scholarly journals Bite me: Blue tails as a ‘risky-decoy’ defense tactic for lizards

2014 ◽  
Vol 60 (3) ◽  
pp. 333-337 ◽  
Author(s):  
P. W. Bateman ◽  
P. A. Fleming ◽  
B. Rolek
Keyword(s):  
The Body ◽  
Lizard Species ◽  
Predatory Bird ◽  
Clay Model ◽  
Predatory Attack ◽  
Caudal Autotomy ◽  
Brown Clay

Abstract Many lizard species use caudal autotomy to escape entrapment. Conspicuous coloration may increase the likelihood of being attacked, but if that attack can be directed towards the autotomous tail this may ultimately increase the chances of the lizard surviving a predatory attack. We tested the hypothesis that brightly-colored tails function to divert predatory attention away from the head and body using pairs of blue-tailed and all-brown clay model lizards. Predatory bird attacks on the 24 blue-tailed models occurred sooner (P = 0.001) than attacks on the 24 all-brown models, and over 7 days blue-tailed models were attacked more often than all-brown models (P = 0.007). Blue-tailed models were, however, more frequently attacked on the tail than other parts of the body (P < 0.001), while all-brown models were more frequently attacked on the head and body (P = 0.019) which would be more likely to be fatal for a real lizard. Our results suggest that models with a blue tail were more conspicuous than all-brown models, attracting attacks sooner and more often, but that the attacks were predominantly directed at the tail. It is better for individuals to be attacked unsuccessfully many times, than successfully just once. Having a brightly-colored tail may, therefore, act as a ‘risky decoy’. Despite increased conspicuousness, a blue tail increases the likelihood that the lizard would be able to effect escape through caudal autotomy rather than being grabbed by the head or body.

scholarly journals Deceived by stripes: conspicuous patterning on vital anterior body parts can redirect predatory strikes to expendable posterior organs

2016 ◽  
Vol 3 (6) ◽  
pp. 160057 ◽  
Author(s):  
Gopal Murali ◽  
Ullasa Kodandaramaiah
Keyword(s):  
Mechanistic Explanation ◽  
The Body ◽  
Body Parts ◽  
Psychophysical Procedure ◽  
Anterior Half ◽  
Anterior Body ◽  
Caudal Autotomy

Conspicuous coloration, which presumably makes prey more visible to predators, has intrigued researchers for long. Contrastingly coloured, conspicuous striped patterns are common among lizards and other animals, but their function is not well known. We propose and test a novel hypothesis, the ‘redirection hypothesis’, wherein longitudinal striped patterns, such as those found on the anterior body parts of most lacertilians, redirect attacks away from themselves during motion towards less vulnerable posterior parts, for example, the autotomous tail. In experiments employing human ‘predators’ attacking virtual prey on a touchscreen, we show that longitudinal striped patterns on the anterior half of prey decreased attacks to the anterior and increased attacks to the posterior. The position of stripes mattered—they worked best when they were at the anterior. By employing an adaptive psychophysical procedure, we show that prey with striped patterning are perceived to move slower, offering a mechanistic explanation for the redirective effect. In summary, our results suggest that the presence of stripes on the body (i.e. head and trunk) of lizards in combination with caudal autotomy can work as an effective anti-predator strategy during motion.

scholarly journals Identifikasi dan Pola Infestasi Caplak pada Biawak Air (Varanus salvator, Byers, d. 2000)

2020 ◽  
Vol 4 (1) ◽  
Author(s):  
Kartika Aditiya Amelia ◽  
Rahaju Ernawati ◽  
Poedji Hastutiek ◽  
Muchammad Yunus ◽  
Boedi Setiawan ◽  
...  
Keyword(s):  
The Body ◽  
Lizard Species ◽  
Monitor Lizard ◽  
Varanus Salvator ◽  
Binocular Microscope ◽  
Infestation Pattern

The aim of this study is to identify the type of ticks infestation pattern on water monitor lizard (Varanus salvator, Byers, D. 2000) with regard parameters water monitor lizard species, stadium and region of the water monitor lizard’s body. The total samples of 250 ticks from 30 water monitor lizard (18 male lizards and 12 female lizards) were collected every day starting from noon to evening during July to August 2019 at the monitor slaughtering place in Buduran District, Sidoarjo Regency. The tick samples were identified by the permanent mounting slide method without staining and put in bottles containing 10% KOH for 1-10 hours, then each stadium used a nikon eclipse E100 microscope with a 40x magnification binocular microscope. Data was analyzed using Multiple Correspondance Analytics. The result indicate that 30 V. salvator (100%) are positive infested by tick and the samples obtained consisted of 133 Aponomma sp. and 117 Amblyomma sp. in all regions of the body.

Escape distance and escape latency following simulated rapid bird attacks in an Andean lizard, Phymaturus williamsi

Behaviour ◽  
2018 ◽  
Vol 155 (10-12) ◽  
pp. 861-881 ◽  
Author(s):  
Gustavo A. Fava ◽  
Juan C. Acosta
Keyword(s):  
Functional Relationship ◽  
Escape Latency ◽  
Lizard Species ◽  
Predatory Bird ◽  
Antipredatory Behaviour ◽  
Predatory Birds

Abstract Predatory birds represent the greatest risk for many lizard species. However, little is known about the functional relationship between the escape distance and escape latency of lizards during a rapid bird attack. We hypothesised that escape latency and distance in the Andean lizard species Phymaturus williamsi would increase proportionally, but vary according to the means of escape. Over a three-year period we observed seven types of antipredatory behaviour in 98% P. williamsi lizards on simulated predatory bird attacks. Escape distance and latency were positively correlated. 65% of lizards emerged from their refuge within 2 min of an attack. All of these behaviours were positively correlated with escape latency and distance, although we found the former to be more precise. This study contributes to a better understanding of the general antipredatory behaviour in this species of Andean lizard, and will assist in future decisions concerning its conservation.

Life history and ecology of the elegant snake-eyed skink (Cryptoblepharus pulcher) in south-eastern Australia

2019 ◽  
Vol 67 (1) ◽  
pp. 51
Author(s):  
David A. Pike ◽  
Elizabeth A. Roznik ◽  
Jonathan K. Webb ◽  
Richard Shine
Keyword(s):  
Life History ◽  
Body Size ◽  
Natural Habitat ◽  
The Body ◽  
Lizard Species ◽  
Tropical Environments ◽  
Eastern Australia ◽  
Taxonomic Changes ◽  
Gravid Females ◽  
Incubation Temperatures

Detailed information on life history and ecology is essential for successful conservation and management. However, we have relatively little detailed data on the life history and ecology of most small lizard species, relative to other vertebrates, especially those that have undergone recent taxonomic changes. We studied the ecology of the elegant snake-eyed skink (Cryptoblepharus pulcher), a lizard that occurs on trees, fences, walls, and rock outcroppings in eastern Australia that spans temperate to tropical environments. In our temperate-zone study population living in natural habitat, individuals are active year-round, and gravid females were found during the months of September through December. Sexual maturity is reached in 12 months, lifespan is at least three years, and clutch size is typically two eggs. In laboratory incubation experiments, larger eggs were more likely to hatch. Low incubation temperatures (averaging 23 ± 7.5°C versus high temperatures averaging 26 ± 7.5°C) increased incubation duration significantly (range 56–72 days versus 40–51 days) and reduced the body size of hatchlings significantly (17.8 mm versus 18.7 mm snout–vent length). Skinks sheltered beneath small rocks that were not shared simultaneously with predatory snakes, and that reached average temperatures that were up to 3°C warmer during the day than unused rocks. Preferred microhabitats include substrates of rock or soil, and the largest rocks were occasionally shared by up to four individuals of all body size/sex combinations (5.8% of observations were shared, 30.2% of individual rocks were shared). Our study expands upon knowledge of the widespread genus Cryptoblepharus by providing detailed life history and ecological information on C. pulcher that can serve as a baseline for future studies.

Influence of detectability and ability to escape on natural selection of conspicuous autotomous defenses

1991 ◽  
Vol 69 (3) ◽  
pp. 757-764 ◽  
Author(s):  
William E. Cooper Jr. ◽  
Laurie J. Vitt
Keyword(s):  
Natural Selection ◽  
Simple Model ◽  
Conditional Probability ◽  
Body Part ◽  
Probability Of Detection ◽  
The Body ◽  
Body Parts ◽  
Lizard Species ◽  
Predator Prey ◽  
Selection Of

Antipredatory adaptations in which a predator's attack is diverted to body parts that may be sacrificed or are less vulnerable sometimes depend upon the conspicuousness of the body part attacked. The predator's attention is drawn to the emphasized part, which serves as a decoy. Such defenses appear paradoxical in that they increase the probability of detection. However, they simultaneously increase the probability of postdetectional escape enough to decrease the overall probability of being killed. Based on probabilities of detection and of escape following detection, a simple model predicts the conditions in which autotomy and related defenses are favored. For a conspicuous decoy, equilibrium values of the increases in probabilities of detection and of escape following detection are given. Data on the conditional probability of escape after detection are discussed for the scincid lizards Eumeces fasciatus and E. laticeps, which have brightly colored autotomous tails. Versions of the model that split the predator–prey encounter into several successive stages are outlined briefly and illustrated by the data for the two lizard species. Strategies for measuring the probabilities and testing the model's predictions are considered.

scholarly journals Bipedalism in lizards: whole–body modelling reveals a possible spandrel

2003 ◽  
Vol 358 (1437) ◽  
pp. 1525-1533 ◽  
Author(s):  
Peter Aerts ◽  
Raoul Van Damme ◽  
Kristiaan D'Août ◽  
Bieke Van Hooydonck
Keyword(s):  
Evolutionary Biology ◽  
The Body ◽  
Whole Body ◽  
Functional Explanation ◽  
Bipedal Locomotion ◽  
Front Part ◽  
Lizard Species ◽  
Step Cycle ◽  
Biologically Relevant ◽  
Starting Point

This paper illustrates how simple mechanical models based on morphological, ethological, ecological and phylogenetic data can add to discussions in evolutionary biology. Bipedal locomotion has evolved on numerous occasions in lizards. Traits that appear repeatedly in independent evolutionary lines are often considered adaptive, but the exact advantages of bipedal locomotion in lizards remain debated. Earlier claims that bipedalism would increase maximal running speed or would be energetically advantageous have been questioned. Here, we use ‘whole body’ mechanical modelling to provide an alternative solution to the riddle. The starting point is the intermittent running style combined with the need for a high manoeuvrability characterizing many small lizard species. Manoeuvrability benefits from a caudal shift of the centre of mass of the body (body–COM), because forces to change the heading and to align the body to this new heading do not conflict with each other. The caudally situated body–COM, however, might result in a lift of the front part of the body when accelerating (intermittent style), thus resulting in bipedal running bouts. Based on a momentum–impulse approach the effect of acceleration is quantified for a mechanical model, a virtual lizard (three segments) based on the morphometrics of Acanthodactylus erythrurus (a small lacertid lizard). Biologically relevant input (dimensions, inertial properties, step cycle information, etc.) results in an important lift of the front part of the body and observable distances passively covered bipedally as a consequence of the acceleration. In this way, no functional explanation of the phenomenon of lizard bipedalism is required and bipedalism can probably be considered non–adaptive in many cases. This does not exclude, however, some species that may have turned this consequence to their benefit. For instance, instantaneous manipulation of the position of the centre of the body–COM allows stable, persisting bipedal running. Once this was achieved, the bipedal spandrel could be exploited further.

scholarly journals DOES APOSEMATIC COLORATION REDUCE PREDATION RISK IN SNAKES? A SHORT PERIOD EXPERIMENT USING PLASTICINE SNAKE MODELS

2020 ◽  
Vol 14 (2) ◽  
pp. 35
Author(s):  
Tatiane Bertuzzi ◽  
David Santos de Freitas ◽  
Luiz Liberato Costa Corrêa ◽  
Alice Pozza Rodrigues ◽  
Mateus De Oliveira ◽  
...  
Keyword(s):  
Predation Risk ◽  
The Body ◽  
The Other ◽  
Warning Sign ◽  
Dorsal Part ◽  
Color Patterns ◽  
Aposematic Coloration ◽  
Short Period ◽  
Predatory Attack ◽  
Red Coloration

Aposematism in an anti-predation mechanism that occurs when animals exhibit conspicuous signals, which are often of a contrasting color patterns, to alert potential predators of their unpalatability or toxicity. This study aims to test (in a short period) the effectiveness of aposematic coloration by comparing the predatory attack upon snakes models with and without an alert coloration on the body. To simulate snakes, we made 80 greenish plasticine snake models. Half of the models had a red strip on the dorsal part of the body, imitating an aposematic coloration. The other half of the models had only a greenish tint. The models were exposed to predators for 12 hours in an area with countryside vegetation.. Among the 20 models showing signs of predation, 65% were purely greenish models and 35% were models with red coloration on the back. Attaks at extremities (head and tail) were meaningly more frequent on models with red coloration. Our results suggest the efficiency of red coloration as a warning sign and anti-predation mechanism, since the models with red coloration, imitating aposematic preys, were less preyed and were attacked preferentially at the extremities, which suggests caution by the predator.

scholarly journals Patterns of infestation by chigger mites in four diurnal lizard species from a restinga habitat (Jurubatiba) of Southeastern Brazil

2003 ◽  
Vol 63 (3) ◽  
pp. 393-399 ◽  
Author(s):  
M. Cunha-Barros ◽  
M. Van Sluys ◽  
D. Vrcibradic ◽  
C. A. B. Galdino ◽  
F. H. Hatano ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Body Size ◽  
Standard Deviation ◽  
The Body ◽  
Southeastern Brazil ◽  
Body Parts ◽  
Lizard Species ◽  
Chigger Mite ◽  
The Relationship ◽  
Janeiro State

We studied the parasitism by larvae of the chigger mite Eutrombicula alfreddugesi on the lizard community of Restinga de Jurubatiba, Rio de Janeiro State, Southeastern Brazil. We investigated the patterns of infestation (prevalence and intensity) of chigger mites in four sympatric lizards: Tropidurus torquatus, Mabuya agilis, M. macrorhyncha and Cnemidophorus littoralis. All lizards collected were checked for the presence of mites, which were counted under stereomicroscope. We tested the relationship between intensity of infestation and lizard body size for each species using regression analysis. The prevalences and mean intensities (+ one standard deviation) of infestation on each host species were, respectively: 100%; 86.4 + 94.6 in T. torquatus (n = 62); 100%; 20.9 + 9.3 in M. agilis (n = 7); 100%; 11.1 + 13.1 in M. macrorhyncha (n = 12); and 95.2%; 19.1 + 16.8 in C. littoralis (n = 21). Only for C. littoralis did body size significantly affect the intensity of infestation (r = 0.27, p = 0.02). For all lizard species, the body parts where chiggers occurred with the highest intensity were those of skin folds and joint regions.

scholarly journals Effects of Caudal Autotomy on the Locomotor Performance of Micrablepharus Atticolus (Squamata, Gymnophthalmidae)

2021 ◽  
Author(s):  
Naiane Arantes Silva ◽  
Gabriel Henrique O. Caetano ◽  
Pedro Henrique Campelo ◽  
Vitor Hugo Gomes Lacerda Cavalcante ◽  
Leandro Braga Godinho ◽  
...  
Keyword(s):  
Natural Environments ◽  
Locomotor Performance ◽  
Lizard Species ◽  
Long Tail ◽  
Sprint Speed ◽  
Behavioral Traits ◽  
Improve Model ◽  
Caudal Autotomy ◽  
First Time

Caudal autotomy is a dramatic adaptation used by many lizard species to evade predators. Most studies to date indicate that caudal autotomy impairs lizard locomotor performance. Surprisingly, some species bearing the longest tails show negligible impacts of caudal autotomy on sprint speed. Part of this variation has been attributed to lineage effects. For the first time, we model the effects of caudal autotomy on the locomotor performance of a gymnophthalmid lizard, Micrablepharus atticolus, characterized by a long and bright blue tail. To improve model accuracy, we incorporated the effects of several covariates. We found that body temperature, pregnancy, mass, collection site, and the length of the regenerated portion of the tail were the most important predictors of locomotor performance in Micrablepharus atticolus. However, sprint speed was unaffected by tail loss. Apparently, the long tail of M. atticolus is more useful when using undulation amidst the leaf litter and not when using quadrupedal locomotion on a flat surface. Our findings highlight the intricate relationships among physiological, morphological, and behavioral traits. We suggest that future studies about the impacts of caudal autotomy among long-tailed lizards should consider the role of different microhabitats/substrates on locomotor performance, using laboratory conditions that closely mimic their natural environments.

Chamber refilling in Nautilus

1982 ◽  
Vol 62 (2) ◽  
pp. 469-475 ◽  
Author(s):  
Peter D. Ward ◽  
Lewis Greenwald
Keyword(s):  
The Body ◽  
Shell Material ◽  
Neutral Buoyancy ◽  
Body Chamber ◽  
Predatory Attack

Freshly captured Nautilus macromphalus were observed to place new cameral liquid into emptied or partially emptied chambers, both at the surface and at 250 m, in response to sudden buoyancy increase. The sudden addition of buoyancy was accomplished either through removal of cameral liquid from chambers, removal of shell material from the apertural region of the body chamber, or by cementing buoyant corks on the sides of the shell. A maximal refilling rate of 100 μl/h was observed. The osmolality of refilled cameral liquid was observed to match closely the osmolality of the original cameral liquid. The refilling mechanism allows Nautilus to regain neutral buoyancy after sudden buoyancy gain, such as could be expected to occur from shell loss due to predatory attack on the Nautilus, or from shell breakage.

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