Larval habitat preference of Potamophylax rotundipennis (Insecta: Trichoptera) was examined under natural conditions. The result of this study indicated a high preference for stone to sand and detritus, and preference for the low depth of water. This preference resulted that P. rotundipennis larvae showed a homogenous distribution along the stream-reach, but not across it

Schmera, Dénes

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241F O L I A H I S T O R I C O - N A T U R A L I A M U S E I  M A T R A E N S I S2002 26: 241–243Notes on the larval habitat preference and microdistributionof Potamophylax rotundipennis (Insecta: Trichoptera)in a stream reach of the Börzsöny Mountains(Northern Hungary)DÉNES SCHMERAABSTRACT: Larval habitat preference of Potamophylax rotundipennis (Insecta: Trichoptera) was examinedunder natural conditions. The result of this study indicated a high preference for stone to sand and detritus,and preference for the low depth of water. This preference resulted that P. rotundipennis larvae showed ahomogenous distribution along the stream-reach, but not across it.IntroductionPotamophylax rotundipennis (BRAUER 1857) is a common caddisfly (Insecta: Trichoptera)species in the Northern Mountains, Hungary (UHERKOVICH & NÓGRÁDI 1994, KISS et al.1995, 1999; ANDRIKOVICS et al. 1995). In spite of its commonness, there are only a fewliterature data on the biology of the species. KRISKA (2001) states that the characteristicsubstratum of the habitat determines the case building material of the larvae. Hence, the casecould be build from plant or mineral materials depending upon the substratum being presenton the bottom. However, under labour conditions, P. rotundipennis shows preference forpebbles and gravel to sand (HIGLER 1975), and a substratum change could be indicated atdifferent larval stages (OLÁH 1972). Under natural conditions, this preference has not beenconfirmed yet. In this study, I aimed to support or not, whether P. rotundipennis larvae showpreference for gravel under natural conditions. If P. rotundipennis larvae can be found mostlyon gravel in field, then substrate preference can be regarded as the most important factoreffecting the microdistribution of P. rotundipennis. If the preference experiment in labour(HIGLER 1975) receive rejection, then other factors influence the microdistribution ofP. rotundipennis larvae.Material and methodsBörzsöny Mountains (Northern Hungary) are a series of separate mountain peaks, which has been created byvolcanic activity in the Tertiary. The study area at Bernecebaráti (N48°01’ E18°55’), 200 m above see level, lies inthe northern part of the Börzsöny Mountains, consisting of andesite and andesite-tuff. Here runs the Bernecei stream.The depth of the water varies from 5 to 32 cm. As a result of a former study (SCHMERA 1999) a sampling site andtime was fixed at a natural, undisturbed stream reach. Caddisfly larvae were collected from the area of 240 × 150 cmdivided into 160 elemental cells (the size of every elemental cell was 15 × 15 cm). In other words, a grid was fittedon the stream reach in order to get statistically acceptable information about the position of every caddisfly individualcollected under the grid. The longer brink of the grid (horizontal direction) was positioned across the axis of thestream, the shorter brink of the grid was positioned parallel with the stream (vertical direction). Caddisflies werecollected individually on 24. 04. 1998., 23. 05. 1998. and on 07. 06. 1998. The substrate type, from which eachindividual was collected, the position of the elemental cell and the depth of the water were recorded. The followingsubstrate types were regarded: sand, stone and detritus. The identification based on the work of WARINGER & GRAF(1997). The identification of the larvae was supported by light trap catches (KISS & SCHMERA 1999).The normal distribution of the data set was tested by Kolmogorov-Smirnov test by the help of STATISTICAprogram (STATSOFT, 2000). The homogeneity of the variables (both in vertical and in horizontal direction) wascalculated by Kruskal-Wallis test.Results and DiscussionFour Potamophylax rotundipennis individuals were collected on 24 March, 94 individuals on23 May and 2 individuals on 27 June. The preference for substrate type shows the followingpicture: 62.8% of the collected individuals was on stones, 25.5% on sand and 11.7% ondetritus. Fig. 1 shows the preference of P. rotundipennis for the depth of the water in thestudied stream reach. Most of the individuals prefer two, three or five centimetre depth water.The highest number of individuals was collected in May; thus, this data set was only used toindicate the spatial dependence of the caddisfly species. The normal distribution should berejected based on Kolmogorov-Smirnov test (d=0.4328, p<0.01), so non-parametric statisticswas used to indicate the homogeneity of the variables. The vertical direction of the gridshould be accepted as homogenous (Kruskal-Vallis test: H=7.288, df=9, p=0,6072). It meansthat the spatial pattern of P. rotundipennis is homogeneous along the stream in the studiedstream reach. On the other hand, the homogeneity of the horizontal direction of the gridshould be rejected (Kruskal-Vallis test: H=33.25, df=9, p=0.0001). As a result of this studythe spatial pattern of P. rotundipennis is not at all homogenous across the steam in the studiedstream reach.A lot of information is available about the ecological preference of different caddisflyspecies to their habitats. BEISEL et al. (1998) found that the substrate might have the majoreffect on the macroinvertebrate assemblages in a stream and current velocity and water depthemerged as secondly factors. This study confirmed the known substrate preference ofPotamophylax rotundipennis larvae under natural conditions and contributed to theinterpretation of spatial distribution of P. rotundipennis in streams.AcknowledgementI thank Dr. Ferenc Samu and Prof. Péter Bíró for their comments on a former draft of themanuscript, Árpád Bezecky, Ákos Schmera, Zsolt Vass, Katalin Wágnerné Gálicz and ZsoltWágner for their assistance in the filed works.242Fig. 1. Frequency distribution of Potamophylax rotundipennisfor the depth of the water in centimetre.ReferencesANDRIKOVICS, S., O. KISS, L. MIKUS & L. VIZSLÁN (1995): Contributing to the knowledge of the Trichoptera of theZempén Mountains, North Hungary. – Acta Acad. Agriensis 21: 117–123. (In Hungarian)BEISEL, J.-N., P. USSEGLIO-POLATERA, S. THOMAS & J-C. MORETEAU (1998): Stream community structure in relationto spatial variation: the influence of mesohabitat characteristics. – Hydrobiologia 389: 73–88.HIGLER, L. W. G. (1975): Reaction of some caddis larvae (Trichoptera) to different types of substrate in anexperimental stream. – Freshwater Biology 5: 151–158.KISS, O., S. ANDRIKOVICS, G. SZIGERTVÁRI & I. FISLI (1999): Trichoptera from a light trap near the Eger brook atSzarvaskő (Bükk Mountains, North Hungary). – Proc. 9th Int. Symp. on Trichoptera p. 165–170.KISS, O., E. KÓKAI & G. KONCZ (1995): Trichoptera in the Csermely stream near Uppony. – Acta Acad. Agriensis21: 327–339. (In Hungarian)KISS, O. & D. SCHMERA (1999): Trichoptera from a light trap in the Börzsöny Mountains, northern Hungary, 1996.– Proc. 9th Int. Symp. on Trichoptera p. 171–174.KRISKA, GY. (2001): Case building strategy of Potamophylax rotundipennis (Brauer)(Trichoptera, Limnephilidae).– Hidrológiai Közlöny 81: 403–404. (In Hungarian)OLÁH, J. (1972): The relationships between the feeding and habitat preference at Potamophylax rotundipennisBrauer larvae (Trichoptera). – Állatatni Közlemények 59: 106–110. (In Hungarian)SCHMERA, D. (1999): Change of structural characteristics of caddisflies (Insecta: trichoptera) along the Bernecei stream(Börzsöny Mountains, Northern Hungary) – Természetvédelmi Közlemények 8: 173–183. (In Hungarian)StatSoft, Inc. (2000) STATISTICA for Windows [Computer program manual]. Tulsa, OK.UHERKOVICH, Á. & S. NÓGRÁDI (1994): Further studies on caddisfly (Trichoptera) fauna of the Northern Mountains,Hungary. – Fol-hist. Nat. Mus. Matr. 19: 77–95WARINGER, J. & W. GRAF (1997): Atlas der Östereichischen Köcherfliegenlarven. pp. 286. (Facultas Universitat-verlag) Wien.SCHMERA, DénesPlant Protection InstituteHungarian Academy of Sciences1525 BUDAPEST, POB. 102, HUNGARYE-mail: schmera@julia-nki.hu243

Case building strategy of Potamophylax rotundipennis

Contributing to the knowledge of the Trichoptera of the Zempén Mountains, North Hungary.

Further studies on caddisfly (Trichoptera) fauna of the Northern Mountains, Hungary.

Plant Protection Institute Hungarian Academy

Reaction of some caddis larvae (Trichoptera) to different types of substrate in an experimental stream.

The relationships between the feeding and habitat preference at Potamophylax rotundipennis Brauer larvae (Trichoptera).

Trichoptera from a light trap near the Eger brook at Szarvaskő (Bükk Mountains, North Hungary).

Trichoptera in the Csermely stream near Uppony.

Notes on the larval habitat preference and microdistribution of Potamophylax rotundipennis (Insecta: Trichoptera) in a stream reach of the Börzsöny Mountains (Northern Hungary)

Notes on the larval habitat preference and microdistribution of Potamophylax rotundipennis (Insecta: Trichoptera) in a stream reach of the Börzsöny Mountains (Northern Hungary)

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