Elevated temperatures diminish the effects of a highly resistant rice variety on the brown planthopper

This study compares the effects of temperature (constant at 15, 20, 25, 30 and 35 degrees C) on adult longevity, oviposition, and nymph development of the brown planthopper, Nilaparvata lugens, on susceptible and resistant rice varieties. The resistant variety contained the BPH32 gene. In our experiments, nymphs failed to develop to adults at 15, 20 and 35 degrees C on either variety. Host resistance had its greatest effect in reducing adult survival at 20-25 degrees C and its greatest effect in reducing nymph weight gain at 25 degrees C. This corresponded with optimal temperatures for adult survival (20-25 degrees C) and nymph development (25-30 degrees C). At 25 and 30 degrees C, adult females achieved up to three oviposition cycles on the susceptible variety, but only one cycle on the resistant variety. Maximum egg-laying occurred at 30 degrees C due to larger numbers of egg batches produced during the first oviposition cycle on both the susceptible and resistant varieties, and larger batches during the second and third oviposition cycles on the susceptible variety; however, resistance had its greatest effect in reducing fecundity at 25 degrees C. This revealed a mismatch between the optimal temperatures for resistance and for egg production in immigrating females. Increasing global temperatures could reduce the effectiveness of anti-herbivore resistance in rice and other crops where such mismatches occur.

Automated summary

This study compared the effects of temperature on adult longevity, oviposition, and nymph development of the brown planthopper on susceptible and resistant rice varieties. Results showed that resistant varieties had the greatest impact on adult survival at 20-25 degrees C and nymph weight gain at 25 degrees C. However, resistance also led to reduced fecundity at 25 degrees C, revealing a mismatch between optimal temperatures for resistance and egg production in immigrating females, which could be impacted by increasing global temperatures.