| Popis: |
Climate change is now unequivocal and influences crops and the incidence of insect pests. Understanding the spatially variable, species-specific, and complex effects of climate change is essential in developing an appropriate pest management strategy. The two dimensions of climate change i.e., elevated temperature ( e Temp.) and elevated CO _2 ( e CO _2 ) influence insect herbivores. In the present study, the growth and development of an invasive insect pest, fall armyworm, Spodoptera frugiperda (J E Smith) (Lepidoptera: Noctuidae) on maize at e CO _2 and e Temp conditions using CO _2 and temperature Gradient Chambers (CTGC) was estimated. Dilution of bio-chemical constituents was noted with lower leaf nitrogen (9%–14%), higher carbon (3%–11%), higher C : N (18%–26%), and higher tannins (13%) in maize foliage at e CO _2 + e Temp levels. A significant influence on primary parameters of insect viz., higher total consumption by larvae (38%), extended larval duration (13%) with increased larval weights (17%), and differential pupal weights (14%) in successive generations was recorded at e CO _2 + e Temp compared to ambient. Their effect was continued on various insect performance indices also, with higher relative consumption rate, RCR (40%), lower relative growth rate, RGR (11%), and varied approximate digestibility (AD), the efficiency of conversion of ingested food (ECI) and digested food (ECD) of S frugiperda larvae. The interactive effect of e CO _2 and e Temp led to a higher Potential Population Increase Index (PPII) (19%) due to higher fecund adults. The effect of e CO _2 offsets the impact of e Temp when interacting together on some of the insect parameters. The present results indicate that e CO _2 and e Temp play a key role in influencing the growth and development of S frugiperda indicating higher pest incidence in future climate change periods. |
