Precipitation change accentuates or reverses temperature effects on aphid dispersal

Abstract

Global temperatures are generally increasing, and this is leading to a well documented advancement and extension of seasonal activity of many pest insects. Effects of changing precipitation have received less attention, but might be complex because rain and snow are increasing in some places but decreasing in others. This raises the possibility that altered precipitation could accentuate, or even reverse, the effects of rising temperatures on pest outbreaks. We used >592 K aphid suction-trap captures over 15 years, in the heavily farmed central USA, to examine how the activity of Aphis glycines (soybean aphid), Rhopalosiphum maidis (corn aphid), and Rhopalosiphum padi (bird cherry-oat aphid) changed with variation in both temperature and precipitation. Increasing precipitation caused late-season flight activity of A. glycines and early-season activity of R. padi to shift earlier, while increasing temperature did the same for early-season activity of A. glycines and R. maidis.In these cases, precipitation and temperature exhibited directionally similar, but independent, effects. However, precipitation sometimes mediated temperature effects in complex ways. At relatively low temperatures, greater precipitation generally caused late-season flights of R. maidis to occur earlier. However, this pattern was reversed at higher temperatures with precipitation delaying late-season activity. In contrast, greater precipitation delayed peak flights of R. padi at lower temperatures, but caused them to occur earlier at higher temperatures. So, in these two cases the interactive effects of precipitation on temperature were mirror images of one another. When projecting future aphid flight phenology, models that excluded precipitation covariates consistently underpredicted the degree of phenological advance for A. glycines and R. padi, and underpredicted the degree of phenological delay for R. maidis under expected future climates. Overall, we found broad evidence that changing patterns of aphid flight phenology could only be understood by considering both temperature and precipitation changes. In our study region, temperature and precipitation are expected to increase in tandem, but these correlations will be reversed elsewhere. This reinforces the need to include both main and

Is there a relationship between the density of Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) and Aphis gossypii Glover (Hemiptera: Aphididae)? Spatial analysis of moth-aphid abundance across cotton fields located southeast of the Caspian Sea

“…Other studies have reported a negative relationship between different types of aphids and rainfall, especially species with smaller bodies (Kaakeh and Dutcher, 1993). In agreement with present studies, ight activity of Aphis glycines (soybean aphid) and early-season activity of Rhopalosiphum padi (bird cherry-oat aphid) (Crossley et al 2022) or Macrosiphum euphorbiae on potato (Solanum tuberosum) (Beetge and Krüger 2019) shifts earlier with increasing precipitation. Both of the mentioned studies regarded the regulatory role of temperature on precipitation.…”

Coexistence between similar invaders: The case of two cosmopolitan exotic insects

“…Meanwhile, predation rates by H. axyridis increased with increasing temperature up to 35°C and were markedly decreased below 25°C (Islam et al, 2021). Both species had positive associations with warmer‐than‐average temperatures in mid or late summer, which could be associated with temperature‐modified activity of prey aphids (Crossley et al, 2022). Within this region of the midwestern US, direct and/or indirect responses of H. axyridis and C. septempunctata to temperature and precipitation have contributed to niche differences and cyclical patterns of dominance over time.…”

“…Coccinella septempunctata temperatures in mid or late summer, which could be associated with temperature-modified activity of prey aphids (Crossley et al, 2022). Within this region of the midwestern US, direct and/or indirect responses of H. axyridis and C. septempunctata to temperature and precipitation have contributed to niche differences and cyclical patterns of dominance over time.…”

Coexistence between similar invaders: The case of two cosmopolitan exotic insects

“…Meanwhile, predation rates by H. axyridis increased with increasing temperature up to 35°C, and were markedly decreased below 25°C (Islam et al 2021). Both species had positive associations with warmer-than-average temperatures in mid or late summer, which could be associated with temperature-modified activity of prey aphids (Crossley et al 2022). Within this region of the midwestern US, direct and/or indirect responses of H. axyridis and C. septempunctata to temperature and precipitation have contributed to niche differences and cyclical patterns of dominance over time.…”