 Bailee Slack Camdenton High School
Background
Information:
Helicoverpa zea
-most costly
agricultural pest in
country
-can damage up to
50 % of sweet corn
crop in southern
states
-leaves the crop
susceptible to
diseases
- Insecticides are
inefficient in many
cases
http://extension.missouri.edu/explore/images/g07110art02.jpg
Background
Information:
Microplitis
croceipes
-identify hosts
through a scent
found in host frass
-deposit eggs inside a
host using
kairomones
-have associative
learning capabilities
-can prevent up to
1,800,000 corn ear
worms from ever
developing
http://images.usatoday.com/news/_photos/2005/12/26/wasp-inside-3.jpg
Purposes
 Whether or not the parasitoid wasp Microplitis croceipes
could be conditioned to associate the natural scent of
corn with their host Helicoverpa zea in order to act as a
more effective form of biological pest control.
 To create a device to capture the ovipositor probing
exhibited during wasp testing so that farmers or
distributors of the M. croceipes can ensure that wasps
have been correctly trained to associate hosts with the
corn scent before releasing them into the field.
 To create a device to capture the ovipositor probing
exhibited during wasp testing so that farmers can use it
to quickly and easily detect early corn ear worm
infestation.
Hypotheses
 After the Microplitis croceipes has been exposed to the
natural corn scent in association with stinging a host
during training sessions, they will later exhibit foraging
behaviors when exposed to the corn scent without a host.
 Microplitis croceipes that have been exposed to only the
corn scent or only the host during the training sessions
with no host will not demonstrate foraging behaviors
when later exposed to the corn scent.
 A modified version of the “Wasp Hound” can be
developed to view ovipositor probing during training.
 A modified version of the “Wasp Hound” can be
developed for farmers use to easily detect early corn ear
worm infestations.
Variables
 The independent variable in this study was the wasps
that had been exposed to the corn scent in association
with depositing eggs in a host.
 The dependent variables in this study were the
reactions of each group of wasps to the corn scent after
each training session.
 The constant variables were: the wasps’ diet (amount
of food, what they were fed, and how often they were
fed), the wasps’ cages (all identical), how old the wasps
were when tested, location of testing, gender of
specimens (female), amount of time exposed to stimulus,
the software used to observe the testing
Control Group
 The control groups were the wasps exposed only to
the corn scent and the wasps exposed only to the
hosts.
Method
Setup Phase
-aim: to condition
wasps to actively
search for hosts
-cocoons are
received
-wasps are placed
into rearing cages
-females are placed
into labeled jars
for
experimentation
-Wasp Hound
http://www.nrc.govt.nz/upload/5352/Tomato%20frui
t%20worm%20wasps%20(200).jpg
Initial
Training Phase
-trained inside “Wasp
Hound”
-given acclimation
period then video
recorded using webcam
Initial Testing
-all wasps were exposed
to corn scent inside
wasp hound one at a
time
-video was recorded
from webcam
Revised
Training
-spoke with Dr. Rains
-tinfoil was used to
cover corn sample and
holes were made
-conditioned and
control host groups are
re-trained on tinfoil so
that egg depositing is
visible
Final Training/
Testing
-after no results were
visible in “Wasp
Hound” were visible, it
was decided to train the
wasps to associate corn
scent with food
-while the first
experimental wasp was
trained, ovipositor
probing was observed
-it was decided to
record the number of
ovipositor probes per
minute
Modified “Wasp
Hound”:
Laboratory
Testing
-“Wasp Hound” could
not be used to observe
all behavioral cues
-The Olfactinator was
created to observe
training
Modified “Wasp
Hound”: Field
Testing
-problems with
outdoors
-hallway used for
testing
-Olfactinator was
connected to laptop and
rolled down hallway
Results
Results
Wasp Group
Mean # of
Ovipositor
Thrusts
Control Hosts
0
Control Corn
0
Conditioned
39.44
p<.001
significant
Wasp 1
Wasp 2
Wasp 3
Conclusions
 The initial hypothesis that Microplitis croceipes could be trained to correctly
associate the host Helicoverpa zea with the scent of corn was supported (p < 0.001)
 The initial hypotheses that Microplitis croceipes that have only been exposed to the
corn scent or those only exposed to Helicoverpa zea (hosts) during training sessions
would not demonstrate foraging behaviors when later exposed to the corn scent was
supported. (Mean number of “control corn” and “control corn” wasp ovipositor
probes=0)
 The initial hypothesis that a modified version of the “Wasp Hound” could be created
to view ovipositor probing and other foraging behaviors during training was
supported.
 The initial hypothesis that a modified version of the “Wasp Hound” could be created
to allow farmers to easily test their fields for early corn ear worm infestations is
currently still being developed with results pending more field trials; however, early
results indicate that this is possible.
Future Studies
 Collect enough data to adequately determine
whether or not the Olfactinator could be used to
detect early corn ear worm infestations
 Condition Microplitis Croceipes to other crops
affected by the Helicoverpa Zea.
 Develop a device to train Microplitis Croceipes in
mass
 Determine how long Microplitis croceipes retain
their conditioned behavior
Applications
 The Olfactinator could be used for
corn ear worm detection, which
could help farmers know if they have
an infestation that needs controlled
(pending more results)
 The Olfactinator can be used for
laboratory training and testing of the
wasps
 Data suggests that wasps can make a
significant connection between
parasitizing a host and the scent of
corn, implying that they could be
conditioned to search the corn for
hosts, and act as biological pest
control

Could potentially prevent 1,800,000 corn ear
worms from ever being born