scholarly journals SUCCESSFUL PREDATION OF INVASIVE SOUTH AMERICAN CANE TOADS (RHINELLA MARINA) BY SOUTHERN WATERSNAKES (NERODIA FASCIATA)

2021 ◽  
Author(s):  
Jordan Donini ◽  
J. Sean Doody
Keyword(s):  
Field Data ◽  
South American ◽  
Native Range ◽  
Cane Toad ◽  
Sympatric Populations ◽  
Rhinella Marina ◽  
Toxin Resistance ◽  
Southwest Florida ◽  
Nerodia Fasciata ◽  
In The Wild

South American Cane Toads (Rhinella marina) have been introduced into several regions outside of their native distribution. Outside of their native range, few predators have been documented preying upon R.marina due to their potent toxins secreted in defense. However, prevalence of a toxin resistance gene makes it possible for some snakes of the sub-family Natricinae to consume native toads. We documented successful consumption of the invasive cane toad by the Southern Watersnake (Nerodia fasciata) in southwest Florida, both in the wild and in the laboratory. Southern Watersnakes from populations that existed both with and without cane toads successfully consumed toad prey without obvious ill-effect. Southern Watersnakes in southwest Florida are thus resistant to, and readily consume cane toads, an otherwise relatively predator-free invasive species in Florida. More dietary field data and controlled experiments that measure resistance to multiple prey items, sizes, and frequency will serve to determine the extent to which Southern Watersnakes can impact the size and structure of sympatric populations of cane toads.

scholarly journals Discovery of Novel Viruses Associated With the Invasive Cane Toad (Rhinella marina) in Its Native and Introduced Ranges

2021 ◽  
Vol 12 ◽  
Author(s):  
Alice G. Russo ◽  
Emma F. Harding ◽  
Grace J. H. Yan ◽  
Daniel Selechnik ◽  
Simon Ducatez ◽  
...  
Keyword(s):  
Invasion History ◽  
The Novel ◽  
Native Range ◽  
Cane Toad ◽  
Pcr Screening ◽  
Rhinella Marina ◽  
Low Genetic Diversity ◽  
Native And Introduced Ranges ◽  
Metagenomic Approach

Cane toads (Rhinella marina) are notoriously successful invaders: from 101 individuals brought to Australia in 1935, poisonous toads now cover an area >1.2 million km2 with adverse effects on native fauna. Despite extensive research on the role of macroparasites in cane toad invasion, viral research is lagging. We compared viral prevalence and diversity between toads in their native range (French Guiana, n=25) and two introduced ranges: Australia (n=151) and Hawai’i (n=10) with a metatranscriptomic and metagenomic approach combined with PCR screening. Australian toads almost exclusively harbor one of seven viruses detected globally. Rhimavirus-A (Picornaviridae) exhibited low genetic diversity and likely actively infected 9% of sampled Australian toads extending across ~2,000km of Northern Australia and up to the current invasion front. In native range cane toads, we identified multiple phylogenetically distinct viruses (Iridoviridae, Picornaviridae, Papillomaviridae, and Nackedna-like virus). None of the same viruses was detected in both ranges, suggesting that Australian cane toads have largely escaped the viral infection experienced by their native range counterparts. The novel native range viruses described here are potential biocontrol agents, as Australian toads likely lack prior immunological exposure to these viruses. Overall, our evidence suggests that there may be differences between viruses infecting cane toads in their native vs. introduced ranges, which lays the groundwork for further studies on how these viruses have influenced the toads’ invasion history.

scholarly journals Long distance homing in the cane toad (Rhinella marina) in its native range

2021 ◽  
Author(s):  
Daniel A Shaykevich ◽  
Andrius Pasukonis ◽  
Lauren A O'Connell
Keyword(s):  
Home Range ◽  
Life Histories ◽  
French Guiana ◽  
Spatial Behavior ◽  
Native Range ◽  
Cane Toad ◽  
Short Term ◽  
Long Distance ◽  
Rhinella Marina ◽  
Current Paradigm

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.

scholarly journals Premating barriers in young sympatric snail species

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Arina L. Maltseva ◽  
Marina A. Varfolomeeva ◽  
Arseniy A. Lobov ◽  
Polina O. Tikanova ◽  
Egor A. Repkin ◽  
...  
Keyword(s):  
Gene Flow ◽  
Snail Species ◽  
Sympatric Populations ◽  
Gastropod Species ◽  
Shell Size ◽  
Closely Related Species ◽  
Partial Canonical Correspondence Analysis ◽  
In The Wild ◽  
Isolation Index

AbstractSympatric coexistence of recently diverged species raises the question of barriers restricting the gene flow between them. Reproductive isolation may be implemented at several levels, and the weakening of some, e.g. premating, barriers may require the strengthening of the others, e.g. postcopulatory ones. We analysed mating patterns and shell size of mates in recently diverged closely related species of the subgenus Littorina Neritrema (Littorinidae, Caenogastropoda) in order to assess the role of premating reproductive barriers between them. We compared mating frequencies observed in the wild with those expected based on relative densities using partial canonical correspondence analysis. We introduced the fidelity index (FI) to estimate the relative accuracy of mating with conspecific females and precopulatory isolation index (IPC) to characterize the strength of premating barriers. The species under study, with the exception of L. arcana, clearly demonstrated preferential mating with conspecifics. According to FI and IPC, L. fabalis and L. compressa appeared reliably isolated from their closest relatives within Neritrema. Individuals of these two species tend to be smaller than those of the others, highlighting the importance of shell size changes in gastropod species divergence. L. arcana males were often found in pairs with L. saxatilis females, and no interspecific size differences were revealed in this sibling species pair. We discuss the lack of discriminative mate choice in the sympatric populations of L. arcana and L. saxatilis, and possible additional mechanisms restricting gene flow between them.

Cane toad ( Rhinella marina ) vitamin A, vitamin E, and carotenoid kinetics

Zoo Biology ◽  
2021 ◽  
Author(s):  
Tarra Freel ◽  
Elizabeth Koutsos ◽  
Larry J. Minter ◽  
Troy Tollefson ◽  
Frank Ridgley ◽  
...  
Keyword(s):  
Vitamin E ◽  
Vitamin A ◽  
Cane Toad ◽  
Rhinella Marina

scholarly journals Biochemical and histological changes in liver ofNectomys squamipes naturally infected bySchistosoma mansoni

2013 ◽  
Vol 22 (4) ◽  
pp. 519-524 ◽  
Author(s):  
Sócrates Fraga da Costa Neto ◽  
Vinicius Menezes Tunholi Alves ◽  
Victor Menezes Tunholi Alves ◽  
Juberlan Silva Garcia ◽  
Marcos Antônio José dos Santos ◽  
...  
Keyword(s):  
Liver Glycogen ◽  
Serum Glucose ◽  
Hepatic Glycogen ◽  
South American ◽  
Wild Rodents ◽  
Histological Changes ◽  
In The Wild ◽  
Phases Of Development ◽  
Liver Fragments ◽  
Glucose Formation

The South American water rat Nectomys squamipes is a wild mammal reservoir of Schistosoma mansoni in Brazil. In the present study, wild rodents were collected in the field and categorized into two groups: infected and uninfected by S. mansoni. Blood was collected to analyze changes in the serum glucose level (mg/dL) and liver fragments were used to determine the hepatic glycogen content (mg of glucose/g tissue). The histological examination showed inflammatory granulomatous lesions in different phases of development in the liver of rodents naturally infected with S. mansoni, in some cases with total or partial occlusion of the vascular lumen. Early lesions were characterized by the presence of inflammatory infiltrate around morphologically intact recently deposited eggs. Despite the significance of these histological lesions, the biochemical changes differed in extent. N. squamipes naturally infected byS. mansoni showed no variation in hepatic glycogen reserves. These findings were accompanied by a significant increase in plasma glucose contents, probably as a consequence of amino acids deamination, which are degraded, resulting in the formation of intermediates used as precursors for the glucose formation, without compromising the reserves of liver glycogen. In the wild, naturally infected N. squamipes can maintainS. mansoni infections without undergoing alterations in its carbohydrate metabolism, which minimizes the deleterious effects of S. mansoni.

scholarly journals KNOCK! KNOCK! WHO'S THERE? AN ETHNOARCHAEOLOGICAL APPROACH IN FRENCH GUIANA

2017 ◽  
Vol 28 (1) ◽  
pp. 6-27
Author(s):  
Stéphen Rostain
Keyword(s):  
Field Data ◽  
French Guiana ◽  
South American ◽  
Archaeological Preservation ◽  
Ethnographic Data ◽  
Natural Degradation ◽  
Tropical Lowlands ◽  
The Village ◽  
The Guianas ◽  
Cultural Rules

Amazonia and the Guianas possess exceptional potential for ethnoarchaeological studies because of the precolumbian heritage of modern-day Amerindian people. Surprisingly, minimal scholarship of this nature has been conducted in the South American lowlands. On the French Guiana coast, Maillard, a small Palikur village, was abruptly abandoned in 1990. I initiated an ethnoarchaeological study to pinpoint important differences between the interpretation of archaeological and ethnographic data. I recorded the topography of features and remains, compiled an inventory of artifacts and the contents of discard areas, inventoried the cultivated trees present, and described the characteristics of the surroundings. After analyzing the data using classical methods of archaeological inference to obtain a complete reconstruction of the village and the customs of its inhabitants, I invited the chief into his now-abandoned village to describe the settlement as it was while inhabited. In the twenty years since, I have made several visits to track the natural degradation of the site. This ethnoarchaeological approach shows that archaeologists dealing with field data can make many mistakes. Conversely, ethnographic accounts are distorted by the cultural rules and interdictions of interviewees. This experiment suggests the need for prudence in our interpretations and hypotheses, especially in the tropical lowlands, where archaeological preservation is particularly poor.

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
Keyword(s):  
Adult Male ◽  
Reproductive Effort ◽  
Hormone Secretion ◽  
Reproductive Hormone ◽  
Cane Toad ◽  
Short Term ◽  
Rhinella Marina ◽  
Testosterone Secretion ◽  
Metabolite Concentrations ◽  
Corticosterone Metabolites

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.

Paysandisia archon (South American palm borer).

2021 ◽  
Author(s):  
P. Riolo ◽  
Sandro Nardi
Keyword(s):  
Buenos Aires ◽  
Invasive Pest ◽  
South American ◽  
Native Range ◽  
Plant Mortality ◽  
Protective Measures ◽  
North East ◽  
Palm Trees ◽  
Council Directive ◽  
American Palm

Abstract P. archon is a Neotropical castniid species. It is not considered a pest in most of its native range, probably because it lives mainly on wild palm trees and not on crops; however, Houlbert (1918) and Bourquin (1933) reported that it had the potential to become a serious pest of palms. It was accidentally introduced to Europe from Argentina, as larvae hidden in imported palm trees, mostly Butia yatay and Trithrinax campestris. In Europe, where it is spreading rapidly, P. archon was first found in 2001 in Spain (Aguilar et al., 2001), France (Drescher and Dufay, 2001; Sarto i Monteys and Aguilar, 2001) and Italy (Espinosa et al., 2003; Riolo et al., 2004) and is considered an invasive species in these countries. It is already an invasive pest in France, Italy and Spain, where serious damage and plant mortality has been reported (1000 palm trees have been destroyed) and has become a pest in Buenos Aires, where it was introduced from north-east Argentina (Sarto i Monteys and Aguilar, 2005). The moth is currently listed in the EPPO A2 List (n. 338) of 'Pests recommended for regulation as quarantine pests' (OEPP/EPPO, 2008) and in European Phytosanitary Legislation in AnnexII/Part A/Section II (COMMISSION DIRECTIVE 2009/7/EC of 10 February 2009 amending Annexes I, II, IV and V to Council Directive 2000/29/EC on protective measures against the introduction into the Community of organisms harmful to plants or plant products and against their spread within the Community).

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