Using Rhodamine to Tag Mites for Studies of Pre‐ and Post‐Copulatory Sexual Selection

• Published in: Ecology and evolution 2024-11, Vol.14 (11), p.e70525-n/a
• Main Authors: Shavrova, Anastasia J., Buzatto, Bruno A., Kasumovic, Michael M.
• Format: Article
• Language: English
• Subjects: animal behaviour; Animal reproduction; Arachnids; Behavior; Competition; Evolutionary Ecology; Females; Fluorescence; Fluorescent indicators; Food cans; Genetic markers; Insects; Invertebrates; Males; Rhodamine; Sexual selection; Sperm; Success; Tagging; tracking
• ISSN: 2045-7758; 2045-7758
• DOI: 10.1002/ece3.70525

ABSTRACT Our understanding of sexual selection is advancing with new technologies that tag individuals or their sperm, revealing how females use post‐copulatory processes to discriminate between competing mates. Many tagging methods have been devised primarily for model insect organisms like Drosophila or Gryllidae. Developing such novel methods, however, is expensive and requires intensive investment. In this experiment, we trial the use of Rhodamine B (RhB) and Rhodamine 110 (Rh110) in a small arachnid, the bulb mite Rhizoglyphus echinopus, for pre‐ and post‐copulatory observations as it is a relatively inexpensive and simple way to tag individuals and their ejaculate proteins. First, we tested whether RhB and Rh110 applied to food can be used as a tagging method to track and distinguish between individuals. Second, we explored whether Rhodamine applied in this way can be used to track sperm transfer. We found that both tagging probes worked well in tagging individuals and that we were able to distinguish between individuals using both LED and fluorescent microscopy. We also found that Rhodamine degraded rapidly in the animals, likely due to their fast metabolism. Due to the rapid degradation, we observed variable results in the sperm transfer trials. We suggest multiple uses for Rhodamine and highlight other invertebrates where this method may come into use for the study of sexual selection. We trial the use of Rhodamine, for the first time in arachnids. We first trial the method for behavioural ecology and evolution trials to track the individuals within large population sizes. Furthermore, we trial this method for post‐copulatory studies that investigate sperm competition and female cryptic choice.