Biogeographic Patterns of Hosts and Their Ectoparasites

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Biogeographic Patterns of Hosts and Their
Ectoparasites
Jason D. Weckstein and Kevin P. Johnson
Illinois Natural History Survey - CBD
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Matching Distributions
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Range Restricted Parasite
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Widespread Parasite
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Replacement Parasites
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Why Chewing Lice?
1) Simple Life History.
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Louse Life Cycle
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Why Chewing Lice?
1) Simple Life History.
2) Primarily transmitted between mates
and between parents and offspring.
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Why Chewing Lice?
1) Simple Life History.
2) Primarily transmitted between mates
and between parents and offspring.
3) Often specialized on living on one region of
the host body.
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Why Chewing Lice?
1) Simple Life History.
2) Primarily transmitted between mates
and between parents and offspring.
3) Often specialized on living on one region of
the host body.
4) Often host specific.
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Why Chewing Lice?
1) Simple Life History.
2) Primarily transmitted between mates
and between parents and offspring.
3) Often specialized on living on one region of
the host body.
4) Often host specific.
5) Birds often host multiple genera of lice.
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Problems in Understanding the Geographic
Distribution of Chewing Lice
1) Taxonomic revision based on host associations.
e.g. The Colpocephalum (Mallophaga Menoponidae)
of the Pelecaniformes
2) Specimens are often sorted by host rather
than biogeographic region.
3) Researchers almost never report the absence
of lice in a particular geographic region.
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Outline of Examples
1) Gaps in Parasite Distributions
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(Moyer et al., 2002)
Tucson
Weslaco
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(Moyer et al., 2002)
Louse Prevalence
Tucson
Weslaco
P lt 0.001
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Outline of Examples
1) Gaps in Parasite Distributions
2) Replacement Parasites
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Pectinopygus spp. Distribution
(Clay, 1964)
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Pectinopygus spp. Distribution
(Clay, 1964)
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Perfect Cospeciation
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Outline of Examples
1) Gaps in Parasite Distributions
2) Replacement Parasites
3) Biogeography and Host Switching
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-Restricted to toucans
-Microhabitat specialists
-Sedentary
-Phoresis
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MtDNA
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Austrophilopterus cancellosus
83
99
73
89
100
100
100
100
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Questions
1) Cospeciation?
2) Degree of host specificity?

• How does host and parasite biology explain
• the host association patterns and cophylogenetic
• history?

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Perfect Cospeciation
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Austrophilopterus cancellosus
83
99
73
89
100
100
100
100
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Austrophilopterus cancellosus
83
99
73
73
89
100
100
100
100
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Austrophilopterus cancellosus
83
99
73
73
89
100
100
100
100
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How can we explain this lack of Cospeciation and
host specificity?
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Austrophilopterus cancellosus
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Austrophilopterus cancellosus
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Austrophilopterus cancellosus
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How are Austrophilopterus switching hosts?
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Phoresis by Ischnocerans
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Hole-Nesting
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Toucan Louse Conclusions
1) Cospeciation is rare between Austrophilopterus
lice and toucan hosts.
2) Austrophilopterus lice are not highly host
specific, but are geographically specific.
3) Host-switching is likely the cause of
incongruence.
4) Austrophilopterus has a widespread host
distribution but has biogeographic structure.
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Outline of Examples
1) Gaps in Parasite Distributions
2) Replacement Parasites
3) Biogeography and Host Switching
4) Deep Biogeographic Structure
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0.5 substitutions/site
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Coloceras
Kodocephalon suborbiculatum
0.5 substitutions/site
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Coloceras
True Coloceras (Tendeiro, 1973)
0.5 substitutions/site
0.5 substitutions/site
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0.5 substitutions/site
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Nitzschiella (Tendeiro, 1969)
0.5 substitutions/site
0.5 substitutions/site
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0.5 substitutions/site
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0.5 substitutions/site
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Dove Phylogeny
Treron waalia
Goura victoria
Phapitreron leucotis
Phapitreron amethystina
Hemiphaga novaeseelandiae
Ducula bicolor
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22 Cospeciation Events
P lt 0.001
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Host Group
Body Louse Phylogeny
Mid-sized Doves
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Biogeography
Body Louse Phylogeny
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Dove Body Louse Conclusions
1) Dove body lice in general show significant
levels of cospeciation.
2) Not all genera of dove body lice show lots of
cospeciation.
3) Where host switching is relatively common,
host group phylogenetic signal should be weak
relative to biogeographic signal.
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Factors affecting the Biogeographic Structure of
Lice
1) Host specificity.
2) Parasite mobility.
3) Dispersal abilities of phoretic vectors like
Hippoboscid flies.
4) Presence of climatic or biogeographic barriers
to louse dispersal that do not affect the host.
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Why is Biogeography important in studies of
parasites?
1) Cospeciation is not ubiquitous.
2) Many parasites have distributions that
mismatch a single hosts distribution.
3) Biogeographic information can help us to
identify host-switching events in cophylogenetic
analyses.
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