Warming with Temperature Oscillations Alter the Thermal Responses of Two Aphid Species, Acyrthosiphon pisum and Megoura crassicauda, and Parasitoid, Aphidius ervi

<p>Organisms naturally experience diurnal temperature fluctuations and variable extreme environmental events rather than only staticthermal regimes. Therefore, experimental studies that use only static mean daily, monthly or yearly temperatures overlook the possible influence of diurnal temperature fluctuations. Exposure to fluctuating temperatures enables an organism to perform more 'naturally' as they have a period of recovery, whereas under constant temperature, they do not have thermal recovery periods. By applying both fluctuating and constant temperatures, this study compares the impacts of elevated temperature on the fitness and demographic parameters of the aphids Acyrthosiphon pisum and Megoura crassicauda Mordvilko. We use four fluctuating temperature regimes that are increased by +0 °C, +2 °C, +4 °C and +5 °C from field-recorded, fluctuating base temperatures and four constant temperatures of 19 °C, 21 °C, 23 °C and 24 °C as treatments and also use a control temperature of 25 °C. We find that A. pisum and M. crassicauda exhibited faster development, quicker generation time (GT), lower population doubling time (DT), increased intrinsic rate of increase (rm) and a finite rate (λ) under warming conditions. In contrast, adult longevity, survival period, fecundity, net reproductive rate (R0), age-specific survivorship (lx) and age-specific fecundity (mx) were negatively affected by warming. The fluctuating thermal regimes improved overall fitness and all demographic parameters of both aphid species; therefore, we identify that daily fluctuating temperatures play a vital role in monitoring and predicting natural population dynamics. These results have implications for the experimental forecasting of natural population dynamics under climate change and global warming predictions.</p>

<p>Data for the Development and survival of juvenile aphids were observed every day at the nine temperature treatments by detecting their moulting and mortality. Moulting was identified by the occurrence of cast skins of the first to four instars. The number of days after birth to death, moulting of each instar, survival, adult longevity, and birth of first nymphs were recorded every 24 hours.</p>

<p>Thesis dataset summaries<br>Chapter 2<br>
<ul><li>Life table data of Pea aphid</li>
<li>Life table data of Megoura</li></ul></p>

<p>Chapter 3<ul><li>
Ctmax </li>
<li>Merabolism</li></ul></p>

<p>Chapter 4<ul><li>
Pea aphid</li>
<li>Parasitoids</li></ul></p>