Serenading Males: Is singing

necessary to find a lady?

Courtney DunnKerry HarringtonNancy HuynhDebbie Huynh

Background

● Drosophila melanogasteroCommonly 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.

Fruit Fly Courtship

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?

Question

Does the ability to sing influence mating in Drosophila?

Hypotheses

Ho: Singing ability has no influence on mating

H1: Males who sing will mate more.

MethodsWeek 1:

●Cultured Wild-Type, Wingless, and Held-out flies (Day 1)

o Making vials with water

o Getting maggots from stock

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)

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 females20 Wild-type males 20 Wingless males 20 Held-out males

Tested Matings

●Wild-Type Females x Wild-Type MalesoTo observe normal mating behavior

●Wild-Type Females x Wingless MalesoTo observe the effect of no song being produced

●Wild-Type Females x Held-Out MalesoTo control whether or not the presence of wings

alone influences courtship

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.

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.

DiscussionDiscussion (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?

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

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.