DOI: 10.5061/dryad.qfttdz0t8
title: Stable isotope analysis of ectoparasites as a tool for understanding trophic interactions with mammalian hosts

description: Climate change is expected to expand the geographic ranges of
 ectoparasites, increasing the transmission of vector-borne diseases and
 thereby necessitating a better understanding of ectoparasite-host trophic
 dynamics. Haematophagous ectoparasites can serve as valuable subsamples of
 their hosts, retaining isotopic values that reflect dietary information in
 both their blood meals and tissues. However, the differences in the
 lifestyles and feeding strategies of lice, fleas, and ticks may influence
 how these isotopic values are preserved. Here, stable isotope values of
 carbon (δ13C) and nitrogen (δ15N) were used to investigate trophic
 interactions between ectoparasites and their mammalian hosts in three
 pairings: lice (Anoplura: Polyplacidae; n = 101) and Eurasian red
 squirrels Sciurus vulgaris, fleas (Siphonaptera: Ceratophyllidae; n = 92)
 and fat dormice Glis glis, and ticks (Ixodida: Ixodidae; n = 16) and
 European hedgehogs Erinaceus europaeus. Our findings indicate
 ectoparasites reflect the dietary patterns of their host, with lice
 exhibiting the closest isotopic values, followed by fleas and ticks. All
 ectoparasites had significantly higher nitrogen isotope values compared to
 those of their hosts, indicative of trophic enrichment, but their carbon
 isotope values varied. Notably, we found that the presence of a blood meal
 did not significantly affect the isotopic values found in lice and fleas,
 while ticks showed a significant difference between exoskeleton and blood
 meal in δ13C values. This study highlights the importance of understanding
 how the life histories of parasite species influence the preservation of
 isotopic host signals in order to be able to utilise stable isotope
 analyses of ectoparasites (particularly lice) to infer host dietary niches
 and preferences, with broader implications for understanding host-parasite
 dynamics and predicting disease transmission pathways.
description: # Stable isotope analysis of ectoparasites as a tool for understanding
 trophic interactions with mammalian hosts Dataset DOI:
 [10.5061/dryad.qfttdz0t8](10.5061/dryad.qfttdz0t8) ## Description of the
 data and file structure Stable isotope ratios of carbon (*δ*13C) and
 nitrogen (*δ*15N) were compared between host (fat dormouse, red squirrel,
 European hedgehog) and ectoparasite (louse, flea, tick) for various
 tissues.  ### Files and variables **File included:** *
 Mortier_et_al._-_Data_Dryad.xlsx - Excel file with four sheets containing
 metadata and stable isotope data for host tissues and ectoparasites.
 **Sheet descriptions:** **Table S1:** Metadata for host specimens and
 associated ectoparasites, including species, collection details, tissue
 types, ectoparasite counts, and feeding status. **Table S2:** *δ*15N and
 *δ*13C values (‰ mean ± SD) of fed and unfed fleas, lice, and ticks, with
 isotopic differences between feeding groups. **Table S3:** Isotopic values
 (‰ mean ± SD) for host tissues (fur, whiskers, muscle, spines) from
 dormice, squirrels, and hedgehogs, with tissue-to-tissue offsets. **Table
 S4:** Paired *δ*15N and *δ*13C values (‰ mean ± SD) for ectoparasites and
 their host tissues, including tissue-specific isotopic offsets. **Missing
 data:** Indicated as N/A. **Compression:** Not applicable. All data are in
 a single Excel file. ## Code/software The data can be viewed using
 standard spreadsheet software (e.g., Microsoft Excel). ## Access
 information Other publicly accessible locations of the data: * None Data
 was derived from the following sources: * All data were collected and
 generated by the authors.