nitidula emahrt sich vor allem von Samen und Grdsern, Aiolopus fhalassi''nus ist pofyphag und tendenziell krduterfressend. FOr Ruspolia nitidula legen die Beobachtungen nahe, daB die Art jahreszeitlich wechselnd die ndhrstoffreichsten Nahrungsressourcen ausbeutet. Schilf wird nur in jungem Zustand gefressen, wdhrend spdter Grassamen die Hauptnahrung darstellen. Danksagung Ein Teil der Beobachtungen erfolgte im Rahmen von Untersuchungen fUr die Bezirksstelle f0r Naturschutz und Landschaftspflege Karlsruhe und fUr das Bayerische Landesamt fiir Umweltschutz, denen fUr die M6glichkeit zur Ver6ffentlichung gedankt sei. Reinhold Treiber lm Westengarten 12 79241 lhringen e-mail : [email protected] Literatur GorrscHALK, E. (1993): Sukzession auf neu angelegten Rebb6schungen im Kaiserstuhl am Beispiel der Heuschrecken. Diplomarbeit Fak. f. Biologie, Univ. Freiburg; 65 S. (unver6ff.). lNGRrScH, & KOHLER (1998): Die Heuschrecken Mitteleuropas. Neue Brehm-Bucherei Bd. 629. 460 S. Magdeburg. lNGRrScH, S. (1 976): Vergleichende Untersuchungen zum Nahrungsspektrum mifteleuropdischer Laubheuschrecken (Saltatoria: Tettigoniidae). Entomol. Z" 20:217224; Stuttgart. R. & ALBRECHT, M. (1996): Die GroBe Schiefkopfschrecke (Raspo/la nifdula Scopolt, 1786) neu f0r Bayern und Wiederfund f0r Deutschland (Orthoptera, Saltatoria). Nachrbl. bayer. Entomol . 45(314). 60-72. M0nchen. TREIBER, R. (1998): f -78 BIOLOGIE nduction of song activity in Oecanthus pellucens (Scoeou, 1763) (Gryllidae, Oecanthinae) Manfred Alban Ffeifer Zusammenfassung Gesangsausfdsung beim Weinhiihnchen (Oecanthus pellucens) Verfasser TRETBER, ARTICULATA 2001 16(1t21:75 Der Autor gibt Hinweise darauf, dass bei Oecanthus pellucens Gesang ausschlieBlich durch Dunkelheit ausgeldst wird. Die Art scheint nicht eine bestimmte Zeit wdhrend der Nacht zu bevorzugen, eine Steuerung der Gesangsaktivitdit durch eine biologische Uhr ist daher nicht anzunehmen. Gesang beginnt unterhalb einer bestimmten Lichtintensitdt, welche normalervveise mit dem Dimmerungseinbruch erreicht wird, und endet am ndchsten Morgen, sofern Nachts nicht eine Minimaltemperatur unterschritten wird. Die Art singt auch tagsUber, wenn durch starke Bewcilkung die Lichtintensitdt reduziert ist. Summary The author gives evidence that song activity in Oecanthus pellucens is induced only by a scotophase. Because it has no preference for a certain time during the natural scotophase the species has no need for a biological clock for the regulation of its song activity at all. Song activity is starting just below a certain light intensity - which is normally reached at dusk - and is ending at dawn or when temperature falls at night below a certain threshold. The species may sing during the day when clouds reduce light intensity. Introduction Chorthippusvagans. In: DETzEL, P. (1998): Die Heuschrecken Baden- W0rttembergs. WANCURA, R. & DErzEL, P. (1998): Aiolopus thalassinus. In: DErzEL, P. (1 998): Die Heuschre- cken Baden-W0rttembergs. Many organisms have an endogenous timekeeper which regulates their activities. In insects this endogenous timekeeper is a so called insect clock. This insect clock mostly follows a circadian rhythm which is calibrated by the alternation of day and night. ln Saltatoria the activities in many species follow a circadian rhythm but there are exceptions. For example in Sclsfocerca gregana no circadian rhythm in locomotion activity was found (Oonnueo 1966). As singing in Saltatoria is an essential activity most species have a preferential time for song activity (FtscHER et al. 1996). For example Metrbpten roeseliiand M. bicolor have higher song activities in the first half of a day (FtscHen et al. 1996). But most known is from light trapping in night flying moth the preference of some species for coming at different hours to the light Saltatoria, like all insects, are poikilothermal animals and they need a minimum air temperature for song activitity or - in diurnal species - sunshine to raise their body temperature by solar radiation. ln Teftigonia viidissima was found that the ARTfCULATA 2001 16 (n) ARTTCULATA 2001 rql/2) FP7 E:6 species prefer singing in warm evenings but is the temperature low the species already sing in the afternoon (NrELsoN & DRErsrG 1970). E:E Oecanthus pellucens adult emerge from the end of July to the beginning of August. On warm days males start singing around sunset and song is performed until late night. When temperature remains above a certain threshold (Snruoen 1995:12 "C) the species may continue singing till dawn (Fig. 1). jtOc) ar(JO E€O PP 9 €-db <nE Methods and results =Oc Etc) Field observations E F* E E= oEg Surprisingly males may even sing during the day. Sander (1995) reports, that in summer, O. pellucens starts singing at dusk, but that in autumn the species often starts singing in the afternoon. DETZEL (1998) also observed singing males on cloudy days. Even on a sunny day I located a singing male in thick bushes while individuals in adjacent grassland were not singing. I also found singing males in the early afternoon when sunlight intensity was strongly reduced by thunder ox(! : | .1' T E€ E(0; stDz : oc =^ P BE 5rt(U clouds. 9<.rP En-s s;.E sxt tLl Observation during the total solar eclipse on the 11'n of August 1999 in SouthWest Germany sE e*n€ Fg { I used the rare opportunity of a total solar eclipse for investigating the song activity of O. pellucens in the nature reserve'Monbijou' near Zweibriicken in the South-West of Rhineland-Palatinate. O. pellucens began singing soon after 8pm at the day prior to the eclipse (Fig. 1), and continued singing until dawn. The eclipse lasted from 11:10 until 13:54 Central European Summertime, and the period of the total eclipse from 12:30 until 12:32. During this 2 minute period of intense darkening only males were heard singing. Capture experiments In my flat in Bobenheim-Roxheim I kept some individuals of the species - which I caught in and around the town - in 1% I pickled cucumber jars. At night they started singing in the same timescale as individuals in nature. As soon as I switched an artificial light on they stopped. When the artificial light was switched off they started singing again within a few minutes. ln an other experiment I covered the jar with dark woollen sheets so that the crickets were subjected to darkness during the day. Within less than five minutes I { I asdrlca ro 6uruurbeq { 00 fli, S l ( d ( { ( 0080 ii68 rr 00:90 61,9 I i I b>-ad 00t,066811 ( { { { e Egt t sE I aF 00005ri8t1 00ta 6630r .qafrts6e {', I (U b:9 EA I oo6ts@n oN?O NFF-FF oo atnleJadual Itr^Boe 6uos 00 0a 1:j6 8 0l (n) ? sE $E:J EEsJg'= J fl ARTfCULATA 2001 16 ";'E F€H o>o Ul= O rr.PI A;HEF €5 PP€ EE:€E 00l00ij8ir s 8;: bi go l { ( they started singing. 0l E Discussion ARTICULATA 2001 The observations in the field and during the solar eclipse show that o. only sings below a certain level of light intensity. Especially in the capture experiment I could give evidence that song activity is rapidly triggered by diminishing light intensity and is switched off immediately in bright light. The immediate reaction to the exogenous factor light implies that song activity itself is not induced by an endogenous biological clock as it is generally assumed for saltatorian insects (lNGRtscH & Koeulen 1998, p234). species which prefer a certain time of day for song activity - such as Metioptera bicolor - may need a biological clock for orientation to the time of day. Also this I call in question because this diurnal active species stopped singing for the span of reduced fight intensity during the solar eclipse (PFEIFER in prep.). o. pellucens starts singing below a certain light intensity and continues throughout the nlght until the temperature declines to below a certain threshold or until the beginning of the next photoperiod at dawn. Explanation of this behaviour requires no recourse to a t6 (1 t2l:79 KURZMITTEILUNG pellucens biological clock, but can be explained purely by response to prevailing light intensity. Author: Manfred Alban Pfeifer AnebosstraBe 4 D 67240 Bobenheim-Roxheim lmagines von Chorthippus mollis (CHAReENTIEn, 1825) und Gomphocerippus rufus (Llt.tueus, 1758) am 15. Dezember 2000 Gabriel Hermann In den Mittagsstunden des 15.12.2000 herrschte im baden-wurttembergischen Aichtal (15 km sUdl. Stuttgart) teils sonnige, aber kuhle und windige Witterung vor. Da im Verlauf des Herbstes bis dato weder stdrkere Fr6ste noch ldnger andauernde Schneelagen aufgetreten waren und der November 2000 im Vergleich zum langjiihrigen Mittel auBergew6hnlich warm blieb, wurde der Versuch unternommen, auf einem sUdexponierten Magerrasen noch Feldheuschrecken aufzufinden. Zwischen voll besonnter Nadelstreu einer dlteren Waldkiefer (Pinus sylvestns) fanden sich schlieRlich sechs Weibchen und ein singendes Mdnnchen der Roten Keulenschrecke (Gomphocerippus rufus) sowie ein Weibchen des Verkannten GrashUpfers (Chorthippus mollis). An der Fundstelle wurden bodennah Temperaturen knapp unter 15"C gemessen. Beide Arten Zihlen im betreffenden Gebiet zu den hiiufigsten Feldheuschrecken und erreichen hier im Spiithohe bis sehr sommer mit unterschiedlichen Vorkommensschwerpunkten - - hohe Abundanzen. References FUr G. rufus waren iihnliche Phdnologie-Daten bereits bekannt. Derzrl (1998, schriftl. Mitt. SMErrAu) gibt fUr Baden-WUrttemberg als spdtestes Nachweisdatum von fmagines den 14.12. an. Adulte Ch. mollis-lndividuen sind in diesem Bundesland dagegen offenbar noch nicht im Monat Dezember gefunden worden (vgl. Phainogramm in BRnNot& GorrscHALK 1998). It. DETZEL, P. (1998): Die Heuschrecken Baden-Wtirtembergs. 580 S. (Ulmer), Stuttgart FrscHER, P.F.; ScHueeRr, H.; FENN, S. & ScHULz, U. (1996): Diurnal song activity in grassland Orthoptera. - Acta Oecologia 17(5): 345-364. s. & KoHLER, G. (1998): Die Heuschrecken Mitteleuropas.460 s. (westarp-wiss.), Magdeburg; lNGRrscH, NTELSoN, E. T. & DRErsrc, H. (1970): The behavior of stridulation in Behaviour 37: 205-251 orthoptera Ensifera. Arbeitsgruppe fUr Tierdkologie und Planung . ODHIAMBo, T.R. (1966): The metabolic effects of the corpus allatum hormone in the male desert locust. ll. Spontaneous locomotoractivity. J. exp. Biol.45: 51-63. PFETFER, M. A. (in prep.): Beobachtungen des Gesangs von Langfuhlerschrecken (Ensifera) wahrend der totalen Sonnenfinstemis am 1 1 . August 1999 in der Pfalz - Hinweise auf eine exogene Steuerung des Gesangsverhaltens. SANDER, U. (1995): Neue Erkenntnisse iiber Verbreitung und Bestandssituation des Weinhdhn- chens oecanfhus pellucens (scopoLr, 1763) (Gryllidae, oecanthinae) im ndrdlichen Rheinland-Pfalz und in Nordrhein-Westfalen. - Articulata 1995 10(1): 73-Bg. ARTICULATA 2OO1 16 Verfasser: Gabriel Hermann (I2I Johann-StrauB-Str. 22 D 70794 Filderstadt Literatur Gor-rscHALr,E.: Chorthippus mollis (CHARPENTIER, 1825). - In: DETZEL, P. (199e): Die Heuschrecken Baden-W0rftembergs. - 580 S. (Ulmer), Stuftgart. BRANDT, D., - In: DETZEL, P. (1998): Die - 580 S. (Ulmer), Stuftgart. DErzEL, P. (1998): Gomphoceippus rufus (L|NMEUS, 1758). Heuschrecken Baden-Wiirttembergs. ARTICULATA 2OO1 16(1 12\