Recruitment rate of gymnophallid metacercariae in the New Zealand cockle Austrovenus stutchburyi: an experimental test of the hitch-hiking hypothesis
- 205 Downloads
The rate at which host organisms accumulate parasites is affected by a number of intrinsic and extrinsic factors. The New Zealand cockle Austrovenus stutchburyi is frequently parasitised by trematodes comprising of two species of echinostomes and a species of gymnophallid that use it as a second intermediate host for trophic transmission to avian definitive hosts. The echinostomes are capable of manipulating the burrowing behaviour of the cockle to enhance their transmission success, whereas the gymnophallid is not capable of host manipulation. Previous studies have found patterns of positive associations between the echinostomes and the gymnophallid. Thus, it is possible that the latter is a “hitch-hiking” parasite that preferentially infects cockles already heavily infected by echinostome metacercariae to enhance its own transmission rate. A field experiment involving cockles forced to remain either above or below the sediment surface to simulate manipulated and non-manipulated cockles was conducted to test the hitch-hiking hypothesis. The gymnophallid was not found to display any preference for either surfaced or buried cockles; therefore, it cannot be considered as a hitch-hiking parasite. Possible alternative reasons for the pattern of positive association between the gymnophallid and the echinostomes are proposed.
KeywordsIntermediate Host Definitive Host Burial Depth Infection Intensity Baseline Group
The authors would like to thank Florian Weller for providing assistance with setting up the field experiment and Clément Lagrue and Kim Bryan-Walker for help with the maintenance of the cockle cages. The experiments conducted for this study comply with the current laws of New Zealand.
- Blundon JA, Kennedy VS (1982) Refuges for infaunal bivalves from blue crab, Callinectes sapidus (Rathbun), predation in Chesapeake Bay. J Exp Mar Biol Ecol 76:201–223Google Scholar
- Bower EA, Bartoli P, Russell-Pinto F, James, BL (1996) The metacercariae of sibling species of Meiogymnophallus, including M. rebecqui comb. nov. (Digenea: Gymnophallidae), and their effects on closely related Cerastoderma host species (Mollusca: Bivalvia). Parasitol Res 82:505–510CrossRefGoogle Scholar
- de Goeij P, Honkoop PJC (2003) Experimental effects of immersion time and water temperature on body condition, burying depth and timing of spawning of the tellinid bivalve, Macoma balthica. Helgoland Mar Res 57:20–26Google Scholar
- El-Darsh HEM, Whitfield PJ (1999) Digenean metacercariae (Timonella spp., Labratrema minimus and Cryptocotyle concava) from the flounder, Platichthys flesus, in the tidal Thames. J Helminthol 73:103–113Google Scholar
- Poulin R (1998) Evolutionary ecology of parasites: From individuals to communities. Chapman & Hall, LondonGoogle Scholar