Oral Presentations
Male Beetle Courtship Analysis by DeepLabCut Technology
Presentation Type
Presentation
Faculty Mentor’s Full Name
Doug Emlen
Faculty Mentor’s Department
DBS
Abstract / Artist's Statement
In species with large male weapons (e.g. antlers, horns, claws), female choice has traditionally been considered relatively weak since males establish dominance among themselves, and the best fighters were presumed to be the best mates. In Japanese rhinoceros beetles (Trypoxylus dichotomus), males with long horns win fights over feeding territories visited by females and females were assumed to be passive. However, it is now clear that females routinely reject males –even large males with long horns—and males must court females with stridulatory songs and trembling, oscillating dances. Why? We hypothesized that hours of repeated battles might exhaust males, depleting their stored energy reserves, and females may be using courtship to select mating partners based on their body condition. Here we tested whether the trembling dances performed by males could signal body condition to females. We restricted food intake for a subset of males and compared the head-dipping and trembling rates of 25 nutrient-stressed and 25 well-fed males. We observed and filmed male courtships and then used DeepLabCut, an estimation algorithm technology, to analyze the courtship dances. Using multiple markers on both the male’s and female’s body, we were able to determine the displacement of their bodies during dances and calculate the speed of their back-and-forth movements. We found that well-fed males trembled faster than the stressed, food-restricted males. While the Emlen Lab is still determining all of the factors that play a role during a courtship, our study utilizing DeepLabCut paints a clearer picture of the function of the trembling dance. Female insects continue to amaze us with the sophistication of their mate choices, and this study reminds us that it isn’t always all about body or weapon size.
Category
Life Sciences
Male Beetle Courtship Analysis by DeepLabCut Technology
UC 330
In species with large male weapons (e.g. antlers, horns, claws), female choice has traditionally been considered relatively weak since males establish dominance among themselves, and the best fighters were presumed to be the best mates. In Japanese rhinoceros beetles (Trypoxylus dichotomus), males with long horns win fights over feeding territories visited by females and females were assumed to be passive. However, it is now clear that females routinely reject males –even large males with long horns—and males must court females with stridulatory songs and trembling, oscillating dances. Why? We hypothesized that hours of repeated battles might exhaust males, depleting their stored energy reserves, and females may be using courtship to select mating partners based on their body condition. Here we tested whether the trembling dances performed by males could signal body condition to females. We restricted food intake for a subset of males and compared the head-dipping and trembling rates of 25 nutrient-stressed and 25 well-fed males. We observed and filmed male courtships and then used DeepLabCut, an estimation algorithm technology, to analyze the courtship dances. Using multiple markers on both the male’s and female’s body, we were able to determine the displacement of their bodies during dances and calculate the speed of their back-and-forth movements. We found that well-fed males trembled faster than the stressed, food-restricted males. While the Emlen Lab is still determining all of the factors that play a role during a courtship, our study utilizing DeepLabCut paints a clearer picture of the function of the trembling dance. Female insects continue to amaze us with the sophistication of their mate choices, and this study reminds us that it isn’t always all about body or weapon size.