Effect of poor manageability and low nutritional value of cyanobacteria on Daphnia magna life history performance

Abstract

Cyanobacteria may reduce Daphnia fitness through their toxicity, low nutritional value or poor manageability. In this study, the relative importance of the low nutritional value and poor manageability of cyanobacteria on Daphnia life history were determined. To separate these two aspects of cyanobacteria impact, short or long filaments of Cylindrospermopsis raciborskii were given as food to five clones of Daphnia magna either alone or together with the green alga Scenedesmus obliquus. Feeding with short cyanobacterial filaments caused reductions in growth rate (,45%) and fecundity (,60%) in some clones. The deleterious effects caused by cyanobacterial poor nutritional quality could be completely overcome by supplementation with highquality food. Long cyanobacterial filaments caused greater reductions in growth rate (,65%) and fecundity (,80%) in the most affected clones, and the addition of high-quality food only partially diminished the effects of poor filament manageability. In Daphnia fed with long filaments, there was no correlation between body size at maturity and fecundity, and the maximum fecundity was reached by individuals of intermediate size. Decreased body size may, thus, represent an adaptive mechanism against interference with food collection caused by long filaments. The pattern of responses to different food regimes was similar in all Daphnia clones, but they differed in the absolute values of the life history parameters affected. Differences in the fecundity of Daphnia caused by the presence of cyanobacteria may affect clonal composition of cladoceran assemblages, thus, cyanobacteria can shape microevolutionary changes in Daphnia populations.

Application of dual stable isotopes in investigating the utilization of two wild dominant filamentous algae as food sources for Daphnia magna

“…This research demonstrated that D. magna does indeed have a certain feeding rate on filamentous algae such as M. granulata and Oscillatoria sp., supporting the view that daphnids can grow and reproduce on a diet dominated by filamentous cyanobacteria (Repka 1998). Furthermore, the treatment groups which contained a small quantity of good quality food (S. obliquus) showed higher carbon and nitrogen isotopic turnover rates driven by both growth and metabolism (k þ m) relatively, demonstrating that the poor nutritional value of filamentous algae could be completely overcome by supplementation (Bednarska et al 2014).…”

“…Other research showed that the weight-specific ingestion rates of D. magna were higher on the shorter Oscillatoria filaments than on the longer ones (Gulati et al 2001). Furthermore, cyanobacteria can shape microevolutionary changes in Daphnia populations (Bednarska et al 2014). It was also observed that the filaments of both Melosira and Oscillatoria were inadequate food source for Daphnia because they could not sustain growth and reproduction of planktonic animals as well as unicellular algae could not sustain growth and reproduction of planktonic animals as well as unicellular algae, such as Scenedesmus (Porter & Orcutt 1980;Haney 1987;Lampert 1987;DeBernardi & Giussani 1990;Bednarska et al 2014).…”

“…Cladocerans, especially Daphnia, form a key link in energy and nutrient mobilization between primary producers and higher trophic levels in most aquatic ecosystems (Gliwicz & Lamper 1990;Sterner & Hessen 1994;Jansson et al 2007;Lampert 2011;Sanni et al 2013;Bednarska et al 2014). Burns et al (1989) provided evidence that Daphnia carinata was able to collect trichomes of Anabaena minutissima var.…”

Differences in cell wall of thin and thick filaments of cyanobacterium Aphanizomenon gracile SAG 31.79 and their implications for different resistance to Daphnia grazing

“…A similar trend was reported by Oberhaus et al (2007), who found that Daphnia pulicaria Forbes is capable of effective grazing only on short (50-100 µm) filaments of Planktothrix rubescens De Candolle ex Gomont. Quite recently, Bednarska et al (2014) provided evidence that the consequences of the filament length for Daphnia can be manifested throughout the lifetime of these organisms. Daphnids exposed to longer (>50 µm) filaments of Cylindrospermopsis raciborskii (Woloszynska) Seenayya & Subba Raju were smaller in size at the first reproduction and had a lower fecundity than the animals that fed on filaments shorter than 50 µm.…”

Setae thickening in Daphnia magna alleviates the food stress caused by the filamentous cyanobacteria

“…Other researchers revealed that Daphnia could abort eggs when filamentous cyanobacteria were present, and this phenomenon intensified at higher temperatures (Bednarska and Slusarczyk 2013). Bednarska with coworkers also found evidence that reduction of Daphnia fitness in response to cyanobacterial filaments strongly depends on filaments length (Bednarska et al 2014). According to the aforementioned study, long filaments ([50 lm) caused a greater reduction in somatic growth and fecundity in most clones of D. magna, in comparison with short filaments (\50 lm).…”