Scent chemistry and patterns of thermogenesis in male and female cones of the African cycad Encephalartos natalensis (Zamiaceae)

Suinyuy, Terence N.; Donaldson, John S.; Johnson, Steven D.

doi:10.1016/j.sajb.2010.08.014

“…Many of the volatile compounds and compound classes identified in this study are known to occur in other cycads (Pellmyr et al ., 1991; Terry et al ., 2004a, b; Azuma & Kono, 2006, Proches & Johnson, 2009; Suinyuy, Donaldson & Johnson, 2010) and other plants (Knudsen et al ., 2006). Out of 87 identified compounds, only five compounds occurred in high relative amounts (≥ 30%) in at least one population (Table 1).…”

Section: Discussionmentioning

confidence: 99%

“…It is noteworthy that the barrier between northern and southern populations of E. villosus at the Umtamvuna river is also the contact zone for two other cycad species that are closely related to one another (Treutlein et al ., 2005): Encephalartos natalensis north of the Umtamvuna and Encephalartos altensteinii to the south. The odour compound (3 E )‐1,3‐octadiene, which dominated the odour profile of E. villosus north of the Umtamvuna, is also the dominant compound in cone volatiles of E. natalensis (Suinyuy et al ., 2010). In addition, at least one of the pollinators of E. villosus also occurs on E. natalensis (Donaldson, 1997; T. N. Suinyuy, unpubl.…”

Section: Discussionmentioning

confidence: 99%

Geographical variation in cone volatile composition among populations of the African cycad Encephalartos villosus

Suinyuy

¹

,

Donaldson

²

,

Johnson

³

2012

Biological Journal of the Linnean Society

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Variation in traits across species distribution ranges is often indicative of diversifying evolution that can lead to speciation. Of particular interest is whether traits vary clinally or abruptly because the latter pattern can be indicative of incipient speciation. Understanding of intraspecific variation in chemical traits is still in its infancy because studies of population variation have tended to focus on morphology or neutral genetic markers. To address these issues, the composition of cone volatile odours was examined in ten populations of the South African cycad Encephalartos villosus across its range in the Eastern Cape and KwaZulu Natal using headspace sampling and analysis by gas chromatography‐mass spectrometry. Because volatiles play a key role in attracting pollinators to cones of Encephalartos cycads and may thus reflect local adaptation to pollinators, pollinator assemblages were also investigated in the ten populations of E. villosus. Volatile compounds from populations in the north of the distribution range were dominated by unsaturated hydrocarbons, whereas, in the southern populations, nitrogen‐containing compound and terpenoids were the major compounds. A shift between southern and northern populations appeared to occur at the Umtamvuna River, where populations had odour profiles with components of both the northern and southern populations. However, one population in the north (Vernon Crookes Nature Reserve) had a quantitatively similar odour profile to the populations in the extreme south of the range. These results reveal strong interpopulation variation in the cone scent of E. villosus, including variation in the relative emission of dominant compounds that may play key functional role in this pollination system. However, pollinator assemblages did not differ across the different populations, which suggest that these patterns were produced by co‐evolution or drift, rather than by pollinator shifts. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 106, 514–527.

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“…In deceptive pollination systems involving automimicry in dioecious plants, pollination is a collateral benefit for female plants because insects do not profit from visiting female sexual structures ( Little, 1983 ; Willson & Agren, 1989 ; Dufaÿ & Anstett, 2003 ). In cycads, females mimic the fragrance profile and thermogenesis pattern of males but this mimicry is not perfect, and females emit odors in lower amounts, with small variations in the volatile compounds ( Pellmyr et al, 1991 ; Terry et al, 2004 ; Donaldson, 2007 ; Proches & Johnson, 2009 ; Suinyuy, Donaldson & Johnson, 2010 ). As in other model-mimicry systems, the closer the mimic is to the model, the better the reproductive success ( Peter & Johnson, 2008 ).…”

Section: Discussionmentioning

confidence: 99%

Best in the company of nearby males: female success in the threatened cycad,Zamia portoricensis

Lazcano-Lara

¹

,

Ackerman

²

2018

PeerJ

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Variation in plant reproductive success is affected by ecological conditions including the proximity of potential mates. We address the hypothesis that spatial distribution of sexes affects female reproductive success (RS) in the dioecious cycad, Zamia portoricensis. Are the frequencies of males, operational sex ratios, and distances to the nearest mate associated with RS in females? We studied the spatial distribution of sexes in two populations in Puerto Rico and compared RS of target females with the number of males and operational sex ratios. Population structure suggests regular successful recruitment. Adults, males, and females were randomly distributed with respect to one another. Reproductive success of females was highly variable, but was higher in neighborhoods with more males than females and generally decreased with increasing distance to the nearest male, becoming statistically significant beyond 190 cm. This possible mate-finding Allee effect indicates that pollinator movement among plants may be limited for this mutually dependent plant-pollinator interaction. Yet being close to male plants is a matter of chance, perhaps a factor generating the high intra-population genetic diversity in Z. portoricensis.

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“…In deceptive pollination systems involving automimicry in dioecious plants, pollination is a collateral benefit for female plants because insects do not profit from visiting female sexual structures (Little 1983;Willson & Ågren, 1989;Dufaÿ & Anstett, 2003). In cycads, females mimic the fragrance profile and thermogenesis pattern of males but this mimicry is not perfect, and females emit odors in lower amounts, with small variations in the volatile compounds (Pellmyr et al, 1991;Terry et al, 2004;Donaldson, 2007;Proches & Johnson, 2009;Suinyuy, Donaldson, & Johnson, 2010). As in other model-mimicry systems, the closer the mimic is to the model, the better the reproductive success (Peter & Johnson 2008).…”

Section: Reproductive Successmentioning

confidence: 99%

Peer Review #1 of "Best in the company of nearby males: female success in the threatened cycad, Zamia portoricensis (v0.1)"

2018

0

View full text Add to dashboard Cite

Variation in plant reproductive success is affected by ecological conditions including the proximity of potential mates. We address the hypothesis that spatial distribution of sexes affects female reproductive success (RS) in the dioecious cycad, Zamia portoricensis. Are the frequencies of males, operational sex ratios, and distances to the nearest mate associated with RS in females? We studied the spatial distribution of sexes in two populations in Puerto Rico and compared RS of target females with the number of males and operational sex ratios. Population structure suggests regular successful recruitment. Adults, males, and females were randomly distributed with respect to one another. Reproductive success of females was highly variable, but was higher in neighborhoods with more males than females and generally decreased with increasing distance to the nearest male, becoming statistically significant beyond 190 cm. This possible mate-finding Allee effect indicates that pollinator movement among plants may be limited for this mutually dependent plant-pollinator interaction. Yet being close to male plants is a matter of chance, perhaps a factor generating the high intra-population genetic diversity in Z. portoricensis.

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Scent chemistry and patterns of thermogenesis in male and female cones of the African cycad Encephalartos natalensis (Zamiaceae)

Cited by 17 publications

References 40 publications

Geographical variation in cone volatile composition among populations of the African cycad Encephalartos villosus

Geographical variation in cone volatile composition among populations of the African cycad Encephalartos villosus

Best in the company of nearby males: female success in the threatened cycad,Zamia portoricensis

Peer Review #1 of "Best in the company of nearby males: female success in the threatened cycad, Zamia portoricensis (v0.1)"

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