Phenotypic plasticity in Cichlidogyrus spp. (Monogenea: Dactylogyridae) parasitizing Lake Tanganyika cichlid tribes using a geometric morphometric approach: the roles of host phylogeny and locality Phenotypic plasticity in Cichlidogyrus spp. (Monogenea: Dactylogyridae) parasitizing Lake Tanganyika cichlid tribes using a geometric morphometric approach: the roles of host phylogeny and locality
| Title in English | Phenotypic plasticity in Cichlidogyrus spp. (Monogenea: Dactylogyridae) parasitizing Lake Tanganyika cichlid tribes using a geometric morphometric approach: the roles of host phylogeny and locality |
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| Year of publication | 2018 |
| Type | Conference abstract |
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| Description | Morphological plasticity is the ability of an organism to express different phenotypes depending on biotic and/or abiotic factors of the environment [1]. A lot of consideration has been given to phenotypic plasticity in monogeneans. This group is, so far, the best model system for addressing fundamental ecological and evolutionary questions on parasites [2]. The morphology of their haptor allows the attachment to the fish gills and is crucial for their survival [3]. It also influences the parasite’s specialization and adaptation to the host species, and considerably contributes to host specificity [4]. Variability of the sclerotized structures seems to be more pronounced in generalist species [3]. African cichlids have been extensively studied for their monogenean parasite fauna. Host specificity in Cichlidogyrus Peperna, 1960, which represents the most diverse monogenean genus parasitizing African cichlids, ranges from strict specialists to generalists. Previous studies have led to some preliminary understanding of morphological evolution in Cichlidogyrus. To date, investigations about phenotypic plasticity in monogenean parasites involved only non-Tanganyikan cichlid hosts or deep-water species of the Tanganyika system [5]. Our study aimed to determine whether or not conspecific species of Cichlidogyrus from different Lake Tanganyika cichlid tribes living in various localities exhibit differently shaped and sized dorsal and ventral anchors. A geomorphometric approach allows to investigate morphological plasticity patterns among populations of monogeneans in any ecological system and in a broad biogeographic and evolutionary context. We applied a landmark-based geomorphometric approach on four species of Cichlidogyrus sampled from various host species and from various localities along the Lake. The studied Cichlidogyrus species include i) a generalist species C. nshomboi isolated from representatives of two phylogenetically distinct cichlid tribes: Boulengerochromini represented by Boulengerochromis microlepis, and Perissodini by Perissodus microlepis and Plecodus straeleni; (ii) an intermediate specialist represented by C. gillardinae from the gills of congeneric hosts living in sympatry: Astatotilapia burtoni and A. stappersii (Haplochromini); (iii) a strict specialist represented by C. gistelincki from ’Ctenochromis‘ horei (Tropheini), a cichlid with good dispersal capacities of the shallow intermediate habitat; and finally (iv) C. milangelnari from Cyprichromis microlepidotus (Cyprichromini), a strict specialist of a poorly dispersing cichlid of the deep rocky waters. Geomorphometric analysis revealed significant differences in dorsal and ventral anchors between C. nshomboi individuals parasitizing the representatives of boulengerochromine and perissodine cichlids. The same result was observed between parasite individuals of perissodine hosts sampled from the Burundese and Congolese coastlines. However, no significant differences were found between individuals of C. nshomboi parasitizing P. microlepis and P. straeleni, both sampled from the Congolese shoreline. Significant differences were observed between individuals of C. milangelnari sampled from Burundese and Congolese parts of the lake, and C. gistelincki from some Burundese localities. In C. gillardinae parasitizing two different congeneric hosts, significant differences were observed only in the dorsal anchors. Future plans Preparation of two research papers focused on geomorphometry of Cichlidogyrus parasites using the data set presented above, and one phylogenetic paper including molecular data presented in previous ECIP meetings. Finally, in cooperation with colleagues from the University of Basel, we will prepare a manuscript focussing on parasite species infecting haplochromine cichlids inhabiting Lake Tanganyika and some neighboring freshwater systems. This study was supported by Czech Science Foundation, project No. P505/12/G112 (ECIP). |
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