Toads prey upon scorpions and are resistant to their venom: A biological and ecological approach to scorpionism

Light, camera, action: Behavioral responses of the yellow scorpion Tityus serrulatus to different lights

Scorpions cause 150k+ accidents per year in Brazil. Control of their populations involves manual collection and pesticides. Here we tested if light could be used to attract or repel the yellow scorpion Tityus serrulatus, the main responsible for accidents in the country. Based on previous studies on scorpion´s physiological and behavioral reactions to light, we tested wavelengths that correspond to red, green and violet, controlling temperature, absolute irradiance and electromagnetic stimuli. We built a ring arena divided into 5 parts and had the individuals freely walking in the presence of a light/control. We released the scorpions either away from the LED to test attraction or close to the LED to test repellency. Results showed avoidance to green light, and violet light on a smaller portion, that could be due to wavelengths, since those correspond to primary and secondary response peaks of the animal photoreceptors, due to the absolute irradiance of lights or both. These two wavelengths, therefore, have potential for scorpion control and deserve further investigations.

Experimental approach to the dislodging effect and the mortality of a pesticide in the yellow scorpion Tityus serrulatus

Accidents with scorpions are a problem in several regions of the world. In Brazil, the number of accidents is sometimes higher than 160k/year, and the responsible for most accidents and deaths is the yellow scorpion Tityus serrulatus. Unfortunately, there are few publications testing the effectiveness of most of the products for chemical control of scorpions. Using the pesticide Bifentol, we tested: I-the effect of the pesticide on the mortality of T. serrulatus, II-whether the scorpion avoids areas with pesticide and, III-whether it leaves the shelter if pesticide is applied. In the first experiment, we applied pesticide or water on the dorsal region of the scorpion or substrate according to treatment. For five days we noted whether the scorpion slide (dead) or clung to the substrate (alive) after turning the arena vertically to left and right. After five days, no pesticide-treated scorpions were alive while all water-treated scorpions were. In the second experiment, we placed two shelters, applied pesticide and/or water inside the shelter. We then released a scorpion on the opposite side. We scored latency to enter one of the shelters and the choice made by the scorpions. We did not find differences in latency or in the choice made. In the third experiment, we applied the pesticide or water to the shelter where the scorpion was being maintained, and, on the following day, we recorded whether the scorpion had left the shelter. None of the scorpions left the shelters and only one died. Thus, we obtained evidence that a pesticide can kill scorpions, but we did not find a dislodging effect.