The influence of life history characteristics on flea (Siphonaptera) species distribution models

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Authors

Van der Mescht, Luther
Le Roux, Peter Christiaan
Matthee, Conrad A.
Raath, Morgan Jade
Matthee, Sonja

Journal Title

Journal ISSN

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Publisher

BioMed Central

Abstract

BACKGROUND : Ectoparasites exhibit pronounced variation in life history characteristics such as time spent on the host and host range. Since contemporary species distribution (SD) modelling does not account for differences in life history, the accuracy of predictions of current and future species’ ranges could differ significantly between life history groups. RESULTS : SD model performance was compared between 21 flea species that differ in microhabitat preferences and level of host specificity. Distribution models generally performed well, with no significant differences in model performance based on either microhabitat preferences or host specificity. However, the relative importance of predictor variables was significantly related to host specificity, with the distribution of host-opportunistic fleas strongly limited by thermal conditions and host-specific fleas more associated with conditions that restrict their hosts’ distribution. The importance of temperature was even more pronounced when considering microhabitat preference, with the distribution of fur fleas being strongly limited by thermal conditions and nest fleas more associated with variables that affect microclimatic conditions in the host nest. CONCLUSIONS : Contemporary SD modelling, that includes climate and landscape variables, is a valuable tool to study the biogeography and future distributions of fleas and other parasites taxa. However, consideration of life history characteristics is cautioned as species may be differentially sensitive to environmental conditions.

Description

Additional file 1: Calculation of coefficients of harmonic regression for climate variables and topography in R. Description of data: R script illustrating the production of the coefficients of harmonic regression for climate variables and topography.
Additional file 2: Collinearity among the 19 final individual predictor variables. All final predictor variables had correlation values below 0.7 or above−0.7. Description of data: The table contains collinearity among final 19 predictor variables chosen for modelling.
Additional file 3: List of predictor variables indicating their respective reference codes. Description of data: The table contains a list of all predictor variables considered for this study and their abbreviations as reference codes.
Additional file 4: Calculation of the true skill statistic (TSS) for each replicate of the 10-fold cross-validation from MaxEnt output in R. Description of data: R script illustrating the calculation of the true skill statistic (TSS) for each replicate of the 10-fold cross-validation from MaxEnt output.
Additional file 5: Variable importance (i.e. percent relative predictor variable individual contribution) in MaxEnt models, averaged across flea species based on (a) microhabitat preference and (b) host specificity (see Additional file 2 for variable reference code). Significant differences in the contribution of predictor variables between the two categories of species are indicated by asterisks: *** P < 0.001, ** P < 0.01, * P < 0.05. Description of data: The bar plot figure illustrate variable importance (i.e. percent relative predictor variable individual contribution) in MaxEnt models, averaged across flea species based on microhabitat preference and host specificity.

Keywords

Siphonaptera, MaxEnt, Host specificity, Microhabitat preference, Life history, Climate envelope modelling, Species distribution (SD), True skill statistic (TSS), Area under the curve (AUC)

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Citation

Van der Mescht, L, Le Roux, PC, Matthee, CA, Raath, MJ & Matthee, S 2016, 'The influence of life history characteristics on flea (Siphonaptera) species distribution models', Parasites and Vectors, vol. 9, art. no. 178, pp. 1-10.