Extreme heat alters the performance of hosts and pathogen

Abstract

The frequency and intensity of extreme heat in the environment have increased in the last decade. Extreme heating events (EHE) have wide-ranging impacts on biological systems from the molecular to the community level. However, the impacts of EHE have been poorly studied in pathogen–host systems. Here, we explore how EHE affects the interaction among the insect hosts, Osmia cornifrons and Osmia lignaria, and a protozoan pathogen, Crithidia mellificae. We compared changes in the upper limit for locomotion of hosts (Ctmax), thermal boldness (voluntary exposure to Extreme Temperature Zones – ETZ) between healthy and infected host exposed to EHE, and the effect of host Ctmax on pathogen growth rate. Our results showed that 1-day EHE significantly reduced the upper limit for locomotion of hosts by an average of 4 °C in healthy and 7 °C in infected hosts. Further, EHE significantly reduced the protozoan pathogen growth rate. EHE also reduced the hosts’ voluntary exposure to (or transit across) extreme (hot or cold) temperature zones (ETZ). Our results show that EHE reduces both hosts’ heat tolerance and pathogen fitness, and shed light on the implications of EHE on host–pathogen dynamics under warmer world.

Extreme heat reduces host and parasite performance in a butterfly–parasite interaction

“…Both monarchs and OE spores are known to survive in habitats where midday temperatures surpass 34°C [44,84,85], likely because they experience relief from the heat at night, and through behavioural thermoregulation where caterpillars seek shade, thus altering the internal temperature environment experienced by OE [86]. Future studies should therefore use fluctuating temperatures, simulated heatwaves, or shorter pulses of extreme temperatures to assess impacts on infection outcomes [15,44,[87][88][89]. Additionally, experiments should assess whether parasite strains from different locations or infecting different host populations (e.g.…”

Heat Pre-Treatment Modified Host and Non-Host Interactions of Powdery Mildew with Barley Brassinosteroid Mutants and Wild Types

“…However, it is important to note that changing climate (connected to elevated temperatures) may promote the breaking down of this resistance. Heat pre-treatment modified host and non-host interactions [13], and infection of barley by Bh, results in a so-called host plant-pathogen interaction, but barley in specific circumstances (under high temperature stress) may be attacked also by Blumeria graminis f. sp. tritici (Bgt; powdery mildew of wheat), representing a non-host interaction.…”