Performance in Survival,Development and Reproduction of Aphis glycines Matsumura Virginoparae at High Temperatures

The soybean aphid,Aphis glycines Matsumura,is an important pest of soybean,which is native to Asia.In this study,A.glycines fed on soybean(AgFS)and A.glycines fed on wild soybean(AgFW)were reared at 25℃,27℃,29℃,31℃,33℃and 35℃,respectively,and some of the life parameters were determined.At temperature ranging from 25℃to 31℃,nymphs of AgFS and AgFW all developed into adults successfully.Only a few nymphs of AgFS and AgFW developed into adults at 33℃and no nymphs could develop into adults at 35℃.Lifespan,fecundity and body size of AgFS and AgFW adults all decreased gradually with temperatures increasing from 25℃to 33℃.At 25℃,the intrinsic rate of increase of AgFS was as big as that at 27℃,which was smaller than that at 29℃,but was bigger than that at 31℃.Intrinsic rate of increase of AgFW decreased gradually with temperatures increasing from 25℃to 31℃.Nymph stage duration of AgFW was longer than or as long as that of AgFS;adult lifespan of AgFW was shorter than or as long as that of AgFS.Adult fecundity,intrinsic rate of increase and adult body size of AgFW were all smaller than or as big as those of AgFS.It showed that AgFS and AgFW both survived and developed well at temperature ranging from 25℃to 31℃,and AgFW was more adaptive to low temperatures.These results were important to study the adaptability of A.glycines to high temperatures and for predicting its dynamics in the temperature keeping rising region.

Effects of Constant High Temperature on Survival,Development and Reproduction of Aphis glycines Matsumura

Life cycle of Aphis glycines Matsumura is characterized as heteroecious and holocyclic.Temperature is one of the most important abiotic factors that can affect development and reproduction of A.glycines.In this study,A.glycines were fed on G.max at five constant temperatures,27℃,29℃,31℃,33℃ and 35℃.The development and reproduction of A.glycines were studied in the laboratory and the data were compared to controls on G.max at 25℃.The results showed that most of A.glycines nymphs developed into adults successfully at temperature range from 25℃ to 33℃,but only a few nymphs could develop into adult at 35℃.Longevity,fecundity and body sizes of A.glycines adults all decreased gradually when temperature increased from 25℃ to 33℃.Intrinsic rate of increase of A.glycines at 27℃ was as big as that at 29℃,which were bigger than those at 25℃,31℃ and 33℃.At 35℃,no offspring were deposited by adults.It provided information on development and reproduction of A.glycines exposed to high temperatures,which was important to study the adaptability of A.glycines to environmental temperature and for predicting its dynamics in soybean field in northeast China.

Leaf temperature of soybean grown under elevated CO2 increases Aphis glycines （Hemiptera＂ Aphididae） population growth

Plants grown under elevated carbon dioxide （CO2） experience physiological changes that influence their suitability as food for insects. To determine the effects of living on soybean （Glycine max Linnaeus） grown under elevated CO2, population growth of the soybean aphid （Aphis glycines Matsumura） was determined at the SoyFACE research site at the University of Illinois, Urbana-Champaign, Illinois, USA, grown under elevated （550μL/L） and ambient （370 μL/L） levels of CO2. Growth of aphid populations under elevated CO2 was significantly greater after 1 week, with populations attaining twice the size of those on plants grown under ambient levels of CO2. Soybean leaves grown under elevated levels of CO2 were previously demonstrated at SoyFACE to have increased leaf temperature caused by reduced stomatal conductance. To separate the increased leaf temperature from other effects of elevated CO2, air temperature was lowered while the CO2 level was increased, which lowered overall leaf temperatures to those measured for leaves grown under ambient levels of CO2. Aphid population growth on plants grown under elevated CO2 and reduced air temperature was not significantly greater than on plants grown under ambient levels of CO2. By increasing Glycine max leaf temperature, elevated CO2 may increase populations of Aphis glycines and their impact on crop productivity.