The study tested whether singing ability influences mating success in Drosophila melanogaster (fruit flies). Wild-type females were paired with either wild-type males (that can sing), wingless males (that cannot sing), or held-out males (with wings but cannot sing). Mating behaviors were observed over 10 minutes. Results showed 80% of wild-type male-female pairs successfully mated, while none of the wingless or held-out male pairs mated. A chi-square test rejected the null hypothesis, indicating singing ability does influence mating success in fruit flies. Follow-up experiments could modify the study design to further test the hypothesis or explore related questions.

1. Serenading
Males: Is
singing
necessary to
find a lady?
Courtney Dunn
Kerry Harrington
Nancy Huynh
Debbie Huynh

2. Background
● Drosophila melanogaster
oCommonly known as the “Fruit Fly”
●Can be found in a variety of environments
●“Fruit Fly” species known to have an elaborate
courtship ritual prior and during mating.

4. Fruit Fly Courtship

5. Previous Courtship Studies
●J. Sivinski, T. Burk, J.C. Webb – “Acoustic
courtship signals in the Caribbean fruit fly,
Anastrepha suspensa”
oVirgins became more active when song was
presented.¤Males that did not produce songs
remained coupled to female for shorter periods.
●Does this hold true for D. melanogaster?

6. Question
Does the ability to sing influence mating in
Drosophila?

7. Hypotheses
Ho: Singing ability has no influence on mating
H1: Males who sing will mate more.

8. Methods
Week 1:
●Cultured Wild-Type, Wingless, and Held-out flies
(Day 1)
o Making vials with water
o Getting maggots from stock

9. Week 2:
● Iced and separated female wild-types and wild-type, wingless and held-out
males into individual vials (Day 7)
● Paired wild-type female to random male for 10 minutes and observed and
collected data (Day 8)
● Cultured more Wild-types, wingless, and held-out flies (Day 8)
● Iced and separated female wild-types and wild-type, wingless and held-out
males into individual vials (Day 9)

10. Week 3:
● Added wild-type female to each vial for 10 minutes and and observed and
collected data (Day 15)
Total flies used: 60 Wild-type females
20 Wild-type males
20 Wingless males
20 Held-out males

11. Tested Matings
●Wild-Type Females x Wild-Type Males
oTo observe normal mating behavior
●Wild-Type Females x Wingless Males
oTo observe the effect of no song being produced
●Wild-Type Females x Held-Out Males
oTo control whether or not the presence of wings
alone influences courtship

12. Results
Chi-Square Test Values
-Expected Values:
[row total] x [column total] / grand total
-Degrees of Freedom:
[# columns] x [# rows -1]= 2
- Critical Value: 5.99
- Chi- Square Value: 11.61
-Reject Ho.
Mating
Observed
Mating
Expected
No Mating
Observed
No Mating
Expected
Wingless 0 5.3 20 14.7
Wild Type 16 5.3 4 14.7
Held-out 0 5.3 20 14.7
totals 16 44
Couples were observed for courtship behaviors (i.e. chasing, holding-out of
wings, mounting) for ten minute intervals. None of the mutant males
presented the courtship behavior in the allotted time span, whereas 80% of
the wild-type males successfully mounted females.

13. Figure 1. Number of Fly Couples Attempting to Mate. The mutant males
did not successfully initiate mating behaviors with virgin, wild-type females.
There were twenty males from each category: wingless, wild-type, and Held-
out. Each male was randomly paired with wild-type females and were
observed for 10 minutes for courtship behaviors. Statistical Test: Chi-Square
value: 11.61 (critical value: 5.99) Reject Ho.

14. Discussion
Discussion (6 pts): How do your results compare with previous studies? How
would you modify your experiment to test the null hypothesis more rigorously?
What follow up experiments would you like to do?

15. Conclusion
Conclusion (2 pt): A final conclusion will help your audience
remember your main point.

16. Effectiveness of presentation
Clarity, organization, no spelling or grammatical errors (5 pts)
Visual impact (5 pts): effective use of graphics, visual appeal, artistic quality, creativity
(avoid excessive use of Power Point tricks that distract the audience from main points)
Legibility (4 pts): use lettering sufficiently large to be read, don’t overcrowd slides, generally use light letters on
dark backgrounds
Miscellaneous (4 pts): eye contact, speak clearly and loudly enough to be heard, be professional in dress and
style (formal dress is not necessary), engage the audience, make effective use of time, etc.
Length of presentations: 5-6 minutes expected, 12 minutes maximum allowed
Presentations at scientific meetings are usually limited to 12 minutes. If a scientist can present a year or more of
work in 12 minutes, then we should be able to present one experiment in < 10 minutes. All members of the
group are expected to contribute a portion of the presentation unless they are sick.
Presentations can be nerve-racking, but they are a very effective way of communicating your discoveries and of
advertising yourself as a competent scientist.