Temperature-Dependence of Predator-Prey Dynamics in Interactions Between the Predatory Fungus Lecophagus sp. and Its Prey L. inermis Rotifers

Abstract

Temperature is considered an important factor that influences the bottom-up and top-down control in water habitats. We examined the influence of temperature on specific predatory-prey dynamics in the following two-level trophic system: the predatory fungus Lecophagus sp. and its prey Lecane inermis rotifers, both of which originated from activated sludge obtained from a wastewater treatment plant (WWTP). The experiments investigating the ability of conidia to trap rotifers and the growth of fungal mycelium were performed in a temperature range that is similar to that in WWTPs in temperate climate. At 20 °C, 80% of the conidia trapped the prey during the first 24 h, whereas at 8 °C, no conidium was successful. The mycelium growth rate was the highest at 20 °C (r = 1.44) during the first 48 h but decreased during the following 24 h (r = 0.98), suggesting the quickest use of resources. At a medium temperature of 15 °C, the tendency was opposite, and the r value was lower during the first 48 h. At 8 °C, the growth rate was very low and remained at the same level even though numerous active rotifers were potentially available for the fungus. The temperature also influences the production of new conidia; on the 7th day, new conidia were observed in 96% of the wells at 20 °C, but no new conidia were observed at 8°C. These results show that the prey (rotifers)-predator (Lecophagus) dynamics in WWTPs is temperature-dependent, and a temperature of 8 °C is a strongly limiting factor for the fungus. Moderate temperatures ensure the most stable coexistence of the fungus and its prey, whereas the highest temperature can promote the prevalence of the predator.Electronic supplementary materialThe online version of this article (10.1007/s00248-017-1060-5) contains supplementary material, which is available to authorized users.

The Relations Between Predatory Fungus and Its Rotifer Preys as a Noteworthy Example of Intraguild Predation (IGP)

“…[28] and Lecophagus sp. clones [39]. Rotifers are trapped by adhesive knobs of fungus usually by mouth region, then Fig.…”

Effects of polyaluminum chloride (PAX-18) on the relationship between predatory fungi and Lecane rotifers

“…Rotifers inhabiting activated sludge are also endangered by predacious fungi (Pajdak-Stós et al 2016 ; Fiałkowska and Pajdak-Stós 2018 ). Our experiments showed that rotifers subjected simultaneously to PAX solution and conidia of Lecophagus sp.…”

“…Lecophagus sp. strain Z1 originates from a wastewater treatment plant located in southern Poland, as detailed by Fiałkowska and Pajdak-Stós ( 2018 ). The strain was isolated to pure culture on potato dextrose agar using the methods of Barron ( 2004 ).…”

“…Although predatory fungi feeding on rotifers were reported from natural environments (Sommerstorff 1911 ; Barron et al 1990 ; Glockling 1997 ; Tanabe et al 1999 ; McInnes 2003 ), until recently, reports on their occurrence in WWTPs were scarce (Cooke and Ludzack 1958 ; Pipes and Jenkins 1965 ; Sladka and Ottova 1973 ). In the last few years, however, it turned out that predatory fungi trapping rotifers are quite common in full-scale WWTPs (Fiałkowska et al 2016 ) and that they could be a real danger for rotifer populations inhabiting activated sludge (Pajdak-Stós et al 2016 ; Fiałkowska and Pajdak-Stós 2018 ).…”

Evidence does not support the conclusion that Hexarthra intermedia (Rotifera, Monogononta, Flosculariaceae) causes mortality in Bosmina longirostris (Cladocera, Diplostraca, Branchiopoda)

“…(1) Ciliates and heliozoans engulf whole rotifers (Wallace et al, 2015). (2) Soil and aquatic fungi feed as saprophytic parasites on rotifers and nematodes (Barron, 1980;Robb & Barron, 1982;Barron & Szijarto, 1984;Fialkowska & Pajdak-Stós, 2018).…”