Pollination by deceit in nutmeg (Myristica insipida, Myristicaceae): floral displays and beetle activity at male and female trees

Pollination by deceit in Myristica insipida, a beetle-pollinated nutmeg, was hypothesized to operate on intersexual differences in flower production and longevity, producing a daily fluctuation between floral display maxima and minima. Sticky traps were used to continuously monitor beetle activity. Flower production and naturally occurring intersexual differences in display were recorded. Male and female trees flowered in synchrony producing daily display maxima at 1800-0600 and display minima at 1400-1800. Rewarding male trees produced three times the number of flowers of female trees, but the greater longevity of female flowers reduced the intersexual difference in display maxima to a factor of two. There was no intersexual difference in display minima. Beetles were demonstrated to be sensitive to differences in both maximum and minimum displays on rewarding male trees, a necessary prerequisite for directional selection on display size. Beetle captures were significantly higher at male trees during floral display maxima, and no intersexual differences in capture rate occurred during floral display minima. However, capture rates at male trees did not decline as predicted, and the pattern of captures was consistent with crepuscular activity. Beetle captures at male and female trees were lower from 1800 to 0600 and 1000 to 1400, and higher from 0600 to 1000 and 1400 to 1800, but the differences were only significant at female trees. These data suggests that foraging errors are numerous, frequent, and the result of overall foraging activity.     

Neolignans from Virola carinata

The wood of Virola carinata (Benth.) Warb. contains besides the known neolignans (+)-guaiacin and (?)-galcatin, (?)-isootobaphenol [(2R,3S,4S)-4-guaiacyl-2,3-dimethyl-6,7-methylenedioxytetralin], in addition to 7,4′-dimethoxyflavanone.     

Eusiderins and 1,3-diarylpropanes from Virola species

Trunk wood of Virola divergens Ducke and V. guggenheimii W. Rodrigues (Myristicaceae) contains the 1,3-diarylpropanes virolane and (2S)-virolanol. The latter species contains in addition the benzodioxane-type neolignan eusiderin. Bark of V. pavonis (A. DC.) A.C. Smith contains two novel representatives of this group, rel-(2S, 3R)-7-allyl-5-methoxy-2-(3′, 4′, 5′-trimethoxyphenyl- and rel-(2S, 3R)-7- allyl-5-methoxy-2-(3′,4′-dimethoxyphenyl)-3-methyl-benzodioxane, designated eusiderin-C and eusiderin-D, respectively.     

Neolignans from Virola elongata

The bark of Virola elongata contains the new 8.8′-neolignan, 1-(3,4-dimethoxyphenyl)2,3-dimethyl-4-piperonylbutan-1-one besides the known 8.8′, 2.7′-neolignans, 4-hydroxy-2,3-dimethyl-6,7-dimethoxy-4-piperonyl-1-tetralone and 4-hydroxy-2,3-dimethyl-5,6-methylenedioxy-4-piperonyl-1-tetralone.     

Further lignoids from Virola sebifera

From the fruits of Virola sebifera 2,3-dibenzylbutanes were isolated together with tetralin and naphthalene neolignans. 2,3-Dimethyl-4-piperonyl-4-veratrylbutan-1-ol, a further constituent, probably arises by a retro-Friedel-Crafts reaction from a tetralin neolignan. An additional component was identified as a dimeric neolignan.     

Neolignans of Virola surinamensis

Elemicin, galbacin, veraguensin and two new neolignans, surinamensin and virolin, were isolated and characterized from the leaves of Virola surinamensis.     

Lignans of Horsfieldia iryaghedhi

A detailed chemical investigation of extracts of the bark, leaf and timber of Horsfieldia iryaghedhi collected in Sri Lanka, led to the isolation of (+)-asarinin, dodecanoylphloroglucinol and (?)-dihydrocubebin.     

Neolignans from fruits of Virola elongata

Fruits of Virola elongata contain, besides the furofuranoid lignans eudesmin, epieudesmin and fargesin, the aryl-benzyl-methyl tetrahydrofuran neolignans magnostellins A and C. The absolute configuration of the magnostellins was detennined.     

Structural confirmation of spiroelliptin from Iryanthera elliptica by synthesis

Spiroelliptin, a spiro[cyclohexadienone-1,1′-tetralin] from Iryanthera elliptica, was synthesized by a novel process which involved the catalytic hydrogenation of the appropriate chalcone. This and other spiro[methoxycyclobexadienone-1,1′-tetralin] derivatives, obtained by the same process or by the oxidative coupling of the appropriate 1,3-diarylpropanes, were used as models in the compilation of ¹H and ¹³C NMR data allowing the recognition of three such naturally occurring structural types.