1
|
Plata Á, Züst T, Bermejo A, Beitia FJ, Tena A. Exotic predators can sequester and use novel toxins from exotic non-coevolved prey. Proc Biol Sci 2024; 291:20232478. [PMID: 38471556 DOI: 10.1098/rspb.2023.2478] [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: 11/06/2023] [Accepted: 02/05/2024] [Indexed: 03/14/2024] Open
Abstract
Defensive chemicals of prey can be sequestered by some coevolved predators, which take advantage of prey toxins for their own defence. The increase in the number of invasive species in the Anthropocene has resulted in new interactions among non-coevolved predator and prey species. While novelty in chemical defence may provide a benefit for invasive prey against non-coevolved predators, resident predators with the right evolutionary pre-adaptations might benefit from sequestering these novel defences. Here, we chose a well-known system of invasive species to test whether non-coevolved predators can sequester and use toxins from exotic prey. Together with the invasive prickly pear plants, cochineal bugs (Dactylopius spp.) are spreading worldwide from their native range in the Americas. These insects produce carminic acid, a defensive anthraquinone that some specialized predators sequester for their own defence. Using this system, we first determined whether coccinellids that prey on cochineal bugs in the Mediterranean region tolerated, sequestered, and released carminic acid in reflex bleeding. Then, we quantified the deterrent effect of carminic acid against antagonistic ants. Our results demonstrate that the Australian coccinellid Cryptolaemus montrouzieri sequestered carminic acid, a substance absent in its coevolved prey, from exotic cochineal bugs. When attacked, the predator released this substance through reflex bleeding at concentrations that were deterrent against antagonistic ants. These findings reveal that non-coevolved predators can sequester and use novel toxins from exotic prey and highlights the surprising outcomes of novel interactions that arise from species invasions.
Collapse
Affiliation(s)
- Ángel Plata
- Centro de Protección Vegetal y Biotecnología, Instituto Valenciano de Investigaciones Agrarias, Valencia, Spain
| | - Tobias Züst
- Department of Systematic and Evolutionary Botany, University of Zürich, Zürich, Switzerland
| | - Almudena Bermejo
- Centro de Citricultura y Producción Vegetal, Instituto Valenciano de Investigaciones Agrarias, Valencia, Spain
| | - Francisco José Beitia
- Centro de Protección Vegetal y Biotecnología, Instituto Valenciano de Investigaciones Agrarias, Valencia, Spain
| | - Alejandro Tena
- Centro de Protección Vegetal y Biotecnología, Instituto Valenciano de Investigaciones Agrarias, Valencia, Spain
| |
Collapse
|
2
|
Sawada K, Inoue T, Mori N, Mori A, Kamijo T. DO Toxic Invasive Prey Become a Toxin Source for Native Consumers? J Chem Ecol 2023:10.1007/s10886-023-01460-z. [PMID: 37882872 DOI: 10.1007/s10886-023-01460-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 10/09/2023] [Accepted: 10/11/2023] [Indexed: 10/27/2023]
Abstract
Toxic organisms can become food that potentially harms consumers. When these organisms become invasive species, the harm often turns to a serious threat that disrupts native ecosystems. On the other hand, there are consumers that can exploit toxic organisms for food and sequester intact toxins from them for the consumers' own chemical defense. Therefore, it can be expected that toxic invasive prey can become a toxin source for native consumers. Here, we focused on the relationship between toads, which are one of the major toxic invasive organisms and possess bufadienolides (BDs), and Rhabdophis snakes, which sequester BDs from toads. On Sado Island, Japan, R. tigrinus is native, but no toads had inhabited this island until Bufo japonicus formosus was introduced as a domestic invasive species in 1963 and 1964. At present, invasive toads are distributed only in the southwestern part of the island. We collected a total of 25 and 24 R. tigrinus from areas allopatric and sympatric with toads, respectively. Then, we investigated the possession of BDs and the BD profile of these snakes. We found that only R. tigrinus sympatric with toads possessed BDs, whereas all snakes allopatric with toads lacked BDs. Based on the characteristics of the BD profile, the toxin source was identified as B. j. formosus. Our findings show that a new case of impact caused by toxic invasive species, i.e., "toxin supply to native consumers from invasive prey", could occur.
Collapse
Affiliation(s)
- Kiyoto Sawada
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Ten-nodai, Tsukuba, 305-8572, Ibaraki, Japan.
| | - Takato Inoue
- Division of Applied Life Science, Graduate School of Agriculture, Kyoto University, Sakyo, 606-8502, Kyoto, Japan
| | - Naoki Mori
- Department of Zoology, Graduate School of Science, Kyoto University, Sakyo, 606-8502, Kyoto, Japan
| | - Akira Mori
- Division of Applied Life Science, Graduate School of Agriculture, Kyoto University, Sakyo, 606-8502, Kyoto, Japan
| | - Takashi Kamijo
- Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Ten-nodai, Tsukuba, 305-8572, Ibaraki, Japan
| |
Collapse
|
3
|
Inoue T, Mori A, Yoshinaga N, Mori N. Intrinsic Factors Associated with Dietary Toxin Quantity and Concentration in the Nuchal Glands of a Natricine Snake Rhabdophis Tigrinus. J Chem Ecol 2023; 49:133-141. [PMID: 36881327 DOI: 10.1007/s10886-023-01415-4] [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: 12/20/2022] [Revised: 02/23/2023] [Accepted: 02/24/2023] [Indexed: 03/08/2023]
Abstract
The snake Rhabdophis tigrinus sequesters cardiotonic steroids, bufadienolides (BDs), from ingested toads and stores them in the nuchal glands as defensive toxins. It has previously been shown that there are individual differences in the total quantity of BDs stored in the nuchal glands of adult R. tigrinus and that BD quantities and profiles of R. tigrinus exhibit geographic variation. However, no previous study has examined the total quantity of BDs as a percentage of body mass (relative BD quantity) and the concentration of BDs in the nuchal gland fluid (BD gland concentration). In addition, intrinsic factors that are associated with relative BD quantity and BD concentration have not been examined within a single population. We collected 158 adult snakes from an area of central Japan from May to October and analyzed their BD quantities by UV analysis. We assessed individual differences in BD quantity, relative BD quantity and BD gland concentration. We found that 1) in approximately 60% of the 158 individuals, the BD gland concentration was greater than 50%; 2) body length and body condition are positively correlated with relative BD quantity and BD gland concentration; 3) even in a single population, individual differences of BD quantity are large, and are greater in females than in males; and 4) relative BD quantity and BD gland concentration of females during the gestation season are lower than those during the non-gestation season.
Collapse
Affiliation(s)
- Takato Inoue
- Division of Applied Life Science, Graduate School of Agriculture, Kyoto University, Sakyo, Kyoto, 606-8502, Japan.
| | - Akira Mori
- Department of Zoology, Graduate School of Science, Kyoto University, Sakyo, Kyoto, 606-8502, Japan
| | - Naoko Yoshinaga
- Division of Applied Life Science, Graduate School of Agriculture, Kyoto University, Sakyo, Kyoto, 606-8502, Japan
| | - Naoki Mori
- Division of Applied Life Science, Graduate School of Agriculture, Kyoto University, Sakyo, Kyoto, 606-8502, Japan
| |
Collapse
|
4
|
He QL, Deng K, Wang XP, Chen QH, Wang TL, Wang JC, Cui JG. Heterospecific eavesdropping on disturbance cues of a treefrog. Anim Cogn 2023; 26:515-522. [PMID: 36131103 DOI: 10.1007/s10071-022-01690-w] [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: 03/28/2022] [Revised: 08/30/2022] [Accepted: 09/04/2022] [Indexed: 11/01/2022]
Abstract
Alarm signals and cues are crucial to animal survival and vary greatly across species. Eavesdropping on heterospecific alarm signals and cues can provide eavesdroppers with information about potential threats. In addition to acoustic alarm signals, evidence has accumulated that chemical alarm cues and disturbance cues can also play a role in alerting conspecifics to potential danger in adult anurans (frogs and toads). However, there is very little known about whether disturbance cues are exploited by heterospecifics. In the present study, we conducted a binary choice experiment and a prey chemical discrimination experiment, respectively, to test the responses of a sympatric anuran species (red webbed treefrogs, Rhacophorus rhodopus) and a sympatric predator species (Chinese green tree vipers, Trimeresurus stejnegeri) to disturbance odors emitted by serrate-legged small treefrogs (Kurixalus odontotarsus). In the binary choice experiment, we found that the presence of disturbance odors did not significantly trigger the avoidance behavior of R. rhodopus. In the prey chemical discrimination experiment, compared with odors from undisturbed K. odontotarsus (control odors) and odorless control, T. stejnegeri showed a significantly higher tongue-flick rate in response to disturbance odors. This result implies that disturbance odor cues of K. odontotarsus can be exploited by eavesdropping predators to detect prey. Our study provides partial evidence for heterospecific eavesdropping on disturbance cues and has an important implication for understanding heterospecific eavesdropping on chemical cues of adult anurans.
Collapse
Affiliation(s)
- Qiao-Ling He
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization and Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, No.9 Section 4, Renmin South Road, Chengdu, 610041, China.,University of Chinese Academy of Science, Beijing, 100049, China
| | - Ke Deng
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization and Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, No.9 Section 4, Renmin South Road, Chengdu, 610041, China.
| | - Xiao-Ping Wang
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization and Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, No.9 Section 4, Renmin South Road, Chengdu, 610041, China.,University of Chinese Academy of Science, Beijing, 100049, China
| | - Qing-Hua Chen
- Ministry of Ecology and Environment, South China Institute of Environmental Sciences, Guangzhou, 510530, China
| | - Tong-Liang Wang
- Ministry of Education Key Laboratory for Ecology of Tropical Islands, Key Laboratory of Tropical Animal and Plant Ecology of Hainan Province, College of Life Sciences, Hainan Normal University, Haikou, 571158, China
| | - Ji-Chao Wang
- Ministry of Education Key Laboratory for Ecology of Tropical Islands, Key Laboratory of Tropical Animal and Plant Ecology of Hainan Province, College of Life Sciences, Hainan Normal University, Haikou, 571158, China
| | - Jian-Guo Cui
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization and Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, No.9 Section 4, Renmin South Road, Chengdu, 610041, China.
| |
Collapse
|
5
|
Mohammadi S, Yang L, Bulbert M, Rowland HM. Defence mitigation by predators of chemically defended prey integrated over the predation sequence and across biological levels with a focus on cardiotonic steroids. ROYAL SOCIETY OPEN SCIENCE 2022; 9:220363. [PMID: 36133149 PMCID: PMC9449480 DOI: 10.1098/rsos.220363] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 08/17/2022] [Indexed: 05/10/2023]
Abstract
Predator-prey interactions have long served as models for the investigation of adaptation and fitness in natural environments. Anti-predator defences such as mimicry and camouflage provide some of the best examples of evolution. Predators, in turn, have evolved sensory systems, cognitive abilities and physiological resistance to prey defences. In contrast to prey defences which have been reviewed extensively, the evolution of predator counter-strategies has received less attention. To gain a comprehensive view of how prey defences can influence the evolution of predator counter-strategies, it is essential to investigate how and when selection can operate. In this review we evaluate how predators overcome prey defences during (i) encounter, (ii) detection, (iii) identification, (iv) approach, (v) subjugation, and (vi) consumption. We focus on prey that are protected by cardiotonic steroids (CTS)-defensive compounds that are found in a wide range of taxa, and that have a specific physiological target. In this system, coevolution is well characterized between specialist insect herbivores and their host plants but evidence for coevolution between CTS-defended prey and their predators has received less attention. Using the predation sequence framework, we organize 574 studies reporting predators overcoming CTS defences, integrate these counter-strategies across biological levels of organization, and discuss the costs and benefits of attacking CTS-defended prey. We show that distinct lineages of predators have evolved dissecting behaviour, changes in perception of risk and of taste perception, and target-site insensitivity. We draw attention to biochemical, hormonal and microbiological strategies that have yet to be investigated as predator counter-adaptations to CTS defences. We show that the predation sequence framework will be useful for organizing future studies of chemically mediated systems and coevolution.
Collapse
Affiliation(s)
- Shabnam Mohammadi
- School of Biological Sciences, University of Nebraska, Lincoln, NE, USA
- Institut für Zell- und Systembiologie der Tiere, Universität Hamburg, Hamburg, Germany
- Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Lu Yang
- Wellcome Sanger Institute, Cambridge, UK
| | - Matthew Bulbert
- Department of Biological Sciences, Macquarie University North Ryde, New South Wales, Australia
- Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, University of Oxford Brookes, Oxford, UK
- Max Planck Institute for Chemical Ecology, Jena, Germany
| | | |
Collapse
|
6
|
Mohammadi S, Yang L, Bulbert M, Rowland HM. Defence mitigation by predators of chemically defended prey integrated over the predation sequence and across biological levels with a focus on cardiotonic steroids. ROYAL SOCIETY OPEN SCIENCE 2022; 9:220363. [PMID: 36133149 DOI: 10.6084/m9.figshare.c.6168216] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 08/17/2022] [Indexed: 05/25/2023]
Abstract
Predator-prey interactions have long served as models for the investigation of adaptation and fitness in natural environments. Anti-predator defences such as mimicry and camouflage provide some of the best examples of evolution. Predators, in turn, have evolved sensory systems, cognitive abilities and physiological resistance to prey defences. In contrast to prey defences which have been reviewed extensively, the evolution of predator counter-strategies has received less attention. To gain a comprehensive view of how prey defences can influence the evolution of predator counter-strategies, it is essential to investigate how and when selection can operate. In this review we evaluate how predators overcome prey defences during (i) encounter, (ii) detection, (iii) identification, (iv) approach, (v) subjugation, and (vi) consumption. We focus on prey that are protected by cardiotonic steroids (CTS)-defensive compounds that are found in a wide range of taxa, and that have a specific physiological target. In this system, coevolution is well characterized between specialist insect herbivores and their host plants but evidence for coevolution between CTS-defended prey and their predators has received less attention. Using the predation sequence framework, we organize 574 studies reporting predators overcoming CTS defences, integrate these counter-strategies across biological levels of organization, and discuss the costs and benefits of attacking CTS-defended prey. We show that distinct lineages of predators have evolved dissecting behaviour, changes in perception of risk and of taste perception, and target-site insensitivity. We draw attention to biochemical, hormonal and microbiological strategies that have yet to be investigated as predator counter-adaptations to CTS defences. We show that the predation sequence framework will be useful for organizing future studies of chemically mediated systems and coevolution.
Collapse
Affiliation(s)
- Shabnam Mohammadi
- School of Biological Sciences, University of Nebraska, Lincoln, NE, USA
- Institut für Zell- und Systembiologie der Tiere, Universität Hamburg, Hamburg, Germany
- Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Lu Yang
- Wellcome Sanger Institute, Cambridge, UK
| | - Matthew Bulbert
- Department of Biological Sciences, Macquarie University North Ryde, New South Wales, Australia
- Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, University of Oxford Brookes, Oxford, UK
- Max Planck Institute for Chemical Ecology, Jena, Germany
| | | |
Collapse
|
7
|
Durso AM, Neuman-Lee LA, Hopkins GR, Brodie ED. Stable isotope analysis suggests that tetrodotoxin-resistant Common Gartersnakes (Thamnophis sirtalis) rarely feed on newts in the wild. CAN J ZOOL 2021. [DOI: 10.1139/cjz-2020-0215] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Toxin-resistant predators may suffer costs from eating chemically defended prey and do not feed exclusively on toxic prey. Common Gartersnakes (Thamnophis sirtalis (Linnaeus, 1758)) have been considered the drivers of an evolutionary arms race with highly toxic newts (genus Taricha Gray, 1850), which they consume with few or no deleterious effects. However, how frequently newts are consumed in nature is less clear. To address this question, we investigated the diets of Th. sirtalis at a site in central Oregon where snakes have high levels of resistance and newts have high levels of tetrodotoxin in the skin. Because snake diets are difficult to quantify using traditional means, we used stable isotopes to estimate the proportion of Th. sirtalis diets made up of newts. Our estimate for the proportion of Th. sirtalis diet made up of Rough-skinned Newts (Taricha granulosa (Skilton, 1849)) at this site is 3.2%. Mole Salamanders (genus Ambystoma Tschudi, 1838) were predicted to be the most important prey, followed by slugs, chorus frogs, and mice, with a very minor role for earthworms. Our results demonstrate that even though Th. sirtalis are physiologically capable of consuming toxic prey, they do not often do so. Generalist predators can be exposed to very strong selection from, and exert reciprocal selection on even rarely eaten, chemically defended prey.
Collapse
Affiliation(s)
- Andrew M. Durso
- Department of Biological Sciences, Florida Gulf Coast University, Ft. Myers, FL 33965, USA
- Department of Biology and the Ecology Center, Utah State University, Logan, UT 84322, USA
| | - Lorin A. Neuman-Lee
- Department of Biological Sciences, Arkansas State University, Jonesboro, AR 72404, USA
- Department of Biology and the Ecology Center, Utah State University, Logan, UT 84322, USA
| | - Gareth R. Hopkins
- Department of Biology, Western Oregon University, Monmouth, OR 97361, USA
- Department of Biology and the Ecology Center, Utah State University, Logan, UT 84322, USA
| | - Edmund D. Brodie
- Department of Biology and the Ecology Center, Utah State University, Logan, UT 84322, USA
| |
Collapse
|
8
|
Fukuda M, Mori A. Does an Asian Natricine Snake, Rhabdophis tigrinus, Have Chemical Preference for a Skin Toxin of Toads? CURRENT HERPETOLOGY 2021. [DOI: 10.5358/hsj.40.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Masaya Fukuda
- Department of Zoology, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606–8502, JAPAN
| | - Akira Mori
- Department of Zoology, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606–8502, JAPAN
| |
Collapse
|
9
|
Yoshida T, Ujiie R, Savitzky AH, Jono T, Inoue T, Yoshinaga N, Aburaya S, Aoki W, Takeuchi H, Ding L, Chen Q, Cao C, Tsai TS, Silva AD, Mahaulpatha D, Nguyen TT, Tang Y, Mori N, Mori A. Dramatic dietary shift maintains sequestered toxins in chemically defended snakes. Proc Natl Acad Sci U S A 2020; 117:5964-5969. [PMID: 32094167 PMCID: PMC7084117 DOI: 10.1073/pnas.1919065117] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Unlike other snakes, most species of Rhabdophis possess glands in their dorsal skin, sometimes limited to the neck, known as nucho-dorsal and nuchal glands, respectively. Those glands contain powerful cardiotonic steroids known as bufadienolides, which can be deployed as a defense against predators. Bufadienolides otherwise occur only in toads (Bufonidae) and some fireflies (Lampyrinae), which are known or believed to synthesize the toxins. The ancestral diet of Rhabdophis consists of anuran amphibians, and we have shown previously that the bufadienolide toxins of frog-eating species are sequestered from toads consumed as prey. However, one derived clade, the Rhabdophis nuchalis Group, has shifted its primary diet from frogs to earthworms. Here we confirm that the worm-eating snakes possess bufadienolides in their nucho-dorsal glands, although the worms themselves lack such toxins. In addition, we show that the bufadienolides of R. nuchalis Group species are obtained primarily from fireflies. Although few snakes feed on insects, we document through feeding experiments, chemosensory preference tests, and gut contents that lampyrine firefly larvae are regularly consumed by these snakes. Furthermore, members of the R. nuchalis Group contain compounds that resemble the distinctive bufadienolides of fireflies, but not those of toads, in stereochemistry, glycosylation, acetylation, and molecular weight. Thus, the evolutionary shift in primary prey among members of the R. nuchalis Group has been accompanied by a dramatic shift in the source of the species' sequestered defensive toxins.
Collapse
Affiliation(s)
- Tatsuya Yoshida
- Division of Applied Life Science, Graduate School of Agriculture, Kyoto University, Sakyo, 606-8502 Kyoto, Japan
| | - Rinako Ujiie
- Division of Applied Life Science, Graduate School of Agriculture, Kyoto University, Sakyo, 606-8502 Kyoto, Japan
| | - Alan H Savitzky
- Department of Biology, Utah State University, Logan, UT 84322-5305
| | - Teppei Jono
- Laboratory of Ryukyu Island Biogeography, Tropical Biosphere Research Center, University of the Ryukyus, Nishihara, 903-0213 Okinawa, Japan
| | - Takato Inoue
- Division of Applied Life Science, Graduate School of Agriculture, Kyoto University, Sakyo, 606-8502 Kyoto, Japan;
| | - Naoko Yoshinaga
- Division of Applied Life Science, Graduate School of Agriculture, Kyoto University, Sakyo, 606-8502 Kyoto, Japan
| | - Shunsuke Aburaya
- Division of Applied Life Science, Graduate School of Agriculture, Kyoto University, Sakyo, 606-8502 Kyoto, Japan
| | - Wataru Aoki
- Division of Applied Life Science, Graduate School of Agriculture, Kyoto University, Sakyo, 606-8502 Kyoto, Japan
| | - Hirohiko Takeuchi
- Laboratory of Biology, College of Bioresource Science, Nihon University, Fujisawa, 252-0880 Kanagawa, Japan
| | - Li Ding
- Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041 Sichuan, China
| | - Qin Chen
- Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041 Sichuan, China
| | - Chengquan Cao
- College of Life Sciences, Leshan Normal University, Leshan, 614000 Sichuan, China
| | - Tein-Shun Tsai
- Department of Biological Science and Technology, National Pingtung University of Science and Technology, Neipu Township, 91201 Pingtung, Taiwan
| | | | - Dharshani Mahaulpatha
- Department of Zoology, Faculty of Applied Biological Sciences, University of Sri Jayewardenepura, 10250 Nugegoda, Sri Lanka
| | - Tao Thien Nguyen
- Department of Nature Conservation, Vietnam National Museum of Nature, Vietnam Academy of Science and Technology, Hanoi 100000, Vietnam
- Graduate University of Science and Technology, Vietnam Academy of Science and Technology, Cau Giay, Hanoi 100000, Vietnam
| | - Yezhong Tang
- Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041 Sichuan, China
| | - Naoki Mori
- Division of Applied Life Science, Graduate School of Agriculture, Kyoto University, Sakyo, 606-8502 Kyoto, Japan
| | - Akira Mori
- Department of Zoology, Graduate School of Science, Kyoto University, Sakyo, 606-8502 Kyoto, Japan
| |
Collapse
|
10
|
Okamiya H, Kusano T. Evaluating Movement Patterns and Microhabitat Selection of the Japanese Common Toad (Bufo japonicus formosus) Using Fluorescent Powder Tracking. Zoolog Sci 2018; 35:153-160. [PMID: 29623783 DOI: 10.2108/zs170101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Bufo japonicus formosus (Eastern-Japanese common toad) is endemic to Eastern Japan. As with many Japanese amphibians, little is known about its terrestrial life, especially during the nonbreeding season. This species persists even in highly disturbed urban areas where many other amphibian species have already been extirpated. An understanding of how such species use habitats within remnant landscapes may help to inform management strategies for the conservation of urban ecosystems. We examined the nightly movement patterns, distance traveled, movement range, and microhabitat selection of non-breeding adult B. j. formosus at an urbanized site, using fluorescent powder tracking. We evaluated the usefulness of this tracking method through this survey. We found that the nightly distances traveled by these toads varied greatly among individuals and nights. No sexual differences in movement pattern, distance traveled, and movement range were detected. However, body size significantly affected distance traveled and movement range. We found that toads tended to use areas covered with grasses and mosses more frequently than expected, and to avoid paved areas. Fluorescent powder tracking was effective for the elucidation of movement patterns and habitat selection of amphibians. Our results provide useful information for the conservation of amphibians, especially for species inhabiting urbanized areas.
Collapse
Affiliation(s)
- Hisanori Okamiya
- Department of Biological Sciences, Graduate School of Sciences and Engineering, Tokyo Metropolitan University, Minami-ohsawa 1-1, Hachioji-shi, Tokyo 192-0397, Japan
| | - Tamotsu Kusano
- Department of Biological Sciences, Graduate School of Sciences and Engineering, Tokyo Metropolitan University, Minami-ohsawa 1-1, Hachioji-shi, Tokyo 192-0397, Japan
| |
Collapse
|
11
|
Mohammadi S, Gompert Z, Gonzalez J, Takeuchi H, Mori A, Savitzky AH. Toxin-resistant isoforms of Na+/K+-ATPase in snakes do not closely track dietary specialization on toads. Proc Biol Sci 2017; 283:rspb.2016.2111. [PMID: 27852804 DOI: 10.1098/rspb.2016.2111] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2016] [Accepted: 10/18/2016] [Indexed: 01/23/2023] Open
Abstract
Toads are chemically defended by bufadienolides, a class of cardiotonic steroids that exert toxic effects by binding to and disabling the Na+/K+-ATPases of cell membranes. Some predators, including a number of snakes, have evolved resistance to the toxic effects of bufadienolides and prey regularly on toads. Resistance in snakes to the acute effects of these toxins is conferred by at least two amino acid substitutions in the cardiotonic steroid binding pocket of the Na+/K+-ATPase. We surveyed 100 species of snakes from a broad phylogenetic range for the presence or absence of resistance-conferring mutations. We found that such mutations occur in a much wider range of taxa than previously believed. Although all sequenced species known to consume toads exhibited the resistance mutations, many of the species possessing the mutations do not feed on toads, much less specialize on that food source. This suggests that either there is little performance cost associated with these mutations or they provide an unknown benefit. Furthermore, the distribution of the mutation among major clades of advanced snakes suggests that the origin of the mutation reflects evolutionary retention more than dietary constraint.
Collapse
Affiliation(s)
- Shabnam Mohammadi
- Department of Biology, Utah State University, Logan, UT 84322, USA .,The Ecology Center, Utah State University, Logan, UT 84322, USA
| | - Zachariah Gompert
- Department of Biology, Utah State University, Logan, UT 84322, USA.,The Ecology Center, Utah State University, Logan, UT 84322, USA
| | | | - Hirohiko Takeuchi
- Department of Zoology, Kyoto University, Sakyo, Kyoto 606-8502, Japan.,Seto Marine Biological Laboratory, Field Science Education and Research Center, Kyoto University, 459 Shirahama, Wakayama 649-2211, Japan
| | - Akira Mori
- Department of Zoology, Kyoto University, Sakyo, Kyoto 606-8502, Japan
| | - Alan H Savitzky
- Department of Biology, Utah State University, Logan, UT 84322, USA .,The Ecology Center, Utah State University, Logan, UT 84322, USA
| |
Collapse
|
12
|
Coevolution takes the sting out of it: Evolutionary biology and mechanisms of toxin resistance in animals. Toxicon 2017; 140:118-131. [DOI: 10.1016/j.toxicon.2017.10.026] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 10/06/2017] [Accepted: 10/23/2017] [Indexed: 01/09/2023]
|
13
|
Mohammadi S, French SS, Neuman-Lee LA, Durham SL, Kojima Y, Mori A, Brodie ED, Savitzky AH. Corticosteroid responses of snakes to toxins from toads (bufadienolides) and plants (cardenolides) reflect differences in dietary specializations. Gen Comp Endocrinol 2017; 247:16-25. [PMID: 28347742 DOI: 10.1016/j.ygcen.2017.03.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 03/07/2017] [Accepted: 03/22/2017] [Indexed: 01/24/2023]
Abstract
Toads are chemically defended by cardiotonic steroids known as bufadienolides. Resistance to the acute effects of bufadienolides in snakes that prey on toads is conferred by target-site insensitivity of the toxin's target enzyme, the Na+/K+-ATPase. Previous studies have focused largely on the molecular mechanisms of resistance but have not investigated the physiological mechanisms or consequences of exposure to the toxins. Adrenal enlargement in snakes often is associated with specialization on a diet of toads. These endocrine glands are partly composed of interrenal tissue, which produces the corticosteroids corticosterone and aldosterone. Corticosterone is the main hormone released in response to stress in reptiles, and aldosterone plays an important role in maintaining ion balance through upregulation of Na+/K+-ATPase. We tested the endocrine response of select species of snakes to acute cardiotonic steroid exposure by measuring circulating aldosterone and corticosterone concentrations. We found that Rhabdophis tigrinus, which specializes on a diet of toads, responds with lower corticosterone and higher aldosterone compared to other species that exhibit target-site resistance to the toxins but do not specialize on toads. We also found differences between sexes in R. tigrinus, with males generally responding with higher corticosterone and aldosterone than females. This study provides evidence of physiological adaptations, beyond target-site resistance, associated with tolerance of bufadienolides in a specialized toad-eating snake.
Collapse
Affiliation(s)
- Shabnam Mohammadi
- Department of Biology, Utah State University, 5305 Old Main Hill, Logan, UT 84322-5305, United States; Ecology Center, Utah State University, 5205 Old Main Hill, Logan, UT 84322-5205, United States.
| | - Susannah S French
- Department of Biology, Utah State University, 5305 Old Main Hill, Logan, UT 84322-5305, United States; Ecology Center, Utah State University, 5205 Old Main Hill, Logan, UT 84322-5205, United States
| | - Lorin A Neuman-Lee
- Department of Biology, Utah State University, 5305 Old Main Hill, Logan, UT 84322-5305, United States
| | - Susan L Durham
- Ecology Center, Utah State University, 5205 Old Main Hill, Logan, UT 84322-5205, United States
| | - Yosuke Kojima
- Department of Zoology, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan
| | - Akira Mori
- Department of Zoology, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan
| | - Edmund D Brodie
- Department of Biology, Utah State University, 5305 Old Main Hill, Logan, UT 84322-5305, United States; Ecology Center, Utah State University, 5205 Old Main Hill, Logan, UT 84322-5205, United States
| | - Alan H Savitzky
- Department of Biology, Utah State University, 5305 Old Main Hill, Logan, UT 84322-5305, United States; Ecology Center, Utah State University, 5205 Old Main Hill, Logan, UT 84322-5205, United States
| |
Collapse
|
14
|
Responses of Natricine Snakes to Predatory Threat: A Mini-Review and Research Prospectus. J HERPETOL 2016. [DOI: 10.1670/15-103] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
15
|
Paul SC, Pell JK, Blount JD. Reproduction in Risky Environments: The Role of Invasive Egg Predators in Ladybird Laying Strategies. PLoS One 2015; 10:e0139404. [PMID: 26488753 PMCID: PMC4619405 DOI: 10.1371/journal.pone.0139404] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 09/12/2015] [Indexed: 12/04/2022] Open
Abstract
Reproductive environments are variable and the resources available for reproduction are finite. If reliable cues about the environment exist, mothers can alter offspring phenotype in a way that increases both offspring and maternal fitness (‘anticipatory maternal effects’—AMEs). Strategic use of AMEs is likely to be important in chemically defended species, where the risk of offspring predation may be modulated by maternal investment in offspring toxin level, albeit at some cost to mothers. Whether mothers adjust offspring toxin levels in response to variation in predation risk is, however, unknown, but is likely to be important when assessing the response of chemically defended species to the recent and pervasive changes in the global predator landscape, driven by the spread of invasive species. Using the chemically defended two-spot ladybird, Adalia bipunctata, we investigated reproductive investment, including egg toxin level, under conditions that varied in the degree of simulated offspring predation risk from larval harlequin ladybirds, Harmonia axyridis. H. axyridis is a highly voracious alien invasive species in the UK and a significant intraguild predator of A. bipunctata. Females laid fewer, larger egg clusters, under conditions of simulated predation risk (P+) than when predator cues were absent (P-), but there was no difference in toxin level between the two treatments. Among P- females, when mean cluster size increased there were concomitant increases in both the mass and toxin concentration of eggs, however when P+ females increased cluster size there was no corresponding increase in egg toxin level. We conclude that, in the face of offspring predation risk, females either withheld toxins or were physiologically constrained, leading to a trade-off between cluster size and egg toxin level. Our results provide the first demonstration that the risk of offspring predation by a novel invasive predator can influence maternal investment in toxins within their offspring.
Collapse
Affiliation(s)
- Sarah C. Paul
- Centre for Ecology & Conservation, College of Life & Environmental Sciences, University of Exeter, Penryn Campus, Cornwall, United Kingdom
| | - Judith K. Pell
- J. K. Pell Consulting, Luton, Bedfordshire, United Kingdom
| | - Jonathan D. Blount
- Centre for Ecology & Conservation, College of Life & Environmental Sciences, University of Exeter, Penryn Campus, Cornwall, United Kingdom
- * E-mail:
| |
Collapse
|