POLLINATION ECOLOGY OF RODRIGUEZIA GRANADENSIS (ORCHIDACEAE)

Ecology, 2003

It has been debated whether pollination success in nonrewarding plants that flower in association with nectar-producing plants will be diminished by competition for pollinator visits or, alternatively, enhanced through increased local abundance of pollinators (the magnet species effect). We experimentally evaluated these effects using the nonrewarding bumblebee-pollinated orchid Anacamptis morio and associated nectar-producing plants at a site in Sweden. Pollination success (estimated as pollen receipt and pollen removal) in A. morio was significantly greater for individuals translocated to patches of nectar-producing plants (Geum rivale and Allium schoenoprasum) than for individuals placed outside (ϳ20 m away) such patches. These results provide support for the existence of a facilitative magnet species effect in the interaction between certain nectar plants and A. morio. To determine the spatial scale of these interactions, we correlated the visitation rate to flowers of A. morio with the density of sympatric nectar plants in 1-m 2 and 100-m 2 plots centered around groups of translocated plants, and at the level of whole meadows (ϳ0.5-2 ha). Visitation rate to flowers of A. morio was not correlated with the 1-m 2 patch density of G. rivale and A. schoenoprasum, but showed a significant positive relationship with density of these nectar plants in 100-m 2 plots. In addition, visitation to flowers of A. morio was strongly and positively related to the density of A. schoenoprasum at the level of the meadow. Choice experiments showed that bees foraging on the purple flowers of A. schoenoprasum (a particularly effective magnet species) visit the purple flowers of A. morio more readily (47.6% of choices) than bees foraging on the yellow flowers of Lotus corniculatus (17% of choices). Overall similarity in flower color and shape may increase the probability that a pollinator will temporarily shift from a nectar-producing ''magnet'' plant to a nonrewarding plant. We discuss the possibility of a mimicry continuum between those orchids that exploit instinctive food-seeking behavior of pollinators and those that show an adaptive resemblance to nectar-producing plants.

Plant Species Biology, 2009

The Mediterranean orchid Anacamptis papilionacea, despite showing a typical food-deceptive floral display, has also been reported to frequently attract male pollinators, suggesting a potentiality for sexual attraction. In a survey from a southern Italian population of A. papilionacea and their hybrids with Anacamptis morio, we collected 37 pollinators belonging to five bee species carrying 126 orchid pollinia. The main pollinator of A. papilionacea was Anthophora crinipes male (48.6%), but the number of females was not negligible (22.9%). We also found pollinator sharing between the hybrid and the parental species. Our findings confirm that, contrary to other food-deceptive species, A. papilionacea mainly attracts male insects, but also that, in contrast to sexually deceptive species, this attraction is not specific. We suggest that A. papilionacea adopts a complex mix of food and sexually deceptive pollination and could represent a helpful model for studying the transition between different pollination strategies.

2004

d Background and Aims In New Zealand epiphytic orchids are represented by four genera and eight species. The genera Earina (three species) and Winika (one species) are the most conspicuous and widespread. These are likely to be some of the southernmost distributed genera of epiphytic orchids in the world. d Methods To identify the pollination strategies that have evolved in these orchids, hand-pollination treatments were done and¯oral visitors were observed in several wild populations at two areas of southern North Island (approx. 40°S). Pollen : ovule ratio and osmophores were also studied and the total carbohydrate content of the nectar produced by each species was measured. d Key results Earina autumnalis and Earina mucronata are self-compatible, whereas Earina aestivalis and Winika cunninghamii appear to be partially self-incompatible. All four orchids are incapable of autonomous sel®ng and therefore completely dependent on pollinators to set fruits. Floral visitors observed in the genus Earina belong to Diptera, Coleoptera and Hymenoptera and to Diptera and Hymenoptera in W. cunninghamii. d Conclusions Contrary to many epiphytic orchids in the tropics, the orchid±pollinator relationship in these orchids is unspecialized and¯owers are visited by a wide range of insects. Putative pollinators are¯ies of the families Bibionidae, Calliphoridae, Syrphidae and Tachinidae. All four orchids display anthecological adaptations to a myophilous pollination system such as simple¯owers, well-exposed reproductive structures, easily accessed nectar and high pollen : ovule ratios.

Annals of Botany, 2001

The pollination biology of Aspidogyne argentea, Aspidogyne longicornu and Erythrodes arietina was studied in southeastern Brazil. The three species are self-compatible but are pollinator-dependent. These three orchid species offer nectar as a reward to pollinators and flower visitors. The two Aspidogyne spp. have a dorsally-adhesive viscidium, a feature which precludes pollinators other than bees. Erythrodes arietina flowers are protandrous and show a ventrallyadhesive viscidium. Aspidogyne argentea is visited by halictid bees (here ranked as probable pollinators) and Hesperiidae butterflies. Aspidogyne longicornu is pollinated by females of Euglossa (Euglossini) and visited by the hummingbird Phaethornis ruber and by the euglossine bees Eulaema seabrai (females) and Eulaema cingulata (males). The pollinarium adheres to the ventral surface of the bee labrum, a very difficult place for bees to clean. The dorsally adhesive viscidium in Aspidogyne parallels that of the Spiranthinae genera of the so-called 'Pelexia alliance'. This condition seems to be particularly adaptative under conditions of low-frequency pollinator visits. Erythrodes arietina is pollinated by bees of the genera Paratelrapedia and Osiris which carry the pollinarium on the dorsal surface of their proboscis. Occasionally, these bees remove pollinaria from their mouthparts using their forelegs. In general, in the species studied, a combination of both pollinator behaviour and morphological peculiarities promotes crosspollination.

to determine the reproductive status of the native orchids of the biodiversity "hotspot", Biological corridor tacaná-Boquerón, in the region of soconusco, southeast Mexico, which are suffering the effects of habitat degradation, unsustainable exploitation and potentially, climate change, we analysed the species richness, abundance, habitat and abiotic preferences, pollinaria transport and relation to orchid populations, of male euglossine bees (Hymenoptera: apidea: euglossini) in agroecosystems and forest fragments within the region. using volatile baits we trapped 2,480 bees, consisting of 14 species, during a total of 256 hours, of which 284 individuals (11.5%) had pollinaria of 18 orchid species adhered to their bodies. three species of Eufriesia (E. caerulescens, E. mexicana, E. rugosa) and one species of euglossa (E. villosa) were recorded for the first time. We report Eulaema meriana as the pollinator of the recently rediscovered Plectrophora alata. We did not detect habitat preferences for the species of euglossini captured, and they were frequent, or even more frequent, in intensive coffee plantations, as are many of the orchid species, which can be classified as a disturbed habitat. Bees tended to be more abundant with increasing light intensity and decreasing humidity at each site. there was little indication of pollinator specificity and the position of the pollinaria of each orchid species on the bodies of the bees was also variable. We did not recover any pollinaria from various euglossinophylic, epiphytic orchid species present in the region and three bee species showed signs of population decline. However, our results indicate that many species of orchids with this pollination syndrome are receiving pollination service within an increasingly fragmented and disturbed environment, suggesting that both the orchids and the bees are adapting to the changes.

Plant Ecology, 2011

Variation in within-population floral density can affect interactions between plants and pollinators, resulting in variable pollen export for plants. We investigated the effects of conspecific and heterospecific floral densities on pollination success both of two related, self-compatible, nectar-rewarding orchid species in Ireland, Spiranthes romanzoffiana (rare and listed as endangered) and its congener, S. spiralis (more abundant and not of conservation concern). Floral densities, insect visitation rates, and orchid pollen transport were recorded in multiple quadrats in four populations of both orchid species over their flowering season. We found that conspecific and heterospecific co-flowering plant density affected pollination in both orchid species. For S. romanzoffiana, higher heterospecific density increased pollen removal. For S. spiralis, higher conspecific visitation increased pollen removal and increased heterospecific density decreased pollen deposition. In addition, increased conspecific density increased pollen deposition in both species. This study shows that plants may interact to facilitate or compete for different components of the pollination process, namely; pollinator attraction, pollen removal and deposition. Such interactions have immediate consequences for endangered plant species, as increases in both conspecific and heterospecific coflowering density may ameliorate the negative effects of rarity on pollination, hence overall reproductive success.

2008

Pollen removal and deposition a b s t r a c t Many orchids lack floral nectar rewards and therefore rely on deception to attract pollinators. To determine the effect that a mutation for nectar production would have on overall pollination success of the deceptive orchid Dactylorhiza sambucina, we recorded pollen deposition and removal in flowers of plants that had either been supplemented with an artificial nectar solution or left unmanipulated as controls. Nectar supplementation resulted in significant increases in the proportion of flowers pollinated, regardless of morph colour and the density of plants supplemented in the population. However, nectar supplementation had a significant positive effect on pollinaria removal only for the yellow morph in one experiment in which a low proportion of plants were supplemented. Thus a mutation for nectar production would have a positive effect on overall pollination success in D. sambucina, particularly the female component. The observed patterns are discussed in relation to other factors, such as cross-pollination and the reallocation of nectar resources for other plant functions, which are traditionally considered to shape the rewardless strategies of orchids. (J. Jersá ková ). a v a i l a b l e a t w w w . s c i e n c e d i r e c t . c o m j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / a c t o e c 1146-609X/$ -see front matter ª

Plant Systematics and Evolution, 2013

A population of Luisia curtisii (Orchidaceae: Aeridinae) in northern Thailand was studied with regard to pollination biology. Although a high level of self-compatibility was demonstrated experimentally, the very low natural fruit set (1.4-1.9 %) clearly indicated that the species depends on external agents for pollination. Our observations suggest that L. curtisii is pollinated by beetles, as Lema unicolor (Chrysomelidae) and Clinteria ducalis (Scarabaeidae) were the only flower visitors observed to carry pollinaria of this species. The hypothesis of specialised cantharophily is further supported by 2-methylbutyric acid and caproic acid being striking components of the floral scent. Judging from the lack of nectar and the behaviour of visiting beetles, the pollination system seems to rely on food or brood site deception. Retention of the anther on the pollinarium for some time after pollinarium removal probably reduces the frequency of insect-mediated autogamy and geitonogamy in Luisia curtisii-a possibility that was supported by comparative data on (1) the anther retention time and inflorescence visitation time of Lema unicolor and (2) stigma and anther length in the orchid. Existing reports of specialised beetle pollination in orchids are reviewed, and we conclude that there is accumulating evidence that specialised cantharophily is more common in the Orchidaceae than previously assumed.

Botanical Journal of the Linnean Society, 2020

Rewarding plants can enhance the pollination success of co-occurring plants pollinated by food mimicry. However, it is not always possible to readily discern between the effect of model and magnet species. Here, we tested for mimicry of co-occurring Fabaceae by the rewardless Diuris magnifica (Orchidaceae) and whether the number of flowers of Fabaceae, habitat remnant size and frequency of conspecifics, influenced the pollination success of D. magnifica. Trichocolletes bees were the primary pollinators of D. magnifica, on which they displayed similar behaviour as seen when feeding on Fabaceae. Quantification of spectral reflectance suggested that flowers of Bossiaea eriocarpa, Daviesia divaricata and Jacksonia sternbergiana may represent models for D. magnifica, whereas Hardenbergia comptoniana strongly differed in colour. Orchid pollination success was not directly affected by the number of model flowers, but the pollination rate was enhanced by increased numbers of Hardenbergia fl...

Acta Scientific Agriculture

The orchids are primarily insect pollinated species, yet a variety of pollinators are reported. The pollinators have a considerable role in the evolution of species biodiversity. They exhibit a mutualistic behaviour with orchid species. The orchids have evolved unique floral architecture to accomplish pollination successfully. The morphological diversity of orchid flowers reflects several adaptations to a wide range of pollinators. In this communication, pollination system in orchids is discussed.