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The effects of estrogen on larval and pupal duration in Drosophila melanogaster

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Geoffrey Wingfield

Kalyka Sage

Nadia Green

Katie Schmitt

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Background information:

  • Environmental estrogen concentration has increased due to an excess of contraceptives and industrial, human and rural waste (Bovier et al. 2018)
  • Estradiol (E2) has been shown to decrease the survival rate, lifespans, and fertility of D. melanogaster (Bovier et al. 2018)
  • Few studies have looked at how E2 affects larval stage and pupae duration in the development of D. melanogaster

Hypothesis:

  • Increased doses of Estradiol, 0.1nM and 0.01 nM, will extend the larval and pupal stages; the control group (0.0nM) will have the shortest larval and pupal stages of the three treatments (Kirkbridge-Smith et al. 2001)

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Introduction

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  • 3 concentrations of estradiol in an agar medium: 0.1nM, 0.01nM, 0.0nM.
  • (Roughly) 20 D. melanogaster per treatment.
  • Conditions: Constant 24℃
  • Larval and pupal stage duration measured in hours over 13 days

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A one way ANOVA was run to test for differences between treatment means.

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Methods

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Figure 1: Total Time taken for Larval stage Duration (in 24 hour periods) in three different groups being left in a vial with: Control (no estrogen), Treatment A 0.01nM Estradiol-17β, Treatment B 0.1nM Estradiol-17β). 3 replicates for each group. N= 60 Control, 75 TA, 72 TB. Error Bars are means + SE. Treatments with significant difference to each other have a different letter.

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Results

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Figure 2: Total Time taken for Pupae Duration (in 24 hour periods) in three different groups: Control (no estrogen), Treatment A 0.01nM Estradiol-17β, Treatment B 0.1nM Estradiol-17β). 3 replicates per group. N=61 Control, 73 TA, 67TB.Error Bars are means + SE. Treatments with significant difference to each other have a different letter.

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Results

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  • In both the larval stage duration, we found the input of 0.1nM and 0.01nM Estradiol into the Drosophila melanogaster environment to have no significance on the effect of time taken (hrs) for the specimen to reach the pupal stage. In the pupal stage duration we found the input of 0.01nm Estradiol to slightly decrease the time taken (hrs) to reach the emergent stage when compared to our control group.

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  • Limitations arose through restrictions in time allowed for observation. Variation may have occurred outside observable hours.

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  • In future we could introduce more experiment repeats to mitigate confounding outliers. We could also add extra treatment groups with higher Estradiol concentrations to represent further extremes.

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Conclusions