An Ant-Mimicking Jumping Spider Achieves Higher Predation Probability with Lower Success Rate When Exposed to Ethanol

SIMPLE SUMMARY: Ethanol is a non-negligible factor which affects many animals’ behavior in nature. Jumping spiders can be found in almost every type of environment, and thus can easily make direct contact with ETOH. However, it remains unclear how ETOH affects jumping spiders. In this study, we tested the ETOH preference of jumping spiders. Jumping spiders show a significant preference at a medium concentration and avoidance at a high concentration of ETOH. We also tested the potential benefits jumping spiders may obtain from choosing ETOH in terms of predation probability and prey capture efficiency. We found that although ETOH would decrease the success rate of the first attack, the predation probability would be higher due to the fact that one type of their prey, the fruit fly, showed significant preference for ETOH. Our findings suggest that spiders may have evolved to use ethanol as a signal of the presence of food resources, and also provide a new direction for ETOH-invertebrates interactions. ABSTRACT: Ethanol (ETOH) affects many animals’ behaviour in nature; for example, honeybees become more aggressive after consuming ETOH. In previous studies, scientists have used honeybees and fruit flies as models to determine if they showed a strong preference to ETOH. Moreover, ETOH could affect their locomotion and learning abilities. However, whether and how ETOH affects spiders is unclear as of yet. In this study, we used empirical experiments to determine whether spiders showed preference for ETOH, as well as the potential benefits of spiders choosing ETOH, by using a common spider, Myrmarachne gisti, which has a high probability of contacting ETOH in their habitat. In our experiment, M. gisti showed a significant preference for ETOH. Although the success rate of the first attack was significantly decreased when M. gisti were exposed to ETOH, they had a significantly higher predation probability, since fruit flies also showed a significant preference for ETOH. Our findings suggested that ETOH could affect the prey capture efficiency of M. gisti, and indicated that spiders might evolve to use ETOH to locate a potential hunting place. Taken together, our findings suggested that M. gisti evolved to adapt to ETOH and could use it as a signal of the presence of food resources.