The overall assumption that scorpions are generalist predators is often based on conspicuous information from the literature. Here, we compiled a list of prey consumption by scorpions from different environments in Brazil to produce a documentation of predations by this taxon. This list is based on observations made under natural conditions in Atlantic Forest, Caatinga, and Cerrado formations. We compiled 135 predation instances including 11 scorpion species from field work through 14 years. The observed diet composition of the scorpions was mainly based on cockroaches, crickets, grasshoppers, spiders, and other scorpions. Such data highlights the generalist diet and cannibalism of scorpions with many cannibalistic events among the records of intraguild predation. Overall, this study broadens the knowledge of the diet composition of Brazilian scorpions under natural conditions.

Fear level and intraguild predation are factors that act together to directly influence animal behavior, population dynamics, and community structure. These factors trigger stress, which promotes behavioral, morphological, physiological, and demographic changes, especially in the prey. Some invertebrates, such as scorpions, are known to have a refined chemoreception system to perceive both prey and predators. Therefore, we investigated the ability of an intraguild prey, the scorpion Ananteris mauryi Lourenço, 1982, to detect chemical traces of its predator, the scorpion Tityus pusillus Pocock, 1893. Our goal was to verify whether A. mauryi exhibits antipredator behavior induced exclusively by chemical cues from its predator. Ananteris mauryi specimens were subjected to two experimental treatments: one with and one without traces of T. pusillus. The results showed that A. mauryi tended to avoid substrates with chemical traces of T. pusillus, confirming its capacity for chemical detection. As a result of this perception, changes in behavioral frequencies were triggered, generating an antipredator behavioral repertoire. These findings were supported by behavioral changes, such as tail wagging, which is performed exclusively by scorpions in the presence of a predator and at imminent risk of predation.

Knowledge of the patterns in the spatial distribution of species provides valuable information about the factors (resources and environment) that regulate the use of space by animals. Typically, the distribution of litter-dwelling scorpions in Atlantic forests is correlated with the structure of their microhabitats, although to better understand their natural history more studies on the patterns in their use of space are required. Therefore, we investigated the effect of rainfall on the patterns in the spatial distributions and population densities of two sympatric species of scorpion, Tityus (Archaeotityus) pusillus Pocock 1893 and Ananteris mauryi Louren?o 1982 in a fragment of Atlantic Forest in Brazil. The study was carried out during the dry (September) and rainy (June) months. We collected 501 individuals (268 T. (A.) pusillus and 233 A. mauryi) by actively searching at night using UV lanterns. We found that the spatial distribution and population density of T. (A.) pusillus, but not A. mauryi, were significantly affected by rainfall, with T. (A.) pusillus individuals showing a clumped pattern during the rainy month and random distribution in the dry month. We also found a different response in the population densities of the two species, with T. (A.) pusillus but not A. mauryi being affected by rainfall. Our results indicate that, although co-habiting in leaf litter, these species respond differently to rainfall, which affects their spatial distribution and abundance in this habitat.

Scorpions feed on diverse prey types but are also preyed upon by larger predators. Hunting and defensive strategies can also influence predation success of animals. Ananteris mauryi Lourenço, 1982 (Scorpiones: Buthidae), a relatively small-sized scorpion and an active forager in leaf litter, is frequently preyed on by another scorpion species, Tityus pusillus Pocock, 1893 in the Brazilian Atlantic rainforest. Here, we report the predation of A. mauryi by the predatory ant Ectatomma planidens Borgmeier, 1939 (Hymenoptera: Formicidae) in a tropical rainforest. During a nocturnal active collection of scorpions, an ant (10 mm) was observed biting the prosoma of a scorpion (16 mm) and carrying it posteriorly while moving backwards. This record confirms that a smaller predator is able to prey upon a larger scorpion. We discuss herein the efficiency of Ectatomma species to prey on dangerous predators. In addition, this is the first report of E. planidens in the Pernambuco state, Brazil.