Effect of rearing conditions on the correlation between larval development time and pupal weight of the rice stem borer, Chilo suppressalis

Abstract

A strong positive correlation between development time and body size is commonly assumed. However, the evidence is increasing that the correlation between the two traits can be positive, zero or negative, depending on whether the two traits are under antagonistic or synergistic selection. In the present study, we examined the relation between larval development time and pupal weight of the rice stem borer Chilo suppressalis under laboratory and field conditions. For individuals reared at constant temperatures (22, 25, 28 and 31°C), a longer larval period tended to result in larger pupae, showing a positive correlation between larval development time and pupal weight; whereas for those reared under field conditions, a longer larval period tended to result in smaller pupae at 23.5 and 29.8°C, showing a negative correlation between the two traits. There was no correlation between the two traits at the mean daily temperature of 31°C. At constant temperatures, larval development time shortened significantly as rearing temperature increased, whereas pupae tended to become larger at higher temperatures, although no significant difference was detected among temperatures for pupal weight. Under field conditions, larval development time decreased significantly as the mean daily temperature increased, whereas pupal weight of females increased significantly with the increase in the mean daily temperature, which is an example of the reverse temperature–size rule. Feeding method significantly affected larval development time and pupal weight. For individuals fed on live rice plants, larval development time shortened significantly and pupal weight increased significantly compared with those reared on fresh rice stems.

Larval mannitol diets increase mortality, prolong development, and decrease adult body sizes in fruit flies (Drosophila melanogaster)

“…Several recent studies support the idea that the positive relationship between body size and developmental duration can be reversed due to variable diets, even across different insect taxa [17,40–42]. The phenotypic effects of a mannitol diet on this relationship in D. melanogaster are similar to the effects of high-sugar diets, produced via disrupting the insulin-signaling pathway [10,12,17,18].…”

Expression of alternative developmental pathways in the cabbage butterfly, Pieris melete and their differences in life history traits

“…However, increasing evidence has shown that the reverse TSR in insects is also common. For example, reversals of the TSR have been found in four species of mayfly (Atkinson, ); four species of British grasshoppers (Willott & Hassall, ); the tropical butterfly, Bicyclus anynana (Fischer, Bot, & Brakefield, ); the small cabbage white, butterfly, Pieris rapae (Kingsolver, Massie, Ragland, & Smith, ); the Asian corn borer, Ostrinia furnacalis (He, Tang, Huang, Gao, & Xue, ; Xiao et al, ); and the rice stem borer, Chilo suppressalis (Fu, He, Zhou, Xiao, & Xue, ; Huang, Xiao, He, & Xue, ). As such, why do some insect species follow the TSR and some exhibit the reverse TSR?…”

“…Those species with summer diapause may exhibit the TSR, as indicated by the cabbage beetle, C. bowringi (Tang, He, Chen, Fu, & Xue, ) and this butterfly, P. melete because their reproductive periods occur in the spring and autumn and because these insects have experienced strong selection for body size under relatively low environmental temperatures during the process of evolution. Those species with winter diapause triggered by shortening day lengths combined with high autumn temperatures may exhibit the reverse TSR, as indicated by the Asian corn borer, O. furnacalis (He et al, ; Xiao et al, ), and the rice stem borer, C. suppressalis (Fu et al, ; Huang et al, ). These two species enter winter diapause in response to high autumn temperatures and experience strong selection for body size under warm conditions.…”

“…Ostrinia furnacalis (He, Tang, Huang, Gao, & Xue, 2019;Xiao et al, 2016); and the rice stem borer, Chilo suppressalis (Fu, He, Zhou, Xiao, & Xue, 2016;Huang, Xiao, He, & Xue, 2018). As such, why do some insect species follow the TSR and some exhibit the reverse TSR?…”

“…We speculate whether an insect species follows the TSR or not may be related to its diapause characteristic. Those species with summer diapause may exhibit the TSR, as indicated by the cabbage beetle, C. bowringi (Tang, He, Chen, Fu, & Xue, 2017) Xiao et al, 2016), and the rice stem borer, C. suppressalis (Fu et al, 2016;Huang et al, 2018). These two species enter winter diapause in response to high autumn temperatures and experience strong selection for body size under warm conditions.…”