Progress 09/01/19 to 02/28/22
Outputs
Target Audience: My target audience during this portion of the reporting period has included the broader scientific community. I have presented findings and data from my proposed work to several conferences, both nationally and internationally and published a peer-reviewed article on the data collected. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? Through the granting period, I have had the pleasure of working with 7undergraduate research assistants. Through this work, we gained traction towards to goals of the grant, leading to its successful completion. In addition, training these individuals in the scientific process has allowed them to grow in their proficiency as well as provide them experience in research and academia. I also had the opportunity to mentor one graduate student through the granting period who was essential to experimental success. Professional Development: As I proposed in the grant, I organized a symposium of research seminars at a national conference where we discussed the research ideas proposed in this grant and other related scientific discoveries (many of which also funded through USDA NIFA). In addition to this, I was invited to give 15seminars during the award to dissiminate findings of this work and had one peer-reviewed article published with 3 more to follow this year. How have the results been disseminated to communities of interest? Information and results relating to this work have been primarily disseminated through research talks and seminars given by myself. In the past year, I have given several of these to diverse audiences both nationally and internationally. Additionally, the work has received quite a bit of popular science attention which has led to numerous articles in newspapers, websites, local news and even a radio interview on the BBC. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
The goals of this research are to 1) elucidate the non-consumptive effects of predators on prey performance, 2) identify the mechanism(s) by which risk is perceived, and 3) evaluate how predator cues alone may elicit NCEs which could benefit plant health using a globally important aphid-predator system. Objective 1: Assess how predation risk affects aphid behavior and reproduction Objective 2: Identify the mechanism by which aphids perceive predator risk Objective 3: (a.) Identify semiochemical blend of H. axyridis and (b.) examine for bioactivity? Objective 1: Assess how predation risk affects aphid behavior and reproduction 1. Experiments were conducted to assess how predation risk affects aphid behavior and reproduction in a series of experiments. First, we used a small arena (modified petri-dish) to examine the short-term impact of predator presence on aphid reproduction. Over 3 days we examined total nymphs produced by individual aphid females. Then, we examined these interactions in a larger arena for a longer period of time (14 days). In this case, we also were able to examine the number of winged dispersal morphs formed in offspring of mothers that received predator exposure. 2. We collected data on offspring produced and wing formation. We examined this in both winged and wingless adult females. 3. The presence of both predator cues from H. axyridis predators in a petri dish arena led to a 23% reduction in the overall number of nymphs produced by adult apterous M. persicae over 3 d compared to reproducing adult aphids in control petri dishes where predator cues were absent (Z = -4.08, p < 0.0001). However, when adult alate M. persicae were left to reproduce in the presence of predator cues there was no discernable effect on nymph production compared to predator-free controls (Z = -0.46, p = 0.65). The number of individuals that produced wings after 3 d in petri dishes differed between the predator cue treatment and the predator-free control, with a five-fold increase in alate production in the predator cue treatment (G = 8.73, p = 0.003). Overall, 3% of aphids in the control treatment were winged after 3 d whereas 15% of aphids formed wings in the treatment dishes that left aphids exposed to predator cues. In larger arenas over a longer time period, nymph production differed significantly among treatments (c2= 32.87, p < 0.0001, Figure 4). Pairwise comparisons of the different treatments show that the risk treatment yielded significantly more nymphs than the control and lethal treatments (Z = 3.219, p = 0.0013; Z = 4.903, p < 0.0001, respectively) while lethal treatment had the fewest aphids after 14 d. Alate formation (n = 12) was significantly increased in the risk treatment compared to both the control and lethal treatment where no alates were found during the entire experiment (G = 16.636, p < 0.0001). 4. All data collected resulted in changed in knowledge - this work is currently being prepared for publication. Objective 2: Identify the mechanism by which aphids perceive predator risk 1.Two-arm olfactometer experiments were designed to determine the effects of ladybeetle volatile odor cues on the behavior of the prey insect, M. persicae.Here, the aim was to determine if chemical cues of the predator are responsible for behavioral changes in the prey. 2.We collected data on host choice of both winged and wingless adult aphids. 3.When presented with a choice between a predator-free odor source or an odor source that included H. axyridis predators, adult apterous M. persicae preferred the arm with predator-free control plants (c2= 5.12, p = 0.024). However, when the physical predators were removed from the odor source arena prior to bioassays, the adult apterous aphids no longer preferred predator-free control plants (c2= 3, p = 0.083). In contrast, alate M. persicaepreferred to move towards plants with predators present compared to the predator-free odor source (c2=7.53, p = 0.006), but only when the physical predators were in the odor source arena. When predators were removed from the odor source arena prior to bioassays, we observed equal preference between the olfactometer arms was observed (c2= 0.037, p = 0.847). 4. All data collected resulted in changed in knowledge - this work is currently being prepared for publication. Objective 3: (a.) Identify semiochemical blend of H. axyridis and (b.) examine for bioactivity. We collected and analyzed the headspace volatiles that the ladybeetle produce using GC-MS. We identified major components of the semiochemical blend and looked at which compounds lead to bioactivity in aphid antennae. We have also used the chemical blend in manipulative experiments to determine if the isolated chemical cues influence aphid behavior similar to that of the actual ladybeetle. We are currently analyzing these data and preparing the publication that will be submitted in 2022.
Publications
- Type:
Journal Articles
Status:
Accepted
Year Published:
2021
Citation:
Hermann S.L., Bird S., Ellis D., & Landis D.A. (2021) Predation risk differentially affects aphid morphotypes: impacts on prey behavior, fecundity and transgenerational dispersal morphology. Oecologia. doi: 10.1007/s00442-021-05037-z
- Type:
Journal Articles
Status:
Accepted
Year Published:
2019
Citation:
Hermann S.L., Blackledge, C., Haan, N.L., Myers, A.T., & Landis, D.A. (2019) Predators of monarch butterfly eggs are more diverse than previously recognised. Scientific Reports. 9:14304. doi: 10.1038/s41598-019-50737-5
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2021
Citation:
June 2021 Hermann S.L. & Kansman J. I smell trouble: behavioral modification of aphids in response to natural enemy odor cues. North Central Branch of the Entomological Society of America. Invited Speaker (Virtual)
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2021
Citation:
April 2021 Hermann S.L. Stress across space and time: Leveraging the ecology of fear to influence arthropod populations. International Congress of Biological Control. Invited Speaker. (Virtual)
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2021
Citation:
March 2021 Hermann S.L. Harnessing natural enemy chemistry to reduce pest pressure in agroecosystems. Eastern Branch of the Entomological Society of America Branch Meeting. (Virtual)
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2020
Citation:
August 2020 Hermann S.L. The perils and promise of evaluating non-consumptive effects in agroecosystems. Ecological Society of America Annual Meeting. (Virtual)
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Progress 09/01/20 to 08/31/21
Outputs
Target Audience: My target audience during this portion of the reporting period has included the broader scientific community. I have presented findings and data from my proposed work to several conferences, both nationally and internationally and published a peer-reviewed article on the data collected. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? Through the granting period, I have had the pleasure of working with 7 undergraduate research assistants. Through this work, we gained traction towards to goals of the grant, leading to its successful completion. In addition, training these individuals in the scientific process has allowed them to grow in their proficiency as well as provide them experience in research and academia. I also had the opportunity to mentor one graduate student through the granting period who was essential to experimental success. Professional Development: As I proposed in the grant, I organized a symposium of research seminars at a national conference where we discussed the research ideas proposed in this grant and other related scientific discoveries (many of which also funded through USDA NIFA). In addition to this, I was invited to give 15 seminars during the award to dissiminate findings of this work and had one peer-reviewed article published with 3 more to follow this year. How have the results been disseminated to communities of interest? Information and results relating to this work have been primarily disseminated through research talks and seminars given by myself. In the past year, I have given several of these to diverse audiences both nationally and internationally. Additionally, the work has received quite a bit of popular science attention which has led to numerous articles in newspapers, websites, local news and even a radio interview on the BBC. What do you plan to do during the next reporting period to accomplish the goals?n/a
Impacts
What was accomplished under these goals?
The goals of this research are to 1) elucidate the non-consumptive effects of predators on prey performance, 2) identify the mechanism(s) by which risk is perceived, and 3) evaluate how predator cues alone may elicit NCEs which could benefit plant health using a globally important aphid-predator system. Objective 1: Assess how predation risk affects aphid behavior and reproduction Objective 2: Identify the mechanism by which aphids perceive predator risk Objective 3: (a.) Identify semiochemical blend of H. axyridis and (b.) examine for bioactivity? Objective 1: Assess how predation risk affects aphid behavior and reproduction 1. Experiments were conducted to assess how predation risk affects aphid behavior and reproduction in a series of experiments. First, we used a small arena (modified petri-dish) to examine the short-term impact of predator presence on aphid reproduction. Over 3 days we examined total nymphs produced by individual aphid females. Then, we examined these interactions in a larger arena for a longer period of time (14 days). In this case, we also were able to examine the number of winged dispersal morphs formed in offspring of mothers that received predator exposure. 2. We collected data on offspring produced and wing formation. We examined this in both winged and wingless adult females. 3. The presence of both predator cues from H. axyridis predators in a petri dish arena led to a 23% reduction in the overall number of nymphs produced by adult apterous M. persicae over 3 d compared to reproducing adult aphids in control petri dishes where predator cues were absent (Z = -4.08, p < 0.0001). However, when adult alate M. persicae were left to reproduce in the presence of predator cues there was no discernable effect on nymph production compared to predator-free controls (Z = -0.46, p = 0.65). The number of individuals that produced wings after 3 d in petri dishes differed between the predator cue treatment and the predator-free control, with a five-fold increase in alate production in the predator cue treatment (G = 8.73, p = 0.003). Overall, 3% of aphids in the control treatment were winged after 3 d whereas 15% of aphids formed wings in the treatment dishes that left aphids exposed to predator cues. In larger arenas over a longer time period, nymph production differed significantly among treatments (c2= 32.87, p < 0.0001, Figure 4). Pairwise comparisons of the different treatments show that the risk treatment yielded significantly more nymphs than the control and lethal treatments (Z = 3.219, p = 0.0013; Z = 4.903, p < 0.0001, respectively) while lethal treatment had the fewest aphids after 14 d. Alate formation (n = 12) was significantly increased in the risk treatment compared to both the control and lethal treatment where no alates were found during the entire experiment (G = 16.636, p < 0.0001). 4. All data collected resulted in changed in knowledge - this work is currently being prepared for publication. Objective 2: Identify the mechanism by which aphids perceive predator risk 1.Two-arm olfactometer experiments were designed to determine the effects of ladybeetle volatile odor cues on the behavior of the prey insect, M. persicae.Here, the aim was to determine if chemical cues of the predator are responsible for behavioral changes in the prey. 2.We collected data on host choice of both winged and wingless adult aphids. 3.When presented with a choice between a predator-free odor source or an odor source that included H. axyridis predators, adult apterous M. persicae preferred the arm with predator-free control plants (c2= 5.12, p = 0.024). However, when the physical predators were removed from the odor source arena prior to bioassays, the adult apterous aphids no longer preferred predator-free control plants (c2= 3, p = 0.083). In contrast, alate M. persicaepreferred to move towards plants with predators present compared to the predator-free odor source (c2=7.53, p = 0.006), but only when the physical predators were in the odor source arena. When predators were removed from the odor source arena prior to bioassays, we observed equal preference between the olfactometer arms was observed (c2= 0.037, p = 0.847). 4. All data collected resulted in changed in knowledge - this work is currently being prepared for publication. Objective 3: (a.) Identify semiochemical blend of H. axyridis and (b.) examine for bioactivity. We collected and analyzed the headspace volatiles that the ladybeetle produce using GC-MS. We identified major components of the semiochemical blend and looked at which compounds lead to bioactivity in aphid antennae. We have also used the chemical blend in manipulative experiments to determine if the isolated chemical cues influence aphid behavior similar to that of the actual ladybeetle. We are currently analyzing these data and preparing the publication that will be submitted in 2022.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2021
Citation:
Hermann S.L., Bird S., Ellis D., & Landis D.A. (2021) Predation risk differentially affects aphid morphotypes: impacts on prey behavior, fecundity and transgenerational dispersal morphology. Oecologia. doi: 10.1007/s00442-021-05037-z
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Progress 09/01/19 to 08/31/20
Outputs
Target Audience: My target audience during this portion of the reporting period has included the broader scientific community. I have presented findings and data from my proposed work to several different conference in the past year both internationally and nationally. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? Through the first year of the grant, I have had the pleasure of working with 7undergraduate research assistants. Through this work, we have gained major traction towards to goals of the grant. In addition, training these individuals in the scientific process has allowed them to grow in their proficiency as well as provide them experience in research and academia. I have also had the chance to metnor one graduate student through this grant period. Professional Development: As I proposed in the grant, I organized a symposium of research seminars at a national conference where we discussed the research ideas proposed in this grant and other related scientific discoveries (many of which also funded through USDA NIFA). In addition to this, I was invited to give 15 seminars during the award to dissiminate findings of this work. How have the results been disseminated to communities of interest? Information and results relating to this work have been primarily disseminated through research talks and seminars given by myself. In the past year, I have given several of these to diverse audiences both nationally and internationally. We also had one peer-reviewed article published on the grant outputs in 2021. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
1. The goal of this research is to better understand the ways in which predatory insects can affect prey ecology. When we typically think of predators, we immediately imagine the consumptive effect that they have - that is, direct removal of prey through consumption. However, prey are not defenseless and will initiate anti-predator behavioral and physiological responses upon detection of threat in order to avoid being eaten. These alterations in behavior and physiology can be energetically costly and can have impacts on the overall survival and performance of the insect prey even though they might avoid being eaten. This is considered the non-consumptive effect of predators. The main objective of this work is to identify how predation risk affects behavior and physiology of a major insect pest of agricultural crops and then to use this information to manipulate the distribution and success of this pest in agroecosystems through integrated pest management. 2. During the first year of this grant, I have worked conduct experiments to address the behavioral alterations as well as the physiological changes that occur in response to a common insect predator. When aphid prey are exposed to their ladybeetle predators, we found that they will reduce the number of offspring they produce over a short time period. However, over a longer time period, exposure to predators actually increases overall aphid numbers. In addition, physiological changes were also found: aphids will produce offspring that have wings after being exposed to predators. This suggests that aphids are able to detect the lady beetle predators and response by altering their offspring production and investing in dispersal in the following generation. Importantly, detection of predation risk occurred without physical contact with the predators. In the assays, aphid prey were separated from the predators by mesh which allowed for only chemical and visual cues of the predators to be detected. 3. These results suggest that, by manipulating the presence of predators near crop plants where pest insects reside, we might be able to change the behavior and pshyiology of insect pests in a way that alters their relationship with the host plant. Further, this work suggests that predator cues are enough to elicit behavioral and physiological responses that could affect the interaction between aphid pests and their host plants. Aphids reduce their offspring production at first, which is better for the plants. But, over time, aphids might actually be increasing their populations when in the presence of predator cues which could lead to a negative impact on plants. However, when aphids produce more offspring in the presence of predator cues, we also found that these offspring tend to be winged suggesting they would disperse from the host plant and seek out an alternative host. More work in a field setting will be needed to tease this apart. Objective 1: Assess how predation risk affects aphid behavior and reproduction 1. Experiments were conducted to assess how predation risk affects aphid behavior and reproduction in a series of experiments. First, we used a small arena (modified petri-dish) to examine the short-term impact of predator presence on aphid reproduction. Over 3 days we examined total nymphs produced by individual aphid females. Then, we examined these interactions in a larger arena for a longer period of time (14 days). In this case, we also were able to examine the number of winged dispersal morphs formed in offspring of mothers that received predator exposure. 2. We collected data on offspring produced and wing formation. We examined this in both winged and wingless adult females. 3. The presence of both predator cues from H. axyridis predators in a petri dish arena led to a 23% reduction in the overall number of nymphs produced by adult apterous M. persicae over 3 d compared to reproducing adult aphids in control petri dishes where predator cues were absent (Z = -4.08, p < 0.0001). However, when adult alate M. persicae were left to reproduce in the presence of predator cues there was no discernable effect on nymph production compared to predator-free controls (Z = -0.46, p = 0.65). The number of individuals that produced wings after 3 d in petri dishes differed between the predator cue treatment and the predator-free control, with a five-fold increase in alate production in the predator cue treatment (G = 8.73, p = 0.003). Overall, 3% of aphids in the control treatment were winged after 3 d whereas 15% of aphids formed wings in the treatment dishes that left aphids exposed to predator cues. In larger arenas over a longer time period, nymph production differed significantly among treatments (c2= 32.87, p < 0.0001, Figure 4). Pairwise comparisons of the different treatments show that the risk treatment yielded significantly more nymphs than the control and lethal treatments (Z = 3.219, p = 0.0013; Z = 4.903, p < 0.0001, respectively) while lethal treatment had the fewest aphids after 14 d. Alate formation (n = 12) was significantly increased in the risk treatment compared to both the control and lethal treatment where no alates were found during the entire experiment (G = 16.636, p < 0.0001). Report Date 08/30/2019Page 2 of 5 United States Department of Agriculture Final Report Accession No. 1015415 Project No. MICL08550 4. All data collected resulted in changed in knowledge - this work is currently being prepared for publication. Objective 2: Identify the mechanism by which aphids perceive predator risk 1.Two-arm olfactometer experiments were designed to determine the effects of ladybeetle volatile odor cues on the behavior of the prey insect, M. persicae.Here, the aim was to determine if chemical cues of the predator are responsible for behavioral changes in the prey. 2.We collected data on host choice of both winged and wingless adult aphids. 3.When presented with a choice between a predator-free odor source or an odor source that included H. axyridis predators, adult apterous M. persicae preferred the arm with predator-free control plants (c2= 5.12, p = 0.024). However, when the physical predators were removed from the odor source arena prior to bioassays, the adult apterous aphids no longer preferred predator-free control plants (c2= 3, p = 0.083). In contrast, alate M. persicaepreferred to move towards plants with predators present compared to the predator-free odor source (c2=7.53, p = 0.006), but only when the physical predators were in the odor source arena. When predators were removed from the odor source arena prior to bioassays, we observed equal preference between the olfactometer arms was observed (c2= 0.037, p = 0.847). 4. All data collected resulted in changed in knowledge - this work is currently being prepared for publication. Objective 3: (a.) Identify semiochemical blend of H. axyridis and (b.) examine for bioactivity 1. We collected headspace volatiles of the ladybeetles and assessed the composition of the odor blend using GC.MS. We identified the compounds that make up the odor blend and examined them for bioactivity in the aphid brain using EAG. We used the isolated odor blend in experiments to assess behavioral changes in prey aphids when exposed to ladybeetle odors alone. We are analyzing these data and preparing the final publications for submission in early 2022.
Publications
- Type:
Journal Articles
Status:
Accepted
Year Published:
2021
Citation:
Hermann S.L., Bird S., Ellis D., & Landis D.A. (2021) Predation risk differentially affects aphid morphotypes: impacts on prey behavior, fecundity and transgenerational dispersal morphology. Oecologia. doi: 10.1007/s00442-021-05037-z
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