Data on infection experiments of cane toads

This dataset contains data from an infection experiment described in the paper: “Mayer, M., Schlippe Justicia, L, Shine, R., & Brown, G. P. (2021). Host defense or parasite cue: Skin secretions mediate interactions between amphibians and their parasites. Ecology Letters, in revision”.  Amphibian skin secretions (substances produced by the amphibian plus microbiota) plausibly act as a first line of defense against parasite/pathogen attack, but may also provide chemical cues for pathogens. To clarify the role of skin secretions in host-parasite interactions, we conducted experiments using cane toads (Rhinella marina) and their lungworms (Rhabdias pseudosphaerocephala) from the range-core and invasion-front of the introduced anurans’ range in Australia. Depending on the geographic area, toad skin secretions can reduce the longevity and infection success of parasite larvae, or attract lungworm larvae and enhance their infection success. These striking differences between the two regions were due both to differential responses of the larvae, and differential effects of the skin secretions. Our data suggest that skin secretions play an important role in host-parasite interactions in anurans, and that the arms race between a host and parasite can rapidly generate spatial variation in critical features of that interaction.

Methods

We obtained cane toads from two geographic areas (column 'toad origin'): (1) Mareeba, Queensland (17.03° S, 145.43° E) and (2) Halls Creek, Western Australia (-18.23° S, 127.66° E). Lungworm parasites were collected from naturally-infected toads from Innisfail, QLD and Kununurra, WA (column 'L3 origin'). To investigate if skin secretions act as a defense mechanism by the host or as cue for the parasite, or both, we infected toads that had either intact or reduced skin secretions (column 'skin_secr'). For infection, we placed toads individually into round containers containing 20 L3 in 300 µl water. On the 15th day post-infection, we euthanized the toads and dissected them to count the number of established nematodes in the lungs. We calculated the proportion of L3 entering the lung by dividing the number of L3 that established in the lungs by the number of L3 that entered the host (column 'Prop_entered').

Usage Notes

Explanation of the other columns: ID: The identifier of individual toads used for the experiment. clutch: The identifier of the clutch an individual originated from. SUL_18.01 and SUL_final: The snout-urostyle length of the toads on the infection day and on the final day of the experiment. remaining L3: The number of parasite larvae that remained in the infection chamber post-infection. L3_entered: The number of parasite larvae that entered the host. Total_nematodes: The number of parasites that established in the hosts' lungs.