Directional orientation of migration in an aseasonal explosive-breeding toad from Brazil

Santos, Raquel Rocha; Leonardi, Simone Baratto; Caorsi, Valentina Zaffaroni; Grant, Taran

doi:10.1017/s0266467410000180

Cited by 19 publications

(21 citation statements)

References 22 publications

(48 reference statements)

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“…; Santos et al . ). Although toads may use magnetic cues in some cases (Sinsch ; Landler & Gollmann ), routes to breeding sites appear to be learned and navigated mainly via olfactory cues (Sinsch ; Ishii et al .…”

Section: Discussionmentioning

confidence: 97%

Directional dispersal has not evolved during the cane toad invasion

2015

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Summary1. The ability to disperse along a consistent compass heading strongly affects the rate and efficiency of an animal's displacement, and thus is under selection at the expanding edge of a biological invasion. 2. We used radiotelemetry to assess whether the dispersal direction of cane toads (Rhinella marina) changed as a function of time since invasion, by comparing (i) toads at a single site monitored annually for 10 years subsequent to toad arrival; (ii) toads collected from sites across the species' invaded range in Australia, and radiotracked at a common site; and (iii) the offspring of those transported toads that were reared in captivity under common-garden conditions. 3. The first of these data sets showed non-random directionality, indicating strong spatial sorting operating on this trait: toads moved in a north-westerly direction for the first 6 years post-invasion, but in random directions thereafter. Despite the evidence for trait sorting, no consistent directionality was seen in toads relocated from populations with different invasion histories nor in their offspring. Why do we see no evolutionary shifts? 4. Dispersal directionality of the offspring was not correlated with that of their parents, arguing against a genetic basis to this behavioural trait. Thus, while an expanding invasion front creates an evolutionary pressure for animals to move in a specific direction, evolution of this trait has not occurred in this system because directionality is not heritable. 5. The observed north-westerly movements of toads at the invasion front were due to simple density differentials: in the first few years, most toads arriving at our study site originated from earlier-colonized (and hence denser) populations to the south-east.

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Section: Discussionmentioning

confidence: 97%

Directional dispersal has not evolved during the cane toad invasion

2015

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“…Frequent migrations to and from such breeding ponds have recently been demonstrated for both males and females of the Brazilian toad M . cambaraensis (Santos et al 2010b). This movement of the toads from sheltered areas to congregations around ponds for reproduction and back to the forest, could have important consequences for the foraging strategies and evolution of these species.…”

Section: Discussionmentioning

confidence: 99%

Alkaloids from single skins of the Argentinian toad Melanophryniscus rubriventris (ANURA, BUFONIDAE): An unexpected variability in alkaloid profiles and a profusion of new structures

et al. 2012

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GC-MS analysis of single-skins of ten Melanophryniscus rubriventris toads (five collections of two toads each) captured during their breeding season in NW Argentina has revealed a total of 127 alkaloids of which 56 had not been previously detected in any frog or toad. Included among these new alkaloids are 23 new diastereomers of previously reported alkaloids. What is particularly distinguishing about the alkaloid profiles of these ten collections is the occurrence of many of the alkaloids, whether known or new to us, in only one of the ten skins sampled, despite two skins being obtained from each breeding site of the five populations. Many of the alkaloids are of classes known to have structures with branched-chains (e.g. pumiliotoxins and tricyclic structures) that are considered to derive from dietary mites. A large number of previously reported and new alkaloids are also of unclassified structures. Only a very few 3,5-disubstituted-indolizidine or -pyrrolizidine alkaloids are observed that have a straight-chain carbon skeleton and are likely derived from ant prey. The possible relationship of these collections made during the toad’s brief breeding episodes to sequestration of dietary arthropods and individual alkaloid profiles is discussed.Electronic supplementary materialThe online version of this article (doi:10.1186/2193-1801-1-51) contains supplementary material, which is available to authorized users.

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“…Both methods assume the null‐hypothesis that a given dataset is randomly distributed, with Rayleigh's test assuming unimodally distributed data (Davis & Sampson, ; Hammer et al, ). Both have been applied to modern mobile organisms to test for preferred directions of movement (Aloy, Vallejo, & Juinio‐Meñez, ; Santos, Leonardi, Caorsi, & Grant, ). Relevant p ‐values for these statistics were computed using the past software (Hammer et al, ).…”

Section: Methodsmentioning

confidence: 99%

Slime travelers: Early evidence of animal mobility and feeding in an organic mat world

2019

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Mobility represents a key innovation in the evolution of complex animal life. The ability to move allows for the exploration of new food sources, escapes from unfavorable environmental conditions, enhanced ability to exchange genetic material, and is one of the major reasons for the diversity and success of animal life today. The oldest widely accepted trace fossils of animal mobility are found in Ediacaran‐aged rocks (635–539 Ma). The earliest definitive evidence for movement associated with exploitation of resources for feeding occurs in the White Sea assemblage of the Ediacara Biota—macroscopic, soft‐bodied fossils of Ediacaran age. Here, we evaluate potential support for mobility in dickinsoniomorphs, presenting new data regarding abundant Dickinsonia and associated trace fossils from the Ediacara Member, South Australia. Results quantitatively demonstrate that Dickinsonia was capable of mobility on relatively short, ecological timescales. This organism was bilaterally symmetrical, likely moved via muscular peristalsis, and left trace fossils due to active removal of the organic mat related to feeding. Analogous structures associated with Yorgia indicate that it was also mobile and fed in a similar manner. Morphological evidence suggests that two other modular taxa, Andiva and Spriggina, were able to move but did not feed in a manner that impacted the organic mat. Together, these data suggest that mobility was present in multiple disparate bilaterally symmetrical Ediacaran taxa.

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Directional orientation of migration in an aseasonal explosive-breeding toad from Brazil

Cited by 19 publications

References 22 publications

Directional dispersal has not evolved during the cane toad invasion

Directional dispersal has not evolved during the cane toad invasion

Alkaloids from single skins of the Argentinian toad Melanophryniscus rubriventris (ANURA, BUFONIDAE): An unexpected variability in alkaloid profiles and a profusion of new structures

Slime travelers: Early evidence of animal mobility and feeding in an organic mat world

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