North Central Branch Annual Meeting Online Program
Selection and genetic analysis of behavioral traits of European corn borer (Ostrinia nubilalis), plant abandonment vs. plant establishment
Michael Rausch, Jeremy Kroemer, Susan Moser, and Richard Hellmich
In a selection experiment, we tested whether plant establishment and plant abandonment are heritable traits for the European corn borer, Ostrinia nubilalis. Emerging egg masses were placed on non-Bt corn plants and silking individuals (Silkers) were collected every 15 minutes during a four hour period. Plants were dissected 24 hours later and established individuals (non-Silkers) were collected. Individuals from these two phenotypes were reared to adulthood and mated with moths of the same phenotype. Selection over subsequent generations of the Silker colony showed an increased propensity to abandon the host plant (parental generation 3.1%, 6th generation 38.0%). Selection of the non-Silker colony did not show a consistent trend in plant establishment but was significantly different from the Silker colony at the 6th generation (non-Silker 12.6%, Silker 4.6%). Additionally, we investigated differences in candidate genes in O. nubilalis (foraging, shaker, and slowmo) to better understand the genetic mechanism(s) underlying these two traits. We used quantitative real time (qRT) PCR to determine expression profiles for these genes. Eggs samples from Silking, non-Silking, and a non-selected lab colony were collected at 0, 24, 48, 72, and 96 hours after egg deposition. Also, 1st instars exposed to corn tissue for 4 hours were collected (to mimic conditions of the selection experiment). Expression of foraging and slowmo show significantly higher expression in the Silking colony compared to the non-Silking and non-selected lab colony at the 0 hour time period. Foraging encodes a cGMP dependent protein kinase (PKG) and may affect downstream pathways that influence behavior.
