High prevalence of cestodes in Artemia spp. throughout the annual cycle: relationship with abundance of avian final hosts

Abstract

Brine shrimp, Artemia spp., act as intermediate hosts for a range of cestode species that use waterbirds as their final hosts. These parasites can have marked influences on shrimp behavior and fecundity, generating the potential for cascading effects in hypersaline food webs. We present the first comprehensive study of the temporal dynamics of cestode parasites in natural populations of brine shrimp throughout the annual cycle. Over a 12-month period, clonal Artemia parthenogenetica were sampled in the Odiel marshes in Huelva, and the sexual Artemia salina was sampled in the Salinas de Cerrillos in Almería. Throughout the year, 4-45 % of A. parthenogenetica were infected with cestodes (mean species richness = 0.26), compared to 27-72 % of A. salina (mean species richness = 0.64). Ten cestode species were recorded. Male and female A. salina showed similar levels of parasitism. The most prevalent and abundant cestodes were those infecting the most abundant final hosts, especially the Greater Flamingo Phoenicopterus ruber. In particular, the flamingo parasite Flamingolepis liguloides had a prevalence of up to 43 % in A. parthenogenetica and 63.5 % in A. salina in a given month. Although there was strong seasonal variation in prevalence, abundance, and intensity of cestode infections, seasonal changes in bird counts were weak predictors of the dynamics of cestode infections. However, infection levels of Confluaria podicipina in A. parthenogenetica were positively correlated with the number of their black-necked grebe Podiceps nigricollis hosts. Similarly, infection levels of Anomotaenia tringae and Anomotaenia microphallos in A. salina were correlated with the number of shorebird hosts present the month before. Correlated seasonal transmission structured the cestode community, leading to more multiple infections than expected by chance.

Larval helminths in the invasive American brine shrimp Artemia franciscana throughout its annual cycle

“…The present study, conducted during a full year, is the most exhaustive investigation of parasite infection in A. franciscana to date. In contrast to similar studies of native Artemia (Sánchez et al 2013b), parasite infection was consistently low throughout the year, suggesting that parasites have a crucial role in the competitive success of this highly invasive species.…”

“…However, both studies were based on sampling from limited time periods, and characterisation of the infections in A. franciscana throughout the annual life cycle has not previously been carried out anywhere in the invasive or native range of this New World species. In contrast, a recent study from two sites in southern Spain found consistently high levels of cestode infections in native A. salina (325 km to the east of our study site) and A. parthenogenetica (90 km to the northwest) throughout their annual cycle, which were partly related to the density and biomass of avian definitive hosts (Sánchez et al 2013b).…”

“…This suggests variation between cestode species in their ability to adapt to the new, invasive intermediate host. Furthermore, F. flamingo was consistently more abundant than F. liguloides (Table I), the inverse of what is recorded in native brine shrimps (Sánchez et al 2013b), even though these species share the same final host. The absence of A. tringae in the present material is also surprising since this was the most prevalent and abundant cestode species in another A. franciscana population in a different area of Cádiz Bay .…”

“…In contrast, cestode communities in A. parthenogenetica and in A. salina studied over the whole annual cycle consisted of 9 cestode species each (Sánchez et al 2013b). (Sánchez et al 2013b). This contrasts with mean abundance of helminth parasites in A. franciscana ranging between 0.005 and 0.155 (av.…”

“…For the remaining three cestode species recorded in the present study (Flamingolepis flamingo, Gynandrotaenia stammeri and Eurycestus avoceti), the values of prevalence and abundance are generally similar in invasive and native Artemia spp. (see Sánchez et al 2013b).…”