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Developmental instability and within‐population variation in sex expression by andromonoecious Euphorbia xanti
Author(s) -
Kiflawi Moshe
Publication year - 2000
Publication title -
oikos
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.672
H-Index - 179
eISSN - 1600-0706
pISSN - 0030-1299
DOI - 10.1034/j.1600-0706.2000.890111.x
Subject(s) - fluctuating asymmetry , biology , population , stamen , asymmetry , variation (astronomy) , botany , evolutionary biology , pollen , demography , physics , sociology , astrophysics , quantum mechanics
Within an area spanning approximately 1 km 2 , individuals belonging to a population of andromonoecious Euphorbia xanti range in their sex expression from all‐staminate to all‐cosexual. In this study I attempt to evaluate this variation using measures of non‐directional asymmetry as potential indicators of developmental instability. Assuming that developmental homeostasis and sex allocation are sensitive to the same, or correlated, stress factors, I expected an adaptive explanation to be manifested in a monotonic relationship between asymmetry and ‘femaleness’ (i.e. the per‐plant proportion of cosexual cyathia). Unexpectedly, per‐plant mean asymmetry peaked at intermediate sexuality (femaleness of approx. 0.5). At the same time, intermediate sexuality was qualitatively associated with relatively low probabilities of cosexual cyathia developing fruit. I discuss two hypothetical explanations for these observations.