caa a22 4500 469061154 CHVBK 20180323132857.0 cr unu---uuuuu 170328e19920901xx s 000 0 eng 10.1007/BF01195790 doi (NATIONALLICENCE)springer-10.1007/BF01195790 Gaede K. Institut für Angewandte Zoologie, Freie Universität Berlin, Haderslebener Strasse 9, D-1000, Berlin, Germany aut On the water balance of Phytoseiulus persimilis A.-H. and its ecological significance [Elektronische Daten] [K. Gaede] The net water vapour exchange ofPhytoseiulus persimilis A.-H. is described. Water loss by transpiration increases progressively with ambient temperature. The transpiration rate is directly proportional to the saturation deficit of the air (15 to 30° C) and at constant temperature linearly dependent on the water vapour activity: mT=−0.81 av+0.91 (for av 0.0 to 0.85 at 20°C). Phytoseiulus persimilis is able to absorb water vapour from the unsaturated atmosphere. This occurs above a certain threshold (critical equilibrium activity, CEA), which is av=0.9 at 15 to 25°C and increases to av=0.935 at 30°C. The environmental humidity conditions influencingP. persimilis on the leaf surface are described. The diurnal water vapour profile within the laminar layer at the leaf surface includes periods with water vapour values high enough for these mites to utilize their water vapour sorption capability and to restore a previously-suffered water deficit. In addition,P. persimilis shows a positive hygrotactic behaviour when in a state of water deficit. The survival time of starvingP. persimilis is at least doubled when a possibility to absorb water vapour is available. The water balance at limited food resources is discussed. With a food supply (one prey mite, containing about 5.5 μg water) every 3 days and a water vapour activity of av=0.76 (20°C), water balance is achieved and the survival time is maximal (approximately 120 days). Elsevier Science Publishers B.V. All rights reserved, 1992 Experimental & Applied Acarology Kluwer Academic Publishers 15/3(1992-09-01), 181-198 0168-8162 15:3<181 1992 15 10493 https://doi.org/10.1007/BF01195790 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF01195790 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Gaede K. Institut für Angewandte Zoologie, Freie Universität Berlin, Haderslebener Strasse 9, D-1000, Berlin, Germany aut NATIONALLICENCE 773 0- Experimental & Applied Acarology Kluwer Academic Publishers 15/3(1992-09-01), 181-198 0168-8162 15:3<181 1992 15 10493 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer