PhD: How taste is encoded in the brain of caterpillars & butterflies

Are you a highly motivated and curious PhD candidate, willing to bridge across the fields of neuroscience, ecology and evolutionary biology? Do you want to explore how butterflies and caterpillars use their taste system to recognize the plants they coevolved with? And have you ever wondered if a plant tastes the same to a caterpillar as it does to a butterfly? Then we, at Wageningen University & Research, have an exciting opportunity for you.

You would be leading a PhD study with the aim to decipher the neuronal code used by the taste system of specialist caterpillars and butterflies to recognize their host plant. Insect herbivores and plants are intertwined in an intimate coevolutionary arms race in which plants produce toxic defence compounds and insects in turn evolved detoxification mechanisms allowing them to feed on specific plants. In parallel to these feeding adaptations, insects also evolved specific detection mechanisms for those plants to which they have become adapted.

These detection mechanisms rely on the recognition of certain plant chemicals as sign stimuli and others as deterrent signals. However, how the brain integrates these positive and negative signals is not yet known. Moreover, butterflies and caterpillars of the same species do not always use the same chemical cues, leading to different preferences in the two life stages.

You will use the model system of the cabbage white butterflies, Pieris spp.. These insects lay their eggs almost exclusively on plants containing glucosinolates, toxic compounds to which these insects have specifically adapted. At the same time, most Pieris species avoid cardenolides, a distinct group of defensive chemicals in some Brassica plants. The exception to this rule are Pieris napi butterflies which readily oviposit on cardenolide containing plants, giving us the opportunity to compare the gustatory code both between closely related species and between life stages.

To unravel these different coding mechanisms we will use both intra- and extracellular electrophysiological recordings to measure responses to the different chemical and their combination in the butterfly and caterpillar brain. In addition, we will create mutant butterflies lacking the most relevant receptor genes using Crispr/Cas9 to investigate how the silencing of specific neuronal channels changes the encoding of the host plant in the brain. Combined, these results will provide a unique insight into the neuronal mechanisms underlying the coevolution of insect and plants, which is a major driving factor of biodiversity and has shaped many of today’s terrestrial (agro-) ecosystems.

As a PhD candidate, you will contribute to fundamental research in the context of insect-plant coevolution and sensory ecology. You will be embedded in a diverse group of international scientists and collaborate with colleagues from both in- and outside Wageningen University & Research.

Your duties and responsibilities include:

• Establishing intra- and extracellular electrophysiological recordings from the insect suboesophageal ganglion;
• Visualize neuronal networks in the insect brain, using confocal microscopy and computer reconstructions;
• Generate and maintain transgenic insect lines;
• Supervise MSc and BSc students and assist in lab practicals.

You will work here
The research is embedded within the Laboratory of Entomology Lab of Entomology - WUR, which is led by Prof. Bregje Wertheim (Bregje Wertheim - Wageningen University & Research). You will be co-supervised by Dr. Alexander Haverkamp (Alexander Haverkamp - Wageningen University & Research). In addition, you will also be embedded in the PE&RC graduate school (Home | PE&RC), which will allow you to follow a wide variety of training courses and provide support during your academic journey.