DOI: 10.5061/dryad.15dv41p6v
title: Olfactory performance explains duality of antennal architectural designs in Lepidoptera

description: Male attraction by females through sex pheromones is widespread among
 Lepidoptera, and antennae are key olfactory organs during male
 orientation. Broadly speaking, two designs of antennae coexist in
 Lepidoptera: complex (pectinate) or stick-like (filiform) ones. Pectinate
 antennae have attracted attention because of their multiscale geometry,
 assumed to outperform filiform. Yet, the filiform design is by far more
 common. We compare the olfactory performance of the two designs using
 modeling, particle image velocimetry on 3D-printed scaled-up models, and
 computational simulations. In terms of absolute odor capture, pectinate
 antennae perform better at nearly all flying speeds. However, when
 considering drag, filiform designs are more energy-efficient than
 pectinate ones at low flight speeds, while the reverse holds at high
 speeds. This is due to the differential scaling of drag and molecule
 capture with flight speed. According to our results, small and slow moths
 would bear filiform antennae whereas big and fast moths would have
 pectinate ones, which is the general trend observed in Nature. We discuss
 exceptions to this general pattern and how species could evolve from one
 design to the other by investigating the influence of the antennal
 structural elements.
description: # Olfactory performance explains duality of antennal architectural designs
 in Lepidoptera
 [https://doi.org/10.5061/dryad.15dv41p6v](https://doi.org/10.5061/dryad.15dv41p6v) ## Description of the data and file structure Olfactory performance explains duality in antennal architecture designs in Lepidoptera Content: * Comsol files * PIV velocity fields * Data used in the paper * R scripts ### Files and variables #### File: Data\_used\_in\_the\_paper.zip **Description:** Excel files with data relative to the filiform or the pectinate antenna. 'D10-5' means that the diffusion coefficient is equal to 1e-5m^2/s. 'D10-6' means that the diffusion coefficient is equal to 1e-6m^2/s. When there is neither 'D10-5' nor 'D10-6', the diffusion coefficient is equal to 4.5e-6m^2/s. In the files related to the filiform antenna, the columns are the following: * 1st column 'Velocity (m/s)': velocity of air in m/s; * 2nd column 'Capture (mol/s) - 60um': capture rate of a 60-um filiform antenna in mol/s; * 3rd column 'Drag (N) - 60um': drag of a 60-um filiform antenna in N; * 4th column 'CPE 60 um': Capture-per-energy of a 60-um filiform antenna in mol/J; * 5th column 'Capture (mol/s) - 120um': capture rate of a 120-um filiform antenna in mol/s; * 6th column 'Drag (N) - 120um': drag of a 120-um filiform antenna in N; * 7th column 'CPE 120 um': Capture-per-energy of a 120-um filiform antenna in mol/J; * each line is related to a different air velocity in m/s. In the files related to the pectinate antenna, the columns are the following: * 1st column 'Velocity (m/s)': velocity of air in m/s; * 2nd column 'Leakiness (%)' : leakiness of a pectinate antenna in %; * 3rd column 'Drag (N)': drag of a pectinate antenna in N; * 4th column 'Corrected capture (mol/s)': capture rate of a pectinate antenna in mol/s; * 5th column 'Corrected capture efficiency': capture efficiency of a pectinate antenna in %; * 6th column 'Energy efficiency (mol/J)': capture-per-energy of a pectinate antenna in mol/J; * each line is related to a different air velocity in m/s. The 'Ramuslength' file is related to the performance of a pectinate antenna with various ramus lengths. Thus, the columns are the same except the 2nd column with was added to indicate the length of the ramus in mm and the column for the capture efficieny was deleted. All air velocity was tested for each ramus length so each line corresponds to the combination of one air velocity and one ramus length. The results are presented in the following order: all air velocity for a given ramus length are presented before moving to the next ramus length. The 'Sensillumlength' file is very similar to the 'Ramuslength' one. The only difference is that the varying parameter is the sensillum length instead of the ramus length. This parameter, in the 2nd column, is measured by a scaling factor. 1 means the length of the sensilla is equal to the one of sensilla measured on real antennae. The sensillum length is then scaled up or down according to the scaling factor. #### File: R\_scripts.zip **Description:** Scripts to determine the diameter of the equivalent rami ('Equivalent_cylinder_diameter.r') and the amount of pheromone capture based on the model of Miyatake and Iwashita (1989) ('Antenna_capture.r'). The 'Equivalent_cylinder_diameter.r' file takes the 'Cylinder.txt' file as input. This file should be located in a 'Data' folder in the same folder as the 'Equivalent_cylinder_diameter.r' file. The 'Antenna_capture.r' file takes no input. R version 4.3.3 was used to write these scripts with no additional packages. #### File: PIV\_velocity\_fields.zip **Description:** The PIV velocity fields were obtained from the PIV experiment on a macrostructure whose ramus diameter was set at 105um. The experiments were run in oil and water. In order to keep the Reynolds umber constant, the macrostructure was scaled up by a factor 10. Equivalent velocities Air (m/s) | 0.1 | 0.2 | 0.5 | 1 | 2 | 5 | Water (mm/s) | | 1.28 | 3.21 | 6.41 | 12.8 | 32.1 | Oil (mm/s) | 32.1 | 64.1 | | | | | Each subfolder is related to one measurement and the related velocity and fluid (water or oil) used in the experiment is indicated in the name of the subfolder. 'mmps' means mm/s. In each subfolder, there are two files. The first one, 'B0001.txt', stores the value of the velocity field. Columns 1 and 2 are the x and y coordinates of the measurement in mm. Columns 3 and 4 are the two components of the velocity field in, respectively, the x and y direction and measured in m/s. The second file 'B0002.txt' has the same structure. The difference is that Columns 3 and 4 store the standard deviation of the velocity field in, respectively, the x and y directions and measured in m/s. ## Code/software Comsol models * 'Cylinder.mph' is the model used to calculate the drag and the pheromone capture of a filiform antenna. * 'CylinderRow.mph' is the model used to calculate the drag of an infinite row of infinitely-long cylinders. * 'Microstructure.mph' is the model used to calculate the drag and capture of pheromone by the microstructure, ie, one ramus and its sensilla. * 'Macrostructure.mph' is the model used to calcultae the leakiness and the drag of the macrostructure with modified ramus diameter. * 'Sens_length.mph' is the model used to calculate the drag of the micrsortucture with various sensillum lengths.