Project description:<p>Several herbivorous insects consume certain metabolites from plants for other purposes than nutrition, such as defence. Adults of the turnip sawfly, <em>Athalia rosae</em> take up specific terpenoids, called clerodanoids, from <em>Ajuga reptans</em>. These metabolites are slightly modified by the sawflies and influence their mating behaviour and defence against predators. We characterised these metabolites and investigated their localisation in the insect and the specificity of the uptake and metabolite modification. Therefore, we performed feeding assays with adults and larvae of <em>A. rosae</em> as well as larvae of <em>Spodoptera exigua</em>, followed by chemical analyses. Two main clerodanoid-derived metabolites were detected in the abdomen and thorax but also on the surface of the adults. Small amounts were also found in larvae of the sawfly, while they were not detectable in <em>S. exigua</em>. Our findings provide new insights into the peculiarities of pharmacophagy and specialised metabolism in <em>A. rosae</em>.</p>
