scholarly journals High selfing capability and low pollinator visitation in the epiphyte Pitcairnia heterophylla (Bromeliaceae) at a Costa Rican cloud forest

2016 ◽  
Author(s):  
Luis D. Ríos ◽  
Alfredo Cascante-Marín

AbstractMost epiphytic bromeliads exhibit specialized pollination systems likely to promote out-crossing but, at the same time, possess floral traits that promote autonomous selfing. Adaptations that promote selfing in flowering plants with specialized pollination systems have been considered as a mechanism for reproductive assurance. In this paper, we analyzed the breeding system and pollinator visitation rate of the hummingbird-pollinated bromeliad Pitcairnia heterophylla in order to see if they fit such trend. We performed hand pollination experiments, video recording of floral visitors, and recorded floral traits in order to describe the reproductive and pollination system of the studied species in a cloud forest in Costa Rica. Results from the pollination treatments indicated that P. heterophylla is self-compatible (SCIf = 0.77), capable of autonomous pollination (AFIf = 0.78), and non-agamospermous (AGf = 0.01). Floral traits, such as scentless red flowers, with tubular corolla and nectar production, suggested ornithophily which was confirmed by the video recording of Lampornis calolaemus (Trochilidae) visiting flowers. However, the visitation rate was low (0.6 visits day-1 per plant) based on 918 hours of video recording using trail cameras. We suggest that the high selfing capability of the studied population of P. heterophylla might be related to the low pollinator visitation rate. If low pollinator visitation is common among hummingbird-pollinated and epiphytic bromeliads, then selfing could be a widespread mechanism to enhance their reproductive success.

2017 ◽  
Vol 65 (2) ◽  
Author(s):  
Luis Diego Rios ◽  
Alfredo Cascante-Marín

Pitcairnioideae is the second most diverse subfamily of bromeliads (Bromeliaceae), a group exclusive to tropical regions of the New World. Pitcairnioid bromeliads have floral traits assumed to promote outcrossing through biotic pollination systems; however, the reproductive biology of most of the species of this group has not been documented. Pitcairnia heterophylla is an epiphytic (seldom saxicolous) bromeliad occurring from Southern Mexico, into the Northern Andes. We studied the pollination and breeding system of P. heterophylla in an epiphytic population at a mountain forest in Costa Rica from January to April 2013. We performed hand pollination experiments (agamospermy, autonomous self-pollination, hand self-pollination and hand cross-pollination) on 89 flowers from 23 individuals (3–6 flowers per individual) in 2013 flowering season. Nectar production was measured on 18 unvisited flowers of six individuals with a hand-held refractometer. Simultaneously, floral visitors were recorded on eight individuals with trail cameras for a total of 918 hours (115 ± 52 hours per individual, mean ± SE). Under natural conditions, seed set (540.4 ± 55.2) was similar to manually selfed flowers (516.3 ± 41.5) and autonomously selfed flowers (521.1 ± 29.0), but lower to manually outcrossed flowers (670.2 ± 31.3). The flowers of P. heterophylla are self-compatible, capable of autonomous pollination, and non-agamospermous. Intrafloral self-pollination is facilitated by adichogamy and lack of floral herkogamy. The scentless red flowers of P. heterophylla with tubular corollas and nectar production suggested ornithophilic pollination which was confirmed by video recording of 46 hummingbird visits. The most common floral visitor was the short-billed hummingbird Lampornis calolaemus which accounted for 78 % of the visits. However, the visitation rate during the flowering season was low (0.6 visits per day per plant). Selfing in P. heterophylla might be explained as a mechanism of reproductive assurance and to reduce interspecific pollen flow with taxonomically unrelated plants.


2011 ◽  
Vol 27 (4) ◽  
pp. 393-404 ◽  
Author(s):  
Hamleth Valois-Cuesta ◽  
Pascual J. Soriano ◽  
Juan Francisco Ornelas

Abstract:We investigated morph differences in attributes that contribute to rewarding floral visitors of the distylous shrub Palicourea demissa at La Mucuy cloud forest in Venezuela. In both morphs, we measured nectar production from flowers subjected to repeated removals at 2-h intervals (10 plants per morph) and flowers that accumulated nectar for 24 h (10 plants per morph). In both cases, floral visitors were excluded. In addition, we quantified nectar availability (30 plants per morph), floral visitation (10–12 plants per morph) and legitimate pollination (30 plants per morph) throughout the day. We explored morph differences in the variables mentioned above using analyses of variance, and the effects of nectar variation on floral visitation and legitimate pollination using regression models. We observed 1205 floral visits, grouped into six hummingbird (94.7%) and three insect species (5.3%), across observations (264 h). Coeligena torquata was the most frequent floral visitor (34%) in both morphs (1.4–1.7 visits per plant h−1). Nectar production and availability, and visitation rate were similar between morphs. Visitation rate and legitimate pollen deposition increased with the nectar production in both morphs, but levels of legitimate pollination were higher on short-styled flowers than long-styled flowers. These results show that short-styled and long-styled flowers reward floral visitors equally, but frequency and foraging behaviour of long-billed pollinators can promote asymmetrical legitimate pollination.


2004 ◽  
Vol 52 (1) ◽  
pp. 87 ◽  
Author(s):  
V. M. Saffer

Plants pollinated predominantly by vertebrates are thought to have suites of floral traits (e.g.�colour, conspicuousness, odour) that favour either birds or mammals, with brightly coloured, conspicuous flowers associated with birds and drab, concealed flowers with non-flying mammals. This study examined two other floral traits, diel patterns of nectar production and pollen presentation (anthesis). It would be expected that these would be nocturnal in putatively mammal-pollinated plants and diurnal in bird-pollinated plants. In four Banksia and two Dryandra species, all known to be visited by honeyeater birds and small marsupials at one site in south-western Australia, there was no clear correspondence between visual cues and diel patterns of resource presentation. This lack of correlation between floral traits does not support the idea of specialised pollination syndromes, but rather is consistent with generalised pollination systems.


2004 ◽  
Vol 20 (4) ◽  
pp. 459-469 ◽  
Author(s):  
Carlos García-Robledo ◽  
Gustavo Kattan ◽  
Carolina Murcia ◽  
Paulina Quintero-Marín

This study describes a pollination system in a species of Araceae that involves three species of beetle, one of which is also a fruit predator. In a tropical cloud forest in Colombia, inflorescences of Xanthosoma daguense opened at dusk, releasing a sweet scent and raising their temperature 1–3 °C. Soon after, two species of Scarabaeidae (Dynastinae; Cyclocephala gregaria and C. amblyopsis) and one species of Nitidulidae (Macrostola costulata) arrived with pollen. Cyclocephala beetles remained inside the inflorescence for 24 h. The next night, Cyclocephala beetles left the inflorescence after picking up the freshly shed pollen, almost always moving to the nearest inflorescence available. The probability of inflorescence abortion and number of fruits set after the visit of one individual was equivalent for both Cyclocephala species. However, C. gregaria was much more abundant than C. amblyopsis, so it was the most important pollinator. There was a positive relationship between the number of dynastine visits and the number of fruits produced. Besides carrying pollen to the inflorescences, nitidulid beetles had a negative effect on female reproductive success through fruit predation. Nitidulid larvae developed inside the infructescence and preyed on up to 64% of the fruits. However, 8% of inflorescences not visited by dynastines were probably pollinated by nitidulids, because hand-pollination experiments showed that self-pollination was unlikely. Inflorescences potentially pollinated by nitidulids comprised 25% of the fruit crop in the year of our study. This interaction with a fruit predator that is also a potential pollinator resembles brood-site pollination systems in which pollinators prey on part of the fruit set (e.g. Ficus, senita cacti, Yucca), making this system substantially more complex than previously described dynastine-pollinated systems in aroids.


2003 ◽  
Vol 90 (11) ◽  
pp. 1612-1618 ◽  
Author(s):  
E. Cayenne Engel ◽  
Rebecca E. Irwin

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