Sequential alternation of offspring sex from successive eggs by female green anoles, <i>Anolis carolinensis</i>

Lovern, Matthew B.; Passek, Kelly M

doi:10.1139/z01-210

Cited by 14 publications

(8 citation statements)

References 34 publications

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“…Although support for the Trivers–Willard hypothesis has been reported for birds and mammals (Olsen and Cockburn 1991; Bradbury and Blakey 1998; Nager et al 1999; Cameron 2004; Cockburn et al 2004; Sheldon and West 2004), individual studies often give highly divergent results (Komdeur and Pen 2002; Sheldon and West 2004). Other studies of lizards report no correlation between maternal condition and progeny sex ratios (Lovern and Passek 2002; Uller et al 2006), or contrasting patterns in different study seasons (Olsson and Shine 2001). In some lizards, energetically compromised females apparently invest more resources per egg than those in good condition (Fox and McCoy 2000; Warner et al 2007), reversing the predictions that would otherwise derive from the Trivers–Willard hypothesis.…”

Section: Discussionmentioning

confidence: 93%

“…If mothers in good condition preferentially increase offspring quantity rather than offspring quality, then the original assumptions of the Trivers–Willard hypothesis may not apply. Perhaps consequently, those few studies that have tested the Trivers–Willard hypothesis in lizards have generated mixed results (Fox and McCoy 2000; Olsson and Shine 2001; Lovern and Passek 2002; Uller et al 2006; Warner et al 2007). It is therefore important to test not only the effect of maternal condition on progeny sex ratio, but also the underlying assumptions that maternal condition influences progeny phenotypes, and that maternal condition differentially influences the relative fitness of sons and daughters.…”

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confidence: 99%

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Paternal Condition Drives Progeny Sex-Ratio Bias in a Lizard That Lacks Parental Care

et al. 2010

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Sex-allocation theory predicts that females in good condition should preferentially produce offspring of the sex that benefits the most from an increase in maternal investment. However, it is generally assumed that the condition of the sire has little effect on progeny sex ratio, particularly in species that lack parental care. We used a controlled breeding experiment and molecular paternity analyses to examine the effects of both maternal and paternal condition on progeny sex ratio and progeny fitness in the brown anole (Anolis sagrei), a polygynous lizard that lacks parental care. Contrary to the predictions of sex-allocation theory, we found no relationship between maternal condition and progeny sex ratio. By contrast, progeny sex ratio shifted dramatically from female-biased to male-biased as paternal condition increased. This pattern was driven entirely by an increase in the production of sons as paternal condition improved. Despite strong natural selection favoring large size and high condition in both sons and daughters, we found no evidence that progeny survival was related to paternal condition. Our results emphasize the importance of considering the paternal phenotype in studies of sex allocation and highlight the need for further research into the pathways that link paternal condition to progeny fitness. In their landmark paper on adaptive sex allocation, Trivers and Willard (1973) hypothesized that mothers in a good physiological condition should bias the sex ratio of their progeny in favor of the sex that provides the greatest relative fitness return for a given increase in maternal investment. This influential idea has sparked numerous theoretical extensions and empirical tests in what has become one of the most active research areas in evolutionary biology

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Section: Discussionmentioning

confidence: 93%

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confidence: 99%

Paternal Condition Drives Progeny Sex-Ratio Bias in a Lizard That Lacks Parental Care

et al. 2010

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“…Although it is not the case that each ovary produces just one sex (Lovern and Passek, 2002), under normal conditions females may have a lateral bias in the production of males and females. If such an asymmetry exists in anoles, it would be similar to a phenomenon found in gerbils, in which females more often develop in the left uterine horn and males more often in the right (Clark and Galef,'90).…”

Section: Resultsmentioning

confidence: 99%

“…In a potentially related finding, female anoles tend to produce successive eggs alternately from the left and right ovary (Smith et al,'73) and, in A. carolinensis, they also alternate the sex of their offspring with successive eggs more frequently than expected by chance (Lovern and Passek, 2002). Although it is not the case that each ovary produces just one sex (Lovern and Passek, 2002), under normal conditions females may have a lateral bias in the production of males and females. If such an asymmetry exists in anoles, it would be similar to a phenomenon found in gerbils, in which females more often develop in the left uterine horn and males more often in the right (Clark and Galef,'90).…”

Section: Resultsmentioning

confidence: 99%

Yolk testosterone varies with sex in eggs of the lizard, Anolis carolinensis

Lovern

Wade

2003

J. Exp. Zool.

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In the green anole (Anolis carolinensis), a lizard with genotypic sex determination, yolk testosterone (T) concentration is greater in male-producing than female-producing eggs at oviposition, but the source and potential effects were not clear from previous studies. If yolk T levels are also sex-specific before eggs are laid, a period during which embryonic steroidogenesis is unlikely, it would strongly suggest that the difference in yolk T is maternally derived. We collected yolk samples from eggs shelling within the oviducts of anesthetized females, and then allowed these females to lay the eggs naturally. Eggs were incubated to hatching to determine sex morphologically, and yolk T concentrations were analyzed by radioimmunoassay. As is the case just after they are laid, yolk T is higher in male than female oviductal eggs. To our knowledge, this is the earliest sex difference reported for any yolk steroid. We suggest that maternally derived yolk T levels could influence sex by differentially affecting male- and female-inducing sperm, because fertilization occurs after yolk deposition and ovulation, while the egg is in the oviduct. Our results, together with those of an increasing number of studies, suggest that a relationship between hormones and vertebrate sex determination may be more widespread than generally appreciated.

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“…It is not known which of the two modes A. sagrei displays. We tentatively assume that A. sagrei , which is quite similar in its reproductive ecology to Anolis carolinensis (Lee et al ., 1989), may also have GSD (Lovern & Passek, 2002).…”

Section: Methodsmentioning

confidence: 99%

Climate niche shift in invasive species: the case of the brown anole

Angetter

Lötters

Rödder

2011

Biological Journal of the Linnean Society

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Anolis sagrei, a Cuba and Bahama native lizard, is a successful invader in Florida and adjacent areas. Herein, we focus on conservatism in its climate niche axes and possible congruencies with its natural history properties. The not mutually exclusive hypotheses of the present study explaining its northern range limit are: (1) climatic conditions within species' native and invasive ranges are identical; (2) the species is pre-adapted to novel conditions as a result of historical climate variations; and (3) only some niche axes limit the species' invasive distribution and the observed pattern is explained by an interplay between the potential niche within its native range and life-history. Species distribution models for native and invasive distributions were built on ten bioclimatic variables. Using Schoener's niche overlap index, the degree of niche conservatism among variables was identified. Significances of hypothesis (1) were tested using null-model approaches. Possible climatic pre-adaptations were evaluated by comparing its actual tolerance within its invasive range with that of the Last Glacial Maximum (LGM) within its native range (hypothesis 2). Results of (1) and (2) are discussed in relation to natural history, approaching hypothesis 3. We detect varying overlaps in niche axes, indicating that natural history properties are associated with conservative niche axes. Climatic comparisons with LGM of native and current conditions of invasive range suggest that pre-adaptations are unlikely. Possible shifts in the fundamental niche of the species may have been facilitated by enhanced genetic diversity in northern invasive populations.

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Sequential alternation of offspring sex from successive eggs by female green anoles, Anolis carolinensis

Cited by 14 publications

References 34 publications

Paternal Condition Drives Progeny Sex-Ratio Bias in a Lizard That Lacks Parental Care

Paternal Condition Drives Progeny Sex-Ratio Bias in a Lizard That Lacks Parental Care

Yolk testosterone varies with sex in eggs of the lizard, Anolis carolinensis

Climate niche shift in invasive species: the case of the brown anole

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