Searching for the audience of the weeping lizard's distress call

The evolution and functions of avian and mammalian antipredator calls are well understood, which contrasts with a lack of progress in reptiles. Here, we present the first investigation of the functions of a distress call in a lizard. We studied Liolaemus chiliensis, which emits a short and complex high-pitched scream when it is subdued. We determined the behavioral responses of two potential targets to these calls, conspecifics, and a snake predator. Additionally, we tested whether the chemical environment (presence of chemical scents from conspecifics) modulates the lizards' responses to calls. Both the conspecifics and the predator responded to the distress calls, which triggered a longer period of immobility in the lizards and a reduction in exploratory behavior in the snake, as compared to a white noise. In addition, the lizards in the arena with scents of conspecifics responded to distress calls and noise with more movements and escape attempts. These results suggest that distres

Vocalización de liolaemus chiliensis: explorando su función y la respuesta a la interacción con la información química

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Chemical recognition in a snake-lizard predator-prey system

Artículo de publicación ISIIn a predator-prey interaction, the fitnesses of the predator and the prey depend on their abilities to recognize each other, a process that may involve different sensory modalities. Squamate reptiles are highly dependent on chemical senses for such recognition, and here we explored the ability of a generalist saurophagous snake, Philodryas chamissonis, to discriminate scents of two congeneric and sympatric lizard prey species, Liolaemus nitidus and L. chiliensis. A generalist saurophagous snake might just be sensitive to lizard scents in general, and if so, no discrimination between prey species is expected. However, these lizards use different substrates; L. nitidus basks on rocks, whereas L. chiliensis mainly basks on bushes and rarely on ground. The snake P. chamissonis basks on ground and rocks, and rarely on bushes. Therefore, if the rate of encounter affects the ability to recognize prey, we predict that P. chamissonis would show prey discrimination because scents of L. chiliensis may be encountered less frequently in its habitat. Results showed that the snake had a refined discrimination of lizard prey, reducing tongue flick rate and movements in response to scents from the common prey scents, L. nitidus. We also studied the ability of L. chiliensis to detect the snake and found that snake scents triggered a reduction in activity. The potential infrequent encounter between predator and prey may explain the asymmetric predator-prey recognition, as can be predicted from the "life-dinner" principle.Fondecyt 1090251/112018

Triazole Fungicides Inhibit Zebrafish Hatching by Blocking the Secretory Function of Hatching Gland Cells

In animals, hatching represents the transition point from a developing embryo to a free-living individual, the larva. This process is finely regulated by many endogenous and environmental factors and has been shown to be sensitive to a variety of chemical agents. It is commonly evaluated in bioassays in order to establish the effects of different agents on early development and reproductive capabilities in fish and other aquatic animals. In fish, the breakdown of the chorion is achieved by the secretion of choriolysin by hatching gland cells (HGCs) into the perivitelline space (PVS), coupled with spontaneous movements of the developing larva. In this work, we used zebrafish to assay the effects of a family of widely used agrochemicals—triazoles Triadimefon (FON), Triadimenol (NOL) and free triazole (1,2,4-T)—on hatching success. We found a strong inhibition of hatching by triazole exposure which was correlated with morphological changes and a reduction in the secretory function of the HGCs. As a consequence, the release of choriolytic enzymes by HGCs was reduced. We also found that HGC secretion reduction after exposure to FON can be rescued by co-incubation with a dopamine D2 receptor antagonist but not by antagonists of the D1-like receptors. This suggests a specific pathway through which this family of fungicides may be impairing a critical event in the fish life cycle

Triazole Fungicides Inhibit Zebrafish Hatching by Blocking the Secretory Function of Hatching Gland Cells

In animals, hatching represents the transition point from a developing embryo to a free-living individual, the larva. This process is finely regulated by many endogenous and environmental factors and has been shown to be sensitive to a variety of chemical agents. It is commonly evaluated in bioassays in order to establish the effects of different agents on early development and reproductive capabilities in fish and other aquatic animals. In fish, the breakdown of the chorion is achieved by the secretion of choriolysin by hatching gland cells (HGCs) into the perivitelline space (PVS), coupled with spontaneous movements of the developing larva. In this work, we used zebrafish to assay the effects of a family of widely used agrochemicals—triazoles Triadimefon (FON), Triadimenol (NOL) and free triazole (1,2,4-T)—on hatching success. We found a strong inhibition of hatching by triazole exposure which was correlated with morphological changes and a reduction in the secretory function of the HGCs. As a consequence, the release of choriolytic enzymes by HGCs was reduced. We also found that HGC secretion reduction after exposure to FON can be rescued by co-incubation with a dopamine D2 receptor antagonist but not by antagonists of the D1-like receptors. This suggests a specific pathway through which this family of fungicides may be impairing a critical event in the fish life cycle