Unravelling the diet of flightless grasshoppers for conservation purposes using DNA metabarcoding

Understanding food plant resources is essential for assessing habitat suitability for herbivorous animals, especially for species with limited movement that depend on local resources. However, obtaining this information can be challenging for species whose plant consumption cannot be easily monitored. Here we use DNA metabarcoding techniques to identify the plant species in the faeces of two grasshopper species of the flightless Australian subfamily Morabinae, the endangered Keys’ matchstick grasshopper Keyacris scurra , and the Larapuna matchstick grasshopper, Vandiemenella viatica . DNA sequences from the chloroplast trnL (UAA) and rbcL genes and ribosomal ITS2 region were used to identify the plant species in the diet of these species based on five populations per species. We found a total of 28 plant taxa in the faecal samples of K . scurra and 38 in V . viatica . Indigenous plants from the daisy family Asteraceae dominated the faeces samples of both grasshopper species and myrtle plants from Myrtaceae were also commonly found for V. viatica. Introduced grass species from the Poaceae family were also identified in the diet. PERMANOVAs showed significant differences in the composition of the plant community consumed across sites. Alpha diversity metrics revealed no significant differences between the two grasshopper species; however, significant variation was observed across sites, depending on the choice of markers (e.g., Shannon Index: χ ² (9) = 30.732, p  < 0.001 for ITS2). Our findings should help in revegetation efforts aimed at expanding the range of the two morabine species by identifying suitable plant species.