Progress 10/01/14 to 09/30/17
Outputs
Target Audience:This year, the project provided research opportunities to 3 undergraduate students (including two women), and one graduate student (Nick Aflitto). I presented our findingsto academic audiences at the University of Montana, University of Kentucky, and at the Gordon Research Conference on Plant-Herbivore Interactions. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?In total ten undergraduates, 2 graduate students (Sara Hermann, Nicholas Aflitto), and 1 postdoc (Will Wetzel) conducted research on this project. These students received substantial one on one mentoring from me on experimental design and analysis and scientific writing. The graduate students and postdocs presented their findings at the Plant-Insect Discussion group and international meetings for feedback. How have the results been disseminated to communities of interest?We have presented these results in undergraduate classes, grower fact sheets and multiple scientific meetings. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
In this study, we evaluated how Colorado potato beetles (Leptinotarsa decemlineata), a devastating agricultural pest, perceives the presence of predators by volatile, chemical cues from its stink bug predator, the spined soldier bug (Podisus maculiventris). Our previous research showed that olfactory cues in the lab are sufficient to replicate the full response of the Colorado potato beetle larvae to male predators but not female predators. For this project we measured the effects of predator presence and odors on beetle adults and larvae in the field. First, we measured beetle colonization and abundance in potato plots with and without predators over the potato growing season. We established field plots of potato plants either stocked with predators or left as controls. The predator treatments were accomplished by enclosing the predators in mesh bags on one of the potato plants in each plot. This meant that the predator was present and detectable to beetles but not able to consume beetles. We found that plots with predators had had the same number of adult beetles, but had reduced oviposition and reduced adult feeding damage early in the season compared to control plots. By the middle of the season, the abundance of beetles and damage was not different between treatments. Second, we tested several hypotheses to explain the seasonal differences in the effect of the predator on the adult beetles. We tested whether the beetles acclimated to the presence of the predators but did not find support for this hypothesis. We also did not find evidence that deterioration of the quality of the host plant over the season reduced beetle responses to the predators. Our current hypothesis is that predators reduce their emission of chemical cues over the season, reducing the response of the Colorado potato beetles. Third, we released synthetic predator odors into the field and measured the effects on adult oviposition, larval abundance and plant damage. We established field plots of nine potato plants where we released the predator aggregation pheromone in dispensers or left the plants as controls. We used a five- component blend of Podisus aggregation pheromone that had been identified by Jeffrey Aldrich's group and that we have shown reduces beetle feeding in the lab. The components of the aggregation pheromone blend were purchased from Sigma-Aldrich. We found effects of the synthetic predator pheromone on Colorado potato beetles that persisted over the potato growing season. Adult beetles reduced feeding and oviposition in plots with the synthetic aggregation pheromone. Plants in plots with the predator odor received 40% less damage over the season than plants in control plots. We will continue to investigate the aggregation pheromone in order to develop it into a management technique.
Publications
- Type:
Journal Articles
Status:
Under Review
Year Published:
2018
Citation:
Hermann, S.L. and J.S. Thaler. NON-CONSUMPTIVE EFFECTS OF PREDATOR DRIVES BEHAVIOURAL SHIFTS IN ADULT COLORADO POTATO BEETLES. Oecologia
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Progress 10/01/15 to 09/30/16
Outputs
Target Audience:This year, the project provided research opportunities to 4 undergraduate students (all women), one of whom is African-American and a high-school student. One of these students also conducted independent research related to the project. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Four undergraduates, 1 high school student, 1 graduate student (Nicholas Aflitto), and 1 postdoc (Will Wetzel) conducted research on this project. These students received substantial one on one mentoring from me on experimental design and analysis and scientific writing. The graduate student presented his findings at the Plant-Insect Discussion group for feedback. How have the results been disseminated to communities of interest?This year, these results were presented at the Predator-Prey Gordon ResearchConference in Ventura California. What do you plan to do during the next reporting period to accomplish the goals?We are currently investigating the causes of seasonal variation in the effect of predator presence on the prey and will write this research for publication. We are also continuing to investigate the role of specific predator odors on beetles in different life-stages and the role of plant volatiles in detection of predator odors.
Impacts
What was accomplished under these goals?
In this study, we are evaluating how Colorado potato beetle (Leptinotarsa decemlineata) larvae, a devastating agricultural pest, perceives predator presence by volatile, chemical cues from its stink bug predator, the spined soldier bug (Podisus maculiventris). Our previous research showed that olfactory cues are sufficient to replicate the full response of the Colorado potato beetle to male predators but not female predators. This year, we measured the effects of predator presence on beetles in the field. We established field plots of potato plants either stocked with predators or left as controls. The predator treatments were accomplished by enclosing the predators in mesh bags on one of the potato plants in each plot. This meant that the predator was present and detectable to beetles but not able to consume beetles. We then measured beetle colonization and abundance in the plots over the potato growing season. We found that plots with predators had lower abundances of adult beetles, reduced oviposition and reduced adult feeding damage early in the season compared to control plots. By the middle of the season, the abundance of beetles was not different between treatments.
Publications
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Progress 10/01/14 to 09/30/15
Outputs
Target Audience:This year, the project provided research opportunities to 7 undergraduate students (5 women, 2 men), one of whom is Hispanic and one is the first in her family to attend college. Three of these students also conducted independent research projects related to the project. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Six undergraduates, 1 graduate student, and 1 postdoc student conducted research on this project. These students received substantial one on one mentoring from me on experimental design and analysis and scientific writing. The MsC student presented her findings at the Symposium on Insect Plant Relationships which was a good opportunity for practicing her oral presentation skills and meeting professional colleagues. How have the results been disseminated to communities of interest?The early stages of this research were presented at the Symposium on Insect Plant Interactions in August 2015. What do you plan to do during the next reporting period to accomplish the goals?This coming year we will continue to work on Objective 2 and start on Objective 3, testing the odors in the field.
Impacts
What was accomplished under these goals?
This year, we worked mainly on Objective 2. We measured the headspace odors emitted from stink bugs and found that male stink bugs released three main chemicals (E)2-hexenal, alpha terpineol and benzyl alcohol. The female stink bugs released much lower amounts of these chemicals. We then tested the pure male odor compounds in petri dish behavioral assays and found that 95% of the beetle larvae choose the control over a l% blend of the three main male chemicals. When we tested the odors individually, we found that only alpha terpineol affected larval behavior.
Publications
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