The upper thermal tolerance of the secondary screwworm, Cochliomyia macellaria Fabricius (Diptera: Calliphoridae)

The upper thermal tolerance for a Texas population of the hairy maggot blow fly Chrysomya rufifacies Macquart (Diptera: Calliphoridae)

“…Thus, organismal thermal tolerance is a trait of broad interest from both basic and (B) (A) applied perspectives. Our results align with previous studies of the upper thermal tolerances (Lutterschmidt & Hutchison, 1997;Denlinger & Yocum, 1998;Neven, 2000;Rusch et al, 2019) where exposure to elevated temperatures for extended durations increased the probability of knockdown and decreased the probability of survival (Figs 1 and 2). Knockdown and death likely occurred as a result of heat stress, which depletes energy and water, denatures proteins, and damages cells and tissues (Neven, 2000;Chown et al, 2011;Wigglesworth, 2012), ultimately causing the failure of several vital mechanism, such as but not limited to oxygen delivery, enzyme binding or conformation, cellular functioning, and ion balance (Chiang et al, 1989;Neven, 2000;Klok et al, 2004;Somero, 2004;O'Sullivan et al, 2017).…”

“…The same approach (described above) was taken for comparing the probabilities of knockdown and survival between Cochliomyia macellaria from Rusch et al (2019) and C. rufifacies from the present study, except an interactive effect of species by temperature was used to test for species effects at the different treatment temperatures (see Tables S3-S4 and S7-S8). Furthermore, only the data for flies provided no food or water were compared.…”

“…The experiment and design followed those of Rusch et al (2019). The upper thermal tolerance of adult blow flies (C. rufifacies, n = 1800) was assessed using two metrics, knockdown and survival.…”

“…Thus, the lower thermal tolerance is thought to limit its northward expansion, as C. rufifacies does not overwinter in cold regions and consequently is only found in northern regions of the United States and Canada during summer and early fall (Baumgartner, 1993;Rosati & VanLaerhoven, 2007;Cammack & Nelder, 2010). Similarly, the upper thermal tolerance of C. rufifacies likely plays a role in limiting activity time and microclimate use (Harrison et al, 2012;Rusch et al, 2019), but in warmer regions and seasons. Nicholson (1934) found the general activity (e.g., walking and flying) of C. rufifacies decreased above 35 ∘ C and ceased at 45 ∘ C. Similarly, Mohr and Tomberlin (2015) had low capture success of C. rufifacies during midafternoon hours (∼1245-1845 h) when ambient temperatures were the greatest (up to 38 ∘ C) on summer days in Texas, USA compared to early morning or evening capture rates when temperatures were cooler (<35 ∘ C).…”

“…We also predicted the availability of nutrients would increase the upper thermal tolerance of C. rufifacies (i.e., decrease knockdown and increase survival) as flies would be able to replenish water and nutrients during treatments. To evaluate questions regarding competition with C. macellaria, the upper thermal tolerances (i.e., probabilities of knockdown and survival) of C. rufifacies were compared to the upper thermal tolerances of C. macellaria from that observed in Rusch et al (2019).…”