First finding of deepwater profunda morph of quagga mussel Dreissena bugensis in the European part of its range

Abstract

The deepwater profunda morph of quagga mussel Dreissena bugensis was found for the first time in the European part of its range. The mussels of this morph were found in the Cheboksary Reservoir situated in the midstream of the Volga River (Russian Federation). Traditional and geometric morphometrics confirm the similarity of studied specimens to profunda mussel described from the Great Lakes of North America. In the Cheboksary Reservoir the deepwater mussels live at depth of 26.5 m on sandypebbled substrate at conditions of high water velocity ([0.5 m/s), i. e. in the conditions unusual for American profunda. This fact reflects evident ecological plasticity of this morph. Discovery of the deepwater morph of quagga mussel in the European part of its range indicates that possibility of realization of the deepwater phenotype is inherent to this species. It is suggested that quagga mussel may possess two alternative developmental pathways that could be realized in appropriate conditions. Presumably, certain depth and/or water pressure may serve as signaling factors for activating the ''deepwater'' developmental pathway. The presence of deepwater and shallow-water morphs is very important adaptive feature for sedentary organisms such as dreissenids that are unable to select habitat actively since this feature allows for successful colonization of both deep and shallow water habitats.

Behavioural differences and interactions between two sessile bivalves forming mixed-species assemblages

“…Conversely, they may indicate attempts to burrow in sand instead of attachment or find a suitable attachment site on the spot, without relocation. The former solution is only available for QM, which is capable of surviving in soft sediments (Dermott & Munawar, 1993;Pavlova, 2012). However, it should be noted that the intensity of nonlocomotor movements of mussels exposed to predation cues increased (Experiment 4), whereas burrowing activity decreased in response to the same stimuli (Experiment 2).…”

“…The former result contrasted our hypothesis, as we expected higher mussel aggregation on sand, where no hard substratum alternative to mussel shells was available. However, unlike ZM, QM can thrive on soft sediments (Dermott & Munawar, 1993;Pavlova, 2012). Moreover, due to their rounded ventral side (Beggel, Cerwenka, Brandner, & Geist, 2015), a single QM may experience difficulties in keeping the upright position on a flat hard surface without any support.…”

“…In North America, where both species were introduced at shorter intervals (Ricciardi & Whoriskey, 2004), the scenario has been similar: ZM spread faster but was usually displaced in a few years after the appearance of QM (Patterson, Ciborowski, & Barton, 2005). A number of possible explanations for this displacement have been proposed, including lower energy expenditure (slower metabolism, lower investment into anti-predation defence) (Naddafi & Rudstam, 2013;Stoeckmann, 2003), faster growth (D'Hont, Gittenberger, Hendriks, & Leuven, 2018;Metz et al, 2018;Balogh, Serfőző, bij de Vaate, Noordhuis, & Kobak, 2019), earlier onset of reproduction in the season (Balogh et al, 2018), more efficient feeding (Baldwin et al, 2002), higher tolerance to cold (Orlova et al, 2005;Stoeckmann, 2003), and ability to live on soft sediments (Dermott & Munawar, 1993;Pavlova, 2012) exhibited by QM compared to ZM. Nevertheless, actual reasons for differences in the spread rate and displacement between the two invasive dreissenids remain uncertain.…”

Byssal hairs in the invasive Asian freshwater bivalveLimnoperna fortunei(Mytilidae) in the Paraná River system with comments on this species in South America

“…Morton (1973) described a smooth and shiny periostracum for this species and he made no reference to any projections. Although there have been many ecological and biological studies in native and invaded locations about this species, byssal hairs do not appear to have been reported (Morton 1973, Montalto et al 1999Montalto and Ezcurra de Drago 2003;Montalto and Marchese 2003;Rojas Molina and José de Paggi 2008;Rojas Molina et al 2010, 2012. However, images of individuals with this characteristic can be found on the web (http://ecology.woweb.net/xe/15240) and in at least one paper (Avelar et al 2004).…”

“…This species has been incorporated into the diet of many fish species (Montalto et al 1999;Ferriz et al 2000;Pentchaszadeh et al 2000;García and Montalto 2006;Paolucci et al 2007), and has been recorded as one of the trophic options for crabs in Portunidae and Trichodactylidae (César et al 2003;Torres et al 2012). The impact of the filtering activity of this bivalve on planktonic animals, protozoans and algae can modify plankton density and structure, and can transfer energy and material from the water column to the benthos, thus serving as a link between the planktonic and benthic components of the ecosystem (Rojas Molina and José de Paggi 2008; Boltovskoy et al 2009;Rojas Molina et al 2010, 2012Frau et al 2013). Some authors have mentioned that L. fortunei beds represent a new habitat for benthic invertebrate development (Darrigran et al 1998;Sardiña et al 2011).…”