Caenorhabditis elegans dauers vary recovery in response to bacteria from natural habitat

Abstract

Many species use dormant stages for habitat selection by tying recovery to informative external cues. Other species have an undiscerning strategy in which they recover randomly despite having advanced sensory systems. We investigated whether elements of a species' habitat structure and life history can bar it from developing a discerning recovery strategy. The nematode Caenorhabditis elegans has a dormant stage called the dauer larva that disperses between habitat patches. On one hand, C. elegans colonization success is profoundly influenced by the bacteria found in its habitat patches, so we might expect this to select for a discerning strategy. On the other hand, C. elegans' habitat structure and life history suggest that there is no fitness benefit to varying recovery, which might select for an undiscerning strategy. We exposed dauers of three genotypes to a range of bacteria acquired from the worms' natural habitat. We found that C. elegans dauers recover in all conditions but increase recovery on certain bacteria depending on the worm's genotype, suggesting a combination of undiscerning and discerning strategies. Additionally, the worms' responses did not match the bacteria's objective quality, suggesting that their decision is based on other characteristics.

Multidimensional competition of nematodes affects plastic traits in a beetle ecosystem

“…Pristionchus pacificus dauers were not as prone to actively disperse as beetle-derived dauers (until t = 6 weeks, they were restricted to the beetle compartment) ( Figure 4 ), suggesting another effect of domestication. Indeed, bacteria influence dauer characteristics, and a domesticated strain may be insensitive to those stimuli ( Samuel et al, 2016 ; Bubrig et al, 2020 ). Unexpectedly, P. pacificus did not display exclusively high rates of Eu ( Figure 5 ), in contrast to its morph ratios in lab, >95% ( Werner et al, 2017 ; Sieriebriennikov et al, 2020 ).…”

Nematode Interactions on Beetle Hosts Indicate a Role of Mouth-Form Plasticity in Resource Competition

“…Mainly, the bacteria present on the decaying carcass may play roles both in worm developmental stages and thus dispersal, and mouth form tendencies. Bacterial influence on nematode polyphenisms is well-explored, with several studies demonstrating microbial impact on dauer induction, Eu formation, and predatory rates (Samuel et al, 2016;Akduman et al, 2018Akduman et al, , 2020Bubrig et al, 2020).…”

Transposon-mediated genic rearrangements underlie variation in small RNA pathways

“…Long-read genome assemblies of 17 wild C. elegans strains are presently available [23][24][25][26] , in addition to the reference strain N2. We first performed a multiple pairwise alignment of the eri-6/7 region among these strains (Fig.…”