Temperature effects on ballistic prey capture by a dragonfly larva.

Estefania Quenta Herrera,Olivier Dangles,Sylvain Pincebourde,Jérôme Casas

doi:10.1002/ece3.3975

Estefania Quenta Herrera, Olivier Dangles + Show 2 more

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https://doi.org/10.1002/ece3.3975

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Abstract

Understanding the effects of temperature on prey–predator interactions is a key issue to predict the response of natural communities to climate change. Higher temperatures are expected to induce an increase in predation rates. However, little is known on how temperature influences close‐range encounter of prey–predator interactions, such as predator's attack velocities. Based on the speed–accuracy trade‐off concept, we hypothesized that the increase in predator attack velocity by increasing temperature reduces the accuracy of the attack, leading to a lower probability of capture. We tested this hypothesis on the dragonfly larvae Anax imperator and the zooplankton prey Daphnia magna. The prey–predator encounters were video‐recorded at high speed, and at three different temperatures. Overall, we found that (1) temperature had a strong effect on predator's attack velocities, (2) prey did not have the opportunity to move and/or escape due to the high velocity of the predator during the attack, and (3) neither velocity nor temperature had significant effects on the capture success. By contrast, the capture success mainly depended on the accuracy of the predator in capturing the prey. We found that (4) some 40% of mistakes were undershooting and some 60% aimed below or above the target. No lateral mistake was observed. These results did not support the speed–accuracy trade‐off hypothesis. Further studies on dragonfly larvae with different morphological labial masks and speeds of attacks, as well as on prey with different escape strategies, would provide new insights into the response to environmental changes in prey–predator interactions.

Highlights

The interaction between prey and predators is a key component in determining the flux of nutrients from individuals to ecosystems (Thompson et al, 2012)
We focused on the predator kinematics, we verified that the prey was almost immobile during the interaction to ensure that the level of inaccuracy of the predator was due to the speed–accuracy trade-off and not to the movement of the prey
Because predator size might be a major factor in determining velocity, we analyzed the effect of body, labial mask, and abdomen sizes, and their interactions with temperature

Summary

| INTRODUCTION

The interaction between prey and predators is a key component in determining the flux of nutrients from individuals to ecosystems (Thompson et al, 2012). The accuracy of predators during fast attacks and the prey escape strategy might be major determinants for the capture success and/or failure of the predator (Brechbühl et al, 2011; Soto, Stewart, & McHenry, 2015) Based on this general background, temperature can be expected to modulate the relative velocities of attack and escape of ectothermic predators and prey, thereby altering the strategies of the individuals during the prey–predator interaction. The increase in predator attack velocity at higher temperature might reduce its accuracy, leading to more opportunities for the prey to escape This effect has been called the speed–accuracy trade-off which states that faster choices reduce precision, whereas slower choices are highly accurate (Chittka, Dyer, Bock, & Dornhaus, 2003). We focused on the predator kinematics, we verified that the prey was almost immobile during the interaction to ensure that the level of inaccuracy of the predator was due to the speed–accuracy trade-off and not to the movement of the prey

| MATERIALS AND METHODS

Findings

| DISCUSSION