Genomic insights into kin selection and developmental conflict in co-occurring hairworm parasites

Many parasites manipulate the behaviour or appearance of their host to
improve their own survival or transmission, with manipulation timing
tightly linked to a parasite’s developmental stage. However, host
manipulations are complicated by the presence of co-occurring parasites
within the same host. Conspecific co-occurring parasites of similar
developmental stages, may interact collaboratively to manipulate a host.
However, co-occurring parasites of different developmental stages will
conflict with one another- especially when the manipulation is fatal to
developmentally immature co-occurring parasites. Kin selection further
complicates these interactions by predicting that closely related
co-occurring parasites may not interfere with the other’s manipulation.
Co-occurring hairworm (Nematomorpha) parasites are common, and the water
seeking manipulation mature worms induce is likely lethal to co-occurring
juvenile worms. To understand the role that kin selection may have on
these interactions we assess kin relationships in a wild hairworm
population. We sequence the first New Zealand hairworm (Gordius
paranensis) genome and use reduced representation sequencing to estimate
relatedness among co-occurring worms. We show that co-occurring hairworm
relatedness varies from unrelated to highly related and that both mature
and immature worms inhabit the same host. We discuss how these
developmental and kinship dynamics may shape host manipulations and
hairworm survival.