Corn rootworms (Diabrotica spp.) are among the most destructive pests impacting agriculture in the U.S and are an emerging model for insect... Show moreCorn rootworms (Diabrotica spp.) are among the most destructive pests impacting agriculture in the U.S and are an emerging model for insect-plant interactions. We have a limited understanding of the genome-scale level difference between specialist and generalist corn rootworm species and their interaction with their host plants. Genome sizesof several species in the genus Diabrotica and an outgroup were estimated using flow cytometry. Results indicated that there has been a recent expansion in genome size in the common ancestor of the virgifera group leading to Diabrotica barberi, Diabrotica virgifera virgifera, and Diabrotica virgifera zeae. Comparative genomic studies between the fucata
and virgifera groups of Diabrotica revealed that repeat elements, mostly miniature inverted-transposable elements (MITEs) and gypsy-like long terminal repeat (LTR) retroelements, contributed to genome size expansion.
The initial transcriptional profile in western corn rootworm neonates when fed on different potential host plants demonstrated a strong association between western corn rootworm and maize, which was very distinct from other possible hosts and non-host plants. The results also showed presence of several larval development related transcripts unique to host plants and the presence of several muscle development and stress response related transcripts unique to non-host plants. The effect of the maize defensive metabolite DIMBOA on corn rootworms was studied using a novel plant-free system. The survival of both southern and western corn rootworms was not affected at a low concentration of DIMBOA. However, the concentration above the physiological dose found in plants affected the survival of corn rootworms. DIMBOA had no plant independent effect on these corn rootworms weight gain. Show less
