Sex Change in Plants and Animals

Policansky, David

doi:10.1146/annurev.es.13.110182.002351

Cited by 257 publications

(155 citation statements)

References 88 publications

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“…in herbaceous plants and trees, invertebrates, fishes, amphibians and some mammals ;Caswell 1989). Similarly, in sex-changing organisms, switches in sex are often size or age related (Ghiselin 1969;Warner 1975Warner , 1988Charnov 1982;Policansky 1982). Similar to the findings for many other animals, our histological study reveals that in both of the studied fungiid species, gonad size increases with individual body size.…”

Section: Discussionsupporting

confidence: 79%

“…from male to female or female to male) have been conducted on fishes, the largest and only vertebrate group in which this phenomenon occurs (Munday et al 2006). In invertebrates, it is known to occur in some echinoderms, crustaceans, molluscs and polychaete worms (Policansky 1982;Munday et al 2006). Sex change in both directions (bidirectional sex change) has been reported from several species of animals whose local structure is socially controlled and occasionally changes, i.e.…”

Section: Introductionmentioning

confidence: 99%

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Bidirectional sex change in mushroom stony corals

Loya

Sakai

2008

Proc. R. Soc. B.

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Sex change occurs when an individual changes from one functional sex to another. The direction of sex change occurs mainly from male to female (protandry) or vice versa (protogyny), but sometimes may be bidirectional (repetitive). Here, for the first time in stony corals, we report on a protandrous sex change exhibited by two mushroom corals, Fungia repanda and Ctenactis echinata, with the latter also exhibiting bidirectional sex change. Compared with C. echinata, F. repanda exhibited relatively earlier sex change, significantly slower growth and higher mortality rates, in accordance with sex-allocation theory. Sex ratio in both the species was biased towards the first sex. The bidirectional sex change displayed by C. echinata greatly resembles that of dioecious plants that display labile sexuality in response to energetic and/or environmental constraints. We posit that, similar to these plants, in the studied corals, sex change increases their overall fitness, reinforcing the important role of reproductive plasticity in scleractinian corals in determining their evolutionary success.

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Section: Discussionsupporting

confidence: 79%

Section: Introductionmentioning

confidence: 99%

Bidirectional sex change in mushroom stony corals

Loya

Sakai

2008

Proc. R. Soc. B.

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“…We gathered sex ratio data for sex changing animals by: (1) performing ISI Web of Science database searches using keywords ''sex change'' ϩ ''sex ratio''; (2) searching in key reviews on the topic (Reinboth 1975;Robertson and Warner 1978;Warner and Robertson 1978;Policansky 1982;Charnov and Bull 1989); (3) searching citations in all papers found; (4) directly from the field, for the marine goby Coryphopterus personatus, as part of a larger study (Allsop and West 2004); and (5) using data from our previous comparative studies on life-history variables in sex changing organisms (Allsop and West 2003a,b). In some studies, authors determined sex by macroscopic observation of the genitalia or secondary sexual characters (Cole 1983;Abe and Fukuhara 1996).…”

Section: Data Collectionmentioning

confidence: 99%

“…We are concerned with species in which sex change occurs, also termed sex reversal or sequential hermaphroditism. This has been documented in a variety of fish, invertebrates, and plants (Charnov 1982;Policansky 1982;Allsop and West 2003a). Sex allocation theory suggests that sex change is favored when the reproductive value of an individual varies with age or size, and the relationship is different for males and females.…”

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confidence: 92%

Sex-Ratio Evolution in Sex Changing Animals

Allsop

West

2004

Evolution

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Abstract. Sex allocation theory is often able to make clear predictions about when individuals should facultatively adjust their offspring sex ratio (proportion male) in response to local conditions, but not the consequences for the overall population sex ratio. A notable exception to this is in sex changing organisms, where theory predicts that: (1) organisms should have a sex ratio biased toward the ''first'' sex; (2) the bias should be less extreme in partially sex changing organisms, where a proportion of the ''second'' sex matures directly from the juvenile stage; and (3) the sex ratio should be more biased in protogynous (female first) than in protandrous (male first) species. We tested these predictions with a comparative study using data from 121 sex changing animal species spanning five phyla, covering fish, arthropods, echinoderms, molluscs, and annelid worms. We found support for the first and third predictions across all species. The second prediction was supported within the protogynous species (mainly fish), but not the protandrous species (mainly invertebrates).Key words. Comparative analysis, protandrous, protogynous, sequential hermaphrodite, sex allocation, sex ratio.Received October 16, 2003. Accepted January 8, 2004 Sex allocation theory describes how organisms should divide their resources between male and female reproduction (Charnov 1982). Some of the most striking successes of sex allocation theory have been in explaining cases in which individuals facultatively adjust their offspring sex ratios (proportion male) in response to local conditions (Charnov 1982;Hardy 2002;West et al. 2002a), as originally suggested by Trivers and Willard (1973). For example, numerous parasitic wasps have been shown to lay male eggs on relatively small hosts and female eggs on large hosts, because female offspring gain a greater fitness benefit from extra resources and larger body size (West and Sheldon 2002). In contrast, when such facultative sex ratio adjustment occurs, sex allocation theory has been much less successful in predicting and explaining variation in the overall population or breeding sex ratio (West et al. 2002a). The reason for this is that the population sex ratio is often predicted to depend upon biological details that are rarely known, such as the details of male and female life histories, and whether other behaviors such as clutch size are also facultatively adjusted (Frank 1987(Frank , 1990Weissing 2000, 2002;West and Sheldon 2002).Here we consider a case in which it is possible to make clear predictions for the overall population sex ratio. We are concerned with species in which sex change occurs, also termed sex reversal or sequential hermaphroditism. This has been documented in a variety of fish, invertebrates, and plants (Charnov 1982;Policansky 1982;Allsop and West 2003a). Sex allocation theory suggests that sex change is favored when the reproductive value of an individual varies with age or size, and the relationship is different for males and females. In this case natural select...

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“…Plants of the new species are either function ally female or hermaphroditic and this is supported by observations on plants grown in the author's garden in Windhoek. However, in angiosperms, all forms of dioecy are rarely absolute (Policansky 1982). The possibil ity that at times some structurally bisexual flowers in C. kaokoensis may still be functionally male cannot be excluded.…”

Section: Taxonomic Significance Of Gynodioecy In Cerariamentioning

confidence: 99%