Ann. Zool. Fennici 50: 176–188 ISSN 0003-455X (print), ISSN 1797-2450 (online) Helsinki 28 June 2013 © Finnish Zoological and Botanical Publishing Board 2013 Life cycle and secondary production of mayflies and stoneflies in a karstic spring in the West Carpathians Kvetoslava Bottová* & Tomáš Derka Department of Ecology, Faculty of Natural Sciences, Comenius University, Mlynská Dolina, SK-842 15 Bratislava, Slovakia (*e-mail: [email protected]) Received 30 Nov. 2012, final version received 4 Feb. 2013, accepted 14 Feb. 2013 Bottová, K. & Derka, T. 2013: Life cycle and secondary production of mayflies and stoneflies in a karstic spring in the West Carpathians. — Ann. Zool. Fennici 50: 176–188. This study focused on life strategies of Ephemeroptera and Plecoptera species found in a karstic spring stream at the Malé Karpaty Mts. (West Carpathians, Slovakia), which is characterized by low thermal fluctuations throughout the year (6–10 °C). We exam- ined the life cycle and secondary production of three mayfly species (Baetis alpinus, Baetis rhodani and Rhithrogena semicolorata) and three stonefly species (Protone- mura nitida, Protonemura hrabei and Nemurella pictetii). We found an unusually slow univoltine cycle for P. nitida and an asynchronous life cycle for B. alpinus, with first-stage nymphs occurring almost all year round. Uncommonly low abundances of B. rhodani were found, which indicates that the population lives at its ecological limit. Moreover, for the first time we acquired and analysed the data on secondary produc- tion of P. nitida, which reached the highest values (3335 mg DW m–2 y–1) among all investigated species. In summary, the total annual secondary production of the mayfly community (889 mg DW m–2 y–1) was seven times lower than the annual secondary production of the stonefly community (6233 mg DW –2m y–1). Introduction al. 1997), assuring high values of biomass and representing the main pathway of energy transfer Life history data provide combined environmen- from lower to higher trophic level. Since benthic tal and genetic information about aquatic insect invertebrates play a central role in the flow of populations (Butler 1984). While some species energy and matter through many benthic fresh- have fixed voltinism, others are known to have water food webs (Wallace & Webster 1996), flexible life history patterns under different water measures of secondary production of stream temperature and food levels (Sweeney 1984). communities are very appropriate to characterize Knowledge of life cycles of aquatic species is of ecosystems (Waters 1977, Benke 1984, 1993). fundamental importance for all aspects of stream The magnitude of secondary production of an conservation (Rustigian et al. 2003). aquatic invertebrate population is influenced In several continental aquatic ecosystems, by its life history parameters, especially voltin- benthic macroinvertebrates constitute the main ism (Waters 1979, Benke et al. 1984, Huryn community component responsible for second- & Wallace 2000) and environmental factors, ary production (Robertson 1995, Grubaugh et such as water temperature and water chemistry ANN. ZooL. FeNNICI Vol. 50 • Life cycle and secondary production of mayflies and stoneflies 177 (Sweeney & Vannote 1986, Huryn et al. 1995, stonefly community and a Gammarus fossarum Robinson & Minshall 1998, Kozáčeková et al. population were higher than previously noted 2009). The estimation of secondary production in other types of streams (Beracko et al. 2012, is accomplished by the analysis of various pat- Bottová et al. 2013). terns of the life history of the species (Waters The aim of the present study was to inves- 1979, Benke 1984), and life history patterns tigate the effect of low temperature with mini- may change with environmental conditions. In mal fluctuations throughout the year on the life particular, hydrological and thermal variability cycle, growth and secondary production of three are two of the most important factors affecting mayfly and three stonefly species. life history, especially growth rates and seasonal timing of stream invertebrate life-cycle attributes (Sweeney 1984, Hauer & Benke 1987). Material and methods Water temperature is one of the parameters in stream ecology that determines the overall The studied locality is a karstic spring of the heat of aquatic ecosystems (Coutant 1999). It Stupava stream in the Malé Karpaty Mts. (West influences the growth rate of aquatic organisms Carpathians) (GPS coordinates: 48°15´32.59´´N, (Jensen 1990, Elliott & Hurley 1997) as well as 17°07´6.75´´E). The sampling site is located their distribution (Ebersole et al. 2003). Seasonal about 10 m below the spring in a mature beech and daily variations of water temperatures are forest, at an altitude 328 m a.s.l. (Fig. 1). The important determinants for the distribution of substrate was composed mainly of moss (90%) aquatic species (Vannote et al. 1980). Adap- and stones (10%). Water depth in the channel tation of benthic macroinvertebrates to water was 0.3 m, and the channel was 2.5 m wide. temperature changes is especially apparent in Temperature differences were minimal through- Plecoptera and Ephemeroptera. Plecoptera are out the year (Fig. 2). The mean annual tempera- mostly cool-water species, while Ephemerop- ture was 8.7 °C, minimal recorded temperature tera are common in tropical waters. Both orders was 6 °C and maximal temperature was 10.5 °C. have developed different strategies to adapt to The studied spring is a source of drinking water. their environment (Haidekker & Hering 2008). Quantitative samples of macrozoobenthos For example, successful egg development often were collected monthly, from October 2009 to demands lower temperatures in cold-adapted September 2010, using a Hess sampler (area species like many Plecoptera (Pritchard et al. 0.03 m2, mesh size 0.3 mm). Three samples were 1996). Consequently, these species often have a taken from moss, giving a total area of 0.09 m2, summer diapause to avoid high temperatures. On and four samples were taken from mesolithal, the other hand, warm-adapted species, like many giving a total area of 0.12 m2. Collected material Ephemeroptera, develop faster at higher tem- was preserved in 4% formaldehyde. In the labo- peratures and sometimes have winter quiescence ratory, mayfly and stonefly nymphs were sepa- (Brittain 1990, Pritchard et al. 1996). Some rated from detritus and other taxa, sorted, identi- mayfly species live in cold environments with a fied to species, and counted under a binocular diapause or quiescence in summer. As compared microscope. The presence of mature nymphs with Plecoptera, less information on the develop- (those showing black wind pads) in samples ment of Ephemeroptera under different thermal was used as an indicator of flight period. Water regimes is available (Haidekker & Hering 2008). temperature was recorded hourly with the aid In our previous studies of a constant-temperature of a submerged data logger (VEMCO Minilog spring we found unusual asynchronous and plas- TR) placed in the studied stream. Temperature tic life cycles of representatives of Amphipoda data were averaged for each day to produce (Gammarus fossarum), Plecoptera (Protone- mean daily temperatures (Fig. 2). Size-frequency mura intricata, Leuctra prima) and Ephemerop- histograms representing life cycles were con- tera (Baetis alpinus) (Kozáčeková et al. 2009, structed in Microsoft Excel. Once a month, the Beracko et al. 2012, Bottová et al. 2013). Fur- total body length without cerci of each nymph thermore, the annual secondary productions of a was measured to the nearest 0.1 mm with the 178 Bottová & Derka • ANN. ZooL. FeNNICI Vol. 50 Fig. 1. Location of the sampling site. 11 10 9 8 7 6 5 4 Temperature (°C) Temperature 3 2 1 Fig. 2. Mean daily tem- 0 Jan. Feb. Mar. Apr. May June July Aug. Sep. Oct. Nov. Dec. peratures during the sam- Mean daily temperature (°C) pling period. aid of a micrometer fixed to the binocular micro- Results scope. To avoid measurement errors produced by the curvature of the body, nymphs were Altogether, five species of Ephemeroptera and placed between two slides before measuring seven species of Plecoptera were recorded. Life them. Larvae were sorted into size classes with cycles were described and secondary productions an interval of 0.5 mm. Biomass was calcu- were estimated for three mayfly species: Baetis lated from predetermined length–mass relation- alpinus, Baetis rhodani and Rhithrogena semi- ships for each species according to Burgherr and colorata. The last-mentioned species avoided Meyer (1997) and expressed as dry weight (mg moss and was only found in mesolithal. The DW m–2). most abundant stonefly species were Protone- Secondary production was evaluated using mura nitida, Protonemura hrabei and Nemurella the size-frequency method (Benke 1979, Benke pictetii, and also their life cycles and secondary & Huryn 2006). We applied a correction for the productions were described. Protonemura nitida cohort production interval (CPI, mean develop- was found in mesolithal as well as in the moss, ment time from hatching to final size; Benke thus we compared its abundance, secondary pro- 1979) for each species. Growth was calculated duction and life cycle in both substrates. Only each month as the weighted mean of the nym- few nymphs of Baetis muticus, Ephemerella phal total length, and the mean total length was mucronata, Leuctra prima, Leuctra pseudosig- weighted by the number of individuals in each nifera, Nemoura sciurus and Isoperla