ISSN:
1615-6110
Schlagwort(e):
Arecales
;
Cyclanthales
;
Dilleniaceae
;
Magnoliidae
;
Angiosperm evolution
;
bees
;
beetles
;
dichogamy
;
dicliny
;
insects
;
protandry
;
protogyny
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Biologie
Notizen:
Abstract A review of the literature, compiled over the past 40 years suggests new directions for theories discussing the evolution of reproductive isolation and entomophily in angiosperms. Data on breeding systems suggests that the protoangiosperms may have developed gametophytic self-incompatibility. Protogyny is probably ancestral to protandry and herkogamy. Although the proto-flowers were bisexual wide variation in the number of sexual organs within proto-flowers probably led to labile sexuality and early trends towards dicliny. Beetle-pollination in extant relicts appears too specialized to represent an ancestral condition. Rather, the proto-flowers may have been generalist entomophiles incorporating some beetles,Plecoptera, thrips, micropterigid moths and proto-dipterans into their fluctuating spectra of opportunistic pollinators. Bee-pollination is probably polyphyletic in origin evolving repeatedly from angiosperms showing these generalist syndromes. There is still no correlation between primitive bees (especiallyColletidae) and the relictual angiosperms. Pollen that is usually retained within the anthers following dehiscence and the presence of staminal filaments and styles characterizes most of the flowers of those relictual angiosperms pollinated by specialized, modernApoidea.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF00936071
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