ABSTRACT
The soybean aphid, A. glycines, is an important soybean pest. Harbin, in the Heilongjiang Province, is an area with increasing temperatures in China that faces frequent short-term heatwaves. In this study, the development, reproduction, and morph differentiation of A. glycines have been studied when they were exposed to diurnal at 35 °C for seven days, beginning at different developmental stages. The nymph stage duration of A. glycines was longer, the adult lifespans and total lifespans were shorter, and their bodies were smaller when exposed to a diurnal of 35 °C beginning at the 1st to 4th stadium. The adult reproduction period was shorter, and the adult fecundity and intrinsic rate of increase were smaller than those of aphids reared at a diurnal of 25 °C. A higher and lower proportion of gynoparae and males were deposited as offspring on day 13 by adults when exposed to diurnal at 35 °C, beginning at the 1st to 4th stadium, respectively, than those of aphids reared at a constant of 20 °C. These results are important for predicting the dynamics of A. glycines in Harbin soybeans. This provides evidence that short-term heatwaves are probably useful for controlling A. glycines, by inhibiting development and male morphogenesis.
ABSTRACT
As global warming intensifies, heat waves occur frequently in the summer and autumn in Heilongjiang Province, northeast China. The soybean aphid, Aphis glycines Matsumura, is an important pest of soybean in the region, which faces great survival pressure due to high temperature. In this study, A. glycines fed soybean (AgFS) and wild soybean (AgFW) were exposed to diurnal 35 °C for 7 days begin at different developmental stages, and the development, reproduction, and morph differentiation were studied. When AgFS were exposed to heat waves from the second stadium to the adult stage, they performed worse in adult lifespan and fecundity than the control. When AgFW were exposed to heat waves begin at different developmental stages, the adult lifespan and reproduction period were shortened and reproduction ability decreased. When exposed to heat waves, the adult fecundity and intrinsic rate of increase in AgFW were lower than those of AgFS. Lower proportion of males were deposited on day 13, when AgFS and AgFW were exposed to diurnal 35 °C begin at different developmental stages. The results showed that heat waves lasting for 7 days were likely to be useful in the management of A. glycines, which reduced adult reproduction ability and male differentiation proportion in the offspring and significantly affected AgFW compared to AgFS. These results are important for predicting the dynamics of A. glycines in Heilongjiang, northeast China, where the local environmental temperature is increasing and heat waves occur frequently.
ABSTRACT
The local temperature in the Harbin region of northeast China has been rising, with temperatures above 27°C often being recorded. The soybean aphid, Aphis glycines (Matsumura) (Hemiptera: Aphididae), and foxglove aphid, Aulacorthum solani (Kaltenbach) (Hemiptera: Aphididae), are important pests in soybeans in the region, which face great survival pressure due to rising temperatures. In this study, A. glycines and A. solani were reared at thermoperiods with diurnal temperatures of 25, 27, 29, 31, 33, 35, and 37°C, nocturnal temperature of 20 °C, 70%â ±â 5% relative humidity, and a photoperiod of 14:10 (L: D) hr. Diurnal thermoperiod 25°C was used as control. Some life characteristics of the aphids were assessed. The adaptation of A. solani to high diurnal temperatures was found to be worse than that of A. glycines. Aphis glycines could develop and reproduce successfully at diurnal temperatures of 27-35°C, whereas A. solani could only develop and reproduce at 27-29°C. At diurnal thermoperiods at 25°C, adult lifespan of A. solani was as long as that of A. glycines. When diurnal temperatures increased from 27 to 31°C, adult lifespan of A. solani were shorter than those of A. glycines. At diurnal thermoperiods at 25 and 27°C, the body sizes of A. solani adults were larger than those of A. glycines. At diurnal thermoperiods at 29 and 31°C, the body size of A. solani adults were as large as those of A. glycines. Our results provide important information on the survival, development, and reproduction of A. glycines and A. solani exposed to temperatures above 27°C, which is important for evaluating the adaptability of aphids to high temperatures and predicting their dynamics in soybeans in northeast China, where the local environmental temperature continues to rise.
