Toxicon : official journal of the International Society on Toxinology, 2017
Toads have a pair of glandular accumulations on each side of the dorsal region of the head known ... more Toads have a pair of glandular accumulations on each side of the dorsal region of the head known as parotoid macroglands. These macroglands consist of secretory units (granular glands), each one capped with an epithelial plug. When threatened, toads point one of the parotoids toward the aggressor, and if the aggressor squeezes the parotoid with its teeth, jets of poison will come out of the secretory units and hit the predator's oral mucosa, thereby causing poisoning. Our study focused on the mechanism of parotoid function by comparing parotoids from toads naturally attacked by dogs with those manually compressed. We verified that the process of glandular emptying in response to dog bites is very similar to that following manual compression. We observed that the structure of the plug plays an essential role in the release of the poison jets. Our results suggest that the parotoids may act as "bulletproof vests," reducing the impact of the force exerted by predator attac...
Abstract. Several reports are available regarding ticks parasitizing toads of the family Bufonida... more Abstract. Several reports are available regarding ticks parasitizing toads of the family Bufonidae. Although ticks can attach to different regions of the body, occurrence of these ectoparasites on parotoid macroglands is unfrequent when compared with other regions of body. In this study, using histology and scanning electron microscopy, we analysed a rare case of ticks that were found exclusively lodged inside pores of parotoid macroglands in the cane toad Rhinella marina. Our results indicate that the morphology of toad parotoid pores offers physical protection to tick larvae, favoring successful attachment. Evidences of secretion release from the accessory glands arranged around the parasitized pores seem to constitute a defensive chemical response against parasitism, suggesting a role for these poorly known glands.
Tetrodotoxin (TTX), one of the most toxic substances in nature, is present in bacteria, invertebr... more Tetrodotoxin (TTX), one of the most toxic substances in nature, is present in bacteria, invertebrates, fishes, and amphibians. Marine organisms seem to bioaccumulate TTX from their food or acquire it from symbiotic bacteria, but its origin in amphibians is unclear.Taricha granulosacan exhibit high TTX levels, presumably concentrated in skin poison glands, acting as an agent of selection upon predatory garter snakes (Thamnophis). This co-evolutionary arms race induces variation inT. granulosaTTX levels, from very high to undetectable. Using morphology and biochemistry, we investigated differences in toxin localization and quality between two populations at the extremes of toxicity. TTX concentration within poison glands is related to the volume of a single cell type in which TTX occurs exclusively in distinctive secretory granules, suggesting a relationship between granule structure and chemical composition. TTX was detected in mucous glands in both populations, contradicting the gen...
The American Society of Ichthyologists and Herpetologists, an international society of about 2,00... more The American Society of Ichthyologists and Herpetologists, an international society of about 2,000 professional scientists who specialize in the biology and conservation of fishes, amphibians, and reptiles, strongly opposes traditional rattlesnake roundups. Such roundups promote overexploitation of natural populations of wildlife, unnecessary killing and inhumane treatment of individual animals, degradation of habitat, and promotion of outdated attitudes toward important elements of America’s natural heritage. Found nowhere but in the Americas, and especially diverse in the United States, the more than thirty species of rattlesnakes comprise a distinctive component of North America’s biodiversity, and one that is increasingly imperiled.
Adult two-lined salamanders, Eurycea bislineata, displayed alternative antipredator behaviour to ... more Adult two-lined salamanders, Eurycea bislineata, displayed alternative antipredator behaviour to garter snake, Thamnophis ordinoides, predators. In response to snake tongue-flicks, individual salamanders either ran, jumped or remained immobile. Different populations and ...
... of defence for geckos are ejection of viscous liquid at enemies in Diplidactylus, vocalizatio... more ... of defence for geckos are ejection of viscous liquid at enemies in Diplidactylus, vocalization inPhyllurus, limb extension threat ... behaviour was quite similarto defensive behaviour previously seen in some salamanders of the genera Pseudoeurycea, Bolitoglossa, and Ambystoma ...
Page 1. 302 HERPETOLOGICA [Vol. 34, No. 3 effect of parietalectomy on the thyroid and gonad in fr... more Page 1. 302 HERPETOLOGICA [Vol. 34, No. 3 effect of parietalectomy on the thyroid and gonad in free-living western fence lizards Sceloporus occidentalis. Copeia 1973:662-668. TINKIF, DW, AND L. N. IRWIN. 1965. Lizard ...
Page 1. Am. Midl. Nat. 122:26-33 Food Hoarding by the Least Shrew (Cryptotis parva): Intersexual ... more Page 1. Am. Midl. Nat. 122:26-33 Food Hoarding by the Least Shrew (Cryptotis parva): Intersexual and Prey Type Effects DANIEL R. FORMANOWICZ, JR., PATRICK J. BRADLEY AND EDMUND D. BRODIE, JR. Department ...
Page 1. 1985 NOTES AND DISCUSSION 401 Unpalatability and Toxicity of an Introduced Species (Cinna... more Page 1. 1985 NOTES AND DISCUSSION 401 Unpalatability and Toxicity of an Introduced Species (Cinnabar Moth Larvae) to Native Predators ABSTRACT: The acceptability of an introduced species of prey, cinnabar moth cat ...
Toxicon : official journal of the International Society on Toxinology, 2017
Toads have a pair of glandular accumulations on each side of the dorsal region of the head known ... more Toads have a pair of glandular accumulations on each side of the dorsal region of the head known as parotoid macroglands. These macroglands consist of secretory units (granular glands), each one capped with an epithelial plug. When threatened, toads point one of the parotoids toward the aggressor, and if the aggressor squeezes the parotoid with its teeth, jets of poison will come out of the secretory units and hit the predator's oral mucosa, thereby causing poisoning. Our study focused on the mechanism of parotoid function by comparing parotoids from toads naturally attacked by dogs with those manually compressed. We verified that the process of glandular emptying in response to dog bites is very similar to that following manual compression. We observed that the structure of the plug plays an essential role in the release of the poison jets. Our results suggest that the parotoids may act as "bulletproof vests," reducing the impact of the force exerted by predator attac...
Abstract. Several reports are available regarding ticks parasitizing toads of the family Bufonida... more Abstract. Several reports are available regarding ticks parasitizing toads of the family Bufonidae. Although ticks can attach to different regions of the body, occurrence of these ectoparasites on parotoid macroglands is unfrequent when compared with other regions of body. In this study, using histology and scanning electron microscopy, we analysed a rare case of ticks that were found exclusively lodged inside pores of parotoid macroglands in the cane toad Rhinella marina. Our results indicate that the morphology of toad parotoid pores offers physical protection to tick larvae, favoring successful attachment. Evidences of secretion release from the accessory glands arranged around the parasitized pores seem to constitute a defensive chemical response against parasitism, suggesting a role for these poorly known glands.
Tetrodotoxin (TTX), one of the most toxic substances in nature, is present in bacteria, invertebr... more Tetrodotoxin (TTX), one of the most toxic substances in nature, is present in bacteria, invertebrates, fishes, and amphibians. Marine organisms seem to bioaccumulate TTX from their food or acquire it from symbiotic bacteria, but its origin in amphibians is unclear.Taricha granulosacan exhibit high TTX levels, presumably concentrated in skin poison glands, acting as an agent of selection upon predatory garter snakes (Thamnophis). This co-evolutionary arms race induces variation inT. granulosaTTX levels, from very high to undetectable. Using morphology and biochemistry, we investigated differences in toxin localization and quality between two populations at the extremes of toxicity. TTX concentration within poison glands is related to the volume of a single cell type in which TTX occurs exclusively in distinctive secretory granules, suggesting a relationship between granule structure and chemical composition. TTX was detected in mucous glands in both populations, contradicting the gen...
The American Society of Ichthyologists and Herpetologists, an international society of about 2,00... more The American Society of Ichthyologists and Herpetologists, an international society of about 2,000 professional scientists who specialize in the biology and conservation of fishes, amphibians, and reptiles, strongly opposes traditional rattlesnake roundups. Such roundups promote overexploitation of natural populations of wildlife, unnecessary killing and inhumane treatment of individual animals, degradation of habitat, and promotion of outdated attitudes toward important elements of America’s natural heritage. Found nowhere but in the Americas, and especially diverse in the United States, the more than thirty species of rattlesnakes comprise a distinctive component of North America’s biodiversity, and one that is increasingly imperiled.
Adult two-lined salamanders, Eurycea bislineata, displayed alternative antipredator behaviour to ... more Adult two-lined salamanders, Eurycea bislineata, displayed alternative antipredator behaviour to garter snake, Thamnophis ordinoides, predators. In response to snake tongue-flicks, individual salamanders either ran, jumped or remained immobile. Different populations and ...
... of defence for geckos are ejection of viscous liquid at enemies in Diplidactylus, vocalizatio... more ... of defence for geckos are ejection of viscous liquid at enemies in Diplidactylus, vocalization inPhyllurus, limb extension threat ... behaviour was quite similarto defensive behaviour previously seen in some salamanders of the genera Pseudoeurycea, Bolitoglossa, and Ambystoma ...
Page 1. 302 HERPETOLOGICA [Vol. 34, No. 3 effect of parietalectomy on the thyroid and gonad in fr... more Page 1. 302 HERPETOLOGICA [Vol. 34, No. 3 effect of parietalectomy on the thyroid and gonad in free-living western fence lizards Sceloporus occidentalis. Copeia 1973:662-668. TINKIF, DW, AND L. N. IRWIN. 1965. Lizard ...
Page 1. Am. Midl. Nat. 122:26-33 Food Hoarding by the Least Shrew (Cryptotis parva): Intersexual ... more Page 1. Am. Midl. Nat. 122:26-33 Food Hoarding by the Least Shrew (Cryptotis parva): Intersexual and Prey Type Effects DANIEL R. FORMANOWICZ, JR., PATRICK J. BRADLEY AND EDMUND D. BRODIE, JR. Department ...
Page 1. 1985 NOTES AND DISCUSSION 401 Unpalatability and Toxicity of an Introduced Species (Cinna... more Page 1. 1985 NOTES AND DISCUSSION 401 Unpalatability and Toxicity of an Introduced Species (Cinnabar Moth Larvae) to Native Predators ABSTRACT: The acceptability of an introduced species of prey, cinnabar moth cat ...
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