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

Many animals exhibit complex navigation over different scales and environments. Navigation studies in amphibians have largely focused on species with life histories that require accurate spatial movements, such as territorial poison frogs and migratory pond-breeding amphibians that show fidelity to mating sites. However, other amphibian species have remained relatively understudied, leaving open 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 site fidelity, we tested their ability to return home following translocations of 500 and 1000 meters. Toads were able to travel in straight trajectories back to home areas, suggesting 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.

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

10.1101/2021.06.16.448742 ◽

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.

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Increased rates of dispersal of free-ranging cane toads (Rhinella marina) during their global invasion

Scientific Reports ◽

10.1038/s41598-021-02828-5 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Richard Shine ◽

Ross A. Alford ◽

Ryan Blennerhasset ◽

Gregory P. Brown ◽

Jayna L. DeVore ◽

...

Keyword(s):

French Guiana ◽

Native Range ◽

Rhinella Marina ◽

Range Edge ◽

Population Spread ◽

Eastern Australia ◽

Tropical Australia ◽

Free Ranging ◽

Global Invasion ◽

Daily Changes

AbstractInvasions often accelerate through time, as dispersal-enhancing traits accumulate at the expanding range edge. How does the dispersal behaviour of individual organisms shift to increase rates of population spread? We collate data from 44 radio-tracking studies (in total, of 650 animals) of cane toads (Rhinella marina) to quantify distances moved per day, and the frequency of displacement in their native range (French Guiana) and two invaded areas (Hawai’i and Australia). We show that toads in their native-range, Hawai’i and eastern Australia are relatively sedentary, while toads dispersing across tropical Australia increased their daily distances travelled from 20 to 200 m per day. That increase reflects an increasing propensity to change diurnal retreat sites every day, as well as to move further during each nocturnal displacement. Daily changes in retreat site evolved earlier than did changes in distances moved per night, indicating a breakdown in philopatry before other movement behaviours were optimised to maximise dispersal.

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Encounters between freshwater crocodiles and invasive cane toads in north-western Australia: does context determine impact?

Australian Zoologist ◽

10.7882/az.2020.015 ◽

2020 ◽

Vol 41 (1) ◽

pp. 94-101

Author(s):

Gregory S Clarke ◽

Cameron M Hudson ◽

Richard Shine

Keyword(s):

Western Australia ◽

French Guiana ◽

Native Range ◽

Taste Aversion Learning ◽

Rhinella Marina ◽

Physiological Tolerance ◽

Crocodylus Johnstoni ◽

A Site ◽

Riverine Systems ◽

North Western

ABSTRACT The potent defensive chemicals of cane toads (Rhinella marina) protect them against predators that lack coevolved physiological tolerance to those toxins. That relative invulnerability may explain why major injuries (such as limb loss) appear to be rare in cane toads from most of their global range; however, we noted frequent predator-induced injuries (>4% of adults) in samples from within the toad’s native range (in French Guiana) and from a site (Lake Argyle) in north-western Australia. Toads at Lake Argyle enter the edge of the lake at night to rehydrate, exposing them to foraging freshwater crocodiles (Crocodylus johnstoni). Crocodiles rarely consume toads, but the attacks often result in loss of a limb. Because limbs contain relatively little toxin, attacks to the limbs expose a crocodile to nauseating but non-lethal amounts of toxin; and hence, facilitate taste aversion learning by the predator. The context of the encounters, such as differences in geography, may help to explain why the invasion of cane toads has not significantly impacted on crocodile populations at this site, in contrast to heavy impacts reported from nearby riverine systems.

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Spatial ecology of cane toads (Rhinella marina) in their native range: a radiotelemetric study from French Guiana

Scientific Reports ◽

10.1038/s41598-021-91262-8 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Jayna L. DeVore ◽

Richard Shine ◽

Simon Ducatez

Keyword(s):

Invasive Species ◽

Body Condition ◽

Spatial Ecology ◽

French Guiana ◽

Source Region ◽

Behavioural Flexibility ◽

Native Range ◽

Environmental Niche ◽

Rhinella Marina ◽

Free Ranging

AbstractLike most invasive species, cane toads have attracted less research in their native range than in invaded areas. We radio-tracked 34 free-ranging toads in French Guiana, a source region for most invasive populations, across two coastal and two rainforest sites. Coastal toads generally sheltered in pools of fresh or brackish water but nocturnally foraged on beaches, whereas rainforest toads sheltered in forested habitats, moving into open areas at night. Over five days of monitoring, native toads frequently re-used shelters and moved little between days (means = 10–63 m/site) compared to invasion-front toads from Australia (~ 250 m). Larger toads moved less between days, but displaced in more consistent directions. At night, foraging toads travelled up to 200 m before returning to shelters. Foraging distance was related to body condition at coastal sites, with toads in poorer body condition travelling farther. Rain increased the probability of coastal toads sheltering in the dry habitats where they foraged. Dispersal and rainfall were lower at coastal sites, and the strategies utilized by coastal toads to minimize water loss resembled those of invasive toads in semi-desert habitats. This global invader already exhibits a broad environmental niche and substantial behavioural flexibility within its native range.

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Man-made habitats - hotspots of evolutionary game between grass, fungus and fly

Biodiversity Research and Conservation ◽

10.2478/v10119-009-0017-z ◽

2009 ◽

Vol 15 (1) ◽

pp. 47-52 ◽

Cited By ~ 3

Author(s):

Marlena Lembicz ◽

Paweł Olejniczak ◽

Ziemowit Olszanowski ◽

Karolina Górzyńska ◽

Adrian Leuchtmann

Keyword(s):

Life Cycle ◽

Life Histories ◽

Early Stage ◽

Scientific Evidence ◽

Evolutionary Game ◽

Long Distance ◽

Puccinellia Distans ◽

New Man ◽

Epichloë Typhina ◽

Vegetative Season

Man-made habitats - hotspots of evolutionary game between grass, fungus and flyThe origin and effects of an evolutionary game between species from three different kingdoms (plants, fungi and animals) are presented. We provide scientific evidence that the interaction discovered in man-made habitats leads to an early stage of coevolution. The grassPuccinellia distanswas observed to rapidly spread in new man-made habitats, while at the same time, it was colonised by the fungusEpichloë typhina.The invasion of infected grasses is accompanied by alterations in life histories of both species:P. distansdeveloped features promoting long-distance spreading, whereasE. typhinachanged its life cycle by forming sexual structures for the second time, later in the vegetative season. This enables the fungus to make use of the late shoots of the grass for sexual reproduction, even though it cannot be completed because the vector of spermatia necessary for fertilisation, femaleBotanophilaflies, is not present at that time. This indicates that such uncoordinated evolutionary processes had taken place before interactions between organisms became so specialised that it is difficult to presume they were the result of natural selection. Moreover, these processes could have been initiated in man-made habitats that, in particular circumstances, can become coevolutionary hotspots.

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Aboveground Herbivory Influences Belowground Defense Responses in Maize

Frontiers in Ecology and Evolution ◽

10.3389/fevo.2021.765940 ◽

2021 ◽

Vol 9 ◽

Author(s):

Lise Pingault ◽

Saumik Basu ◽

Prince Zogli ◽

W. Paul Williams ◽

Nathan Palmer ◽

...

Keyword(s):

European Corn Borer ◽

Proteinase Inhibitors ◽

Insect Pest ◽

Diabrotica Virgifera Virgifera ◽

Defense Responses ◽

Short Term ◽

Long Distance ◽

Corn Borer ◽

Root Physiology ◽

Aboveground Herbivory

The European corn borer (ECB; Ostrinia nubilalis) is an economically damaging insect pest of maize (Zea mays L.), an important cereal crop widely grown globally. Among inbred lines, the maize genotype Mp708 has shown resistance to diverse herbivorous insects, although several aspects of the defense mechanisms of Mp708 plants are yet to be explored. Here, the changes in root physiology arising from short-term feeding by ECB on the shoot tissues of Mp708 plants was evaluated directly using transcriptomics, and indirectly by monitoring changes in growth of western corn rootworm (WCR; Diabrotica virgifera virgifera) larvae. Mp708 defense responses negatively impacted both ECB and WCR larval weights, providing evidence for changes in root physiology in response to ECB feeding on shoot tissues. There was a significant downregulation of genes in the root tissues following short-term ECB feeding, including genes needed for direct defense (e.g., proteinase inhibitors and chitinases). Our transcriptomic analysis also revealed specific regulation of the genes involved in hormonal and metabolite pathways in the roots of Mp708 plants subjected to ECB herbivory. These data provide support for the long-distance signaling-mediated defense in Mp708 plants and suggest that altered metabolite profiles of roots in response to ECB feeding of shoots likely negatively impacted WCR growth.

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Variation in winter site fidelity within and among individuals influences movement behavior in a partially migratory ungulate

PLoS ONE ◽

10.1371/journal.pone.0258128 ◽

2021 ◽

Vol 16 (9) ◽

pp. e0258128

Author(s):

Timothy J. Fullman ◽

Brian T. Person ◽

Alexander K. Prichard ◽

Lincoln S. Parrett

Keyword(s):

Site Fidelity ◽

Rangifer Tarandus ◽

First Passage Time ◽

Cost Benefit ◽

Movement Behavior ◽

Long Distance ◽

Directed Movement ◽

Movement Trajectories ◽

Wintering Areas ◽

Wintering Area

Many animals migrate to take advantage of temporal and spatial variability in resources. These benefits are offset with costs like increased energetic expenditure and travel through unfamiliar areas. Differences in the cost-benefit ratio for individuals may lead to partial migration with one portion of a population migrating while another does not. We investigated migration dynamics and winter site fidelity for a long-distance partial migrant, barren ground caribou (Rangifer tarandus granti) of the Teshekpuk Caribou Herd in northern Alaska. We used GPS telemetry for 76 female caribou over 164 annual movement trajectories to identify timing and location of migration and winter use, proportion of migrants, and fidelity to different herd wintering areas. We found within-individual variation in movement behavior and wintering area use by the Teshekpuk Caribou Herd, adding caribou to the growing list of ungulates that can exhibit migratory plasticity. Using a first passage time–net squared displacement approach, we classified 78.7% of annual movement paths as migration, 11.6% as residency, and 9.8% as another strategy. Timing and distance of migration varied by season and wintering area. Duration of migration was longer for fall migration than for spring, which may relate to the latter featuring more directed movement. Caribou utilized four wintering areas, with multiple areas used each year. This variation occurred not just among different individuals, but state sequence analyses indicated low fidelity of individuals to wintering areas among years. Variability in movement behavior can have fitness consequences. As caribou face the pressures of a rapidly warming Arctic and ongoing human development and activities, further research is needed to investigate what factors influence this diversity of behaviors in Alaska and across the circumpolar Arctic.

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

Australian Journal of Zoology ◽

10.1071/zo11070 ◽

2011 ◽

Vol 59 (4) ◽

pp. 264 ◽

Cited By ~ 14

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.

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Observations of Long-distance Post-release Dispersal by Reintroduced Bison (Bison bison)

The Canadian Field-Naturalist ◽

10.22621/cfn.v131i3.1825 ◽

2018 ◽

Vol 131 (3) ◽

pp. 221-224 ◽

Cited By ~ 2

Author(s):

Thomas S. Jung ◽

Nicholas C. Larter

Keyword(s):

Site Fidelity ◽

Performance Metrics ◽

Survival Rates ◽

Release Site ◽

Bison Bison ◽

Dispersal Ability ◽

Initial Population ◽

High Survival ◽

Long Distance ◽

Straight Line Distance

Key objectives of wildlife reintroduction projects should include encouraging post-release site fidelity and high survival rates of founding individuals. Yet, few studies empirically evaluate these performance metrics for released individuals. Bison(Bison bison) restoration is receiving renewed interest by wildlife managers. To inform new bison reintroduction projects, we provide an observation of a 375-km (straight-line distance) post-release movement of three bison bulls from a release site in Yukon, Canada, in 1988. In addition, we note 250-km and 155-km post-release movements of bison in the Northwest Territories, Canada, in 1980 and 1998, respectively. These observations demonstrate the dispersal ability of bison encountering new environments. Wildlife managers planning for new bison reintroductions should consider means to enhance post-release site fidelity to limit long-distance dispersal and mortality and maximize initial population growth.

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Cost Index Predictions for Construction Engineering Based on LSTM Neural Networks

Advances in Civil Engineering ◽

10.1155/2020/6518147 ◽

2020 ◽

Vol 2020 ◽

pp. 1-14 ◽

Cited By ~ 1

Author(s):

Jiacheng Dong ◽

Yuan Chen ◽

Gang Guan

Keyword(s):

Neural Network ◽

Support Vector ◽

Short Term ◽

Cost Index ◽

Long Distance ◽

Research Knowledge ◽

Construction Engineering ◽

Engineering Cost ◽

Optimization Mechanism

In recent years, the cost index predictions of construction engineering projects are becoming important research topics in the field of construction management. Previous methods have limitations in reasonably reflecting the timeliness of engineering cost indexes. The recurrent neural network (RNN) belongs to a time series network, and the purpose of timeliness transfer calculation is achieved through the weight sharing of time steps. The long-term and short-term memory neural network (LSTM NN) solves the RNN limitations of the gradient vanishing and the inability to address long-term dependence under the premise of having the above advantages. The present study proposed a new framework based on LSTM, so as to explore the applicability and optimization mechanism of the algorithm in the field of cost indexes prediction. A survey was conducted in Shenzhen, China, where a total of 143 data samples were collected based on the index set for the corresponding time interval from May 2007 to March 2019. A prediction framework based on the LSTM model, which was trained by using these collected data, was established for the purpose of cost index predictions and test. The testing results showed that the proposed LSTM framework had obvious advantages in prediction because of the ability of processing high-dimensional feature vectors and the capability of selectively recording historical information. Compared with other advanced cost prediction methods, such as Support Vector Machine (SVM), this framework has advantages such as being able to capture long-distance dependent information and can provide short-term predictions of engineering cost indexes both effectively and accurately. This research extended current algorithm tools that can be used to forecast cost indexes and evaluated the optimization mechanism of the algorithm in order to improve the efficiency and accuracy of prediction, which have not been explored in current research knowledge.

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