Electromagnetic Sensitivity of Drosophila melanogaster

Amir Shanehsazzadeh

(Upper Merion Area High School, King of Prussia, PA 19406, USA)

June 2016 - August 2016

Experiment Conducted Under the Guidance of

DOCTOR AMANDA PURDY

(Fox Chase Cancer Center, Philadelphia, PA, USA)

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Acknowledgements

I would like to express immense gratitude to Dr. Amanda Purdy, the head of Fox Chase’s

TRIP Initiative, for providing me the opportunity to participate in TRIP and for her guidance

throughout the entire research process. I would like to thank Dr. Glenn Rall, Mr. Omar Harris,

and Ms. Trinity Pellegrin for their assistance in the laboratory. I would also like to thank Fox

Chase Cancer Center and Temple University for sponsoring and hosting the TRIP Initiative.

Finally, I would like to thank my family who supported me throughout this experience

with their guidance, support, and criticism.

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Table of Contents

I. Abstract 3

II. Introduction………………………………………………………………………………4

A. The Basis for Drosophila melanogaster

B. Electromagnetism: A Biophysical Approach

C. Objectives, Research Problem, and Hypothesis

III. Materials and Methodology…………………………………………………………… 6

A. Materials

B. Construction of Electromagnets

C. Setting Up Fly Cultures

D. Method of Testing Flies

E. Data Collection

IV. Results……………………………………………………………………………… 10

A. Behavioral Observations

B. Survivability Rates

C. Development Rates

V. Discussion and Conclusions…………… …………………………………………… 13

A. Analysis of Behavioral Observations

B. Analysis of Survivability Rates

C. Analysis of Development Rates

D. Conclusions

E. Significance of Findings and Future Directions

VI. References…………………………………………………………………………… 19

VII. Appendix……………………………………………………………………………… 20

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I. Abstract Long-term conditioning of fruit flies, Drosophila melanogaster, with electromagnetic fields was implemented in order to measure variation in the behavior of the model organism. The specific objective of this study was to measure variation in positional behavior in flies that were conditioned within electromagnetic fields. The parental generation (n=3) and first generation progeny (n=3) of flies were conditioned within the electromagnetic fields and were subsequently tested using a topological assay which served to record the position of the flies in response to either the presence or absence of an electromagnet. A total of 720 adult flies and 700 progeny flies were utilized in this study. The electromagnets utilized were copper wire solenoids. The survivability and development rates of the flies were also monitored to measure health impacts. A second variable was the presence of an iron supplement in the diet of the flies. Iron, being a micronutrient of the fruit flies (Mandilaras et al.), was expected to increase survivability and development rates (control hypothesis). Once the data sets were gathered, 2-Proportion Z-Tests were used to test for statistical significance. After analysis of the data, it was concluded that the electromagnetic fields impacted the behavior of the flies as preferential positional behavior towards the fields was observed. These findings were consistent with a study (Gegear et al.) regarding the short-term magnetoreception of Drosophila melanogaster. There was no evidence to suggest that the iron supplements impacted the behavioral effects of the flies, but the iron supplements did increase survivability and development rates, as expected.

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II. Introduction

The Basis for Drosophila melanogaster

The fruit fly has been used time and time again and has resulted in successful biological

experiments for years. The utilization of this organism allowed for the gathering of large

amounts of data in a short period of time due to their high frequency and short period of

reproduction. Furthermore, the fruit fly’s known behavioral responses, such as its negative

geotaxis, were simple to monitor and provided concise, yet relevant data to analyze.

Furthermore, Drosophila melanogaster has been confirmed to be

magnetoreceptive. A study (Gegear et al.) investigating this

phenomenon was done by knocking out the gene encoding the

cryptochrome 1 (CRY1) protein (see figure I.1) from the

organisms and setting a water-glucose choice test with

electromagnetic fields. Removal of the gene that encoded CRY1

prevented magnetoreception, while magnetoreception occurred

with the cryptochrome 1 pigment being present. Studies have yet

to prove whether or not magnetite has any impact on the magnetoreception of the fruit flies, and

understanding the coevolution of the two proposed hypotheses is essential in better

understanding how exactly the mechanisms have evolved and for what reason they have done so.

Furthermore, understanding magnetoreception in animalia is essential for human society, which

progressively increases EMF output through technological advancement (NIOSH: EMFs in the

Workplace). Today, humans are subject to large magnetic fields from electronics and medical

imaging in the form of MRI. There have also been claims (Park et al.) in recent years of healing

properties of EMFs, but the validity of said claims have been considerably refuted.

Figure II.1: CRY 1 Pigment (Source: Wikipedia)

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Electromagnetism: A Biophysical Approach

Electromagnetism, in a physical sense, is the creation of a magnetic field as a result of charged

particles. Fundamental electromagnetic theory states that a current will produce an

electromagnetic field surrounding the current, which ultimately creates a magnetic field.

Reception of electromagnetic fields (EMFs) is the least researched animal sense, but it has been

confirmed in multiple organisms through two theoretical pathways. The first method (Cadiou et

al.) is by the usage of specially designed organs (or organelles on a unicellular basis such as that

of the magnetotactic bacteria), which recognize the magnetic field of the Earth with the usage of

magnetite (iron oxide) or iron sulfide. The aforementioned bacteria have specially designed

magnetosomes (Blakemore et al.), organelles that are so sensitive that they permit the bacteria to

line up with the Earth’s magnetic fields. The other method (Wolfgang et al.) is a result of

cryptochrome 1, which is an ocular pigment that when excited by blue light forms free radicals

(Ritz et al.) with specific molecular orbital orientations. These orientations are altered by Earth’s

electromagnetic field (or external electromagnetic fields) resulting in magnetoreception.

Objectives, Research Problem, and Hypothesis

The primary objective of this study was to determine whether or not prolonged exposure to

electromagnetic fields would result in behavioral changes of Drosophila melanogaster. The

secondary objective was to see whether or not the supplementation of the fruit flies’ diets with an

edible iron compound would alter the aforementioned magnetic effects. The research questions

asked whether or not prolonged exposure to electromagnetic fields would result in behavioral

changes and whether or not the addition of iron results enhanced or deterred magnetic effects.

The primary independent variable was the conditioning of the flies with electromagnetic fields,

and the secondary independent variable was the presence of an iron supplement in the diets of

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the flies. The primary dependent variable was variable positional behavior, and the secondary

dependent variable was a change in survivability and development rates. It was hypothesized that

long term exposure to electromagnetic fields would result in preferential positional behavior

towards electromagnetic fields after long-term potentiation and acclimation to the fields. It was

also hypothesized that the addition of iron to the fruit flies’ diets would impact the behavioral

changes if the flies utilized iron-containing compounds for magnetoreception The control

hypothesis stated that iron supplements would increase survivability and development rates due

to it being an essential micronutrient of Drosophila melanogaster (Mandilaras et al.). No

hypothesis was made regarding the effects of electromagnetic exposure on survivability and

development rates.

III. Materials and Methodology

Materials

All laboratory materials and fruit-fly pertaining materials were kindly provided by Dr. Amanda

Purdy and the TRIP program (see figure II.1).

Standard laboratory equipment and materials

(provided by the TRIP program), including a mortar

and pestle, beakers, distilled water, and magnetic

stirrers were used in this experiment. The iron

supplements and components of the electromagnets

were purchased commercially. Relatively little risk

was presented in this study, as neither hazardous

equipment nor materials were utilized in this

experiment. Standard laboratory procedures were used.

Figure III.1: Materials List

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Construction of Electromagnets

The electromagnets utilized in this study

were standard solenoids constructed out of

copper magnet wire (see figure II.2).

Solenoids are large coils of an insulating

wire which when connected to a source of

current produce considerably strong magnetic fields.

Two types of magnets were used: one without an iron

core (weak magnet) and one with an iron core (strong

magnet). The weaker solenoid was constructed by

wrapping the 30-gauge magnet wire around a testing

vial. The stronger solenoid was constructed by wrapping

the 30-gauge magnet wire around an iron nail. A

multimeter and magnetometer were used to measure the

current and magnetic strength, respectively, of the

solenoids (see figure II.3).

Setting up Fly Cultures

Initially, the vials were labeled using laboratory tape based on the presence or lack of the iron

supplement and the presence of no magnet, the weak magnet, or the strong magnet. The six

labels used were NN (no iron, no magnet), DN (iron, no magnet), NW (no iron, weak magnet),

DW (iron, weak magnet), NS (no iron, strong magnet), and DS (iron, strong magnet). A large

container of fly food (a simple aggregation of molasses, sugar, and cornstarch), prepared by

TRIP staff, was heated in a microwave until it reached liquid state. Ten milliliters of the liquid

Figure III.3: Electromagnet Measurements

Figure III.2: Iron-Core Solenoid

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food was placed in the vial, and 0.1 mL of a 10.0 mM ferrous sulfate supplement solution was

inserted into the vials that were meant to have said solution. The ferrous sulfate solution was

prepared by weighing out the appropriate number of moles (after converting moles to grams)

needed to create the appropriate concentration (10.0 mM) in the predetermined volume of

distilled water. To sort the flies, they were first knocked out using CO2 gas and subsequently

placed on a CO2 bed. Flies were separated based on gender into groups of 20 flies. Each testing

group contained 40 flies, 20 males and

20 females. In total, there were 6 test

groups and three trials done, giving a

sample size of (6)(40)(3)=720 adult

generation flies. Furthermore,

approximately 700 progeny flies were

born from the adult generations. After

the flies were inserted, the electromagnets were subsequently inserted into the vials. After the

magnets were connected to batteries, the vials were placed in an incubator with an internal

temperature of 250 C (see figure IV. 3). Incubation periods occurred between Tuesday and

Thursday (2-day exposure) and then from Thursday to the subsequent Tuesday (7-day exposure).

After one week of incubation, the adult generation flies were disposed of into a 50% (100-proof)

ethanol solution. Incubation of the vials continued in the exact same manner in order to grow the

progeny flies, which were disposed of in the exact same manner with the ethanol solution two

weeks after the initial setup of the correspondent adult generation of flies. The batteries were also

replaced on every Thursday after the 2-day exposure and on Tuesdays for the progeny groups.

Attempts were made to ensure that the batteries were always charged; the multimeter was

Figure III.4: Experimental Setup

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utilized before each re-installation of batteries to guarantee that the used batteries still contained

charge even after the exposure period. Furthermore, the benefit of utilizing solenoids is that they

produce electromagnetic fields even without current, thus any unrecorded failure of batteries

would be somewhat negligible in the end. Overall, the incubation procedure was modeled off of

the process used in the study by Gegear et al., however to compensate for the usage of weaker

magnets, a long-term exposure period of a few days to a week was implemented, as opposed to

the earlier usage of hour-long exposure periods by Gegear et al.

Method of Testing Flies

A topological assay (see figure II.5) was designed to test the behavioral responses of the flies in

response to the presence and absence of electromagnetic fields (see figure IV. 4). Two vials were

attached with parafilm, and a magnet (either weak or strong) was placed in one of the vials. Five

trials were utilized for each group of flies (see figure). Flies were knocked out with CO2 gas and

placed in the test chamber. After 10 minutes of rest, testing began. The flies were tapped to the

bottom of the test chamber and a camera

was used to record their motion for 30

seconds. After each test the

electromagnets were adjusted to a

different position or the magnets were

interchanged to complete the different

trials. The strong magnet was placed

within the testing chamber by knocking

out the flies using an ice bath and opening and

resealing the chamber. Placing magnets in different regions (bottom or top) of the testing

Figure III.5: Electromagnetic Behavioral Assay

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chamber created a variation in the magnetic strength of the respective region. Flies show

negative geotaxis as they move upwards against the direction of gravity. Any deviation (i.e. an

increase or decrease in the number of flies in a region after a magnet was placed in that region)

from this expected behavior would indicate a response to the magnetic fields. Each group used

two vials for its testing chamber to prevent cross-contamination. The testing magnets were

designed identically to those used for conditioning, and measurements using the multimeter and

magnetometer were done for these electromagnets as well.

Data Collection

Testing was done on Tuesdays and Thursdays for adult generation flies, and on Thursdays for

progeny generation flies. Trials of the electromagnetic behavioral assay were recorded using a

camera. Recording reduced error significantly since the entire motion of the flies could be

reviewed. Before each testing session, the number of living fruit flies, pupa, and eclosed pupa

were recorded in order to monitor survivability and development rates.

IV. Results

Behavioral Observations

The figures below indicate the results of the electromagnetic behavioral assay. The titles of the

graphs represent the test group being presented. For the following graphs, the x-axis records the

five different testing situations, which can be seen in the diagram of the electromagnetic

behavioral assay (figure II.5). The y-axis measures the percentage of flies in a particular region.

The three colors orange, yellow, and green represent the bottom, middle, and top regions (see

figure II.5) of the behavioral assay. For the experimental group data, it is recommended that the

reader look for “staircase” patterns in the graphs, where adding a magnet in a specific region

resulted in an increase in the number of flies in that region.

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Control Group Data

Experimental Group Data

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Survivability Rates

Prior to every testing session, surviving fruit flies were sorted by gender and counted.

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Development Rates

Prior to every testing session, the number of pupa (eclosed and not eclosed) as well as a

qualitative estimate of relative larvae amounts was measured. It was clearly seen that the relative

quantities of larvae fell into this order for the respective test groups:

NS>DS>NW>DW>NN>DN.

V. Discussion and Conclusions

Analysis of Behavioral Observations

A qualitative interpretation of the graphs shows that there is a positive correspondence between

electromagnetic training and preferential behavior towards magnetic fields. Statistical analysis of

the data derived from the behavioral assay was done in order to measure the validity of said

correspondences. In total, six 1-Tailed 2-Proportion Z-tests (one-tailed since only an increase in

a region is expected) were done for each of the ten test groups. The 2-Proportion Z-tests

measured the p-value (the probability that the change in fly position occurred assuming that the

primary null hypothesis [Ho: no change in fly position in response to magnetic fields] or

secondary null hypothesis [Ho: no secondary change in fly position in response to varying

magnetic fields] were true) in the following six orientations of the electromagnetic behavioral

assay tests: test 2 vs. test 1, test 3 vs. test 1, test 3 vs. test 2 (for these tests the change in the

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number of flies in the bottom regions was measured since the magnet was placed at the bottom

and the alternate hypothesis [Ha] is a positive relationship) test 4 vs. test 1, test 5 vs. test 1, test 5

vs. test 4 (for these tests the change in the number of flies in the top regions was measured since

the magnet was placed at the top and the alternate hypothesis [Ha] is again a positive

relationship). In the following section, the p-values produced from the Z-tests of three test groups

is shown (see Appendix for the entirety of the p-values).

2-Proportion Z-Tests: Drug, Weak Magnet, 2-Day Exposure

Orientation 2 v. 1 3 v. 1 3 v. 2 4 v. 1 5 v. 1 5 v. 4

p-value 0.01 0.099 0.14 0.019 0.099 0.19

2-Proportion Z-Tests: No Drug, Weak Magnet, 7-Day Exposure

Orientation 2 v. 1 3 v. 1 3 v. 2 4 v. 1 5 v. 1 5 v. 4

p-value 0.035 0.058 0.20 0.14 0.31 0.27

2-Proportion Z-Tests: No Drug, Strong Magnet, Progeny

Orientation 2 v. 1 3 v. 1 3 v. 2 4 v. 1 5 v. 1 5 v. 4

p-value 0.0068 0.00040 0.12 0.17 0.069 0.27

The 2-Proportion Z-Tests provided a set of p-values, which indicated the probability of the

variation in data occurring assuming that Ho is true. A high p-value (>0.05) indicates a failure to

reject the null hypothesis, whereas a low p-value (<0.05) indicates a rejection of the null

hypothesis. In the four primary test orientations (2 v. 1, 3 v. 1, 4 v. 1, 5 v.1), the 2-Proportion Z-

Tests produced low p-values for the most part. The downward-oriented (2 v.1, 3 v. 1) test

orientations had particularly low p-values, all of which were lower than 0.13. The lowest p-value

of 0.000050 indicates a significant positive correspondence between conditioning in magnetic

fields and response to magnetic fields. The upward-oriented (4 v. 1, 5 v. 1) tests included low p-

values but not as low when compared to the downward-oriented tests. All p-values in this

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category were lower than 0.36, and the lowest p-value was 0.0056. The low values do indicate a

likely positive correspondence between training in magnetic fields and response to magnetic

fields, which leads to a rejection of the primary null hypothesis. These higher p-values are a

result of the fact that the majority of the flies moved to the top region in the control test (test 1),

and thus there was a reduced change in the increase in the number of flies in the top region. The

final two orientations (3 v. 2, 5 v. 4) were implemented to see if the flies could not only detect

magnetic fields but also measure and remember the relative strength of the magnet they were

conditioned in. These orientations produced moderate p-values and a few low p-values, which

indicates that there potentially is a gradient effect of the fly responses to different strength

magnets, however the gathered data is not significant enough to reject the secondary null

hypothesis, leading to the conclusion that there is not enough statistical evidence that the flies are

capable of measuring EMF strength, in addition to detecting EMFs.

Analysis of Survivability Rates

Overall, no conclusive evidence was seen for magnetic fields resulting in increased or decreased

survivability rates for the flies. The one outlier in the data is seen in both groups trained in strong

magnetic fields. After 7 days, the

survivability of these groups decreased

considerably to the extent that all flies

died in certain groups. This is a

statistical anomaly due to the fact that

the food of the flies was tainted and

made toxic by the high strength magnet

(see figure IV.1). The copper and iron

Figure V.1: Error Analysis

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ions in the strong electromagnet led to acidification of the solution as acidic divalent and

trivalent cations leached into the solution. The fly food in the strong magnet groups became a

dark green color and subsequently the flies in these test groups died at extremely high rates.

Analysis (see figure IV.1) was done to ensure that this absurdly high death rate was a result of

the tainted fly food, and not actually the electromagnet. The food was replicated; a control vial

and a vial with an identical high-strength solenoid placed withwere created. After 7 days the food

in the test group of food had turned a similar dark green color. The pH of the solutions was

measured. The measurements showed a pH value of 7.20 for both solutions on day 0, a value of

7.20 for the unadulterated solution on day 7, and a value of 4.25 for the dark green solution on

day 7. This major contrast indicates that the dark green fly food was 1000 times more acidic than

the original food, resulting in major acidosis of the fruit flies, which caused the higher death rate.

Analysis of Development Rates

No considerable changes in development as a result of the electromagnetic fields were seen in

the data. The only potential variation could be the qualitative number of relative amounts of

larvae, which increased as magnetic strength increased. This may indicate that the magnetic

fields blocked the development of some larvae from becoming pupa, however the amounts of

pupa were not considerably lower, and the qualitative measurement cannot be used to prove

correspondence. In the future, it might be beneficial to dispose of the food and count exactly

how many larvae were in the vial, but there was not enough time to complete this task.

Conclusions

The statistical analysis of the data acquired from the electromagnetic behavioral assay showed a

clear positive taxis towards the electromagnetic fields for flies trained within the electromagnetic

fields for long periods of time, as we were able to reject the primary null hypothesis. The

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positive response indicates that the flies were both capable of sensing the electromagnetic fields

and acclimatizing to the fields. Progeny group flies showed a higher magnitude of behavioral

responses than the parental group flies, which may be a result of the fact that they had spent their

entire life cycle within an electromagnetic field. A positive correlation was seen in the

magnitude of the training fields’ strengths and the magnitude of the resultant behavioral

responses. There was no significant statistical evidence that would lead to the conclusion that the

magnetoreception abilities of the flies possessed a gradient effect as little distinction in

preference was seen when different strength magnets were utilized in the behavioral assay. The

addition of iron supplements had no effect on the magnitude of the behavioral responses, which

indicates that the flies did not utilize iron-containing compounds (magnetite or iron sulfide) in

magnetoreception. As expected, the presence of an iron supplement (iron being a micronutrient

of the flies) increased survivability and development rates as evident by the higher survival and

eclosion rates seen in the groups that were given iron supplements. Electromagnetic fields had no

evident effect on survivability and development rates, despite the slight increase in the number of

larvae in groups exposed to the electromagnetic fields, however this observation cannot be used

to make a conclusion due to it being a qualitative measurement only.

Significance of Findings and Future Directions

There is a definite need to continue experimentation with the effects of electromagnetic fields on

animalia. As previously mentioned, a study by the NIOSH showed that in recent years there have

been continued increases in the strength of EMFs that industrial workers are exposed to. This

same study showed that there was a potential linkage between increased EMF strength and

increased cancer rates, particularly blood cancers. This increased rate of cancer could be a result

of oxidative stress as a result of free radicals produced by human CRY1, a pigment that is

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involved in the proper function of the circadian rhythm. Repeated trials will serve to

considerably increase the validity of the conclusions. Despite the relatively large sample size of

more than 1400 flies, and the relatively low p-values, which were produced in the statistical

analysis, further experimentation would allow a more definitive answer to the research questions.

Different concentrations of the ferrous sulfate solution should be added to the diets of the flies in

order to more conclusively determine whether or not iron compounds are utilized by Drosophila

melanogaster in its magnetoreception. Different strength electromagnets should be used in order

to derive a lower bound for the flies’ magnetoreceptive capabilities and to see potential impacts

of stronger EMFs on their health. Increased EMF diversity would more conclusively show

whether or not a correlation between EMF strength and the magnitude of the behavioral effects

exists, a conclusion that was not significantly supported by this experiment. Higher strength

electromagnets capable of encompassing the vials without being inserted within the vials and

still producing considerably strong electromagnetic fields should be utilized to prevent the

acidification of the fly food, and the subsequent error that arose from this issue. The flies should

also be bred to the 2nd generation of progeny (and potentially even to further generations) in

order to see any longer term effects, which may not have been seen in the parent and/or the 1st

generation progeny groups. Implementing a similar test on mammals, such as mice, which

actually possess Cryptochrome 1 pigments, would prove an interesting endeavor in the future.

Although it is unlikely that the mice possess magnetoreceptive capabilities due to such a sense

being relatively vestigial in a mammal, their possession of the CRY1 pigment is very interesting

as it may be either a vestigial component of their genome from past ancestors or its

magnetoreceptive function may be currently repressed. Potentially, strong electromagnetic fields

could increase the expression of CRY1 genes, which could induce magnetoreceptive abilities.

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VI. References

Blakemore, R. (1975). "Magnetotactic Bacteria". Science. 190 (4212): 377–379.

Bowman, Joseph. "NIOSH Fact Sheet: EMFs in the Workplace". United States National Institute

for Occupational Safety and Health.

Cadiou, Hervé; McNaughton, Peter A (2010). "Avian magnetite-based magnetoreception: a

physiologist's perspective". Journal of the Royal Society Interface. The Royal Society.

Gegear, Robert J.; Amy Casselman; Scott Waddell; Steven M. Reppert (August 2008).

"Cryptochrome mediates light-dependent magnetosensitivity in Drosophila". Nature.

Mandilaras, Konstantinos; Pathmanathan, Tharse; Missirlis, Fanis. Iron Absorption in

Drosophila melanogaster; Nutrients. 2013 May

Park, Robert L. (2000). Voodoo Science: The Road from Foolishness to Fraud. New York, New

York: Oxford University Press.

Ritz, Thorsten; Adem, Salih; Schulten, Kraus. "A Model for Photoreceptor-Based

Magnetoreception in Birds". Biophysical Journal. 78: 707–718.

Wolfgang, Wiltschko; Roswitha, Wiltschko (August 2008). "Magnetic orientation and

magnetoreception in birds and other animals". Journal of Comparative Physiology A.

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VII. Appendix

Continuation of Statistical Analysis of Behavioral Data

2-Proportion Z-Tests: No Drug, Weak Magnet, 2-Day Exposure

Orientation 2 v. 1 3 v. 1 3 v. 2 4 v. 1 5 v. 1 5 v. 4

p-value 0.0020 0.0089 0.25 0.031 0.15 0.19

2-Proportion Z-Tests: No Drug, Strong Magnet, 2-Day Exposure

Orientation 2 v. 1 3 v. 1 3 v. 2 4 v. 1 5 v. 1 5 v. 4

p-value 0.0097 0.000050 0.022 0.047 0.0056 0.15

2-Proportion Z-Tests: Drug, Strong Magnet, 2-Day Exposure

Orientation 2 v. 1 3 v. 1 3 v. 2 4 v. 1 5 v. 1 5 v. 4

p-value 0.14 0.0076 0.077 0.15 0.022 0.15

2-Proportion Z-Tests: Drug, Weak Magnet, 7-Day Exposure

Orientation 2 v. 1 3 v. 1 3 v. 2 4 v. 1 5 v. 1 5 v. 4

p-value 0.020 0.079 0.24 0.13 0.24 0.34

2-Proportion Z-Tests: No Drug, Weak Magnet, Progeny

Orientation 2 v. 1 3 v. 1 3 v. 2 4 v. 1 5 v. 1 5 v. 4

p-value 0.0034 0.039 0.14 0.011 0.12 0.076

2-Proportion Z-Tests: Drug, Weak Magnet, Progeny

Orientation 2 v. 1 3 v. 1 3 v. 2 4 v. 1 5 v. 1 5 v. 4

p-value 0.021 0.068 0.28 0.083 0.35 0.039

2-Proportion Z-Tests: Drug, Strong Magnet, Progeny

Orientation 2 v. 1 3 v. 1 3 v. 2 4 v. 1 5 v. 1 5 v. 4

p-value 0.13 0.028 0.18 0.27 0.069 0.15