scholarly journals Tactical reproductive parasitism via larval cannibalism in Peruvian poison frogs

2008 ◽  
Vol 5 (2) ◽  
pp. 148-151 ◽  
Author(s):  
Jason L Brown ◽  
Victor Morales ◽  
Kyle Summers
Keyword(s):  
Choice Experiment ◽  
Genetic Analyses ◽  
Poison Frog ◽  
Poison Frogs ◽  
Reproductive Parasitism

We report an unusual example of reproductive parasitism in amphibians. Dendrobates variabilis , an Amazonian poison frog, oviposits at the surface of the water in small pools in plants and deposits tadpoles within the pools. Tadpoles are highly cannibalistic and consume young tadpoles if they are accessible. Deposition of embryos and tadpoles in the same pool is common. Genetic analyses indicate that tadpoles are frequently unrelated to embryos in the same pool. A pool choice experiment in the field demonstrated that males carrying tadpoles prefer to place them in pools with embryos, facilitating reproductive parasitism via cannibalism.

scholarly journals Evidence that toxin resistance in poison birds and frogs is not rooted in sodium channel mutations and may rely on “toxin sponge” proteins

2021 ◽  
Vol 153 (9) ◽  
Author(s):  
Fayal Abderemane-Ali ◽  
Nathan D. Rossen ◽  
Megan E. Kobiela ◽  
Robert A. Craig ◽  
Catherine E. Garrison ◽  
...  
Keyword(s):  
Ion Channel ◽  
Sodium Channel ◽  
Small Molecule ◽  
Resistance Mechanism ◽  
Poison Frog ◽  
Poison Frogs ◽  
Toxin Resistance ◽  
Voltage Gated ◽  
Primary Driver ◽  
Toxin Sequestration

Many poisonous organisms carry small-molecule toxins that alter voltage-gated sodium channel (NaV) function. Among these, batrachotoxin (BTX) from Pitohui poison birds and Phyllobates poison frogs stands out because of its lethality and unusual effects on NaV function. How these toxin-bearing organisms avoid autointoxication remains poorly understood. In poison frogs, a NaV DIVS6 pore-forming helix N-to-T mutation has been proposed as the BTX resistance mechanism. Here, we show that this variant is absent from Pitohui and poison frog NaVs, incurs a strong cost compromising channel function, and fails to produce BTX-resistant channels in poison frog NaVs. We also show that captivity-raised poison frogs are resistant to two NaV-directed toxins, BTX and saxitoxin (STX), even though they bear NaVs sensitive to both. Moreover, we demonstrate that the amphibian STX “toxin sponge” protein saxiphilin is able to protect and rescue NaVs from block by STX. Taken together, our data contradict the hypothesis that BTX autoresistance is rooted in the DIVS6 N→T mutation, challenge the idea that ion channel mutations are a primary driver of toxin resistance, and suggest the possibility that toxin sequestration mechanisms may be key for protecting poisonous species from the action of small-molecule toxins.

scholarly journals Pumiliotoxin metabolism and molecular physiology in a poison frog

2020 ◽  
Author(s):  
Aurora Alvarez-Buylla ◽  
Cheyenne Y. Payne ◽  
Charles Vidoudez ◽  
Sunia A. Trauger ◽  
Lauren A. O’Connell
Keyword(s):  
Gene Expression ◽  
Small Molecules ◽  
Physiological Changes ◽  
Molecular Physiology ◽  
Physiological Mechanisms ◽  
Poison Frog ◽  
Poison Frogs ◽  
Immune System Function ◽  
Expression Of Genes ◽  
Frog Species

ABSTRACTPoison frogs bioaccumulate alkaloids for chemical defense from their arthropod diet. These small molecules are sequestered from their gastrointestinal tract and transported to the skin for storage. Although many alkaloids are accumulated without modification, some poison frog species can metabolize pumiliotoxin (PTX 251D) into the more potent allopumiliotoxin (aPTX 267A). Despite extensive research characterizing the chemical arsenal of poison frogs, the physiological mechanisms involved in the sequestration and metabolism of individual alkaloids is unknown. We performed a feeding experiment with the Dyeing poison frog (Dendrobates tinctorius) to ask if this species can metabolize PTX 251D into aPTX 267A and what gene expression changes are associated with PTX 251D exposure in the intestines, liver, and skin. We found that D. tinctorius can metabolize PTX 251D into aPTX 267A, and that PTX 251D exposure changed the expression of genes involved in immune system function and small molecule metabolism and transport. These results show that individual alkaloids can modify gene expression across poison frog tissues and suggest that different alkaloid classes in wild diets may induce specific physiological changes for accumulation and metabolism.

scholarly journals Rapid toxin sequestration modifies poison frog physiology

2021 ◽  
pp. jeb.230342
Author(s):  
Lauren A. O'Connell ◽  
Jeremy D. O'Connell ◽  
Joao A. Paulo ◽  
Sunia A. Trauger ◽  
Steven P. Gygi ◽  
...  
Keyword(s):  
Small Molecule ◽  
Chemical Defenses ◽  
Protein Abundance ◽  
Poison Frog ◽  
Poison Frogs ◽  
Toxin Binding ◽  
Physiological Adaptations ◽  
Molecule Transport ◽  
Protein Classes ◽  
Small Molecule Transport

Poison frogs sequester chemical defenses from their diet of leaf litter arthropods for defense against predation. Little is known about the physiological adaptations that confer this unusual bioaccumulation ability. We conducted an alkaloid-feeding experiment with the Diablito poison frog (Oophaga sylvatica) to determine how quickly alkaloids are accumulated and how toxins modify frog physiology using quantitative proteomics. Diablito frogs rapidly accumulated the alkaloid decahydroquinoline within four days, and dietary alkaloid exposure altered protein abundance in the intestines, liver, and skin. Many proteins that increased in abundance with decahydroquinoline accumulation are plasma glycoproteins, including the complement system and the toxin-binding protein saxiphilin. Other protein classes that change in abundance with decahydroquinoline accumulation are membrane proteins involved in small molecule transport and metabolism. Overall, this work shows poison frogs can rapidly accumulate alkaloids, which alter carrier protein abundance, initiate an immune response, and alter small molecule transport and metabolism dynamics across tissues.

scholarly journals Sexual conflict and deception in poison frogs

2014 ◽  
Vol 60 (1) ◽  
pp. 37-42 ◽  
Author(s):  
Kyle Summers
Keyword(s):  
Sexual Selection ◽  
Reproductive Success ◽  
Sexual Conflict ◽  
Female Reproductive Success ◽  
Poison Frog ◽  
Poison Frogs ◽  
Dendrobates Auratus

Abstract I review evidence that females deceive males in the context of sexual selection and sexual conflict in the green poison frog, Dendrobates auratus. In this species, males mate polygynously when they have the opportunity, but polygyny imposes a cost on female reproductive success. Some females attempt to guard their mates when those males are approached by other females. This behavior involves both aggression toward other females and active “pseudo-courtship” of the male. This courtship is hypothesized to be a deceptive signal that functions to prevent the male from mating with other females. Observational and comparative evidence is presented in support of the predictions of this hypothesis. This form of deception is compared to similar behaviors that occur in other species, and the possibility that other forms of deception occur in poison frogs is discussed.

scholarly journals Poison frogs rely on experience to find the way home in the rainforest

2014 ◽  
Vol 10 (11) ◽  
pp. 20140642 ◽  
Author(s):  
Andrius Pašukonis ◽  
Ian Warrington ◽  
Max Ringler ◽  
Walter Hödl
Keyword(s):  
Spatial Learning ◽  
Local Area ◽  
Direct Path ◽  
Learning Abilities ◽  
Poison Frog ◽  
Poison Frogs ◽  
Direction Finder ◽  
Allobates Femoralis ◽  
Way Finding

Among vertebrates, comparable spatial learning abilities have been found in birds, mammals, turtles and fishes, but virtually nothing is known about such abilities in amphibians. Overall, amphibians are the most sedentary vertebrates, but poison frogs (Dendrobatidae) routinely shuttle tadpoles from terrestrial territories to dispersed aquatic deposition sites. We hypothesize that dendrobatid frogs rely on learning for flexible navigation. We tested the role of experience with the local cues for poison frog way-finding by (i) experimentally displacing territorial males of Allobates femoralis over several hundred metres, (ii) using a harmonic direction finder with miniature transponders to track these small frogs, and (iii) using a natural river barrier to separate the translocated frogs from any familiar landmarks. We found that homeward orientation was disrupted by the translocation to the unfamiliar area but frogs translocated over similar distances in their local area showed significant homeward orientation and returned to their territories via a direct path. We suggest that poison frogs rely on spatial learning for way-finding in their local area.

scholarly journals Sodium channel toxin-resistance mutations do not govern batrachotoxin (BTX) autoresistance in poison birds and frogs

2020 ◽  
Author(s):  
Fayal Abderemane-Ali ◽  
Nathan D. Rossen ◽  
Megan E. Kobiela ◽  
Robert A. Craig ◽  
Catherine E. Garrison ◽  
...  
Keyword(s):  
Sodium Channel ◽  
Small Molecule ◽  
Resistance Mechanism ◽  
Resistance Mutations ◽  
Poison Frog ◽  
Poison Frogs ◽  
Toxin Resistance ◽  
Voltage Gated ◽  
Channel Function ◽  
Toxin Sequestration

AbstractPoisonous organisms carry small molecule toxins that alter voltage-gated sodium channel (Na✓) function. Among these, batrachotoxin (BTX) from Pitohui toxic birds and Phyllobates poison frogs, stands out because of its lethality and unusual effects on Nav function. How these toxin-bearing organisms avoid autointoxication remains poorly understood. In poison frogs, a Nav DIVS6 pore-forming helix N→T mutation has been proposed as the BTX resistance mechanism. Here, we show that this variant is absent from Pitohui and poison frog Navs, incurs a strong cost that compromises channel function, and fails to produce BTX-resistant channels when tested in the context of poison frog Navs. We further show that captive-raised poison frogs are BTX resistant, even though they bear BTX-sensitive Navs. Hence, our data refute the hypothesis that BTX autoresistance is rooted in Nav mutations and instead suggest that more generalizable mechanisms such as toxin sequestration act to protect BTX-bearing species from autointoxication.

scholarly journals Alkaloid avoidance in poison frog tadpoles

2022 ◽  
Author(s):  
Eugenia Sanchez ◽  
Travis Ramirez ◽  
Lauren A O'Connell
Keyword(s):  
Locomotor Activity ◽  
Secondary Metabolites ◽  
Feeding Behavior ◽  
Chemical Defense ◽  
Poison Frog ◽  
Poison Frogs ◽  
Frog Tadpoles ◽  
Ranitomeya Imitator

Animals show a spectrum of avoidance-tolerance to foods containing toxic secondary metabolites. However, this spectrum has not been evaluated in animals that may actively seek out these compounds as a chemical defense. Poison frogs sequester toxic and unpalatable alkaloids from their diet, and in some species, tadpoles are exposed to these toxins before the development of their skin granular glands, which are used for toxin compartmentalization. Here, we examined the effects of the alkaloid decahydroquinoline (DHQ) in tadpoles of the Mimetic poison frog, Ranitomeya imitator, using alkaloid supplemented food. We found that although their survival is lowered by the alkaloid, their development is only mildly affected, with no evident effects on their growth. Furthermore, locomotor activity and feeding behavior was altered in the first week of DHQ treatment, probably in part through nicotinic blockade. However, after two weeks, tadpoles learned to avoid the alkaloid by visiting the food area only when necessary to eat. Our results suggest that poison frogs navigate the avoidance-tolerance spectrum during the development of their sequestration machinery.

Who cares for the eggs? Analysis of egg attendance behaviour in Ranitomeya imitator, a poison frog with biparental care

Behaviour ◽  
2021 ◽  
pp. 1-12
Author(s):  
Lisa M. Schulte ◽  
Kyle Summers
Keyword(s):  
Parental Care ◽  
Biparental Care ◽  
Poison Frog ◽  
Poison Frogs ◽  
Different Types ◽  
Ranitomeya Imitator ◽  
Males And Females ◽  
General Care

Abstract Dendrobatid poison frogs are known for their diverse parental care behaviours, including terrestrial egg attendance. While usually this behaviour is conducted by males, this study compared the pre-hatching investment of males and females in Ranitomeya imitator, a species with biparental care. Although males tended to spend more time with their eggs overall, there was no difference between sexes when comparing different types of care behaviour. Furthermore, both sexes increased general care behaviour when caring for more than one clutch. The finding that the sexes are relatively equal in their contribution to basic parental care forms provides a basis to understand why biparental care is stable in this species.

A new species of Andean poison frog, Andinobates (Anura: Dendrobatidae), from the northwestern Andes of Colombia

Zootaxa ◽  
2013 ◽  
Vol 3620 (1) ◽  
pp. 163-178 ◽  
Author(s):  
ADOLFO AMÉZQUITA ◽  
ROBERTO MÁRQUEZ ◽  
RICARDO MEDINA ◽  
DANIEL MEJÍA-VARGAS ◽  
TED R. KAHN ◽  
...  
Keyword(s):  
New Species ◽  
Phylogenetic Trees ◽  
High Elevation ◽  
Advertisement Call ◽  
Unique Combination ◽  
Phenotypic Data ◽  
Poison Frog ◽  
Poison Frogs ◽  
Colombian Andes ◽  
A New Species

The poison frogs of the Colombian Andes, Pacific lowlands and Panamahave been recently recognized as a new, monophyletic and well-supported genus: Andinobates. The species richness and distribution within Andinobates remain poorly understood due to the paucity of geographic, genetic and phenotypic data. Here we use a combination of molecular, bioacoustic and morphometric evidence to describe a new species of Andean poison frog: Andinobates cassidyhornae sp. nov. from the high elevation cloud forests of the Colombian Cordillera Occidental, in the northwestern Andes. The new species is associated to the bombetes group and characterized by a unique combination of ventral and dorsal color patterns. Data on 1119 bp from two mitochondrial markers allowed us to reject the null hypotheses that A. cassidyhornae sp. nov. is part of the phenotypically similar and geographically less distant species: A. opisthomelas, A. virolinensis or A. bombetes. The best available phylogenetic trees and the genetic distance to other Andinobates species further support this decision. Altogether, the advertisement call parameters unambiguously separated A. cassidyhornae sp. nov. calls from the calls of the three closest species. The new species adds to a poorly known and highly endangered genus of poison frogs that requires further studies and urgent conservation measures.

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