Another potential cost of tail autotomy: tail loss may result in high ectoparasite loads in Sceloporus lizards

2018 ◽  
Vol 39 (2) ◽  
pp. 191-202 ◽  
Author(s):  
Víctor Argaez ◽  
Israel Solano-Zavaleta ◽  
J. Jaime Zúñiga-Vega

Abstract Tail autotomy is a common phenomenon in lizards that increases the chances of immediate survival during a predation event or agonistic encounter. However, despite short-term benefits, tail regeneration may also impose costs. Several studies have demonstrated that tail loss compromises other vital functions such as lipid storage, reproduction, and the immune system. Several lizard species are hosts of mites and ticks. Here we evaluated in three lizard species from the genus Sceloporus, whether individuals that have lost their tails and invested energy in tail regeneration are more susceptible to ectoparasites. Using a multimodel inference framework, we examined if tail loss and regeneration, as well as sex, body condition, and season (dry or rainy) predict ectoparasite load. Our results indicate that investing energy and resources in tail regeneration compromises defence against ectoparasites. These costs differed between sexes and among species. Overall, ectoparasite load increases during the rainy season and is on average higher in males. In S. grammicus, during the rainy season, males with regenerated tails and in poor body condition had more ectoparasites than males with intact tails in good body condition. In S. megalepidurus, we observed the same effect during the rainy season but in females rather than males. In S. torquatus, we found no effect of tail loss on ectoparasite load. We discuss the possibility that differences observed among species reflect differences in both species-specific physiological trade-offs and local environmental conditions.

2013 ◽  
Vol 63 (3) ◽  
pp. 369-380 ◽  
Author(s):  
Hong-Liang Lu ◽  
Xiang Ji ◽  
Wei-Guo Du

Tail autotomy is an efficient predator escape form, but imposes locomotor costs in many lizard species. It has been hypothesized that locomotor impairment following tail autotomy results from the altered running dynamics or loss of energy available for locomotion, but there is a paucity of data available to demonstrate such effects. We evaluated the locomotor costs of tail loss in a viviparous skink, Sphenomorphus indicus, and examined whether locomotor costs were related to changes in gait characteristics and metabolic rate. Of 24 field-captured adult males with original intact tails, 12 individuals were used as experimental animals, and the remaining 12 as controls. Locomotor performance and CO2 production were measured for the experimental skinks before and after tail removal; the same parameters were measured at the same time for the control skinks. Compared with tailed skinks, the mean locomotor speed and stamina of tailless skinks was reduced by approximately 26% and 17%, respectively. At any given speed, tailless skinks had a shorter stride length for hindlimbs (but not for forelimbs) and a greater stride frequency than did tailed skinks. In S. indicus, locomotor impairment may be a result of the reduced stride length, and energetic constraints on stride frequency. We found no significant change in standard metabolic rate after the skinks underwent tail removal, which may reflect a minor effect on energy expenditure for maintenance. Although the reduction in metabolically active tissue might cause a lower metabolic rate, tail regeneration counteracted such an effect because it was energetically expensive.


2021 ◽  
pp. jeb.234054
Author(s):  
Stefanie S. Bradley ◽  
Erika Howe ◽  
Leah R. Bent ◽  
Matthew K. Vickaryous

Amongst tetrapods, mechanoreceptors on the feet establish a sense of body placement and help to facilitate posture and biomechanics. Mechanoreceptors are necessary for stabilizing the body while navigating through changing terrains or responding to a sudden change in body mass and orientation. Lizards such as the leopard gecko (Eublepharis macularius) employ autotomy – a voluntary detachment of a portion of the tail, to escape predation. Tail autotomy represents a natural form of significant (and localized) mass loss. Semmes-Weinstein monofilaments were used to investigate the effect of tail autotomy (and subsequent tail regeneration) on tactile sensitivity of each appendage of the leopard gecko. Prior to autotomy, we identified site-specific differences in tactile sensitivity across the ventral surfaces of the hindlimbs, forelimbs, and tail. Repeated monofilament testing of both control (tail-intact) and tail loss geckos had a significant sensitization effect (i.e., decrease in tactile threshold, maintained over time) in all regions of interest except the palmar surfaces of the forelimbs in post-autotomy geckos, compared to baseline testing. Although the regenerated tail is not an exact replica of the original, tactile sensitivity is shown to be effectively restored at this site. Re-establishment of tactile sensitivity on the ventral surface of the regenerate tail points towards a (continued) role in predator detection.


Author(s):  
Zulkar Nain ◽  
Md Ariful Islam ◽  
Sadrul Hasan Chowdhury ◽  
Sadia Afroza

Regeneration of lost tail is of great importance to lizards. Anolis carolinensis, a green lizard, is capable of regenerating its tail efficiently after autotomy. Hence, it is considered as a model organism in regeneration study. A. carolinensis shed its tail in order to distract the predator’s attention and thus makes a way to escape. Restoring of the amputated tail takes several days and the mechanism is currently clearly understood. Although save its life, tail regeneration is associated with the impairment of several vital functions in Anoles. In addition, various differences have been observed between original and regenerated tail in terms of mechanism and structure. To date, very little work has been conducted on tail autotomy and regeneration at molecular and genetic level. The genes responsible for regeneration in anoles are identified recently. These genes are evolutionarily conserved through all tetrapod vertebrates. They are, however, in a state of ‘switched-off’ in other vertebrates including humans. Consequently, a throughout study of these so called ‘switched-off’ genes may provide a way of restoring lost organs in human, and thus could revolutionize the modern medical science.


1997 ◽  
Vol 75 (4) ◽  
pp. 542-548 ◽  
Author(s):  
P. H. Niewiarowski ◽  
J. D. Congdon ◽  
A. E. Dunham ◽  
L. J. Vitt ◽  
D. W. Tinkle

Potential costs and benefits of tail autotomy in lizards have been inferred almost exclusively from experimental study in semi-natural enclosures and from indirect comparative evidence from natural populations. We present complementary evidence of the costs of tail autotomy to the lizard Uta stansburiana from detailed demographic study of a natural population. On initial capture, we broke the tails of a large sample of free-ranging hatchlings (560) and left the tails of another large sample (455) intact, and then followed subsequent hatchling growth and survival over a 3-year period. Surprisingly, in 1 out of the 3 years of study, survival of female hatchlings with broken tails exceeded that of female hatchlings with intact tails. Furthermore, no effects of tail loss on survivorship were detected for male hatchlings. However, in 2 years when recaptures were very frequent (1961, 1962), growth rates of hatchlings with broken tails were significantly slower than those of their counterparts with intact tails. We discuss our results in the broader context of estimating the relative costs and benefits of tail autotomy in natural populations, and suggest that long-term demographic studies will provide the best opportunity to assess realized fitness costs and benefits with minimum bias. We also describe how experimentally induced tail autotomy can be used as a technique to complement experimental manipulation of reproductive investment in the study of life-history trade-offs.


2018 ◽  
Vol 285 (1892) ◽  
pp. 20182141 ◽  
Author(s):  
Stefania Casagrande ◽  
Michaela Hau

The trade-off between reproductive investment and survival is central to life-history theory, but the relative importance and the complex interactions among the physiological mechanisms mediating it are still debated. Here we experimentally tested whether baseline glucocorticoid hormones, the redox system or their interaction mediate reproductive investment–survival trade-offs in wild great tits ( Parus major ). We increased the workload of parental males by clipping three feathers on each wing, and 5 days later determined effects on baseline corticosterone concentrations (Cort), redox state (reactive oxygen metabolites, protein carbonyls, glutathione peroxidase [GPx], total non-enzymatic antioxidants), body mass, body condition, reproductive success and survival. Feather-clipping did not affect fledgling numbers, chick body condition, nest provisioning rates or survival compared with controls. However, feather-clipped males lost mass and increased both Cort and GPx concentrations. Within feather-clipped individuals, GPx increases were positively associated with reproductive investment (i.e. male nest provisioning). Furthermore, within all individuals, males that increased GPx suffered reduced survival rates. Baseline Cort increases were related to mass loss but not to redox state, nest provisioning or male survival. Our findings provide experimental evidence that changes in the redox system are associated with the trade-off between reproductive investment and survival, while baseline Cort may support this trade-off indirectly through a link with body condition. These results also emphasize that plastic changes in individuals, rather than static levels of physiological signals, may mediate life-history trade-offs.


2021 ◽  
Author(s):  
◽  
Cielle Stephens

Ecological restoration often involves revegetation. I have investigated the impact of revegetation on the distribution, abundance and body condition of skinks on Stephens Island (Takapourewa). I tested the prediction that only one, Oligosoma infrapunctatum, of the four skink species (Oligosoma lineoocellatum, O. nigriplantare polychroma, O. infrapunctatum andO. zelandicum) will benefit in terms of abundance and distribution from revegetation. Stephens Island is a Wildlife Sanctuary in the north-western Marlborough Sounds, New Zealand. The island is known for its diverse and abundant reptile community. Prior to the mid 19th century Stephens Island was covered in forest. Nearly 80% of this forest was destroyed following the establishment of a lighthouse and farm on the island in 1894. In 1989, when the control of Stephens Island passed to the Department of Conservation, reforestation became a key conservation goal. Stephens Island is currently a mosaic of different habitat types from pasture to coastal forest. Pitfall traps caught skinks for a mark-recapture study in four replicated habitat types: forest, tussock, pasture and replanted.<br><br>Oligosoma lineoocellatum comprised 75% of all individuals caught. Densities of O. lineoocellatum were higher in replanted habitat (3020/ha in December and 3770/ha in March) than tussock (2690/ha in December and 2560/ha in March) and lowest in the pasture (1740/hain December and 1960/ha in March). Rates of captures were too low to perform density estimates for the other three species. Trap occupancy rates indicate O. nigriplantare polychroma is more common in the tussock habitat, and O. infrapunctatum is more common in the replanted habitat. Few O. zelandicum were found, primarily in the tussock habitat. Pasture areas replanted 13 years ago (now scrub habitat) support a higher diversity and abundance of skinks. Forest areas remain depauperate of skinks. Skink preference for replanted areas suggests that, for now, revegetation benefits their populations, possibly due to greater food sources, lower predation pressure and a wider thermal range.<br><br>Body condition (log weight/ log snout-vent length) and proportion of tail loss of skinks were similar in the different habitat types. However, both O. nigriplantare polychroma and O.lineoocellatum had higher body condition in the replanted than the tussock habitat. Juvenile skinks had significantly lower body condition and a lower proportion of tail loss. Skink body condition was not negatively affected by revegetation or by different habitats, despite the large differences between the habitats. Revegetation currently benefits skink populations. Maintaining a mosaic of habitat types is recommended, because, should revegetation create more forest habitat through plantations or plant succession, it is likely that the population of all four species of skink will decline.<br>


2015 ◽  
Vol 2 (4) ◽  
pp. 150108 ◽  
Author(s):  
Camila Vera-Massieu ◽  
Patrick M. Brock ◽  
Carlos Godínez-Reyes ◽  
Karina Acevedo-Whitehouse

Variations in immune function can arise owing to trade-offs, that is, the allocation of limited resources among costly competing physiological functions. Nevertheless, there is little information regarding the ontogeny of the immune system within an ecological context, and it is still unknown whether development affects the way in which resources are allocated to different immune effectors. We investigated changes in the inflammatory response during early development of the California sea lion ( Zalophus californianus ) and examined its association with body condition, as a proxy for the availability of energetic resources. We found that the relationship between inflammation and body condition varied according to developmental stage and circulating levels of leucocyte populations, a proxy for current infection. Body condition was related to the magnitude of the inflammatory response during two of the three developmental periods assessed, allowing for the possibility that the availability of pup energetic reserves can limit immune function. For older pups, the ability to mount an inflammatory response was related to their circulating levels of neutrophils and the neutrophil to lymphocyte ratio, implying that the infection status of an individual will influence its ability to respond to a new challenge. Our results suggest that trade-offs may occur within the immune system and highlight the importance of taking into account ontogeny in ecoimmunological studies.


2010 ◽  
Vol 60 (1) ◽  
pp. 97-113 ◽  
Author(s):  
Marciano Valtierra-Azotla ◽  
Bradford Lister ◽  
Andrés García

AbstractWe investigated behavioral responses of two lizards, Sceloporus melanorhinus and S. utiformis, to environmental seasonality in a tropical dry forest of western Mexico. We conducted focal observations of individuals in the field during both the rainy and dry seasons and compared perch use, foraging and social behaviors and displacement activity within and between species. Our results indicate that seasonal changes occur in the behavior and activity of both male and female S. melanorhinus and S. utiformis. Feeding frequency, social displays, and distances travelled increased significantly in both species during the rainy season. These seasonal changes tended to be more pronounced in the arboreal species; S. melanorhinus. Surprisingly, female S. melanorhinus perched higher than males during the rainy season. Most of the observed changes are similar to the responses to seasonality observed in other lizards, both for species that exist within our study area, and for species that inhabit other seasonal environments in tropical and temperate ecosystems. Thus, the seasonal patterns in behavior documented in this study may represent a general set of behavioral strategies that allow lizards to better adapt to seasonal fluctuations in their environment, such as changes in predation pressure, variation in resource levels, and differences in insolation, temperature, and moisture levels.


Copeia ◽  
1998 ◽  
Vol 1998 (2) ◽  
pp. 376 ◽  
Author(s):  
Stanley F. Fox ◽  
Jason M. Conder ◽  
Allie E. Smith

2017 ◽  
Vol 284 (1847) ◽  
pp. 20162538 ◽  
Author(s):  
Jhan-Wei Lin ◽  
Ying-Rong Chen ◽  
Ying-Han Wang ◽  
Kuen-Chih Hung ◽  
Si-Min Lin

Caudal autotomy in lizards has intrigued scientists for more than 100 years. Because of the relative lack of literature under natural conditions, the complicated association among field autotomy rate, real predation pressure, the long-term cost of tail loss, and the benefit of regeneration remains equivocal. In this study, we conducted a 7-year capture–mark–recapture (CMR) programme with a wild population of a sexually dichromatic lizard, Takydromus viridipunctatus . We used autotomy indexes and a contemporary bird census mega-dataset of four predatory birds as predictors to examine the association between tail loss and predation pressure. We further estimated the survival cost of tail loss and alleviation by regeneration under natural conditions through CMR modelling. We found that large and small avian predators affect lizard survival through the following two routes: the larger-sized cattle egret causes direct mortality while the smaller shrikes and kestrels are the major causes of autotomy. Following autotomy, the survival rate of tailless individuals over the next month was significantly lower than that of tailed individuals, especially males during the breeding season, which showed a decline of greater than 30%. This sex-related difference further demonstrated the importance of reproductive costs for males in this sexually dichromatic species. However, the risk of mortality returned to baseline after the tails were fully grown. This study indicates the benefit of tail regeneration under natural conditions, which increases our understanding of the cost–benefit dynamics of caudal autotomy and further explains the maintenance of this trait as an evolutionarily beneficial adaption to long-term predator–prey interactions.


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