Life-history traits of the Asian corn borer Ostrinia furnacalis in relation to temperature and geographical latitude

Life-history traits from four geographical populations (tropical LD population，subtropical GZ and YS populations and temperate LF population) of the Asian corn borer, Ostrinia furnacalis were investigated at a wide range of temperatures. The larval and pupal developmental time of both females and males was significantly shortened with increasing rearing temperature, and the growth rate was positively correlated with temperature in all populations. However, the relationship between body size and rearing temperature in O. furnacalisdid not follow the temperature–size rule; all populations exhibited the highest pupal and adult weight at high or intermediate temperatures. Acrossing all populations at each temperature, female pupae were significantly larger than males, showing a female biased sexual size dimorphism. Contrary to Rensch’s rule, the sexual size dimorphism was increased with rising temperature. Male pupae lost significantly more weight during metamorphosis compared to females.  The proportionate weight loss varied significantly among different populations. Adult longevity of both females and males was significantly decreased with increasing temperature in all populations. All populations exhibit a rather female-biased adult longevity.

Development time and growth rate did not show a latitudinal gradient, the subtropical YX population had the longest developmental time at 20, 22, 24, 26 28 and 30 °C and the temperate LF population had the highest growth rate at 20 and 24 °C; whereas at 26, 28 and 30 °C, the highest growth rate was seen in the subtropical GZ population. The GZ population had the highest female pupal weight at 20, 22, 24, 26, 28 and 30 °C, whereas The LF population had the lowest female pupal weight at the same temperatures. The subtropical GZ population exhibited the largest degree of dimorphism while the temperate LF exhibited the smallest. Adult longevity was significant different among populations at each temperature.

All the results concerning life history traits in this study demonstrate that the pattern of life history varies with temperature and latitude. Therefore, our results emphasize the importance of performing a life history experiment with a wide range of populations under a range of environmental conditions.