Changes in urinary testosterone and corticosterone metabolites during short-term confinement with repeated handling in wild male cane toads (Rhinella marina)

2011 ◽  
Vol 59 (4) ◽  
pp. 264 ◽  
Author(s):  
Edward J. Narayan ◽  
Frank C. Molinia ◽  
John F. Cockrem ◽  
Jean-Marc Hero

Stressors generally decrease testosterone secretion and inhibit reproduction in animals. Urinary testosterone and corticosterone metabolite concentrations were measured in adult male cane toads (Rhinella marina) at the time of capture from the wild and during 24 h of confinement with repeated handling. Mean urinary testosterone concentrations increased 2 h after capture, were significantly elevated above initial concentrations at 5 h, and then declined. Mean testosterone concentrations remained elevated 24 h after capture. Mean urinary corticosterone concentrations increased after capture, were significantly elevated above initial concentrations at 2 h, and remained elevated thereafter. This is the first report in amphibians of an increase in testosterone excretion after capture from the wild, with previous studies showing either no change or decline in testosterone. This finding may be associated with the mating strategy and maintenance of reproductive effort in the cane toad, a species that shows explosive breeding and agonistic male–male interactions during breeding. The finding that testosterone excretion increases rather than decreases after capture in male cane toads shows that it should not be generally assumed that reproductive hormone secretion will decrease after capture in amphibians.

2007 ◽  
Vol 69 (7) ◽  
pp. 791-801 ◽  
Author(s):  
R. Medhamurthy ◽  
G. Priyanka ◽  
M.K. Vinuthan ◽  
A.M. Manjunatha

2015 ◽  
Vol 42 (4) ◽  
pp. 302 ◽  
Author(s):  
Ian J. Radford ◽  
Richard Fairman

Context Changed fire regimes are an important threatening process to savanna biodiversity. Fire-sensitive vegetation such as pindan and its fauna may be particularly susceptible to fire impacts. Invasion by alien species is an additional threatening process. The toxic anuran Rhinella marina is a well publicised invader of savannas. Little is known of impacts in many habitats. Aims To test the hypotheses (1) that fire responses among pindan fauna are greater than general savanna responses, and (2) that cane toad-invasion impacts will be reduced relative to riparian habitats. Methods Reptiles, frogs, invertebrates and mammals were surveyed seven times from 2008 to 2012, four times before and three times following R. marina invasion. Time since last fire was recorded during each survey. Vegetation change was measured. Key results Pindan vegetation structural recovery took 4–5 years, whereas fauna recovery took only 1 year. Ground active agamids, combined Scincidae, fossorial skinks and ground-layer invertebrates responded positively to recent fire. Skinks of Ctenotus spp. declined in size after fire. Short-term fauna responses reflect rapid re-establishment of herbaceous cover. Fauna responses were detected following R. marina invasion, including increases in frogs of Uperoleia spp. and skinks of Carlia spp., and decreases in Lerista griffini and ground-layer invertebrates. Insufficient data were available to test for responses among large predators; however, >50% lower Varanus spp. trap success occurred post-invasion. No invasion response was detected among small mammals. Conclusions Pindan fauna fire responses were similar to those of savannas. Fauna responses to Rhinella marina invasion were relatively minor compared with those previously reported in riparian habitats and this may be related to the lower abundance of the invader here than in previous studies in riparian or more fertile habitats. Implications The dominant obligate seeding tree in pindan woodland, A. tumida, requires >4 years with no high-intensity fires for re-establishment of the dominant tree. Fire management should aim to minimise extensive fires to reduce impacts on fire-sensitive fauna. Persistence of large predators after cane-toad invasion suggests possible refuge value of low-productivity pindan savannas.


2021 ◽  
Author(s):  
Daniel A Shaykevich ◽  
Andrius Pasukonis ◽  
Lauren A O'Connell

Many animals exhibit complex navigation over different scales and environments. Navigation studies in amphibians have largely focused on species with life histories that require advanced spatial capacities, such as territorial poison frogs and migratory pond-breeding amphibians that show fidelity to mating sites. However, other species have remained relatively understudied, leaving the possibility that well-developed navigational abilities are widespread. Here, we measured short-term space use in non-territorial, non-migratory cane toads (Rhinella marina) in their native range in French Guiana. After establishing home range, we tested their ability to return to home following translocations of 500 and 1000 meters. Toads were able to travel in straight trajectories back to home areas, suggesting map-like navigational abilities similar to those observed in amphibians with more complex spatial behavior. These observations break with the current paradigm of amphibian navigation and suggest that navigational abilities may be widely shared among amphibians.


1996 ◽  
Vol 88 ◽  
pp. 62 ◽  
Author(s):  
Eva Alvarez ◽  
Antonio Blanco ◽  
Nuria Márquez ◽  
Ana I. Esquifino ◽  
Anunciación Lafuente

Zoo Biology ◽  
2021 ◽  
Author(s):  
Tarra Freel ◽  
Elizabeth Koutsos ◽  
Larry J. Minter ◽  
Troy Tollefson ◽  
Frank Ridgley ◽  
...  

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