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ARS Home » Midwest Area » Ames, Iowa » Corn Insects and Crop Genetics Research » Research » Publications at this Location » Publication #300271
Title: On-plant selection and genetic analysis of European corn borer (Lepidoptera: Crambidae) behavioral traits: plant abandonment versus plant establishment

Author
item RAUSCH, MICHAEL - Iowa State University
item KROEMER, JEREMY - Iowa State University
item GASSMANN, AARON - Iowa State University
item Hellmich Ii, Richard

Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/8/2014
Publication Date: 9/8/2014
Citation: Rausch, M.A., Kroemer, J.A., Gassmann, A.J., Hellmich II, R.L. 2014. On-plant selection and genetic analysis of European corn borer (Lepidoptera: Crambidae) behavioral traits: plant abandonment versus plant establishment. Environmental Entomology. 43(5):1254-1263. https://doi:10.1603/EN14107.

Interpretive Summary: Insects commonly develop resistance to chemical insecticides and increasingly there is evidence that they also can develop resistance to genetically engineered crops. Behavior could be a factor for some types of insect resistance. This research shows a behavioral trait, plant abandonment, responds to selection and how it is inherited. We investigated plant abandonment and plant establishment traits for the European corn borer, Ostrinia nubilalis, on maize by conducting a laboratory selection experiment and by quantifying patterns of gene expression. Egg masses with emerging larvae were placed on maize plants and silking larvae were collected every 15 minutes during a 4 hour period to generate a plant abandonment colony. Plants were dissected 24-72 hours later and larvae were collected for a plant establishment colony. Selection over subsequent generations of the plant abandonment colony showed an increased propensity to abandon the host plant. Selection of the plant establishment colony did not show a consistent trend but was significantly different from the plant abandonment colony at the 6th generation. Quantitative real time polymerase chain reaction (qRT-PCR) was used to determine expression profiles for two genes related to behavior (“foraging” and “Onslmo”). Eggs samples from the two selected colonies and a non-selected laboratory colony were collected at five time points after egg laying; and young larvae were sampled after exposure to maize tissue. The “foraging” and “Onslmo” genes showed significantly higher expression in the plant abandonment colony compared to the plant establishment and non-selected lab colonies at the 0 hour time period. The “foraging” gene encodes an enzyme that may influence behavior. The results of this research offer further insights into insect behavior that could potentially influence resistance evolution. This information will be useful to scientists interested in insect behavior and insect resistance management.

Technical Abstract: Although some studies have investigated how insect behavior could influence resistance evolution to transgenic plants, none have determined if behavioral traits respond to selection pressure and how they may be inherited. We investigated plant establishment and plant abandonment traits for the European corn borer, Ostrinia nubilalis, by conducting a laboratory selection experiment and by quantifying patterns of gene expression. Egg masses with emerging larvae were placed on maize plants and silking individuals were collected every 15 minutes during a 4 hour period to generate a plant abandonment colony (PA). Plants were dissected 24-72 hours later and larvae were collected for a plant establishment (PE) colony. Selection over subsequent generations of the PA colony showed an increased propensity to abandon the host plant (parental generation 3.1%, 6th generation 38.0%). Selection of the PE colony did not show a consistent trend in plant establishment but was significantly different from the PA colony at the 6th generation (plant establishment trait PE 12.6%, PA 4.6%). Quantitative real time (qRT) PCR was used to determine expression profiles for behavior associated genes (foraging and Onslmo). Eggs samples from the two selected colonies and a non-selected laboratory colony were collected at 0, 24, 48, 72, and 96 hours after egg deposition, and first instar larvae were sampled after exposure to maize tissue. Foraging and Onslmo showed significantly higher expression in the PA colony compared to the PE and non-selected lab colonies at the 0 hour time period. Foraging encodes a cGMP dependent protein kinase (PKG) that may affect downstream pathways influencing behavior. The results of this research offer further insights into insect behavior that could potentially influence resistance evolution.