Fig. 2
From: Inverse resource allocation between vision and olfaction across the genus Drosophila
External comparison of visual and olfactory system. Red color signifies vision or predicted visual bias, while blue indicates olfaction or potential olfactory bias. a All 62 species measured for eye and funiculus surface area, where six species were selected for additional measurements. These flies were selected to compare species with similar antennal surface area but contrasting eye sizes (e.g., D. pseudotalamancana and D. funebris, or D. americana and D. busckii) or species with similar eye size but contrasting antennal sizes (e.g., D. americana and D. funebris). We also selected two well-established species, D. melanogaster and D. suzukii, for an additional comparison and points of reference. b Inverse correlation between ommatidium number and sensillum number when corrected for head size from six species of Drosophila, suggesting a possible tradeoff between these sensory systems at the periphery. c All species were photographed for more detailed measurements of eye and antennal features across several frontal and lateral views. Highlighted in blue are the antennal surface area, and in red, the eye surface area. d Shown are the sensillum density metrics taken from stacked lambda mode scans (maximum intensity projections) of the anterior portion of the antenna for all six species examined, identifying strong differences for example in trichoid sensillum density, where potentially olfactory biased species (in blue) showed the significantly larger trichoid densities. Error bars represent standard deviation. e Ommatidium counts from each species, which illustrates the large differences in visual capabilities across this genus of fly, with some species having 2–3 times larger eyes. Boxplots represent the median (bold black line), quartiles (boxes), as well as the confidence intervals (whiskers). d, e Means with the same letter are not significantly different from each other (ANOVA with Tukey–Kramer multiple comparison test). f Expanded study to include additional species (that were selected using stratified random sampling), where we show that trichoids are consistently and inversely correlated with increasing eye-to funiculus ratio across the entire genus. (Data are provided at https://doi.org/10.17617/3.1D)
