Behavioural responses of insect herbivores to shading cues

Plants use many cues to get the latest news on their environment, from volatiles released by insect-infested neighbouring plants to light signals from different parts of the spectrum. An important cue for plants to detect competitors and future shading is the ratio between red light (absorbed by foliage) and far-red light (reflected by foliage).


In response to a low red to far-red (R:FR) ratio, plants elongate stems and petioles and change leaf angles to keep up with their neighbours. In addition, a low R:FR ratio affects defence levels by repressing the activity of the jasmonate pathway. As a consequence of R:FR mediated defence, insect herbivores feeding on plants exposed to low R:FR perform better. However, recent experimental results in which caterpillars were feeding on low R:FR exposed plants show that these effects are species dependent. Moreover, results of a pilot experiment where caterpillars were fed on an artificial food source, suggest that R:FR can have a direct effect on the growth rate of caterpillars.

Type of research

In this thesis project you will further explore to what extent herbivores can directly respond to R:FR cues. This will be done by studying herbivore behaviour under contrasting levels of R:FR through various means. For example, one could look at feeding preference or feeding activity under various R:FR regimes. We are looking for a creative, motivated student with good experimental skills. We offer a challenging thesis supervised by enthusiastic supervisors.