Cryptic species and their utilization of indigenous and non-indigenous intermediate hosts in the acanthocephalanPolymorphus minutus sensu lato(Polymorphidae)

Abstract

The bird-infecting acanthocephalan Polymorphus minutus has been suggested to comprise different lineages or even cryptic species using different intermediate hosts. To clarify this open question, we investigated Polymorphus cf. minutus cystacanths originating from amphipod intermediate hosts from 27 sites in Germany and France. Parasites and hosts were identified using integrated datasets (COI and/or morphology for hosts and COI + ITS1-5.8S-ITS2 for parasites).Mitochondrial and nuclear data (ITS1) strongly support the existence of three cryptic species in Polymorphus cf. minutus (type 1-3). These three types reveal a high degree of intermediate host specificity, with Polymorphus type 1 only encountered in Gammarus fossarum type B, Polymorphus type 2 in Echinogammarus sp. and Echinogammarus berilloni, and Polymorphus type 3 in Gammarus pulex and Gammarus roeselii. Our results point to a so far neglected cryptic diversity of the genus Polymorphus in Central Europe. Furthermore, Polymorphus type 2 is most likely a non-native parasite in Germany that co-invaded with E. berilloni from the Mediterranean area. Potentially, type 3 originates from South-East Europe and migrated to Germany by G. roeselii, where it might have captured G. pulex as an intermediate host. Therefore, our findings can be seen in the context of ecological globalization in terms of the anthropogenic displacement of intermediate hosts and its impact on the genetic divergence of the parasites.

Effects of parasites upon non-host predator avoidance behaviour in native and invasive gammarids

“…The estimated increase in avoidance behaviour towards the nonhost predator chemical cues observed in G. fossarum infected with P. minutus in our study was consistent with the 'increased host ability hypothesis', which predicts that parasites increase the avoidance towards non-host predators (Medoc and Beisel, 2008). In Westphalia, the native cryptic parasite P. minutus uses native G. fossarum as an intermediate host but the P. minutus co-invaded the region with invasive gammarids, E. berilloni and G. roeseli from the Mediterranean area and Southeast Europe, respectively (Zittel et al, 2018). Gammarus roeseli transmitted this invasive parasite to G. pulex (Zittel et al, 2018).…”

Unravelling the hidden biodiversity – the establishment of DNA barcodes of fish-parasitizing Acanthocephala Koehlreuther, 1771 in view of taxonomic misidentifications, intraspecific variability and possible cryptic species

“…Cryptic species are known for various species of Acanthocephala (e.g. Steinauer et al ., 2007; Zittel et al ., 2018). For example, the wide distances found between mitochondrial lineages of P. laevis (up to 20%) lead to the assumption of cryptic species (Perrot-Minnot et al ., 2018; Reier et al ., 2019).…”

“…Due to their ambiguous morphological characters (Kennedy, 2006), individual variability (Cleave, 1952) and the potential occurrence of cryptic species (e.g. Steinauer et al ., 2007; Zittel et al ., 2018), taxonomic identification of acanthocephalans remains challenging. DNA barcoding has proven as an important tool for species identification, as seen in recent studies on the genus Pomphorhynchus that revealed previous contradictory determinations with a reliable DNA barcoding library (e.g.…”

Amphipod parasites may bias results of ecotoxicological research

“…Furthermore, different li neages of. P. minutus exist in different amphipod species that might potentially differ in their virulence (Zittel et al 2018).…”

“…Cadmium Lower accumulation in cystacanth compared to host tissue; Gismondi et al (2012f) roeselii minutus (Ex) mortality of infected and exposed males decreased compared to uninfected males, while mortality of infected and exposed females increased increased mortality of exposed and infected individuals; metallothioneins not affected by infection status; decreased HSP70 response in exposed and infected individuals compared to exposed should be identified (Krebes et al 2010, Grabner et al 2015. In an analogous manner, early acanthocephalan infections can be detected by specific primers (Zittel et al 2018). Molecular methods allow fast screening of many specimens with high sensitivity.…”