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Guadalupe-Silva A, Zena LA, Hervas LS, Rios VP, Gargaglioni LH, Buck CL, Bícego KC. Classification of sex-dependent specific behaviours by tri-axial acceleration in the tegu lizard Salvator merianae. Comp Biochem Physiol A Mol Integr Physiol 2024; 298:111744. [PMID: 39293558 DOI: 10.1016/j.cbpa.2024.111744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Revised: 09/13/2024] [Accepted: 09/13/2024] [Indexed: 09/20/2024]
Abstract
Validated patterns of behaviour detected by tri-axial acceleration in the laboratory can be used for remote measurements of free-living animals. The tegu lizard naturally occupies diverse biomes in South America and presents ecological threats in regions where it was artificially introduced. We aimed to validate the use of tri-axial acceleration to distinguish among behaviours of male and female tegus in captivity by comparing observed behaviours to recorded acceleration data. Adult animals were externally fitted with an accelerometer fixed between their scapulae to quantify anteroposterior, lateral, and dorsoventral acceleration. Video recordings of cameras positioned on the walls of the animal-holding arena documented behaviours. Behaviour patterns, such as resting, walking, and eating, were identified for both sexes, and nest building in females and courtship and copulation in males. Random Forest algorithm was used to validate the behaviour patterns from accelerometry data based on two models, random split (70 % training-30 % validation; RS) and leave-one-out (divided by individual; LOO). Although LOO showed lower accuracies than RS for all the acceleration data, nest building in females and copulation in males had high accuracies in both models. In contrast, the lowest accuracies for walking and eating indicates they may involve more inconsistent movement patterns. Comparing the results from RS and LOO, female behaviours may be more identifiable in the field using triaxial accelerometry than males. The identification of behaviours by accelerometry, especially related to reproduction, without the necessity for direct observation of the tegus would be helpful for conservation purposes, for both natural and invasive populations.
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Affiliation(s)
- Ane Guadalupe-Silva
- School of Agricultural and Veterinary Sciences, São Paulo State University (UNESP), Jaboticabal, SP, Brazil.
| | | | - Livia Saccani Hervas
- School of Agricultural and Veterinary Sciences, São Paulo State University (UNESP), Jaboticabal, SP, Brazil.
| | | | - Luciane H Gargaglioni
- School of Agricultural and Veterinary Sciences, São Paulo State University (UNESP), Jaboticabal, SP, Brazil.
| | - C Loren Buck
- Northern Arizona University, Flagstaff, AZ, USA.
| | - Kênia C Bícego
- School of Agricultural and Veterinary Sciences, São Paulo State University (UNESP), Jaboticabal, SP, Brazil.
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Parker MR, Tillman EA, Nazarian LA, Barlowe ML, Lincoln JM, Kluever BM. Skin lipids alone enable conspecific tracking in an invasive reptile, the Argentine black and white tegu lizard (Salvator merianae). PLoS One 2023; 18:e0293591. [PMID: 37906547 PMCID: PMC10617720 DOI: 10.1371/journal.pone.0293591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Accepted: 10/17/2023] [Indexed: 11/02/2023] Open
Abstract
Locating potential mates in non-native habitats is one of the most important challenges faced by invasive vertebrate species. The Argentine black and white tegu lizard (Salvator merianae) is a major invasive reptile species in the contiguous United States and is rapidly expanding its range across Florida and the Southeast, in part due to inadequate management strategies and tools. Because a wide array of reptiles, especially squamates (snakes and lizards), have been well-studied for their reliance on chemical cues to locate conspecifics, our project aimed to isolate chemical cues from tegus and assess the ability of adult males and females to use only these cues to make navigation decisions within a Y-maze. Previously, we found that both males and females can follow conspecific scent trails, but the nature of the specific cues used by the tegus was unknown. In this study, we extracted skin lipids from male and female shed skins acquired during the breeding season then tested the extracts for bioactivity at different dilutions prior to Y-maze trials. Both sexes showed positive reactions (e.g., tongue-flicking, nose taps, scratching) to 2:1 skin lipid:hexane dilutions. In the Y-maze, males (n = 7) and females (n = 7) were run in three types of trailing scenarios with these skin lipid extracts: Male-only (pooled lipid extracts from male shed skins), Female-only (extracts from female shed skins), and Male vs. female. Regardless of the tegu lipid type present, tegus preferred to follow the conspecific lipid trail when paired with a neutral control (peanut oil; 2:1 dilution). They also preferred opposite-sex skin lipid trails when paired with same-sex skin lipid trails. We analyzed our results further by comparing them to those of Richard, Bukovich, et al. (2020). We found a synchronization effect of the skin lipids: sex differences in behavior detectable in the scent trail trials were absent when only conspecific skin lipids were present in the environment. Our results indicate that skin lipids alone are sufficient to facilitate mate tracking in S. merianae, these chemical cues induce reliable behavior, and extracted skin lipids have potential for modifying movement patterns of an invasive reptile in their non-native range. If leveraged in concert with current tegu management strategies (i.e., trapping), extracted skin lipids have the potential to bolster management efficacy but field trials are a requisite next step.
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Affiliation(s)
- M. Rockwell Parker
- Department of Biology, James Madison University, Harrisonburg, VA, United States of America
| | - Eric A. Tillman
- National Wildlife Research Center, Florida Field Station, Wildlife Services, U.S. Department of Agriculture, Gainesville, FL, United States of America
| | - Lauren A. Nazarian
- Department of Biology, James Madison University, Harrisonburg, VA, United States of America
| | - Megan L. Barlowe
- Department of Biology, James Madison University, Harrisonburg, VA, United States of America
| | - Julianna M. Lincoln
- Department of Biology, James Madison University, Harrisonburg, VA, United States of America
| | - Bryan M. Kluever
- National Wildlife Research Center, Florida Field Station, Wildlife Services, U.S. Department of Agriculture, Gainesville, FL, United States of America
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Betancourt S, Irizarry KJL, Falk BG, Rutllant J, Khamas W. Micromorphological study of the upper digestive tract of the Argentine tegu (Salvator merianae). Anat Histol Embryol 2022; 51:259-268. [PMID: 35083779 DOI: 10.1111/ahe.12786] [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: 09/13/2021] [Revised: 01/11/2022] [Accepted: 01/12/2022] [Indexed: 11/29/2022]
Abstract
Argentine black and white tegus (Salvator merianae) are omnivorous lizards native to southeastern Brazil, Uruguay, eastern Paraguay and northern Argentina, and are invasive species in Florida and Georgia, USA. They are opportunistic feeders, which is what allow them to have such a diverse variety of foods. Tegus raised a particular concern due to their adaptive capability to different environments. Our goal was to provide a micromorphology baseline of oesophagus and stomach and correlate findings with their dietary and invasive capabilities. Four Argentine black and white tegus were used for this study. We collected and processed specimens from oesophagus and stomach using standard histological techniques and stained tissue sections using Haematoxylin and Eosin (H&E), Periodic Acid Schiff (PAS), Alcian Blue (AB) and Verhoef's elastic stains. The oesophagus was lined with ciliated pseudostratified columnar epithelium (PSCE) with goblet cells. Gut-associated lymphoid tissues (GALT) were present occasionally in the oesophagus and more frequently in the stomach. Tunica muscularis (Tm) of the oesophageal-gastric junction had distinct smooth muscle which could function as a sphincter. The mucosa of the stomach was lined with simple columnar epithelium (SC). The glands had neck and dark oxyntico-peptic cells. The pyloric sphincter had more GALT and mucus cells than other regions. The Tm outer layer is thinner than the inner. Presence of large number of goblet cells would support faster transit of the bolus. The short digestive tract and the histological features observed are consistent with the ability of tegus consumption of large amount of food.
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Affiliation(s)
| | - Kristopher J L Irizarry
- College of Veterinary Medicine, Western University of Health Sciences, Pomona, California, USA
| | - Bryan Glenn Falk
- South Florida Natural Resources Center, Everglades National Park, Homestead, Florida, USA
| | - Josep Rutllant
- College of Veterinary Medicine, Western University of Health Sciences, Pomona, California, USA
| | - Wael Khamas
- College of Veterinary Medicine, Western University of Health Sciences, Pomona, California, USA
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Feuka AB, Nafus MG, Yackel Adams AA, Bailey LL, Hooten MB. Individual heterogeneity influences the effects of translocation on urban dispersal of an invasive reptile. MOVEMENT ECOLOGY 2022; 10:2. [PMID: 35033211 PMCID: PMC8761355 DOI: 10.1186/s40462-022-00300-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 01/03/2022] [Indexed: 05/28/2023]
Abstract
BACKGROUND Invasive reptiles pose a serious threat to global biodiversity, but early detection of individuals in an incipient population is often hindered by their cryptic nature, sporadic movements, and variation among individuals. Little is known about the mechanisms that affect the movement of these species, which limits our understanding of their dispersal. Our aim was to determine whether translocation or small-scale landscape features affect movement patterns of brown treesnakes (Boiga irregularis), a destructive invasive predator on the island of Guam. METHODS We conducted a field experiment to compare the movements of resident (control) snakes to those of snakes translocated from forests and urban areas into new urban habitats. We developed a Bayesian hierarchical model to analyze snake movement mechanisms and account for attributes unique to invasive reptiles by incorporating multiple behavioral states and individual heterogeneity in movement parameters. RESULTS We did not observe strong differences in mechanistic movement parameters (turning angle or step length) among experimental treatment groups. We found some evidence that translocated snakes from both forests and urban areas made longer movements than resident snakes, but variation among individuals within treatment groups weakened this effect. Snakes translocated from forests moved more frequently from pavement than those translocated from urban areas. Snakes translocated from urban areas moved less frequently from buildings than resident snakes. Resident snakes had high individual heterogeneity in movement probability. CONCLUSIONS Our approach to modeling movement improved our understanding of invasive reptile dispersal by allowing us to examine the mechanisms that influence their movement. We also demonstrated the importance of accounting for individual heterogeneity in population-level analyses, especially when management goals involve eradication of an invasive species.
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Affiliation(s)
- Abigail B. Feuka
- U.S. Department of Agriculture Animal and Plant Health Inspection Service, National Wildlife Research Center, 4101 Laporte Ave, Fort Collins, CO 80521-2154 USA
- Colorado State University, Department of Fish, Wildlife, and Conservation Biology and Graduate Degree Program in Ecology, Fort Collins, CO 80523-1474 USA
| | - Melia G. Nafus
- U.S. Geological Survey, Fort Collins Science Center, 2150 Centre Avenue, Building C, Fort Collins, CO 80526-8118 USA
| | - Amy A. Yackel Adams
- U.S. Geological Survey, Fort Collins Science Center, 2150 Centre Avenue, Building C, Fort Collins, CO 80526-8118 USA
| | - Larissa L. Bailey
- Colorado State University, Department of Fish, Wildlife, and Conservation Biology and Graduate Degree Program in Ecology, Fort Collins, CO 80523-1474 USA
| | - Mevin B. Hooten
- The University of Texas at Austin, Department of Statistics and Data Sciences, Welch 5.216, 105 E 24th St D9800, Austin, TX 78705-1576 USA
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Currylow AF, Collier MAM, Hanslowe EB, Falk BG, Cade BS, Moy SE, Grajal‐Puche A, Ridgley FN, Reed RN, Yackel Adams AA. Thermal stability of an adaptable, invasive ectotherm: Argentine giant tegus in the Greater Everglades ecosystem, USA. Ecosphere 2021. [DOI: 10.1002/ecs2.3579] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Affiliation(s)
- Andrea F. Currylow
- U.S. Geological Survey South Florida Field Station Fort Collins Science Center 40001 SR 9336 Homestead Florida 33034 USA
| | - Michelle A. M. Collier
- U.S. Geological Survey South Florida Field Station Fort Collins Science Center 40001 SR 9336 Homestead Florida 33034 USA
| | - Emma B. Hanslowe
- U.S. Geological Survey South Florida Field Station Fort Collins Science Center 40001 SR 9336 Homestead Florida 33034 USA
| | - Bryan G. Falk
- U.S. Geological Survey South Florida Field Station Fort Collins Science Center 40001 SR 9336 Homestead Florida 33034 USA
| | - Brian S. Cade
- U.S. Geological Survey Fort Collins Science Center 2150 Centre Avenue Building C Fort Collins Colorado 80526 USA
| | - Sarah E. Moy
- U.S. Geological Survey South Florida Field Station Fort Collins Science Center 40001 SR 9336 Homestead Florida 33034 USA
| | - Alejandro Grajal‐Puche
- U.S. Geological Survey South Florida Field Station Fort Collins Science Center 40001 SR 9336 Homestead Florida 33034 USA
| | - Frank N. Ridgley
- Conservation and Research Department Zoo Miami 12400 SW 152nd Street Miami Florida 33177 USA
| | - Robert N. Reed
- U.S. Geological Survey Fort Collins Science Center 2150 Centre Avenue Building C Fort Collins Colorado 80526 USA
| | - Amy A. Yackel Adams
- U.S. Geological Survey Fort Collins Science Center 2150 Centre Avenue Building C Fort Collins Colorado 80526 USA
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“Tessie” Offner MT, Campbell TS, Johnson SA. Diet of the Invasive Argentine Black and White Tegu in Central Florida. SOUTHEAST NAT 2021. [DOI: 10.1656/058.020.0210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Marie-Therese “Tessie” Offner
- Department of Wildlife Ecology and Conservation, University of Florida, 110 Newins–Ziegler Hall, PO Box 110430, Gainesville, FL 32611-0430
| | - Todd S. Campbell
- Department of Biology, University of Tampa 401 W. Kennedy Boulevard, Tampa, FL 33606-1490
| | - Steve A. Johnson
- Department of Wildlife Ecology and Conservation, University of Florida, 110 Newins–Ziegler Hall, PO Box 110430, Gainesville, FL 32611-0430
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Goetz SM, Steen DA, Miller MA, Guyer C, Kottwitz J, Roberts JF, Blankenship E, Pearson PR, Warner DA, Reed RN. Argentine Black and White Tegu (Salvator merianae) can survive the winter under semi-natural conditions well beyond their current invasive range. PLoS One 2021; 16:e0245877. [PMID: 33690637 PMCID: PMC7946314 DOI: 10.1371/journal.pone.0245877] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 01/09/2021] [Indexed: 11/19/2022] Open
Abstract
The Argentine Black and White Tegu (Salvator merianae, formerly Tupinambis merianae) is a large lizard from South America. Now established and invasive in southern Florida, and it poses threats to populations of many native species. Models suggest much of the southern United States may contain suitable temperature regimes for this species, yet there is considerable uncertainty regarding either the potential for range expansion northward out of tropical and subtropical zones or the potential for the species establishing elsewhere following additional independent introductions. We evaluated survival, body temperature, duration and timing of winter dormancy, and health of wild-caught tegus from southern Florida held in semi-natural enclosures for over a year in Auburn, Alabama (> 900 km northwest of capture location). Nine of twelve lizards emerged from winter dormancy and seven survived the greater-than-one-year duration of the study. Average length of dormancy (176 d) was greater than that reported in the native range or for invasive populations in southern Florida and females remained dormant longer than males. Tegus grew rapidly throughout the study and the presence of sperm in the testes of males and previtellogenic or early vitellogenic follicles in female ovaries at the end of our study suggest the animals would have been capable of reproduction the following spring. The survival and overall health of the majority of adult tegus in our study suggests weather and climate patterns are unlikely to prevent survival following introduction in many areas of the United States far from their current invasive range.
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Affiliation(s)
- Scott M. Goetz
- U.S. Geological Survey, Fort Collins Science Center, Fort Collins, Colorado, United States of America
- * E-mail:
| | - David A. Steen
- Fish and Wildlife Research Institute, Florida Fish and Wildlife Conservation Commission, Gainesville, Florida, United States of America
| | - Melissa A. Miller
- Department of Wildlife Ecology and Conservation, Fort Lauderdale Research and Education Center, University of Florida, Davie, Florida, United States of America
| | - Craig Guyer
- Department of Biological Sciences, College of Sciences and Mathematics, Auburn University, Auburn, Alabama, United States of America
| | - Jack Kottwitz
- Department of Anatomy, Physiology, and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, Alabama, United States of America
| | - John F. Roberts
- Department of Comparative, Diagnostic, and Population Medicine, College of Veterinary Medicine, University of Florida, Gainesville, Florida, United States of America
| | - Emmett Blankenship
- All Pets Emergency and Referral Center, Alpharetta, Georgia, United States of America
| | - Phillip R. Pearson
- Centre for Conservation, Ecology, and Genetics, Institute for Applied Ecology, University of Canberra, Bruce, Australian Capital City, Australia
| | - Daniel A. Warner
- Department of Biological Sciences, College of Sciences and Mathematics, Auburn University, Auburn, Alabama, United States of America
| | - Robert N. Reed
- U.S. Geological Survey, Fort Collins Science Center, Fort Collins, Colorado, United States of America
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