Rhabdias, Stiles & Hassall, 1905

Lettoof, Damian C., Greenlees, Matthew J., Stockwell, Michelle & Shine, Richard, 2013, Do invasive cane toads affect the parasite burdens of native Australian frogs?, International Journal for Parasitology: Parasites and Wildlife 2 (1), pp. 155-164 : 159

3.1. Rhabdias

Overall, the prevalence of adult Rhabdias lungworms differed significantly among anuran species (combining sites; / 2 2 = 12.99, p <0.005; Fig. 1 ). Cane toads were infected at higher intensities than were either L. peronii or L. latopalmata (one-factor ANOVA, F 2,53 = 9.77, p <0.001); the two native species were infected at similar intensities (Tukey’s HSD, p> 0.05). The mean intensity of lungworm infection was generally low in both native frogs (<5) and in cane toads (<20), although some cane toads contained more than 50 lungworms ( Table 3). Both L. peronii and L. latopalmata exhibited a higher prevalence of lungworms at ‘‘cane toad-absent’’ sites than at ‘‘cane toad-present’’ sites ( Fig. 2A ). ANOVA on these data showed that whether or not a frog contained lungworms was affected by its body size (larger frogs were more likely to be infected; mass effect / 2 1 = 6.42, p <0.02) but not its species (/ 2 1 = 2.20, p = 0.14). Frogs from toad-invaded areas had a lower prevalence of lungworm infection (/ 2 1 = 4.32, p <0.04). Lungworm intensity showed the same pattern as prevalence; that is, frogs from ‘‘cane toad-absent sites’’ contained more lungworms per infected host ( Fig. 2B ), as well as having a higher proportion of potential hosts infected. Mean intensity of infection per infected host did not differ significantly with respect to toad presence (F 1,1.19 = 4.84, p = 0.24), frog species (F 1,8.48 = 3.084, p = 0.12) or frog mass (F 1,9.50 = 0.12, p = 0.74). The overall parasite burden

A 100

90

individuals 80 70 60

infected 40 30 50

of

20

%

10

0

due to Rhabdias infection was thus higher in frogs collected from ‘‘toad-present’’ versus ‘‘toad-absent’’ sites (ANOVA, effect of body size F 1,49.22 = 6.42, p <0.02; effect of species F 1,11.35 = 0.14, p = 0.71; effect of toad presence F 1,8.22 = 7.87, p <0.025).

Figures

Fig. 1. (A) Prevalence (% of anurans infected) and (B) intensity (mean number of worms per infected host) of parasitic lungworms in cane toads and native anuran from northern NSW. Bars represent standard errors.

Fig. 2. (A) Prevalence (% of anurans infected) and (B) intensity (mean number of worms per infected host) of parasitic lungworms in anurans from cane toadpresent, and cane toad-absent areas in northern NSW. Bars represent standard errors.