caa a22 4500 386361886 CHVBK 20180307111918.0 cr unu---uuuuu 161130e198902 xx s 000 0 eng 10.4039/Ent121131-2 doi S0008347X00028571 pii (NATIONALLICENCE)cambridge-10.4039/Ent121131-2 EFFECTS OF CONSTANT AND FLUCTUATING TEMPERATURES ON IMMATURE DEVELOPMENT AND AGE-SPECIFIC LIFE TABLES OF RHOPALOSIPHUM PADI (L.) (HOMOPTERA: APHIDIDAE) [Elektronische Daten] Relationships between temperature and immature developmental rates of apterous and alate Rhopalosiphum padi (L.) were determined in laboratory experiments conducted at constant and fluctuating temperatures. Lower and upper thresholds for development were 5.78 and 25.09 °C, respectively. Studies at fluctuating temperatures which simulated average and extreme low and high temperatures occurring during late-spring in eastern South Dakota were conducted to determine developmental rates and age-specific life table statistics. Developmental rates for cohorts exposed to variable temperatures were similar to expected developmental rates determined from constant temperature studies. Age-specific life table statistics differed among alate and apterous R. padi exposed to identical temperature regimes. On a day time scale, population growth rates of either morph increased with increasing temperature. When data were expressed on a degree-day time scale, population growth rates were similar for cohorts of either morph exposed to low and average temperature regimes. Population growth rates declined for cohorts of both morphs exposed to high temperatures. Equations were provided that estimate age-specific survival and natality for fluctuating temperatures. Stable nymphal instar distributions for apterous R. padi were similar at all temperatures; for populations with stable age structures, approximately 55, 15, 10, 7, and 10% of individuals would be first, second, third, and fourth nymphal instars, and adults, respectively. Copyright © Entomological Society of Canada 1989 Elliott N.C. Northern Grain Insects Research Laboratory, Agricultural Research Service, U.S. Department of Agriculture, Brookings, South Dakota, USA 57006 Kieckhefer R.W. Northern Grain Insects Research Laboratory, Agricultural Research Service, U.S. Department of Agriculture, Brookings, South Dakota, USA 57006 The Canadian Entomologist Cambridge University Press 121/2(1989-02), 131-140 0008-347X 121:2<131 1989 121 TCE https://doi.org/10.4039/Ent121131-2 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.4039/Ent121131-2 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Elliott N.C. Northern Grain Insects Research Laboratory, Agricultural Research Service, U.S. Department of Agriculture, Brookings, South Dakota, USA 57006 NATIONALLICENCE 700 1- Kieckhefer R.W. Northern Grain Insects Research Laboratory, Agricultural Research Service, U.S. Department of Agriculture, Brookings, South Dakota, USA 57006 NATIONALLICENCE 773 0- The Canadian Entomologist Cambridge University Press 121/2(1989-02), 131-140 0008-347X 121:2<131 1989 121 TCE CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-cambridge