Community interactions govern host-switching with implications for host–parasite coevolutionary history

Abstract

Reciprocal selective effects between coevolving species are often influenced by interactions with the broader ecological community. Community-level interactions may also influence macroevolutionary patterns of coevolution, such as cospeciation, but this hypothesis has received little attention. We studied two groups of ecologically similar feather lice (Phthiraptera: Ischnocera) that differ in their patterns of association with a single group of hosts. The two groups, "body lice" and "wing lice," are both parasites of pigeons and doves (Columbiformes). Body lice are more host-specific and show greater population genetic structure than wing lice. The macroevolutionary history of body lice also parallels that of their columbiform hosts more closely than does the evolutionary history of wing lice. The closer association of body lice with hosts, compared with wing lice, can be explained if body lice are less capable of switching hosts than wing lice. Wing lice sometimes disperse phoretically on parasitic flies (Diptera: Hippoboscidae), but body lice seldom engage in this behavior. We tested the hypothesis that wing lice switch host species more often than body lice, and that the difference is governed by phoresis. Our results show that, where flies are present, wing lice switch to novel host species in sufficient numbers to establish viable populations on the new host. Body lice do not switch hosts, even where flies are present. Thus, differences in the coevolutionary history of wing and body lice can be explained by differences in host-switching, mediated by a member of the broader parasite community.coevolutionary biology | community ecology | phoresy | ectoparasites

Cophylogenetic patterns are uncorrelated between two lineages of parasites on the same hosts

“…For example, a stronger signal of cospeciation in most of the body louse data sets alludes to phoresis behaviour in wing lice, as described previously (Harbison et al, 2008(Harbison et al, , 2009Harbison & Clayton, 2011). For example, a stronger signal of cospeciation in most of the body louse data sets alludes to phoresis behaviour in wing lice, as described previously (Harbison et al, 2008(Harbison et al, , 2009Harbison & Clayton, 2011).…”

Population structure of a vector‐borne plant parasite

“…; Whiteman et al . ; Hoberg & Brooks ; Harbison & Clayton ). The presence of immigrants between host species suggests plasticity or standing variation in host range, a factor also hypothesized to correlate with host‐switching ability (Hoberg & Brooks ).…”

Phylogenetic analysis of symbionts in feather-feeding lice of the genus Columbicola: evidence for repeated symbiont replacements

“…Another possibility is that horizontal symbiont transfers are mediated between different louse species by interspecific mating, as reported for facultative symbionts in the pea aphid [36]. While there is no evidence of interspecific mating in Columbicola spp., it is notable that these lice undergo host switching through phoretic dispersal on hippoboscid louse flies [8]. This could at least facilitate contact between males and females of different louse species.…”

“…Transmission of lice between birds occurs mainly during periods of direct contact, as occurs between parent birds and their offspring in the nest [7]. However, Columbicola are also known to disperse phoretically on hippoboscid louse flies, which are winged parasites of birds [7,8]. True to their name, feather lice feed primarily on feathers, secretions, dead skin and other dermal “debris” [9].…”