Context-dependent oviposition reveals strong association between acceptance and preference in the Mediterranean fruit fly

  1. Benoît Facon
  2. Madeline Chauve
  3. Virginie Ravigné
  4. Bruno Serrate
  5. Myriam Robejean
  6. Antoine Fraimout
  7. Julien Foucaud

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Abstract

Oviposition behavior in phytophagous insects is influenced by different stimuli and plays a key role in pest dynamics and crop loss. This study used 3D-printed artificial fruits varying in colour (yellow, blue, white) and odour (cherry, orange, banana) to test how visual and olfactory cues affect oviposition acceptance (no-choice) and preference (choice). In no-choice assays, the nine artificial fruits displayed sufficiently different visual and olfactory cues to trigger different egg-laying outputs (by a factor 1:3 between the least attractive fruit, white fruit with banana scent and the most attractive fruit, yellow fruit with cherry scent). While cues acted independently in no-choice settings, significant interactions were observed in choice conditions, highlighting multimodal sensory integration. In choice assays, the number of eggs laid and female preference depended on both the characteristics of fruits and their context. However a strong correlation was found between acceptance and preference. The relationship found between acceptance and preference implied that when a fruit seemed preferred in no-choice assays, it was even more preferred in one-choice assays. We finally discussed the practical implications for behavior-based pest management strategies.

Article activity feed

  1. Version published to 10.24072/pcjournal.704
  2. Peer Community In Zoology

    All reviews are in and the paper is solid, but definitely needs more detail in the methods and the claims being made need to be appropriate to the experimental evicence shown however the comments are eminently addressable.  The main manuscript should do a better job of explaining the visual stimuli and describing the stimulus pairs presented as pointed out by two of the reviewers. 

    Please respond with a point by point revision and track changes if substantial changes are being made. 

  3. Peer Community In Zoology

    I like this study and the acceptance vs preference framing. The experiments are clean and the dataset is well organized. With a few focused changes to how the key claim is supported and how the methods are shown, the paper will read much stronger.

    Core point to address

    1. Acceptance → preference is presented as the key claim, but it isn’t justified yet. Right now the text leans on a “reasonable” linear fit and an R². That’s not evidence of predictability. If you want to claim predictability, please demonstrate it:

      Include a Bland Altman style plot so readers can see bias and limits of agreement at a glance.Add predictive checks: cross-validation or a held-out subset; if sample is small, use bootstrap prediction with uncertainty bands.
      Report calibration and error: e.g., calibration curve plus RMSE/MAE for observed vs expected preference.
      Until then, please tone the language down to “association” and avoid the word “predictable.”


    2. Visual and olfactory cues
      The paper attributes differences to “colour” and “odour,” but to interpret colour effects mechanistically, basic spectral reflectance (or at least calibrated RGB + illuminance) is needed. Insects often use chromatic and achromatic (luminance) channels; without controlling luminance and measuring spectra, “colour” may conflate both (Kelber et al., 2003). Please add: (i) reflectance curves or (ii) at minimum device-independent colour specs under the assay illumination, and (iii) light intensity measurements near the fruits. This helps separate hue from luminance, which is important for insect vision.

      For odour, behaviour can depend strongly on release rates and plume structure; please report dispenser types, load quantities, aging, and an estimated release profile or headspace confirmation, or explicitly discuss this as a limitation for field translation (Cardé & Willis, 2008)


    3. Show the setup clearly
      Add a figure (or supplement) with photos of the arena, and close-ups of the 3D-printed fruits under assay illumination so readers see what the flies saw. Also show example egg images with your detection overlays to illustrate what the pipeline is picking up.


    4. Automated egg counting
      This is only briefly mentioned. Please add: how it was trained, any code/model weights you can share, and a simple validation against hand counts on held-out images (with an error or agreement table). A few example panels with overlayed detections would help.

     

    Minor Concerns

    1. Shape as controlled scope
      You purposely held shape constant, which is fine for isolating colour and odour. Please acknowledge that shape and size cues can matter in tephritids and cite classic work by Prokopy and Roitberg. This clarifies the boundary of your conclusions and points to a natural follow up.



    2. Data presentation
      Wherever possible, overlay raw points (jitter/swarm) with a clear summary.
      Anchor the y-axis at zero (or use a clearly marked disjoint axis).
      Standardize “95% CI” (not “IC”). Add sample sizes in each figure caption.

    3. Reproducibility
      Please share the STL/3MF files for the 3D printed fruits linked in the data/code section.

     

     

     


    Title and abstract

     

    Title reflects content: Yes
    Abstract states main findings: Yes (consider softening “predictable” until prediction is shown)
     

     


    Introduction

     

    Questions/predictions clear: Yes
    Background adequate: Yes (add one line noting shape/size cues, with Prokopy, Roitberg et al)
     

     


    Methods

    Replicable with small additions: Mostly (add colour/odour specs; egg counter code, details and validation; STL files)
    Sample sizes clear: Mostly (please add n in captions)
    Stats description: Okay for now (claim of prediction needs the steps above)
     

     


    Results

    Described correctly: Yes, but avoid calling the association “predictable” without prediction tests
    Add Bland Altman style plot and prediction metrics: Requested
     

    Discussion

    Strengths/limits: Add notes on luminance vs colour, odour release, and shape scope
     

     


    Conclusions

    Supported by results: Yes, once predictability is demonstrated or wording is softened
     

     

     

    Thanks for a thoughtful piece of work. With these focused updates, the main story will be both clearer and more convincing.

  5. Peer Community In Zoology

     Title and abstract

    • Does the title clearly reflect the content of the article? [X ] Yes, [ ] No (please explain), [ ] I don’t know
    • Does the abstract present the main findings of the study? [X] Yes, [ ] No (please explain), [ ] I don’t know
    • IntroductionAre the research questions/hypotheses/predictions clearly presented? [X] Yes, [ ] No (please explain), [ ] I don’t know
    • Does the introduction build on relevant research in the field? [X] Yes, [ ] No (please explain), [ ] I don’t know
      Materials and methods
    • Are the methods and analyses sufficiently detailed to allow replication by other researchers? [ ] Yes, [X ] No (please explain), [ ] I don’t know

    Overall, yes, but some information is missing (see my comments below).

    • If applicable (for empirical studies), are sample sizes are clearly justified? [ ] Yes, [X] No (please explain), [ ] I don’t know
    • Are the methods and statistical analyses appropriate and well described? [X] Yes, [ ] No (please explain), [ ] I don’t know

    Results

    • In the case of negative results, is there a statistical power analysis (or an adequate Bayesian analysis or equivalence testing)? [ ] Yes, [X] No (please explain), [ ] I don’t know
    • Are the results described and interpreted correctly? [X ] Yes, [ ] No (please explain), [ ] I don’t know

    Discussion

    • Have the authors appropriately emphasized the strengths and limitations of their study/theory/methods/argument? [ ] Yes, [X] No (please explain), [ ] I don’t know
    • Are the conclusions adequately supported by the results (without overstating the implications of the findings)? [X ] Yes, [ ] No (please explain), [ ] I don’t know 

     

    Comments

    Overall, the manuscript is well written, the references are well chosen, and the experiments appear to have been conducted correctly, although some information is missing (see my minor comments).

    There is just one point that I find problematic in this study, which is the fact that the same group of females was tested twice, with a 2-day interval between tests. I don't really see the point of this. This point is specified in the materials and methods section, but it is not taken into account in the statistical analyses or discussed further. It is also unclear whether the same combinations of odors and colors were used for the same group of females or different ones in the two successive tests. It is well known that generalist phytophagous insects are able to learn from their past experiences, and this can influence their choice of oviposition sites. There are numerous studies demonstrating this, some of which are even cited in this manuscript.
    Therefore, the authors must:
    - Justify why two different tests were carried out on the same group of females and explain whether the same or different combinations were tested.
    - Take into account the test season (1st or 2nd) in the statistical analyses. Were more eggs laid in the first or second session?
    - Discuss these two different oviposition phases in the discussion.
     
    I also have a few minor comments.

    • L. 54 to 56: something is missing in this sentence. Either the authors are referring to olfaction alone (line 54), or olfaction (line 55) should be removed and “in addition” should be added.
    • L. 60-61: I would have removed the part “along neural networks well characterized in Drosophila (Yang et al. 2015)” as I don't really see its relevance here.
    • L.117 to 127: indicate the development cycle duration in your laboratory conditions. It is also not indicated what the individuals were fed for mass rearing.
    • L.126: Please specify the size of the mesh.
    • L.127: The females are the same age, but when did they mate?
    • L.137: If this is based on the literature, please indicate which one.
    • L. 147: What is the distance between the two artificial fruits?
    • L. 62: Please be more specific about the sugar and proteins used.
    • L.280: I would be cautious about this interpretation. It is well known that generalist phytophagous have innate preference hierarchies, but these are not necessarily associated with the performance of their progeny on these hosts. It is also known that this hierarchy can be modulated by past experiences. This poses a problem with regard to the experimental setup used here, put see my major comment.
    • L.314 and in the references: there is a mistake at Rennou.

     

  6. Peer Community In Zoology

    The general context of the study (Facon et al. 2025) lies in the behavioral ecology and sensory biology of agricultural pests.

    Specifically, it focuses on the Mediterranean fruit fly (Ceratitis capitata), a multivoltine generalist and one of the world's most destructive crop pests.  Because the larvae of this species remain on the fruit where they hatch, their survival—and the subsequent degree of crop damage—depends entirely on the oviposition choices made by the female.

    I was intrigued by the dual nature of this scientific question: it builds highly practical knowledge for applied pest management while fundamentally exploring how insects process and make decisions based on individual versus synergistic sensory inputs (visual and olfactory cues). I decided to accept the role of recommender for this article primarily because of my own background and expertise in insect sensory biology, specifically insect vision

    The authors used a highly controlled behavioral experimental design utilizing customizable 3D-printed artificial fruits. They used these artificial fruits to cleanly isolate and manipulate specific visual cues (white, yellow, blue) and olfactory cues (cherry, orange, banana, etc.) across both no-choice and paired-choice assays. What was notable was their methodical comparison of independent versus paired sensory presentations (testing odor and color separately and together in choice vs. no-choice environments), using the number of eggs laid as a direct, quantifiable proxy for preference. This helps them distinguish between host acceptance (laying eggs on a less desirable host if it is the only one available) and host preference. The authors demonstrated that while visual and olfactory cues act independently, they interact significantly when combined. Crucially, they showed that if a specific multimodal combination stimulated high egg-laying in a no-choice assay (high acceptance), Females preferred it even more strongly when it was presented alongside an alternative (high preference).
    The reviewers, who are well-versed in insect sensory biology and agricultural choice assays, were highly positive about the study as a whole. They particularly appreciated the behavioral experiments' setup and focused their constructive feedback almost entirely on optimizing the presentation of the results rather than questioning the fundamental science. During the revision process, the paper's messaging and interpretability were significantly improved. Specifically, based on reviewer feedback, the authors refined their language to better reflect correlation rather than causation. Additionally, they re-plotted several graphs to improve data visualization and expanded upon the rationale behind their methodological decisions.
    I found the study a great example of how careful behavioural experiments can help understand host choice and sensory integration in insects.


    References

    Benoit Facon, Virginie Ravigne, Julien Foucaud, Antoine Fraimout, Myriam Robejean, Bruno Serrate, Madeline Chauve (2025) Context-dependent oviposition reveals strong association between acceptance and preference in the Mediterranean fruit fly. bioRxiv, ver.2 peer-reviewed and recommended by PCI Zoology https://doi.org/10.1101/2025.06.20.660717

  7. Version published to 10.1101/2025.06.20.660717 on bioRxiv