1. The Effects of Wind on Herbivorous Insects
Dhruvika Patel, Tyler Follman, Aleix Valls, Dr. Jason Harmon
Department of Entomology, North Dakota State University, Fargo, ND, 58102
Introduction
Materials and Methods Continued
Discussion
Over the last 50 years, carbon dioxide in the atmosphere
Has increased by over 30% causing changes not only in
temperature, but wind as well.1 As the climate warms, there is
a reduction in the equatorial-polar thermal gradient, which is
accountable for atmosphere circulation. As the gradient
decreases, wind speeds are also expected to decrease.4 This immensely affects herbivorous insects, such as the aphids, which we studied.
Changes in wind can cause plants mechanical
stress(MS), which occurs when tissues are
compressed or stretched by physical movement
arising from wind, touching or rubbing. MS can also
reduce stem elongation and increase radial stem
thickening. This can change a plant’s structure and sap quality.2
Aphids survive on the sap of plants, which makes them a plant lice.
They are pests to crops, reproduce asexually(10-15 per day), and are genetically identical. They use different cues to determine the quality of their host plant such as contact chemical cues.3
We used actual wind (from fans) and different simulated winds to directly and indirectly see how aphid behavior and fecundity are affected by wind.
We hypothesize that with wind affecting plants, the aphids will be effected negatively causing change to occur in their behavior and fecundity.
Experiment 1:
Experiment 3: Indirect Effects of Simulated Wind Using Movement
All the treatments, including control, are infested with 4 aphids enclosed with a tube cage.
Treatment: 6 days
Infest/Count: 3 days
Touch
Repeat steps from experiment 2
Replicated to compare with movement
Movement
16 plant are moved by hand fifteen times on each side for six days.
Movement and Touch
16 plants undergo both movement and touch
Aphids are more negatively affected by fans.
Lower averages of babies per adult on plants that underwent windy conditions
Substantial amount of different in the number of babies per aphid on control vs. to wind-effected plants.
The results recorded less babies overall than what aphids are expected to produce. This can be due to lab environment.
Image obtained from:
Experiment 2:
Supports experiment one results and past experiments.
Partial significance
Clip cages can resist sap flow, but most efficient to count aphids.
(Image obtained from: )
Experiment 3:
The results were similar for all treatments, which means there was no significant result.
The aphids were the last batch left in the colonies, so they could be not fully grown or defected.
A rat infestation during the beginning could have affected plants used in the experiment.
Results
Project Overview
Experiment 1
Hypothesis
Conclusion/Future Work
After conducting experiment, it was found that aphid populations are effected by wind indirectly.
With wind speeds expected to decrease, there can be concerns for farmers and their crops in the future.
Study focuses to help researches understand how to reduce aphid population.
In the future, ecologists and farmers can grasp effects of wind on aphids to create new methods of population control.
Materials and Methods
Experiment 1: Indirect effects of Real Wind on Aphids
15 pots with Fava Bean plants exposed to wind from Honeywell fans and 15 are control group.
Fans turn on twice a day from 9-11 am and 5-7pm.
This happens for 4 days.
After being exposed to the fan, put a tube cage around each pot and place 5 adult aphids onto each plant.
Count aphids every day for 3 days to see fecundity.
Experiment 2: Indirect Effects of Simulated Wind on Aphids Using Touch
Touch
Manually rub 40 Fava plants with a leaf.
Half is control and half is touch group. Touch each plant 2 minutes each day for six days.
After brushing, place a C leaf and a T leaf in a clip cage with 3 aphids on each leaf. Record fecundity and placement every 24 hours.
3rd day: Control and wind are significantly different ((Df=1, F-value= 4.937, p-value=0.0345).
Experiment 2
Acknowledgements
I would like to thank North Dakota Governor’s School for granting me this opportunity, National Science Foundation for the funds towards the Entomology Department, Candida Braun for coordinating the Science Discipline, and my professor and graduate students for allowing me to participate in their research.
Wind speed every 10cm in mph from the fan
Works Cited
Control and touch are partially significantly different ((Df=1, F-value= 2.887, p-value=0.0975).
1) US EPA, O. (n.d.). Climate Change Indicators: Greenhouse Gases. Retrieved from
 2) Moran, P. J., & Cipollini, D. F. (1999). Effect of Wind-induced Mechanical Stress on Soluble Peroxidase Activity and Resistance to Pests in Cucumber. Journal of Phytopathology, 147(5), 313–316.
3) Markovic, D., Glinwood, R., Olsson, U., & Ninkovic, V. (2014). Plant response to touch affects the behaviour of aphids and ladybirds. Arthropod-Plant Interactions, 8(3), 171–181.
4) Barton, B. T. (2014). Reduced wind strengthens top-down control of an insect herbivore.
Ecology, 95(9), 2375–
Experiment 3
Treatments were not significantly different (Df=3, F-value=0.839, p-value=0.474). All treatments had similar results.