Intraspecific divergence in floral‐tube length promotes asymmetric pollen movement and reproductive isolation

2019 ◽  
Vol 224 (3) ◽  
pp. 1160-1170 ◽  
Author(s):  
Corneile Minnaar ◽  
Marinus L. de Jager ◽  
Bruce Anderson
2014 ◽  
Vol 281 (1795) ◽  
pp. 20141420 ◽  
Author(s):  
B. Anderson ◽  
P. Ros ◽  
T. J. Wiese ◽  
A. G. Ellis

Floral tubes are often thought to be a consequence of adaptive specialization towards pollinator morphology. We explore floral tube length evolution within Tritoniopsis revoluta (Iridaceae), a species with considerable geographical tube length variation. We ask whether tube lengths of T. revoluta populations are associated with pollinator proboscis lengths, whether floral divergence occurs in the presence of different pollinators and whether floral convergence occurs between distantly related populations pollinated by the same pollinator. Finally, we ask whether tube length evolution is directional. Shifts between morphologically different pollinators were always associated with shifts in floral morphology, even when populations were very closely related. Distantly related populations had similar tube lengths when they were pollinated by the same pollinator. Shifts in tube length tended to be from short to long, although reversals were not infrequent. After correcting for the population-level phylogeny, there was a strong positive, linear relationship between floral tube length and pollinator proboscis length, suggesting that plants are functionally specialized on different pollinators at different sites. However, because tube length evolution in this system can be a bidirectional process, specialization to the local pollinator fauna is unlikely to result in evolutionary or ecological dead-ends such as canalization or range limitation.


Phytotaxa ◽  
2014 ◽  
Vol 172 (1) ◽  
pp. 31 ◽  
Author(s):  
Sangjin Jo ◽  
Dong-Keun Yi ◽  
Ki-Joong Kim

Melampyrum koreanum (Orobanchaceae) was described recently as an endemic species in Korea. This study examined the distribution range, relationship with the host plant, flower developmental pattern, pollinator, pollination mechanism, and seed development of M. koreanum (Orobanchaceae) on the island of Somaemul-do, Korea. M. koreanum is hemiparasitic and a strong candidate for its host plant is Pinus thunbergii, with which it is distributed sympatrically. The flower of M. koreanum represents a typical hawk moth pollination syndrome. Macroglossum pyrrhostictum Butler (Sphingidae, Lepidoptera), a diurnal hawk moth, is the only efficient pollinator. The proboscis length of M. pyrrhostictum and the floral tube length of M. koreanum are well coordinated, and the positions of the anther and stigma of M. koreanum are mechanically conformed to hawk moth pollination. The results suggest that adaptation to the pollinator is the main factor that has affected the evolution of the longer floral tube of M. koreanum compare to other species. Pollinator conservation in the native range of M. koreanum is an important issue for the conservation of endemic plant species, and it is necessary to establish a conservation plan for the host plant, Pinus thunbergii, as well as M. koreanum.


2016 ◽  
Vol 29 (8) ◽  
pp. 1631-1642 ◽  
Author(s):  
B. Anderson ◽  
A. Pauw ◽  
W. W. Cole ◽  
S. C. H. Barrett

2011 ◽  
Vol 104 (1) ◽  
pp. 129-137 ◽  
Author(s):  
PETRA ROS ◽  
ALLAN G. ELLIS ◽  
BRUCE ANDERSON

2006 ◽  
Vol 66 (1b) ◽  
pp. 279-293 ◽  
Author(s):  
L. P. B. Machado ◽  
L. Madi-Ravazzi ◽  
W. J. Tadei

The process of speciation occurs through the evolution of any of several forms of reproductive isolation between taxa, including inviability of hybrids. In this work, strains derived from allopatric populations of Drosophila buzzatii cluster species were experimentally crossed in order to evaluate their reproductive and cytogenetic relationships, and to contribute toward understanding the reproductive isolation in this group of sibling species. Although intrastrain crosses were highly fertile, we consider it relevant to discuss the differences in intra- and interspecific fertility and fecundity here. Among 30 interspecific crosses, about 63% were partially or completely sterile. Fifty three percent of interspecific F1 crosses (female and male F1 crossed) were also partially or completely sterile, in contrast to only one out of 24 intraspecific F1 crosses that was partially sterile. An analysis of hybrid polytene chromosomes revealed complete synapsis, except in the microchromosomes (VI) and in the proximal region of the X chromosome. The intraspecific divergence observed in this study and the variable degree of chromosome pairing shown here reveal part of the complexity of the speciation process pertinent to Drosophila buzzatii cluster, which is consistent with different traits studied in this cluster.


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