Does a biological invasion modify host immune responses to parasite infection?
Data files
Dec 13, 2024 version files 51.77 KB
Abstract
Biological invasions disrupt the spatial structuring of antagonistic co-evolution between host and parasites. At the same time, the shifting demographic and selective landscapes during invasion can result in rapid evolution of traits in both host and parasite. Hosts at the invasion front may reduce investment into costly immune defences and redistribute those resources to other fitness-enhancing traits. Parasites at the invasion front may have reduced pathogenicity because traits that negatively impact host dispersal are left behind in the expanding range. The host’s immune system is its primary arsenal in the coevolutionary ‘arms race’ with parasites. To assess the effects of invasion history on immune responses to parasite infection we conducted a cross-infection experiment which paired common-garden reared cane toads and lungworm parasites originating from various sites in their invaded range across northern Australia. Infected toads had larger spleens and higher concentrations of eosinophils than did uninfected toads. Infected toads also exhibited lower bacteria-killing ability, perhaps reflecting a trade-off of resources towards defences that are more specifically anthelminthic. The impact of infection intensity on multiple immune measures differed among toads and parasites from different parts of the invasion trajectory, supporting the hypothesis that invasion has disrupted patterns of local adaptation.
README: Does a biological invasion modify host immune responses to parasite infection?
https://doi.org/10.5061/dryad.ghx3ffc09
Description of the data and file structure
Files and variables
Data are from an experiment where cane toads from different sites were exposed to lungworm parasites from different sites. Toad immune responses to infection were then measured.
Missing values are indicated by 'NA'
ID – Individual ID code
infection treatment- Control or exposed to parasites from one of 6 sites: CONT (= control), CNS (= Cairns), FITZ (= Fitzroy Crossing), JAB (= Jabiru), KNX (= Kununurra), ML (= Marlow Lagoon), TWN (= Townsville).
litter- ID code indicating family origin of each toad
toad_site- location from which each toads parents were captured
toad_state- Australian state each capture location was in. 1-WA (= Western Australia), 2-NT (= Northern Territory), 3-QLD (= Queensland).
Exposed to Rhabdias?- Yes vs No variable to indicate whether toad was exposed to Rhabdias or served as an unexposed Control
worm_state- Australian state where the capture site of parasite donor toad was located. 1-WA (= Western Australia), 2-NT (= Northern Territory), 3-QLD (= Queensland).
became infected?- Yes vs No indication of whether parasites were present in the lungs at dissection
immune assay date- date of euthanasia, dissection and immune assays
SVL- snout to vent length (mm) measure of body size at time of euthanasia
Mass- body mass (g) at time of euthanasia
# Rhabdias in lungs- Number of parasites in the lungs at dissection
Spleen length mm- length of spleen at dissection
Allen BKA index- Allen bacteria killing index (% change)
mean luminesence RLU- Average luminescence reading during phagocytosis assay (relative luminescence units)
log mn lumin for figure- log transformed mean luminescence
wbc_conc- white blood cell concentration (cells/ml)
Eo_conc- eosinophil concentration (cells/ml)
Baso_conc- basophil concentration (cells/ml)
Lympho_conc- lymphocyte concentration (cells/ml)
Neut_conc- neutrophil concentration (cells/ml)
Methods
Data are immunological measures taken from common-garden reared cane toads at the end of an experimental crossinfection study. Toads whose parents orignated from different parts of toads' invaded range in Australia were exposed to infective larvae of a lungworm parasite (brought with the toads when they were introduced from South America) from various parts of their range in Australia. A sample of the toads were Conmtrols who were never exposed to infective lungworm larvae.
3-5 months after experimental infections,ads were euthanised and we recorded data on their white blood cell populations, the ability of their plasma to kill bacteria, and the phagocytic ability of whole blood.