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Shaykevich DA, Pareja-Mejía D, Golde C, Pašukonis A, O’Connell LA. Neural and sensory basis of homing behavior in the invasive cane toad, Rhinella marina. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.25.600658. [PMID: 38979178 PMCID: PMC11230440 DOI: 10.1101/2024.06.25.600658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
The behavioral, sensory, and neural bases of vertebrate navigation are primarily described in mammals and birds. However, we know much less about navigational abilities and mechanisms of vertebrates that move on smaller scales, such as amphibians. To address this knowledge gap, we conducted an extensive field study on navigation in the cane toad, Rhinella marina. First, we performed a translocation experiment to describe how invasive toads in Hawai'i navigate home following displacements of up to one kilometer. Next, we tested the effect of olfactory and magnetosensory manipulations on homing, as these senses are most commonly associated with amphibian navigation. We found that neither ablation alone prevents homing, suggesting that toad navigation is multimodal. Finally, we tested the hypothesis that the medial pallium, the amphibian homolog to the hippocampus, is involved in homing. By comparing neural activity across homing and non-homing toads, we found evidence supporting the involvement of the medial pallium, lateral pallium, and septum in navigation, suggesting a conservation of neural structures supporting navigation across vertebrates. Our study lays the foundation to understand the behavioral, sensory, and neural bases of navigation in amphibians and to further characterize the evolution of behavior and neural structures in vertebrates.
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Affiliation(s)
| | - Daniela Pareja-Mejía
- Department of Biology, Stanford University, Stanford, CA, USA
- Graduate Program in Zoology, Universidade Estadual de Santa Cruz, Bahía, Brazil
| | - Chloe Golde
- Department of Biology, Stanford University, Stanford, CA, USA
| | | | - Lauren A. O’Connell
- Department of Biology, Stanford University, Stanford, CA, USA
- Wu Tsai Institute for Neuroscience, Stanford University, Stanford CA, USA
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2
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Du Y, Wang X, Ashraf S, Tu W, Xi Y, Cui R, Chen S, Yu J, Han L, Gu S, Qu Y, Liu X. Climate match is key to predict range expansion of the world's worst invasive terrestrial vertebrates. GLOBAL CHANGE BIOLOGY 2024; 30:e17137. [PMID: 38273500 DOI: 10.1111/gcb.17137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 12/13/2023] [Accepted: 12/16/2023] [Indexed: 01/27/2024]
Abstract
Understanding the determinants of the range expansion of invasive alien species is crucial for developing effective prevention and control strategies. Nevertheless, we still lack a global picture of the potential factors influencing the invaded range expansion across taxonomic groups, especially for the world's worst invaders with high ecological and economic impacts. Here, by extensively collecting data on 363 distributional ranges of 19 of world's worst invasive terrestrial vertebrates across 135 invaded administrative jurisdictions, we observed remarkable variations in the range expansion across species and taxonomic groups. After controlling for taxonomic and geographic pseudoreplicates, model averaging analyses based on generalized additive mixed-effect models showed that species in invaded regions having climates more similar to those of their native ranges tended to undergo a larger range expansion. In addition, as proxies of propagule pressure and human-assisted transportation, the number of introduction events and the road network density were also important predictors facilitating the range expansion. Further variance partitioning analyses validated the predominant role of climate match in explaining the range expansion. Our study demonstrated that regions with similar climates to their native ranges could still be prioritized to prevent the spread of invasive species under the sustained global change.
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Affiliation(s)
- Yuanbao Du
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Xuyu Wang
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- College of Ecology, Lanzhou University, Lanzhou, Gansu Province, China
- Institute of Physical Science and Information Technology, Anhui University, Hefei, Anhui Province, China
| | - Sadia Ashraf
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Weishan Tu
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui Province, China
| | - Yonghong Xi
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Ruina Cui
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Shengnan Chen
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong, Sichuan Province, China
| | - Jiajie Yu
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Lixia Han
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, Hubei Province, China
| | - Shimin Gu
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Yanhua Qu
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Xuan Liu
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
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3
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Schuman MJ, Snyder SL, Smoak CH, Schmid JR. Faunal Diet of Adult Cane Toads, Rhinella marina, in the Urban Landscape of Southwest Florida. Animals (Basel) 2023; 13:2898. [PMID: 37760298 PMCID: PMC10526063 DOI: 10.3390/ani13182898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 09/05/2023] [Accepted: 09/11/2023] [Indexed: 09/29/2023] Open
Abstract
We investigated the diet of cane toads (Rhinella marina) inhabiting urbanized areas in southwest Florida to provide high taxonomic resolution of prey items, contrast toad diets between sampling seasons and sexes, and assess this invasive species' ecological role in the urban landscape. A pest control agency collected cane toads from two golf course communities in Naples, Florida, USA during November-December 2018 (early dry season) and June-July 2019 (early wet season), and faunal stomach contents were quantified from a random subsample of 240 adult toads (30 males and 30 females from each community and season). Yellow-banded millipedes (Anadenobolus monilicornis), big-headed ants (Pheidole spp.), and hunting billbugs (Sphenophorus venatus vestitus) were the most frequently consumed prey items and had the highest total numbers and/or volume with corresponding highest indices of relative importance. There was considerable overlap in the seasonal prey importance values for each golf course community and little if any difference in the importance values between toad sexes in each community. Nonetheless, big-headed ants were the most important prey in both communities during the wet season, while yellow-banded millipedes were the most important dry season prey in one community and hunting billbugs the most important in the other. Despite limited spatiotemporal sampling effort, our results indicated that cane toad was consuming arthropod taxa considered pests in the urban ecosystem. Further studies are needed to investigate the potential effects of human activities and environmental variability on the cane toad diet and to determine whether cane toads act as a biological control for pest populations.
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Affiliation(s)
| | | | | | - Jeffrey R. Schmid
- Conservancy of Southwest Florida, 1495 Smith Preserve Way, Naples, FL 34102, USA; (M.J.S.); (S.L.S.); (C.H.S.)
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4
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Spatial ecology of the invasive Asian common toad in Madagascar and its implications for invasion dynamics. Sci Rep 2023; 13:3526. [PMID: 36864075 PMCID: PMC9981762 DOI: 10.1038/s41598-023-29467-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 02/06/2023] [Indexed: 03/04/2023] Open
Abstract
Invasion dynamics are determined, among other aspects, by the spatial behaviour of invasive populations. The invasive toad Duttaphrynus melanostictus is spreading inland from the eastern coast of Madagascar, causing considerable ecological impacts. Understanding the basic factors determining the spread dynamics can inform management strategies and provide insights into spatial evolutionary processes. We radio-tracked 91 adult toads in three localities along the invasion gradient to determine whether spatial sorting of dispersive phenotypes is occurring, and investigate intrinsic and extrinsic determinants of spatial behaviour. Overall, toads in our study appeared as habitat generalists, and their sheltering behaviour was tied to water proximity, with toads changing shelter more frequently closer to waterbodies. Toads showed low displacement rates (mean = 4.12 m/day) and quite a philopatric behaviour but were able to perform daily movements of over 50 m. We did not detect any spatial sorting of dispersal-relevant traits nor sex- or size-biased dispersal. Our results suggest that toads are more likely to expand their range during the wet season, and that the range expansion is probably dominated by short-distance dispersal at this stage of the invasion, although a future increase in invasion speed is expected, due to the capacity for long-distance movements of this species.
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5
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Komine H, Yasumiba K, Schwarzkopf L. The country toad and the city toad: comparing morphology of invasive cane toads ( Rhinella marina) from rural and urban environments. Biol J Linn Soc Lond 2022. [DOI: 10.1093/biolinnean/blac100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
Urbanization is a principal driver of global biodiversity loss. Although many studies have examined the impacts of urbanization on biodiversity, we are only beginning to study urbanization as an evolutionary force. Urban environments are hotspots for invasive species, but most previous studies have focused on phenotypic changes in native species responding to urbanization. Quantifying the phenotypic responses of invasive species to urbanization may help reveal mechanisms promoting invasion. There are, however, few studies investigating the phenotypic response of invasive species to urbanization. We compared morphological traits of invasive cane toads (Rhinella marina) between urban and rural areas in three cities in north-eastern Australia using generalized linear mixed models. We found that the parotoid glands, which are the major anti-predator defence of toads were smaller in urban than in rural populations. The tibiofibula length of males in urban populations was longer than those in rural populations, but females showed opposite trends, suggesting potential effects of urbanization on sexual dimorphism. These results demonstrate that urbanization drives morphological changes in invasive toads, suggesting they may adapt to urban environments rapidly.
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Affiliation(s)
- Hirotaka Komine
- Institute of Global Innovation Research, Tokyo University of Agriculture and Technology , 3-5-8, Saiwai-cho, Fuchu, Tokyo 183-8509 , Japan
- Faculty of Agriculture, Yamagata University , 1-23, Wakaba-machi, Tsuruoka, Yamagata 997 - 0037, Japan
| | - Kiyomi Yasumiba
- Institute of Agriculture, Tokyo University of Agriculture and Technology , 3-5-8, Saiwai-cho, Fuchu, Tokyo 183 - 8509, Japan
| | - Lin Schwarzkopf
- College of Science and Engineering, Centre for Biodiversity & Climate Change, James Cook University , Townsville , QLD 4811, Australia
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6
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Saunders D, Nguyen H, Cowen S, Magrath M, Marsh K, Bell S, Bobruk J. Radio-tracking wildlife with drones: a viewshed analysis quantifying survey coverage across diverse landscapes. WILDLIFE RESEARCH 2022. [DOI: 10.1071/wr21033] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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7
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Shaykevich DA, Pašukonis A, O'Connell LA. Long distance homing in the cane toad (Rhinella marina) in its native range. J Exp Biol 2021; 225:273860. [PMID: 34940881 PMCID: PMC8917446 DOI: 10.1242/jeb.243048] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 12/16/2021] [Indexed: 11/20/2022]
Abstract
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 m. 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. Summary: Translocation-homing experiments reveal that non-territorial, non-migratory Rhinella marina can navigate to home areas following displacements exceeding regular, natural movements, suggesting a previously unconsidered prevalence of navigational abilities amongst amphibians.
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Affiliation(s)
- Daniel A Shaykevich
- Stanford University, Department of Biology, 371 Jane Stanford Way, Stanford, CA 94305, USA
| | - Andrius Pašukonis
- Stanford University, Department of Biology, 371 Jane Stanford Way, Stanford, CA 94305, USA.,CEFE, Univ Montpellier, CNRS, EPHE, IRD, Montpellier, France
| | - Lauren A O'Connell
- Stanford University, Department of Biology, 371 Jane Stanford Way, Stanford, CA 94305, USA
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8
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Shine R, Alford RA, Blennerhasset R, Brown GP, DeVore JL, Ducatez S, Finnerty P, Greenlees M, Kaiser SW, McCann S, Pettit L, Pizzatto L, Schwarzkopf L, Ward-Fear G, Phillips BL. Increased rates of dispersal of free-ranging cane toads (Rhinella marina) during their global invasion. Sci Rep 2021; 11:23574. [PMID: 34876612 PMCID: PMC8651681 DOI: 10.1038/s41598-021-02828-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 11/15/2021] [Indexed: 02/08/2023] Open
Abstract
Invasions 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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Affiliation(s)
- Richard Shine
- Department of Biological Sciences, Macquarie University, Sydney, NSW, 2109, Australia.
| | - Ross A Alford
- College of Science and Engineering, James Cook University, Townsville, QLD, 4811, Australia
| | | | - Gregory P Brown
- Department of Biological Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | - Jayna L DeVore
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Simon Ducatez
- UMR 241 EIO (UPF, IRD, IFREMER, ILM), Institut de Recherche Pour le Développement (IRD), Papeete, Tahiti, French Polynesia
| | - Patrick Finnerty
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Matthew Greenlees
- Department of Biological Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | - Shannon W Kaiser
- Department of Biological Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | - Samantha McCann
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Lachlan Pettit
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Ligia Pizzatto
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, 2006, Australia.,School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW, 2308, Australia
| | - Lin Schwarzkopf
- College of Science and Engineering, James Cook University, Townsville, QLD, 4811, Australia
| | - Georgia Ward-Fear
- Department of Biological Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | - Benjamin L Phillips
- School of BioSciences, University of Melbourne, Parkville, VIC, 3010, Australia
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9
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Kaiser SW, Greenlees MJ, Shine R. Wildfires modify the parasite loads of invasive cane toads. Biol Lett 2021; 17:20210470. [PMID: 34932921 PMCID: PMC8692031 DOI: 10.1098/rsbl.2021.0470] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 11/30/2021] [Indexed: 11/21/2022] Open
Abstract
The frequency and severity of wildfires are increasing due to anthropogenic modifications to habitats and to climate. Post-fire landscapes may advantage invasive species via multiple mechanisms, including changes to host-parasite interactions. We surveyed the incidence of endoparasitic lungworms (Rhabdias pseudosphaerocephala) in invasive cane toads (Rhinella marina) in near-coastal sites of eastern Australia, a year after extensive fires in this region. Both the prevalence of infection and number of worms in infected toads increased with toad body size in unburned areas. By contrast, parasite load decreased with toad body size in burned areas. By killing moisture-dependent free-living lungworm larvae, the intense fires may have liberated adult cane toads from a parasite that can substantially reduce the viability of its host. Smaller toads, which are restricted to moist environments, did not receive this benefit from fires.
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Affiliation(s)
- Shannon W. Kaiser
- Department of Biological Sciences, Macquarie University, NSW 2109, Australia
| | | | - Richard Shine
- Department of Biological Sciences, Macquarie University, NSW 2109, Australia
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10
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DeVore JL, Shine R, Ducatez S. Spatial ecology of cane toads (Rhinella marina) in their native range: a radiotelemetric study from French Guiana. Sci Rep 2021; 11:11817. [PMID: 34083703 PMCID: PMC8175754 DOI: 10.1038/s41598-021-91262-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 05/18/2021] [Indexed: 11/09/2022] Open
Abstract
Like 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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Affiliation(s)
- Jayna L DeVore
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Richard Shine
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, 2006, Australia. .,Department of Biological Sciences, Macquarie University, Sydney, NSW, 2109, Australia.
| | - Simon Ducatez
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, 2006, Australia.,Institut de Recherche Pour Le Développement (IRD), UMR 241 EIO (UPF, IRD, IFREMER, ILM), Papeete, Tahiti, French Polynesia
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11
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Variation in size and shape of toxin glands among cane toads from native-range and invasive populations. Sci Rep 2021; 11:936. [PMID: 33441802 PMCID: PMC7806831 DOI: 10.1038/s41598-020-80191-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 12/14/2020] [Indexed: 12/19/2022] Open
Abstract
If optimal investment in anti-predator defences depends on predation risk, invading new regions (and thus, encountering different predators) may favour shifts in that investment. Cane toads offer an ideal system to test this prediction: expensive anti-predator toxins are stored mainly in parotoid glands whose dimensions are easy to measure, and toad invasions have changed the suites of predators they encounter. Although plasticity may influence parotoid morphology, comparisons between parents and progeny revealed that gland dimensions were highly heritable. That heritability supports the plausibility of an evolved basis to variation in gland dimensions. Measurements of 3779 adult toads show that females have larger glands than males, invasive populations have larger glands than in the native-range, and that parotoid sexual size dimorphism varies strongly among invaded areas. Geographic variation in parotoid morphology may be driven by predation risk to both adult toads and offspring (provisioned with toxins by their mother), with toxins allocated to eggs exacerbating the risk of cannibalism but reducing the risk of interspecific predation. Investment into chemical defences has evolved rapidly during the cane toad’s international diaspora, consistent with the hypothesis that organisms flexibly adjust resource allocation to anti-predator tactics in response to novel challenges.
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12
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Kosmala GK, Brown GP, Shine R, Christian K. Skin resistance to water gain and loss has changed in cane toads ( Rhinella marina) during their Australian invasion. Ecol Evol 2020; 10:13071-13079. [PMID: 33304517 PMCID: PMC7713918 DOI: 10.1002/ece3.6895] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 09/14/2020] [Accepted: 09/18/2020] [Indexed: 11/19/2022] Open
Abstract
The water-permeable skin of amphibians renders them highly sensitive to climatic conditions, and interspecific correlations between environmental moisture levels and rates of water exchange across the skin suggest that natural selection adapts hydroregulatory mechanisms to local challenges. How quickly can such mechanisms shift when a species encounters novel moisture regimes? Cutaneous resistance to water loss and gain in wild-caught cane toads (Rhinella marina) from Brazil, USA (Hawai'i) and Australia exhibited strong geographic variation. Cutaneous resistance was low in native-range (Brazilian) toads and in Hawai'ian populations (where toads were introduced in 1932) but significantly higher in toads from eastern Australia (where toads were introduced in 1935). Toads from recently invaded areas in western Australia exhibited cutaneous resistance to water loss similar to the native-range populations, possibly because toads are restricted to moist sites within this highly arid landscape. Rates of rehydration exhibited significant but less extreme geographic variation, being higher in the native range than in invaded regions. Thus, in less than a century, cane toads invading areas that impose different climatic challenges have diverged in the capacity for hydroregulation.
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Affiliation(s)
- Georgia K. Kosmala
- School of Life and Environmental SciencesUniversity of SydneySydneyNSWAustralia
| | - Gregory P. Brown
- School of Life and Environmental SciencesUniversity of SydneySydneyNSWAustralia
- Department of Biological SciencesMacquarie UniversitySydneyNSWAustralia
| | - Richard Shine
- School of Life and Environmental SciencesUniversity of SydneySydneyNSWAustralia
- Department of Biological SciencesMacquarie UniversitySydneyNSWAustralia
| | - Keith Christian
- Research Institute for the Environment and LivelihoodsCharles Darwin UniversityDarwinNTAustralia
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13
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Silva AFD, Malhado AC, Correia RA, Ladle RJ, Vital MV, Mott T. Taxonomic bias in amphibian research: Are researchers responding to conservation need? J Nat Conserv 2020. [DOI: 10.1016/j.jnc.2020.125829] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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14
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Fischer MT, Ringler M, Ringler E, Pašukonis A. Reproductive behavior drives female space use in a sedentary Neotropical frog. PeerJ 2020; 8:e8920. [PMID: 32337103 PMCID: PMC7169969 DOI: 10.7717/peerj.8920] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 03/16/2020] [Indexed: 12/04/2022] Open
Abstract
Longer-range movements of anuran amphibians such as mass migrations and habitat invasion have received a lot of attention, but fine-scale spatial behavior remains largely understudied. This gap is especially striking for species that show long-term site fidelity and display their whole behavioral repertoire in a small area. Studying fine-scale movement with conventional capture-mark-recapture techniques is difficult in inconspicuous amphibians: individuals are hard to find, repeated captures might affect their behavior and the number of data points is too low to allow a detailed interpretation of individual space use and time budgeting. In this study, we overcame these limitations by equipping females of the Brilliant-Thighed Poison Frog (Allobates femoralis) with a tag allowing frequent monitoring of their location and behavior. Neotropical poison frogs are well known for their complex behavior and diverse reproductive and parental care strategies. Although the ecology and behavior of the polygamous leaf-litter frog Allobates femoralis is well studied, little is known about the fine-scale space use of the non-territorial females who do not engage in acoustic and visual displays. We tracked 17 females for 6 to 17 days using a harmonic direction finder to provide the first precise analysis of female space use in this species. Females moved on average 1 m per hour and the fastest movement, over 20 m per hour, was related to a subsequent mating event. Traveled distances and activity patterns on days of courtship and mating differed considerably from days without reproduction. Frogs moved more on days with lower temperature and more precipitation, but mating seemed to be the main trigger for female movement. We observed 21 courtships of 12 tagged females. For seven females, we observed two consecutive mating events. Estimated home ranges after 14 days varied considerably between individuals and courtship and mating associated space use made up for ∼30% of the home range. Allobates femoralis females spent large parts of their time in one to three small centers of use. Females did not adjust their time or space use to the density of males in their surroundings and did not show wide-ranging exploratory behavior. Our study demonstrates how tracking combined with detailed behavioral observations can reveal the patterns and drivers of fine-scale spatial behavior in sedentary species.
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Affiliation(s)
| | - Max Ringler
- Department of Evolutionary Biology, University of Vienna, Vienna, Austria.,Department of Behavioral and Cognitive Biology, University of Vienna, Vienna, Austria
| | - Eva Ringler
- Department of Evolutionary Biology, University of Vienna, Vienna, Austria.,Department of Behavioral and Cognitive Biology, University of Vienna, Vienna, Austria.,Messerli Research Institute, University of Veterinary Medicine Vienna, Medical University Vienna, University of Vienna, Vienna, Austria
| | - Andrius Pašukonis
- Department of Behavioral and Cognitive Biology, University of Vienna, Vienna, Austria.,Department of Biology, Stanford University, Stanford, CA, United States of America
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15
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DeVore JL, Shine R, Ducatez S. Urbanization and translocation disrupt the relationship between host density and parasite abundance. J Anim Ecol 2020; 89:1122-1133. [PMID: 31945186 DOI: 10.1111/1365-2656.13175] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 11/19/2019] [Indexed: 11/28/2022]
Abstract
The species interactions that structure natural communities are increasingly disrupted by radical habitat change resulting from the widespread processes of urbanization and species translocations. Although many species are disadvantaged by these changes, others thrive in these new environments, achieving densities that exceed those in natural habitats. Often the same species that benefit from urbanization are successful invaders in introduced habitats, suggesting that similar processes promote these species in both environments. Both processes may especially benefit certain species by modifying their interactions with harmful parasites ('enemy release'). To detect such modifications, we first need to identify the mechanisms underlying host-parasite associations in natural populations, then test whether they are disrupted in cities and introduced habitats. We studied the interaction between the cane toad Rhinella marina, a globally invasive species native to South America, and its Amblyomma ticks. Our field study of 642 cane toads across 46 sites within their native range in French Guiana revealed that 56% of toads carried ticks, and that toads with ticks were in poor body condition relative to uninfected conspecifics. Across natural and disturbed habitats tick prevalence and abundance increased with toad density, but this association was disrupted in the urban environment, where tick abundance remained low even where toad densities were high, and prevalence decreased with density. Reductions in the abundance of ticks in urban habitats may be attributable to pesticides (which are sprayed for mosquito control but are also lethal to ticks), and our literature review shows that tick abundance is generally lower in cane toads from urban habitats across South America. In the invasive range, ticks were either absent (in 1,960 toads from Puerto Rico, Hawai'i, Japan and Australia) or less abundant (in Florida and the Caribbean; literature review). The positive relationship between host density and parasite abundance is thought to be a key mechanism through which parasites regulate host populations; anthropogenic processes that disrupt this relationship may allow populations in urban and introduced habitats to persist at densities that would otherwise lead to severe impacts from parasites.
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Affiliation(s)
- Jayna L DeVore
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, Australia
| | - Richard Shine
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, Australia.,Biological Sciences, Macquarie University, Sydney, NSW, Australia
| | - Simon Ducatez
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, Australia.,CREAF (Centre for Ecological Research and Forestry Applications), Cerdanyola del Vallès, Catalonia, Spain
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16
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Greenlees MJ, Harris S, White AW, Shine R. The establishment and eradication of an extra-limital population of invasive cane toads. Biol Invasions 2018. [DOI: 10.1007/s10530-018-1681-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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17
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Gruber J, Brown G, Whiting MJ, Shine R. Behavioural divergence during biological invasions: a study of cane toads ( Rhinella marina) from contrasting environments in Hawai'i. ROYAL SOCIETY OPEN SCIENCE 2018; 5:180197. [PMID: 29765696 PMCID: PMC5936961 DOI: 10.1098/rsos.180197] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 03/12/2018] [Indexed: 06/08/2023]
Abstract
Invasive species must deal with novel challenges, both from the alien environment and from pressures arising from range expansion per se (e.g. spatial sorting). Those conditions can create geographical variation in behaviour across the invaded range, as has been documented across regions of Australia invaded by cane toads; range-edge toads are more exploratory and willing to take risks than are conspecifics from the range-core. That behavioural divergence might be a response to range expansion and invasion per se, or to the different environments encountered. Climate differs across the cane toads' invasion range from the wet tropics of Queensland to the seasonally dry climates of northwestern Western Australia. The different thermal and hydric regimes may affect behavioural traits via phenotypic plasticity or through natural selection. We cannot tease apart the effects of range expansion versus climate in an expanding population but can do so in a site where the colonizing species was simultaneously released in all suitable areas, thus removing any subsequent phase of range expansion. Cane toads were introduced to Hawai'i in 1932; and thence to Australia in 1935. Toads were released in all major sugarcane-growing areas in Hawai'i within a 12-month period. Hence, Hawai'ian cane toads provide an opportunity to examine geographical divergence in behavioural traits in a climatically diverse region (each island has both wet and dry sides) in the absence of range expansion subsequent to release. We conducted laboratory-based behavioural trials testing exploration, risk-taking and response to novelty using field-caught toads from the wet and dry sides of two Hawai'ian islands (Oahu and Hawai'i). Toads from the dry side of Oahu had a higher propensity to take risks than did toads from the dry side of Hawai'i. Toads from Oahu were also more exploratory than were conspecifics from the island of Hawai'i. However, toads from wet versus dry climates were similar in all behaviours that we scored, suggesting that founder effects, genetic drift, or developmentally plastic responses to ecological factors other than climate may have driven behavioural divergence between islands.
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Affiliation(s)
- Jodie Gruber
- School of Life and Environmental Sciences, The University of Sydney, Sydney, New South Wales, Australia
| | - Gregory Brown
- School of Life and Environmental Sciences, The University of Sydney, Sydney, New South Wales, Australia
| | - Martin J. Whiting
- Department of Biological Sciences, Macquarie University, North Ryde, New South Wales, Australia
| | - Richard Shine
- School of Life and Environmental Sciences, The University of Sydney, Sydney, New South Wales, Australia
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18
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McCann SM, Kosmala GK, Greenlees MJ, Shine R. Physiological plasticity in a successful invader: rapid acclimation to cold occurs only in cool-climate populations of cane toads ( Rhinella marina). CONSERVATION PHYSIOLOGY 2018; 6:cox072. [PMID: 29399360 PMCID: PMC5786208 DOI: 10.1093/conphys/cox072] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 11/03/2017] [Accepted: 11/30/2017] [Indexed: 06/07/2023]
Abstract
Physiological plasticity may facilitate invasion of novel habitats; but is such plasticity present in all populations of the invader or is it elicited only by specific climatic challenges? In cold-climate areas of Australia, invasive cane toads (Rhinella marina) can rapidly acclimate to cool conditions. To investigate whether this physiological plasticity is found in all invasive cane toads or is only seen in cool climates, we measured the acclimation ability of toads from across Australia and the island of Hawai'i. We collected toads from the field and placed them at either 12 or 24°C for 12 h before measuring their righting response as a proxy for critical thermal minimum (CTmin). Toads from the coolest Australian region (New South Wales) demonstrated plasticity (as previously reported), with exposure to 12°C (vs. 24°C) decreasing CTmin by 2°C. In toads from other Australian populations, CTmins were unaffected by our thermal treatments. Hawai'ian toads from a cool, wet site also rapidly acclimated to cool conditions, whereas those from warmer and drier Hawai'ian sites did not. Thermal plasticity has diverged among populations of invasive cane toads, with rapid acclimation manifested only in two cool-climate populations from widely separated sites. Predictions about the potential range of invasive species thus must consider the possibility of geographic (intraspecific) heterogeneity in thermal plasticity; data from other parts of the species' range may fail to predict levels of plasticity elicited by thermal challenges.
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Affiliation(s)
- Samantha M McCann
- School of Life and Environmental Sciences, University of Sydney, Room 442, Heydon-Laurence Building (A08) Science Road, New South Wales 2006, Australia
| | - Georgia K Kosmala
- School of Life and Environmental Sciences, University of Sydney, Room 442, Heydon-Laurence Building (A08) Science Road, New South Wales 2006, Australia
| | - Matthew J Greenlees
- School of Life and Environmental Sciences, University of Sydney, Room 442, Heydon-Laurence Building (A08) Science Road, New South Wales 2006, Australia
| | - Richard Shine
- School of Life and Environmental Sciences, University of Sydney, Room 442, Heydon-Laurence Building (A08) Science Road, New South Wales 2006, Australia
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19
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Evolutionary shifts in anti-predator responses of invasive cane toads (Rhinella marina). Behav Ecol Sociobiol 2017. [DOI: 10.1007/s00265-017-2367-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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20
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Kosmala G, Christian K, Brown G, Shine R. Locomotor performance of cane toads differs between native-range and invasive populations. ROYAL SOCIETY OPEN SCIENCE 2017; 4:170517. [PMID: 28791174 PMCID: PMC5541569 DOI: 10.1098/rsos.170517] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 06/08/2017] [Indexed: 06/07/2023]
Abstract
Invasive species provide a robust opportunity to evaluate how animals deal with novel environmental challenges. Shifts in locomotor performance-and thus the ability to disperse-(and especially, the degree to which it is constrained by thermal and hydric extremes) are of special importance, because they might affect the rate that an invader can spread. We studied cane toads (Rhinella marina) across a broad geographical range: two populations within the species' native range in Brazil, two invasive populations on the island of Hawai'i and eight invasive populations encompassing the eastern, western and southern limits of the toad invasion in Australia. A toad's locomotor performance on a circular raceway was strongly affected by both its temperature and its hydration state, but the nature and magnitude of those constraints differed across populations. In their native range, cane toads exhibited relatively low performance (even under optimal test conditions) and a rapid decrease in performance at lower temperatures and hydration levels. At the other extreme, performance was high in toads from southern Australia, and virtually unaffected by desiccation. Hawai'ian toads broadly resembled their Brazilian conspecifics, plausibly reflecting similar climatic conditions. The invasion of Australia has been accompanied by a dramatic enhancement in the toads' locomotor abilities, and (in some populations) by an ability to maintain locomotor performance even when the animal is cold and/or dehydrated. The geographical divergences in performance among cane toad populations graphically attest to the adaptability of invasive species in the face of novel abiotic challenges.
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Affiliation(s)
- Georgia Kosmala
- School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Keith Christian
- Research Institute for the Environment and Livelihoods, Charles Darwin University, Casuarina, Northern Territory 0909, Australia
| | - Gregory Brown
- School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Richard Shine
- School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales 2006, Australia
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Lettoof DC, Lyons JA, Shine R, Maniel G, Mayer M, Natusch DJD. Cane toads beneath bird rookeries: utilization of a natural disturbance by an invasive species. Curr Zool 2017; 64:433-439. [PMID: 30108623 PMCID: PMC6084566 DOI: 10.1093/cz/zox041] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 06/03/2017] [Indexed: 11/13/2022] Open
Abstract
Many invasive species exploit anthropogenically disturbed habitats, but most of those taxa evolved long before humans. Presumably, then, an ability to use natural (non-anthropogenic) disturbances pre-adapted invaders to a world later degraded by people. Studies on invasive species in naturally disturbed habitats thus can clarify the ancestral niche of invaders. In the Australian tropics, metallic starlings Aplonis metallica nest communally in emergent rainforest trees during the wet-season, and invasive cane toads Rhinella marina join other predators (mammals, birds, reptiles, and other anurans) to exploit the food resources beneath those trees. Compared to conspecifics found along nearby roads through the forest, cane toads beneath bird-nesting trees occur at higher densities, and are smaller in body size. The sex ratio is female-biased, and recapture records suggest that females may be philopatric at these sites (whereas recaptures were rare for both sexes found along the roads). Some toads were found under the same trees in successive wet-seasons. Spooling showed that distances moved per night were similar along the road versus under the trees, but toads under trees showed lower net displacements. Diets also differed (based upon scat analysis), with tree toads feeding more on beetles and less on ants. These nutrient-rich hotspots are exploited primarily by adult females and juvenile toads, whereas adult males congregate at breeding sites. By magnifying pre-existing intraspecific divergences in habitat use, bird rookeries may enhance population viability of cane toads by enabling critical age and sex classes to exploit food-rich patches that are rarely used by adult males.
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Affiliation(s)
- Damian C Lettoof
- School of Life and Environmental Sciences, University of Sydney, NSW, Australia
| | | | - Richard Shine
- School of Life and Environmental Sciences, University of Sydney, NSW, Australia
| | | | - Martin Mayer
- Faculty of Arts and Sciences, University College of Southeast Norway, Bø i Telemark, Norway
| | - Daniel J D Natusch
- School of Life and Environmental Sciences, University of Sydney, NSW, Australia
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22
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Pizzatto L, Both C, Brown G, Shine R. The accelerating invasion: dispersal rates of cane toads at an invasion front compared to an already-colonized location. Evol Ecol 2017. [DOI: 10.1007/s10682-017-9896-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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23
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Hudson CM, Brown GP, Shine R. Athletic anurans: the impact of morphology, ecology and evolution on climbing ability in invasive cane toads. Biol J Linn Soc Lond 2016. [DOI: 10.1111/bij.12827] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Cameron M. Hudson
- School of Life and Environmental Sciences; University of Sydney; A08 Sydney NSW 2006 Australia
| | - Gregory P. Brown
- School of Life and Environmental Sciences; University of Sydney; A08 Sydney NSW 2006 Australia
| | - Richard Shine
- School of Life and Environmental Sciences; University of Sydney; A08 Sydney NSW 2006 Australia
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