Common side-blotched lizard

{{Short description|Species of lizard}} {{Speciesbox | image = Joshua Tree NP - Desert Side-blotched Lizard - 1.jpg | status = LC | status_system = IUCN3.1 | status_ref = <ref name = iucn>{{cite iucn |author=Hammerson, G.A. |author2=Frost, D.R. |author3=Santos-Barrera, G. |year=2007 |title=''Uta stansburiana'' |article-number=e.T64180A12744259 |doi=10.2305/IUCN.UK.2007.RLTS.T64180A12744259.en}}</ref> | genus = Uta | species = stansburiana | authority = [[Spencer Fullerton Baird|Baird]] & [[Charles Frédéric Girard|Girard]], 1852 | range_map = Uta stansburiana distribution.png | subdivision_ranks = Subspecies | subdivision = *''U. s. stansburiana'' [[northern side-blotched lizard]] *''U. s. nevadensis'' [[Nevada side-blotched lizard]] *''U. s. uniformis'' [[plateau side-blotched lizard]] *''U. s. elegans'' [[western side-blotched lizard]] *''U. s. stellata'' [[San Benito side-blotched lizard]] *''U. s. concinna'' [[Cedros side-blotched lizard]] *''U. s. martinensis'' San Martin side-blotched lizard (disputed) *''U. s. taylori'' Taylor's side-blotched lizard (disputed) | synonyms = {{unbulleted list |''Uta concinna'' |''Uta elegans'' |''Uta levis'' |''Uta martinensis'' |''Uta stansburiana hesperis'' |''Uta stellata'' |''Uta wrighti'' |''Uta irregularis'' |''Uta lateralis'' |''Uta nelsoni'' |''Uta tuberculata'' }}  }}

The '''common side-blotched lizard''' ('''''Uta stansburiana''''') is a species of [[side-blotched lizard]] in the [[Family (taxonomy)|family]] [[Phrynosomatidae]]. The species is native to dry regions of the western United States and northern Mexico. It is notable for having a unique form of [[polymorphism (biology)|polymorphism]] wherein each of the three different male morphs utilizes a different strategy in acquiring mates. The three morphs compete against each other following a pattern of [[Rock paper scissors#Analogues in real life|rock paper scissors]], where one morph has advantages over another but is outcompeted by the third.<ref name=S&L1996 /><ref name=Z&S2000 /><ref name=S&L1991 />

==Etymology== The [[Specific name (zoology)|specific epithet]], ''stansburiana'', is in honor of Captain [[Howard Stansbury]] of the US Corps of Topographical Engineers, who collected the first specimens while leading the 1849-1851 expedition to explore and survey the [[Great Salt Lake]] of [[Utah]].<ref>Moll, Edward (2005). "''Uta stansburiana'' Baird and Girard, 1852 - Common Side-blotched Lizard". Sonoran Herpetologist.</ref><ref>Beolens, Bo; Watkins, Michael; Grayson, Michael (2011). ''The Eponym Dictionary of Reptiles''. Baltimore: Johns Hopkins University Press. xiii + 296 pp. {{ISBN|978-1-4214-0135-5}}. (''Uta stansburiana'', p. 251).</ref>

== Taxonomy == [[File:Desert Side-blotched Lizard - Uta stansburiana stejnegeri, White Sands National Monument, Alamogordo, New Mexico.jpg|right|thumb|Image of common side-blotched lizard. A distinguishing feature of this species is the dark blotch behind the front leg, which is clearly seen in this image. The dark blotch is generally less prominent in females than in this male.]] The systematics and [[Taxonomy (biology)|taxonomy]] of the widespread and variable lizards of the [[genus]] ''[[Uta (genus)|Uta]]'' is much disputed.<ref>{{cite journal |last1=Grismer |first1=L. Lee |title=Three New Species of Intertidal Side-Blotched Lizards (Genus Uta) from the Gulf of California, México |journal=Herpetologica |date=1994 |volume=50 |issue=4 |pages=451–474 |jstor=3892721 }}</ref><ref>{{cite journal | last1 = Upton | first1 = Darlene E. | last2 = Murphy | first2 = Robert W. | year = 1997 | title = Phylogeny of the side-blotched lizards (Phrynosomatidae:'' Uta'') based on mtDNA sequences: support for midpeninsular seaway in Baja California | journal = Molecular Phylogenetics and Evolution | volume = 8 | issue = 1| pages = 104–113 | doi = 10.1006/mpev.1996.0392 | pmid = 9242598 }}</ref> Countless forms and morphs have been described as subspecies or even distinct species.<ref>{{cite journal | author = Schmidt, Karl Patterson | year = 1921 | title = New species of North American lizards of the genera ''Holbrookia'' and ''Uta'' | hdl=2246/4613 |hdl-access=free | journal = American Museum Novitates | issue = 22 | pages = 1–6 | author-link = Karl Patterson Schmidt }}</ref> * The forms which occur in most of Mexico (except [[Baja California]]) have been recognized as a very distinct species, the eastern side-blotched lizard, ''Uta stejnegeri''.<ref>{{cite journal|author=Collins, Joseph T. |year=1991 |title=Viewpoint: a new taxonomic arrangement for some North American amphibians and reptiles |url=http://www.cnah.org/pdf_files/5.pdf |journal=Herpetological Review |volume=22 |issue=2 |pages=42–43 |url-status=dead |archive-url=https://web.archive.org/web/20070929092139/http://www.cnah.org/pdf_files/5.pdf |archive-date=2007-09-29 |author-link=Joseph T. Collins }}</ref> * Populations from [[San Benito Island|San Benito]] and [[Cedros Island]]s were separated as distinct species ''Uta stellata'' and ''U. concinna'', but are now included in ''U. stansburiana''. * Those of [[Isla Santa Catalina]] and [[Isla Salsipuedes]], ''[[Santa Catalina side-blotched lizard|U. squamata]]'' and ''[[Salsipuedes Side-blotched Lizard|U. antiqua]]'' are sometimes included in this species, too, but this is certainly not correct in the latter case, and probably in the former also. * Based on the same data that would give ''U. squamata'' species rank, the southern Baja California populations could arguably be split off (as ''Uta elegans''), too. * The proposed subspecies ''martinensis'' and ''taylori'' are probably not valid. * The populations on [[Isla Ángel de la Guarda]], [[Isla Mejia]] and [[Isla Rasa]] almost certainly constitute a [[Angel de la Guarda side-blotched lizard|separate species]] closer to ''[[San Pedro Mártir side-blotched lizard|Uta palmeri]]'', and that of [[San Esteban Island]] may so too, being close to ''squamata''. * The status of the [[Isla Encantada]] group populations named as ''[[Enchanted side-blotched lizard|Uta encantadae]]'', ''[[El Muerto Island side-blotched lizard|U. lowei]]'' and ''[[Swollen-nosed side-blotched lizard|U. tumidarostra]]'' is not completely resolved; these distinct populations are of comparatively recent origin and are sometimes included in this species, but their unique adaptations to living in [[intertidal]] habitat suggest they should be considered distinct; whether as one or as three species remains unresolved.<ref>Murphy, Robert W. & Aguirre-León, Gustavo (2002): The Nonavian Reptiles: Origins and Evolution. ''In:'' Case, Ted & Cody, Martin (eds.): ''A New Island Biogeography of the Sea of Cortés'': 181-220. Oxford University Press. {{ISBN|0-19-513346-3}} [http://labs.eeb.utoronto.ca/murphy/PDFs%20of%20papers/2002%20Murphy%20Nonavian.pdf PDF fulltext] [http://labs.eeb.utoronto.ca/murphy/PDFs%20of%20papers/2002%20Checklist%20Cortes%20Islands.pdf Appendices 2-4]</ref>

[[File:Uta_stansburiana_7963.JPG|right|thumb|The male (pictured above) is more brightly colored than the female and is usually distinguished by the presence of blue spots on its back, especially near the base of the tail. Also, the base of the tail is swollen in the male.<ref name=californiaherps>{{cite web|url= http://www.californiaherps.com/lizards/pages/u.s.elegans.html|title=Western Side-blotched Lizard - Uta stansburiana elegans |author= |date=2018 |website=California Herps |publisher=californiaherps.com |access-date=2018-08-07 }}</ref>]]

==Physical description== The common side-blotched lizard displays a moderate degree of [[sexual dimorphism]]. Males can grow up to 60mm (2.4 inches) from snout to vent, while females are typically a little smaller. Females may have stripes along their backs/sides, or may be relatively drab. Both sexes have a dark blotch on the lateral aspect (side) of the thorax, just behind the front limbs.<ref name=T1967 /> This dark blotch is generally less prominent in females than in males. The degree of pigmentation varies with both sex and population. Some males can have blue flecks spread over their backs and tails, and their sides may be yellow or orange, while others may be unpatterned. Males are usually more brightly colored than females, and often have blue spots on the [[Anatomical_terms_of_location#Dorsal_and_ventral|dorsum]], especially near the base of the tail. Also, males display a [[Hemipenis|hemipenal]] bulge at the base of the tail.<ref name=californiaherps/>

Males of the species exhibit three distinct color [[polymorphism (biology)|polymorphisms]] in their throat colors. The skin of the throat may be orange, blue, or yellow. Coloration of the throat is critical, as it is closely related to the mating behavior of both males and females.<ref name=S&L1996 /><ref name=A&S2001 /> The different throat morphologies displayed by the male side-blotched lizard is also correlated with their sprinting speed. Across all three morphs, sprinting speed is positively correlated with blue hue, the brightness of the yellow throat, and the level of saturation of the orange throats. The relationship between physical capabilities and coloration may play a role in sexual competition amongst male side-blotched lizards.<ref name="Utah State University">{{cite journal |last1=Jensen |first1=Forest |title=Sexual Coloration and Performance Capacity in Male Side-Blotched Lizards (UTA Stansburiana). |url=https://digitalcommons.usu.edu/biology_posters/187/ |journal=Biology Posters |date=November 2017 |publisher=Utah State University}}</ref>

The speed of these male lizards during the end of their reproductive seasons is dependent on their body temperature. The maximum sprinting speed of these lizards is achieved when the body temperature is between 35-38 degrees Celsius.<ref name="John Wiley & Sons">{{cite journal |last1=Waldschmidt |first1=Steve |last2=Tracy |first2=Richard |title=Interactions between a Lizard and Its Thermal Environment: Implications for Sprint Performance and Space Utilization in the Lizard Uta Stansburiana |journal=Ecology |year=1983 |volume=64 |issue=3 |pages=476–484 |publisher=John Wiley & Sons |doi=10.2307/1939967 |jstor=1939967 |bibcode=1983Ecol...64..476W }}</ref>

==Physiology== When comparing populations within wind farms and in neighbouring control sites, no differences in oxidative stress are seen in the side-blotched lizard. In females [[oxidative stress]] also increases with the number of yolk follicles produced.<ref name="Alaasam 2021">{{cite journal|last1=Alaasam|first1=Valentina J.|last2=Keehn|first2=Jade E.|last3=Durso|first3=Andrew M.|last4=French|first4=Susannah S.|last5=Feldman|first5=Chris R.|date=2021|title=Ectoparasite Load Is Reduced in Side-Blotched Lizards (''Uta stansburiana'') at Wind Farms: Implications for Oxidative Stress|journal=Physiological and Biochemical Zoology|volume=94|issue=1|pages=35–49|doi=10.1086/712100|pmid=33296296|s2cid=228076503}}</ref>

=== Genetic determination of throat-color polymorphism === Analysis of DNA nuclear [[microsatellite]]s has provided genetic evidence for the rock-paper-scissors behavior pattern of male side-blotched lizard competition. In populations where all three morphs are present, [[Shared parenting|shared paternity]] between yellow- and blue-throated individuals occurs at a rate significantly below random chance, while shared paternity between yellow- and orange-throated males occurs at a rate significantly above chance. In addition, blue-throated males often shared paternity with orange-throated males, despite having mostly yellow-throated neighbors.<ref name="Z&S2000" />

[[Blood plasma]] [[testosterone]] levels play an important role in the creation of the three male morphs both during and after development. Orange-throated males have 46-48% higher plasma testosterone levels compared to their yellow- or blue-throated counterparts. Experimental elevation of plasma testosterone levels in the other two male morphs led to increases in endurance, aggressiveness, and [[territory (animal)|territory]] size to the degree expressed by normal orange-throated males. In addition, the transformation of yellow-throated males to blue-throated males is accompanied by an increase in their plasma testosterone levels.<ref name="Setal2000" />

Throat color in side-blotched lizards is genetically determined, and has high [[heritability]].<ref name="S&L1996" /> It is determined by a single [[Mendelian inheritance|Mendelian factor]] with three alleles. In males, the ''o'' allele is the [[Genetic dominance|dominant]] allele, and the ''b'' allele is [[recessive]] to the ''y'' allele. Therefore, [[phenotype|phenotypically]] orange-throated males have [[genotype]]s of either ''oo'', ''ob'', or ''oy''. Yellow-throated males have genotypes of either ''yy'' or ''yb'', and blue-throated males are exclusively ''bb''. In females, all individuals with the dominant ''o'' allele are orange-throated, while those lacking an ''o'' allele develop yellow throats.<ref name="A&S2001" />

===Tails=== For the side-blotched lizard, limbs serve as an [[Anti-predator adaptation|anti-predatory defense]] – their ability to survive without a tail allows them to escape predation after being caught. While this defense mechanism can be advantageous, the loss of a tail can also negatively impacts a lizard’s survival and reproduction. For the ''Uta stranburiana'', the loss of a tail is accompanied by a loss of [[social status]] amongst their peers. This can contribute to them having a hard time acquiring and maintaining a superior [[home range]]. The influence of tail loss on survivorship, however, is only significant during conditions of low [[mortality rate|mortality]] – when the overall mortality rate of side-blotched lizards is 30-40% higher than average, the condition of the tail does not impact the survival of adults and [[juvenile (organism)|juvenile]]s.<ref>{{cite journal |last1=Althoff |first1=David M. |last2=Thompson |first2=John N. |title=The effects of tail autotomy on survivorship and body growth of Uta stansburiana under conditions of high mortality |journal=Oecologia |date=December 1994 |volume=100 |issue=3 |pages=250–255 |doi=10.1007/BF00316952 |bibcode=1994Oecol.100..250A |pmid=28307008 |s2cid=7299762 }}</ref> This is because the tails of side-blotched lizards are not energetic lipids stores. As mentioned earlier, lizards that lose their tails are at a greater risk of predation than lizards with their tails intact. Since social status is an important survival mechanism amongst side-blotched lizards, researchers have suggested that the loss of a tail, which contributes to a decrease in social status, forces tailless side-blotched lizards to inhabit more inferior home ranges. Therefore, in addition to losing a physiological [[defense mechanism]] when losing their tails, side-blotched lizards are also inclined to inhabit inferior living conditions which bolsters their risk of predation.<ref>{{cite journal |last1=Wilson |first1=Byron S. |title=Tail injuries increase the risk of mortality in free-living lizards (Uta stansburiana) |journal=Oecologia |date=1992 |volume=92 |issue=1 |pages=145–152 |doi=10.1007/BF00317275 |pmid=28311825 |bibcode=1992Oecol..92..145W |s2cid=13113025 }}</ref>

==Mating== === Rock–paper–scissors mechanism === Male side-blotched lizards exhibit distinct [[polymorphism (biology)|polymorphism]] in their throat colors, and can be divided into three different categories. Each of these three different morphs varies in how it competes for mates, and variation within a breeding population is maintained by a [[Rock paper scissors#Rock paper scissors analogs in nature|rock paper scissors mechanism]] of [[frequency-dependent selection|frequency-dependent]] [[sexual selection]]. A cycle is created where the least common morph of one breeding season often has the largest number of mature living offspring in the next year. This is because one morph does particularly well against another, but poorly in comparison to the third.<ref name="S&L1996">{{cite journal|last=Sinervo|first=B.|author2=C.M. Lively|year=1996|title=The rock–paper–scissors game and the evolution of alternative male strategies|journal=Nature|volume=380|issue=6571|pages=240–243|doi=10.1038/380240a0|bibcode=1996Natur.380..240S|s2cid=205026253}}</ref>

*Orange-throated males are "ultradominant". They are the largest and most aggressive morph, defending relatively large (about 100 m2 or 120 yd2) territories and keeping harems of females with which they mate. They are adept at stealing mates from blue-throated individuals, but are vulnerable to [[cuckoldry]] by the yellow-throated female mimics.<ref name=S&L1996/> Orange-throated males also have significantly reduced yearly survival rates compared to the other two morphs.<ref name="Setal2000">{{cite journal|last=Sinervo|first=Barry |author2=Donald B. Miles |author3=W.Anthony Frankino |author4=Matthew Klukowski |author5=Dale F. DeNardo |year=2000|title=Testosterone, Endurance, and Darwinian Fitness: Natural and Sexual Selection on the Physiological Bases of Alternative Male Behaviors in Side-Blotched Lizards|journal=Hormones and Behavior|volume=38|issue=4|pages=222–233|doi=10.1006/hbeh.2000.1622|pmid=11104640|s2cid=5759575 }}</ref> *Blue-throated males are "dominant". They are intermediate in size, and guard smaller territories containing only a single female. As they only have one mate to defend, they are better at catching yellow-throated sneaks, but are also susceptible to having their mates stolen by the larger, more aggressive orange-throated males.<ref name=S&L1996/> *Yellow-throated males are "[[Sneaking (biology)|sneakers]]". Their coloration is similar to that of sexually mature females, and they typically mimic female "rejection" displays when they encounter dominant orange- or blue-throated males. Unlike the other morphs, yellow-throated males do not hold territories. Instead, they have wide-reaching home ranges that may overlap with several other lizards’ territories.<ref name=S&L1996/><ref name=Setal2000/> They rely on their mimicry to sneak matings with unattended females. This is more easily achieved among the harems kept by orange-throated males than by the single, closely guarded mate of the blue-throated males. Though orange-throated males have the highest mortality rates, yellow-throated males have higher relative rates of posthumous fertilization ([[posthumous birth]]), indicating an increased reliance on [[sperm competition]] as part of their reproductive strategy.<ref name="Z&S2000">{{cite journal|last=Zamudio|first=Kelly R.|author2=Barry Sinervo|year=2000|title=Polygyny, mate-guarding, and posthumous fertilization as alternative male mating strategies|journal=PNAS|volume=97|issue=26|pages=14427–14432|doi=10.1073/pnas.011544998|pmid=11106369|pmc=18935|bibcode=2000PNAS...9714427Z|doi-access=free}}</ref> Yellow-throated males can in specific instances transform into blue-throated males over the course of the breeding season. This transformation is usually triggered by the death of a nearby dominant male, and the blue patches the yellow-throated males develop is qualitatively distinct from the blue patches of genetically blue-throated males. Not all yellow-throated males transform, but when they do, they give up their female mimicry and adopt the "dominant" morph's behavior pattern. No transformations in the other direction, in which dominant males gain yellow-throat coloration, have been observed.<ref name=Setal2000/>

Female side-blotched lizards have also been shown to exhibit behaviorally correlated differences in throat coloration. Orange-throated females are considered [[r-strategist]]s. They typically produce large clutches consisting of many small eggs. In contrast, yellow-throated females are [[K-strategist]]s that lay fewer, larger eggs. Like the male morphs, the frequencies of these two female morphs also cycle with time. However, the cycle is shorter – two years in comparison to the male morphs’ four- or five-year cycle – and is not a result of frequency-dependent sexual selection. Instead, orange-throated females are more successful at lower population densities, where competition for food is less fierce and less selection pressure from [[predation]] occurs.<ref name="A&S2001">{{cite journal|last=Alonzo|first=S.H.|author2=Barry Sinervo|year=2001|title=Mate choice games, context-dependent good genes, and genetic cycles in the side-blotched lizard, ''Uta stansburiana''|journal=Behavioral Ecology and Sociobiology|volume=49|issue=2–3|pages=176–186|doi=10.1007/s002650000265|s2cid=23799664}}</ref> When population density is high and/or when predators abound, yellow-throated females tend to have higher reproductive success. In general, their larger hatchlings have higher short-term and long-term survival rates, and these advantages are magnified in times of scarcity. Side-blotched lizards show displays and aggression shortly after hatching, and even minute differences in size can lead to increased social dominance and capacity to outcompete the smaller hatchlings.<ref name="F&F1984">{{cite journal|last=Ferguson|first=Gary W.|author2=Stanley F. Fox|year=1984|title=Annual Variation of Survival Advantage of Large Juvenile Side-Blotched Lizards, ''Uta stansburiana'': Its Causes and Evolutionary Significance|journal=Evolution|volume=38|issue=2|pages=342–349|doi=10.2307/2408492|jstor=2408492|pmid=28555919}}</ref>

==Reproduction== [[File:Utastansburiana.jpg|225px|thumb|left|Image of common side-blotched lizards mating. The male lizard is on the right, and the female lizard is on the left.]]Female side-blotched lizards lay [[clutch (eggs)|clutches]] with an average of 5.1 eggs and a maximum of 9 eggs in a single clutch. Smaller clutch sizes, often associated with yellow-throated females, have an increased frequency of eggs bursting upon being laid or [[egg binding]], suggesting an upper physiological limit to how much a female can invest in each individual egg she lays.<ref name="S&L1991">{{cite journal|last=Sinervo|first=Barry|author2=Paul Licht|year=1991|title=Proximate Constraints on the Evolution of Egg Size, Number, and Total Clutch Mass in Lizards|journal=Science|volume=252|issue=5010|pages=1300–1302|doi=10.1126/science.252.5010.1300|pmid=17842955|bibcode=1991Sci...252.1300S|s2cid=37108580}}</ref>

The presence of a tail on female side-blotched lizards can impact reproduction. Tailless female lizards have reduced overall [[Survivorship curve|survivorship]] due to the increased risk of predation they experience without this physiological defense mechanism. Although tailless female side-blotched lizards experience an increased risk of death, the loss of a tail does not impose an [[Handicap principle|energetic handicap]] on them that negatively impacts their potential growth and reproduction. Additionally, the lack of a tail in adult males attempting to mate with females during the spring decreases their ability to successfully [[Copulation (zoology)|copulate]] which suggests that tails are sufficient to increase the likelihood of males attracting sexual partners during reproductive seasons.<ref name="Fox McCoy 2000">{{cite journal |last1=Fox |first1=S. F. |last2=McCoy |first2=J. K. |title=The effects of tail loss on survival, growth, reproduction, and sex ratio of offspring in the lizard Uta stansburiana in the field |journal=Oecologia |date=23 February 2000 |volume=122 |issue=3 |pages=327–334 |doi=10.1007/s004420050038 |pmid=28308283 |bibcode=2000Oecol.122..327F |s2cid=25729112 }}</ref> In addition to the way that physiological traits affect female reproduction, the age of females, the environment they inhabit, and the time in the reproductive season also affect female fecundity. A study conducted by researchers at Utah State University confirmed that older females lay more eggs than yearling females and that the annual variations that have been previously observed in female [[fecundity]] are the result of variations in the numbers of clutches (clutch frequency), not by the average size of clutches produced.<ref name="Turner Medica Smith 1973">{{cite report |last1=Turner |first1=F. B. |last2=Medica |first2=P. A. |last3=Smith |first3=D. D. |title=Reproduction and survivorship of the lizard, ''Uta stansburiana'', and the effects of winter rainfall, density and predation on these processes |series=Research Memorandum RM 73-26 |date=1973 |publisher=U.S. Fish and Wildlife Service |url=https://digitalcommons.usu.edu/dbiome_memo/64/ }}</ref>

As the reproductive season progresses for side-blotched lizards, females tend to produce fewer but larger eggs. Researchers hypothesize that this occurs because of the [[Trade-off|tradeoff]] between egg size and clutch size. Later in their reproductive seasons, female lizards are selected to increase their egg size to produce larger and more competitively superior [[hatchling]]s because during this time in the season, food is generally more scarce and juvenile density is high. It has also been suggested that selection favors smaller clutches at the end of the reproductive season because females invest their remaining reproductive energy into their last clutches. Therefore, these females want to ensure that this remaining energy was well spent and that her hatchlings will have a good chance of [[survival]]. With a decreased clutch size, when the female side-blotched lizard allocates her energy into her last clutch, each hatchling will receive more [[parental investment]] from their mother – assuming that the mother’s energy is divided equally among the hatchlings of the smaller clutch.<ref name="Springer">{{cite journal |last1=Nussbuam |first1=Ronald |title=Seasonal Shifts in Clutch Size and Egg Size in the Side-Blotched Lizard, Uta Stansburiana Baird and Girard |journal=Oecologia |year=1981 |volume=49 |issue=1 |pages=8–13 |publisher=Springer|doi=10.1007/BF00376891 |pmid=28309442 |bibcode=1981Oecol..49....8N |hdl=2027.42/47737 |s2cid=22402124 |hdl-access=free }}</ref> Researchers at [[Utah State University]] also verified that clutch frequency is [[Correlation|positively correlated]] with the density of rainfall. Their results indicated that there is a [[Causality|causative association]] between winter rainfall and clutch frequency for female side-blotched lizards. The researchers suggested that air temperatures play an important role in the timing and deposition of the first spring clutch – that increases in winter rainfall induce earlier clutches in female side-blotched lizards.<ref name="Turner Medica Smith 1973"/>

==Speciation== The "rock-paper-scissors" mating strategy is a genetically-based male [[Polymorphism (biology)|polymorphism]] that has been maintained over millions of years throughout many populations of side-blotched lizard in the United States and Mexico. However, speciation has resulted from the formation of reproductive isolation between populations when a population loses of one or more of the male morphologies.<ref name=":1">{{cite journal |last1=Gray |first1=Suzanne M. |last2=McKinnon |first2=Jeffrey S. |title=Linking color polymorphism maintenance and speciation |journal=Trends in Ecology & Evolution |date=February 2007 |volume=22 |issue=2 |pages=71–79 |doi=10.1016/j.tree.2006.10.005 |pmid=17055107 }}</ref><ref>{{cite journal |last1=Corl |first1=Ammon |last2=Lancaster |first2=Lesley T. |last3=Sinervo |first3=Barry |title=Rapid Formation of Reproductive Isolation between Two Populations of Side-Blotched Lizards, Uta stansburiana |journal=Copeia |date=18 December 2012 |volume=2012 |issue=4 |pages=593–602 |doi=10.1643/CH-11-166 |s2cid=86230966 }}</ref> However, speciation due to the loss of a male morph has occurred when populations lose one or more male morphs and become reproductively isolated from populations with the ancestral polymorphism.<ref name=":0">{{cite journal |last1=Corl |first1=Ammon |last2=Davis |first2=Alison R. |last3=Kuchta |first3=Shawn R. |last4=Sinervo |first4=Barry |title=Selective loss of polymorphic mating types is associated with rapid phenotypic evolution during morphic speciation |journal=Proceedings of the National Academy of Sciences |date=2 March 2010 |volume=107 |issue=9 |pages=4254–4259 |doi=10.1073/pnas.0909480107 |doi-access=free |pmid=20160090 |bibcode=2010PNAS..107.4254C |pmc=2840131 }}</ref> For side-blotched lizards, the morph lost most commonly is the sneaker male.<ref name=":0" /> In other cases, speciation has occurred as a result of hybridization between morphs occurring in response to rapid changes in the environment.<ref name=":1" /><ref>{{Cite journal |last1=Wellenreuther |first1=Maren |author-link=Maren Wellenreuther |last2=Svensson |first2=Erik I. |last3=Hansson |first3=Bengt |date=2014 |title=Sexual selection and genetic colour polymorphisms in animals |journal=Molecular Ecology |language=en |volume=23 |issue=22 |pages=5398–5414 |doi=10.1111/mec.12935 |pmid=25251393 |s2cid=5504865 |bibcode=2014MolEc..23.5398W }}</ref>

The loss of a male morph can change selection on the remaining morphs.<ref name=":3">{{cite journal |last1=McLean |first1=Claire A. |last2=Stuart-Fox |first2=Devi |title=Geographic variation in animal colour polymorphisms and its role in speciation |journal=Biological Reviews |date=November 2014 |volume=89 |issue=4 |pages=860–873 |doi=10.1111/brv.12083 |pmid=24528520 |s2cid=4664660}}</ref> In side-blotched lizards, for example, female [[Mate choice|mate preferences]] change after the loss of a male morph, and alleles that once allowed other male morphs to outcompete the lost morph for mates are no longer as beneficial.<ref name=":3" /> These shifts in selection often lead to greater [[Sexual dimorphism|sexual size dimorphism]].<ref name=":3" /> Larger male and female size regularly follow the loss of a polymorphism, as seen in the side-blotched lizards.<ref name=":0" /> Predator-prey dynamic also change after a male morph is lost, with predators evolving to prey on the remaining morphologies.<ref name=":3" />

==Behavior==

===Aggression=== [[File:Fighting Side-blotched Lizards (16625735092) (cropped).jpg|thumb|Fighting]] Dominant male side-blotched lizards are aggressive in the defense of their territories. Upon spotting another [[conspecific]] within their territories, resident individuals enter a state of heightened alertness. They perform one or more "pushups" (vertical bobbing motions), arch their backs, and extend their limbs before approaching the intruder.<ref name="T1967">{{cite journal|last=Tinkle, D.W.|author-link=Donald W. Tinkle|year=1967|title=The life and demography of the side-blotched lizard, ''Uta stansburiana''|journal=University of Michigan Museum of Zoology: Miscellaneous Publications|issue=132}}</ref> If the intruder is another male, the resident follows up by rushing, butting, or nipping at the intruder, which will then usually proceed to run away.

Tail length is important in the determination of [[dominance hierarchy|dominance hierarchies]]. Like many other lizard species, side-blotched lizards use [[autotomy|tail autotomy]] as an escape mechanism. However, a reduction in tail length also confers a loss of social status for both males and females.<ref>{{cite journal|last=Fox|first=Stanley F.|author2=Nancy A. Heger |author3=Linda S. Delay |year=1990|title=Social cost of tail loss in ''Uta stansburiana'': lizard tails as status-signalling badges|journal=Animal Behaviour|volume=39|issue=3|pages=549–554|doi=10.1016/S0003-3472(05)80421-X|s2cid=53179644}}</ref> Males will autotomize their tails less readily than will females, likely due to the increased importance of social status for males. Subordinate females can still mate, but male reproductive success is directly tied to their social status.<ref>{{cite journal|last=Fox|first=Stanley F. |author2=Jason M. Conder |author3=Allie E. Smith|year=1998|title=Sexual Dimorphism in the Ease of Tail Autotomy: ''Uta stansburiana'' with and without Previous Tail Loss|journal=Copeia|volume=1998|issue=2|pages=376–382|doi=10.2307/1447431|jstor=1447431 }}</ref>

====Courtship with aggression==== If the intruder is a female, the male resident will initiate [[courtship display|courtship]], which consists of circling, flank-biting, licking, smelling, shallower head-bobbing, and eventually [[copulation (zoology)|copulation]]. Body shape and [[deference|passivity]] are the main [[sign stimulus|releaser]]s for courtship activity, and males have been observed in trying to court and copulate with smaller lizards of other species, as well as smaller subordinate side-blotched lizards.<ref name="F1966">{{cite journal|last=Ferguson|first=Gary W.|year=1966|title=Releasers of courtship and territorial behaviour in the side blotched lizard ''Uta stansburiana''|journal=Animal Behaviour|volume=14|issue=1|pages=89–92|doi=10.1016/S0003-3472(66)80015-5|pmid=5918254}}</ref>

===Aggression among different morphs=== Side-blotched lizards come in three different morphs; the orange and blue morphs are known to be [[Territory (animal)|territorial]] while the yellow morphs are known to be non-territorial. It is important to understand these differences because the territorial orange and blue morphs rely on [[Spatial ability|spatial processing]] mechanisms to acquire and defend their territories. This suggests that there are differences in neuronal [[Neuroplasticity|plasticity]] across the three morphs in the regions of their brains that are responsible for the processing, recognition, and learning of new spatial information. In a study published by the [[University of Nevada]], researchers confirmed that when territorial side-blotched lizards are placed in larger spaces, the production of new [[neuron]]s in the region of their brains responsible for spatial learning become [[Stimulation|stimulated]]. Interestingly, this does not happen in non-territorial yellow side-blotched lizard morphs which indicates that non-territorial morphs do not have the neuronal capacity to behave territorially in the way that orange and blue morphs can.<ref name=Maged2012>{{cite thesis |last1=Maged |first1=Roxolana |title=Effect of Differential Space Use on Medial and Dorsal Cortical Neurogenesis in Side-Blotched Lizard, Uta Stansburiana |hdl=11714/524 }}{{pn|date=April 2024}}</ref>

The opposing forces of [[sexual selection]] and [[natural selection]] are important for the maintenance of trait variation in alternative reproductive strategies in side-blotched lizards. The OBY locus that determines throat [[phenotype]] in these lizards is an important genetic marker that is influenced by the levels of [[gonadotropin]] hormone modulation of testosterone in male side-blotched lizards. Suzanne Mills confirmed that the oo, ob (orange phenotype), and bb (blue phenotype) males are near their physiological and behavioral capacities for reproductive success. On the other hand, yy and by (yellow phenotype) males are below their physiological maximum. The researchers have proposed that although the levels gonadotropins are important for the maintenance of physiological, [[morphology (biology)|morphological]], and behavioral variation in male side-blotched lizards, they are also responsible for the [[immunosuppression]] of sexual signals in yellow-throated side-blotched male lizards.<ref>{{cite journal |last1=Mills |first1=Suzanne |title=Gonadotropin Hormone Modulation of Testosterone, Immune Function, Performance, and Behavioral Trade-Offs among Male Morphs of the Lizard Uta Stansburiana |journal=The American Naturalist |year=2008 |volume=171 |issue=3 |pages=339–357 |doi=10.1086/527520 |pmid=18201140 |s2cid=24146633 }}</ref>

===Spatial processing=== Although territorial behaviors are important defining differences between the different [[morphology (biology)|morphologies]] of these lizards, environmental experiences play important roles in the [[Cerebral cortex|cortical volume]] of both territorial and non-territorial side-blotched lizards. The phenotypic differences between the different male morphologies of side-blotched lizards can be exacerbated by the experiences that the lizards encounter. LaDage Roth Sinervo et al 2016 confirmed that environmental experiences of both territorial and non-territorial side-blotched lizards affects the cortical volume of their brains. When these lizards grow up in controlled [[Captivity|captive]] environments, the cortical volume of their brains are smaller, regardless of whether they are territorial or not. This is important because spatial recognition and processing occur in the cortical region of their brains and certain behaviors, like territoriality, that are important for survival rely on the recognition of space. Therefore, the experiences that side-blotched lizards have affect their cortical volume and subsequently, their cortical phenotypes.<ref name="LaDage Roth Sinervo et al 2016">{{cite journal |last1=LaDage |first1=Lara D. |last2=Roth |first2=Timothy C. |last3=Sinervo |first3=Barry |last4=Pravosudov |first4=Vladimir V. |title=Environmental experiences influence cortical volume in territorial and nonterritorial side-blotched lizards, Uta stansburiana |journal=Animal Behaviour |date=May 2016 |volume=115 |pages=11–18 |doi=10.1016/j.anbehav.2016.01.029 |s2cid=54415157 |doi-access=free }}</ref> While there is a confirmed relationship between territoriality, spatial informational processing, and neuronal plasticity, researchers have suggested that testosterone plays a role in the regulation of [[Cerebral cortex|medial cortical]] volumes. In addition, research has demonstrated that testosterone affects territorial males more significantly than non-territorial males. This is likely because during the [[reproduction]] season there is an increase in male territoriality, territory size, and testosterone levels. Although more research is needed to confirm that there is a causative relationship between elevated testosterone levels and increases in territorial behaviors, territorial animals rely on [[spatial memory]] to remember the boundaries of their territories which is important for detecting potential female partners that might enter their home space range.<ref name="Frontiers">{{cite journal |last1=LaDage |first1=Lara |title=Increased Testosterone Decreases Medial Cortical Volume and Neurogenesis in Territorial Side-Blotched Lizards (UTA Stansburiana) |journal=Frontiers in Neuroscience |year=2017 |volume=11 |page=97 |publisher=Frontiers |doi=10.3389/fnins.2017.00097 |pmid=28298883 |pmc=5331184 |doi-access=free }}</ref>

==Predation== Side-blotched lizards encounter a [[plethora]] of different predators in the wild and they engage in a variety of [[Escape response|escape behaviors]] to avoid predation. In a study published in the [[Canadian Journal of Zoology]], researchers confirmed that these escape behaviors – [[Flight zone|flight initiation distance]], distance fled, and refuge entry – do not differ depending on what type of predator the lizard encounters or whether that predator is relatively abundant in their environment. Side-blotched lizards do, however, tend to escape more directly towards [[refuge (ecology)|refuge]] when they encounter predatory [[lizard]]s while less directly towards refuge when encountering predatory [[snake]]s.<ref name="Canadian Journal of Zoology">{{cite journal |last1=Wagner |first1=E.A. |last2=Zani |first2=P.A. |title=Escape behavior of Side-blotched Lizards ( Uta stansburiana ) in response to model predators |journal=Canadian Journal of Zoology |date=December 2017 |volume=95 |issue=12 |pages=965–973 |doi=10.1139/cjz-2016-0255 }}</ref>

==Diet and feeding== Side-blotched lizards display feeding behavior which can be influenced by [[sex]] or [[season]]. In a study conducted by Best ''et al.''., these lizards were found to consume diets largely based upon [[arthropod]] populations within the area, within a given season. These populations vary by year, and different arthropod populations will fluctuate seasonally. The study showed a correlation between sex and diet, giving way to a number of theories that speculate why gender has an effect on feeding behavior and diet. One mechanism proposes the behavior differences depend on gender, such as guarding territories and attracting mates, are responsible for, or a contributing factor in, feeding behavior. Alternatively, the sexual difference in feeding behavior could also act in favor of reducing [[intraspecific competition]] for resources, with individuals eating prey appropriate for their respective size (ex. small females consuming smaller prey).<ref>{{cite journal|last=Best|first=Troy L.|author2=A. L. Gennaro|title=Feeding Ecology of the Lizard, ''Uta stansburiana'', in Southeastern New Mexico|journal=Journal of Herpetology|date=September 1984|volume=18|issue=3|pages=291–301|doi=10.2307/1564083|jstor=1564083}}</ref>

Feeding regimes in side-blotched lizards are also influenced by their body temperatures. Waldschmidt, Jones & Porter 1986 confirmed that the body temperature of side-blotched lizards affects their consumption rate of food and the passage time of that ingested food, but body temperature does not affect their [[Digestive rate model|digestive coefficient]]. When the body temperature of the lizard increased between 20 and 36 degrees Celsius, the probability of eating increased [[Curvilinear coordinates|curvilinearly]] while the passage time of ingested food decreased curvilinearly.<ref>{{cite journal |last1=Waldschmidt |first1=Steven R. |last2=Jones |first2=Steven M. |last3=Porter |first3=Warren P. |title=The Effect of Body Temperature and Feeding Regime on Activity, Passage Time, and Digestive Coefficient in the Lizard Uta stansburiana |journal=Physiological Zoology |date=May 1986 |volume=59 |issue=3 |pages=376–383 |doi=10.1086/physzool.59.3.30156109 |s2cid=87385300 }}</ref>

== Parasites == Like most animals, side-blotched lizards are infected by a variety of parasites. Intestinal parasites include [[nematodes]]<ref>{{cite journal |id={{INIST|7905398}} |last1=Lyon |first1=R. E |title=Helminth parasites of six lizard species from Southern Idaho |journal=Proceedings of the Helminthological Society of Washington |date=1986 |volume=53 |issue=2 |pages=291–293 }}</ref> and [[cestodes]].<ref>{{cite journal |last1=Bursey |first1=Charles R. |last2=Goldberg |first2=Stephen R. |title=Oochoristica macallisteri sp. n. (Cyclophyllidea: Linstowiidae) from the side-blotched lizard, Uta stansburiana (Sauria: Phrynosomatidae), from California, USA |journal=Folia Parasitologica |date=2013 |volume=43 |issue=4 |pages=293–296 |url=https://folia.paru.cas.cz/artkey/fol-199604-0009_Oochoristica_macallisteri_sp_n_Cyclophyllidea_Linstowiidae_from_the_side-blotched_lizard_Uta_stansburiana.php }}</ref> Blood parasites include members of the [[Apicomplexa]] such as ''[[Schellackia]] occidentalis'' <ref name="BonorrisBall1955">{{cite journal|last1=Bonorris|first1=Jim S.|last2=Ball|first2=Gordon H.|year=1955|title=''Schellackia occidentalis'' n.sp., a blood-inhabiting coccidian found in lizards in Southern California|journal=Journal of Protozoology|volume=2|issue=1|pages=31–34|doi=10.1111/j.1550-7408.1955.tb02393.x }}</ref> and species of ''[[Lankesterella (alveolate)|Lankesterella]]''.<ref name="QuillfeldtRomeike2018">{{cite journal|last1=Quillfeldt|first1=Petra|last2=Romeike|first2=Tanja|last3=Masello|first3=Juan F.|last4=Reiner|first4=Gerald|last5=Willems|first5=Hermann|last6=Bedolla-Guzmán|first6=Yuliana|year=2018|title=Molecular survey of coccidian infections of the side-blotched lizard ''Uta stansburiana'' on San Benito Oeste Island, Mexico|url=|journal=Parasite|volume=25|pages=43|doi=10.1051/parasite/2018043 |doi-access=free|pmc=6092949|pmid=30109981}}</ref> The tegument is infected by several species of [[mite]]s.<ref name="GoldbergBursey1991">{{cite journal|last1=Goldberg|first1=Stephen R.|last2=Bursey|first2=Charles R.|year=1991|title=Integumental lesions caused by ectoparasites in a wild population of the side-blotched lizard (''Uta stansburiana'')|journal=Journal of Wildlife Diseases|volume=27|issue=1|pages=68–73|doi=10.7589/0090-3558-27.1.68 |pmid=2023329|doi-access=free}}</ref> Out of these, ''[[Neotrombicula]]'' are the most common [[ectoparasites]].<ref name="GoldbergBursey1991" /> The number of ''Neotrombicula'' parasites is reduced in populations of side-blotched lizards near [[wind farms]].<ref name="Alaasam 2021" /> Parasites can alter metabolism and reproductive success of side-blotched lizards due to body temperature changes in response to fighting the infection.<ref>{{cite journal |last1=Paranjpe |first1=D. A. |last2=Medina |first2=D. |last3=Nielsen |first3=E. |last4=Cooper |first4=R. D. |last5=Paranjpe |first5=S. A. |last6=Sinervo |first6=B. |title=Does Thermal Ecology Influence Dynamics of Side-Blotched Lizards and Their Micro-Parasites? |journal=Integrative and Comparative Biology |date=July 2014 |volume=54 |issue=2 |pages=108–117 |doi=10.1093/icb/icu069 |pmid=24920752 |doi-access=free }}</ref>

==References== {{Reflist}}

==External links== *{{Commons-inline|italic=1}} *UC Santa Cruz, [https://news.ucsc.edu/2003/06/367.html Cooperation between unrelated male lizards adds a new wrinkle to evolutionary theory] (Essay on Sinervo & Clobert 2001 paper)

[[Category:Reptiles of the United States]] [[Category:Reptiles described in 1852]] [[Category:Uta]] [[Category:Taxa named by Spencer Fullerton Baird]] [[Category:Taxa named by Charles Frédéric Girard]]