [13]). The strain RS5134 from Ohio represents the most long-lived strain of P. pacificus and has a relatively high brood size of approximately 100 progeny even after a cold storage of 46 weeks. (D) Cross-preference of eight strains in response to RS2333 and RS5134 dauer pheromone (data from [13]).
Fig 2.
Ussing chamber setup and competition assay.
(A) Ussing chamber competition assay setup. (B) Intraspecific competition between RS2333 and RS5134 observed over time. In control experiments (c) both compartments of the Ussing chamber are filled with the same strain, whereas in the competition experiment (e) one compartment contains RS2333 and the other RS5134. Values are mean dauer formation of three replicates. Error bars represent 95% confidence intervals.
Fig 3.
(A) Genetic map of chromosome I. The chromosomal interval associated with the QTL ME25944 contains two gene predictions. (B) RS2333, RS106, and RS5134 resequencing coverage. The 4.3 kb duplicated region is highlighted in red. (C) Copy numbers and organization of Contig44-snap.18 in RS2333 and RS5134. Colored blocks indicate unique sequences flanking the 4.3 kb duplicated region. Red vertical lines represent the 13 SNPs between RS2333 and RS5134.
Table 1.
Dauer formation of transgenic lines, CAN ablated animals, and dau-1 mutants in response to RS2333 and RS5134 pheromone.
Fig 4.
dau-1 expression and phylogeny.
(A) dau-1 is expressed in CAN neurons. Image shows the cell body of the left CAN neuron. Neuronal processes are not visible in this focal plane. (B) dau-1 phylogeny indicates several independent duplications after the speciation event leading to P. pacificus.
Fig 5.
dau-1 genetic and physical ablation.
Dauer formation (mean of three replicates) of CAN ablated and dau-1 mutant animals in response to RS5134 pheromone. Error bars represent 95% confidence intervals. *P<0.05, **P<0.0005, and ***P<0.0001 (Fisher's exact test). See Table 1 for details.
Fig 6.
dau-1 regulates dauer formation and shows a strong dosage effect. One and two copies of dau-1 result in high and low dauer formation, respectively. dau-1 double mutants show increased dauer formation, whereas multiple dau-1 copies inhibit dauer development. Roman numbers represent P. pacificus chromosomes.