Surface Sterilisation Approaches for the Removal of Pollen DNA from Philaenus spumarius

To reliably identify the gut contents of plant-feeding insects, the removal of contaminant plant DNA from the insect surface is necessary. We perform a controlled baseline study to identify possible contamination that may persist after bleach washes. Despite the reported success of these methods, we find that contamination is still present, leading to unreliable results. We hypothesise that pollen is the main source of contamination, its robust nature making it difficult to remove. We conduct a further three experiments, investigating the effectiveness of more robust bleach washes, sterilised gut excision and ultra-violet light as alternative sterilisation approaches. Overall, our findings indicate that we are unable to remove surface contamination while still detecting signals which may originate in the gut. In no experiment did we unequivocally detect plant DNA that originated in the P. spumarius gut.