Nectar Thieves Research Articles

Reproductive success and production of nectar in Mandevilla funiformis (Apocynaceae): accessibility to visitors and effect of floral stage

The herbaceous vine Mandevilla funiformis (Vell.) K. Schum. occurs in open vegetation in the Southern Brazil. The present study was carried out in a sandbank, east of Florianópolis, Santa Catarina State. Floral morphology, nectar features (production pattern, removal effects, and standing crop), floral visitors (including pollinator, robber and thief of nectar), fruit set and seed germination of M. funiformis were studied. Every plant produced an average of 31.5 inflorescences. The average total volume and the average sugar concentration of nectar were 81 μL and 24%, respectively. The bees Epicharis (Anepicharis) dejeanii, Eufriesea violacea, Bombus (Fervidobombus) morio, the hummingbird Amazilia fimbriata, and two species of Hesperiidae were considered potential pollinators. The other species were considered consumers, nectar robbers or nectar thieves. Fruit set was 35.6% and average percentage of seed germination was 68%, indicating that visitors are efficient pollinators. This study was the first to report production and consumption of nectar in different floral stages (pre-anthesis, flower open, and after corolla abscission). The high and continuous production of nectar by M. funiformis, from floral buds in the pre-anthesis until after the corolla abscission show a real food availability in different ways (pollinators, consumers, robbers or thieves of nectar).

Effective hawkmoth pollination in the primarily bee‐pollinated Salvia daiguii—an example of adaptive generalization

AbstractMany plants exhibit floral traits that are directed to specific pollinator groups. Nevertheless, they can also attract less‐adapted pollinators and gain benefits under certain conditions, resulting in adapted generalization. This may be the case in Salvia daiguii (Lamiaceae), an endangered, bee‐pollinated species native to the Tianmenshan National Forest Park, China. The flower appears phenotypically specialized to bees but is also visited by Macroglossum bombylans. In the present study, we test whether the moth is an effective pollinator of S. daiguii. We quantified and compared the frequency of flower visits by bees and moths and the number of pollen grains deposited on the stigma after a single visit. We also recorded the movements of pistils and stamens of S. daiguii and the behavior of the hawkmoth at the flowers. We found that Apis cerana was the predominant pollinator, depositing an average of 4.74 pollen grains on the stigma after a single visit. However, as the style bends downward during anthesis and reaches the same level as the anthers, Macroglossum individuals hovering around the flowers were also able to effectively transfer pollen to the stigma. On average, 1.38 pollen grains were deposited on the stigma during a single visit. We demonstrate for the first time that the hawkmoth is an effective secondary pollinator in the primarily bee‐pollinated S. daiguii. Style bending allows a nectar thief to become a secondary pollinator. The extent of pollinator generalization is thus increased without affecting the fundamental phenotype adapted to bees as the main pollinators.

The effects of florivory on floral attractiveness and fruit production in Daustinia montana (Convolvulaceae)

• Florivory affects floral attractiveness in Daustinia montana . • Pollinator visits decrease when corolla damage increases in Daustinia montana . • Fruit production under natural conditions was greater among intact flowers. Floral attractiveness is a strong determinant of pollination success, although the same attributes that attract pollinators can also attract florivores. Consumption of the corolla and/or reproductive structures can reduce pollinator visitation frequencies and depress fruit and/or seed set. We hypothesized that florivory would negatively affect the visitation frequencies of floral visitors and natural fruit set in Daustinia montana , a herbaceous species endemic to Brazil. We collected inflorescences of D. montana and recorded the numbers of floral structures with signs of florivory, as well as the locations of that damage, to quantify natural florivory. Artificial damage experiments were carried out with the corollas and stamens to experimentally determine the influence of florivory on the frequency of floral visits. We also randomly marked intact flowers and those naturally damaged by florivory and measured fruit set. More intact floral buds were observed under natural conditions than buds damaged by florivory. We observed that all of the analyzed structures (stamens/pistil and corolla) are generally attacked simultaneously, as opposed to only one specific structure. Intact flowers (controls) demonstrated greater rates of pollinator visitation than experimentally damaged flowers. The visitation frequencies of nectar thieves were not different between intact flowers and artificially damaged flowers. Fruit set under natural conditions was greater for intact flowers than for those that had experienced natural florivory. Our data indicated that floral damage had negative effects on floral attractiveness to pollinators. The greater natural production of fruits from intact flowers is indicative of the degree to which florivory can impact plant reproduction.

The explosive flowers of Marsypianthes chamaedrys (Lamiaceae) resort to self-pollination and improve reproduction

Explosive pollination includes a rapid release of floral sexual elements that are enclosed in modified petals, and a subsequent contact with pollinators’ body. It requires specific groups of visitors in order to assure plant reproduction, thus reproductive success is threatened in species with explosive pollination mechanisms, especially when pollinator activity is uncertain. Autogamy can alleviate such a problem by improving plant reproductive output. Here we investigated the mating strategies of Marsypianthes chamaedrys, a species with an explosive pollen release mechanism and whose medicinal properties are broadly investigated, but no data is available regarding its reproduction. We studied its floral morphology, anthesis, floral visitors and breeding system. Flowers have a bilabiate organization with the reproductive structures housed within a lower, keel-like petal lobe. The species is protandrous and flowers have short life span. Only bees were able to activate the explosive mechanism, while butterflies acted as nectar thieves. Marsypianthes chamaedrys is self-compatible and able to autonomously self-pollinate, likely due to the elongation of the pistil within the keel of unvisited flowers. Marsypianthes chamaedrys likely has a mixed mating system, in which bee pollination and autogamy interplay to improve its reproductive output.

Functional specialization for pollination by scoliid wasps and solitary bees of Ampelopsis glandulosa (Vitaceae)

The insect visitors to the flowers of Ampelopsis glandulosa (Vitaceae) were surveyed in western Japan. This plant species has cymose inflorescences with many greenish open flowers that contain copious nectar. Diverse insect species visit the flowers and the number of wasps was greater than that of bees. The most frequent visitor at all study sites was the scoliid wasp Scolia oculata. Solitary halictine and andrenid bees were also relatively frequent visitors at some sites. Because a large amount of yellow pollen from A. glandulosa was attached to the bodies of both wasps and bees, they were considered to be effective pollinators. Although honey-bees and vespid wasps were also frequent visitors at many sites, a negligible amount of yellow pollen was found to be attached to the bodies of a majority of these; therefore, they were not considered to be effective pollinators. Vespid wasps are predators of herbivorous insects and observations revealed that they are nectar thieves of A. glandulosa. Because diverse insects were attracted to A. glandulosa flowers, these flowers appear to be generalists, however, only short-tongued scoliid wasps, halictine bees, and andrenid bees appeared to be effective pollinators. These results therefore suggest that A. glandulosa is functionally specialized for short-tongued hymenopteran pollinators. This study adds to a growing body of work on specialized wasp pollination, a system hitherto mostly known from South Africa.

Pollinators or nectar thieves? The role of malaria-transmitting mosquitoes in pollination

Pollinators or nectar thieves? The role of malaria-transmitting mosquitoes in pollination

Slippery flowers as a mechanism of defence against nectar-thieving ants.

The great diversity of floral characteristics among animal-pollinated plants is commonly understood to be the result of coevolutionary interactions between plants and pollinators. Floral antagonists, such as nectar thieves, also have the potential to exert an influence upon the selection of floral characteristics, but adaptation against floral antagonists has attracted comparatively little attention. We found that the corollas of hornet-pollinated Codonopsis lanceolata (Campanulaceae) and the tepals of bee-pollinated Fritillaria koidzumiana (Liliaceae) are slippery to nectar-thieving ants living in the plant's habitat; because the flowers of both species have exposed nectaries, slippery perianths may function as a defence against nectar-thieving ants. We conducted a behavioural experiment and observed perianth surface microstructure by scanning electron microscopy to investigate the mechanism of slipperiness. Field experiments were conducted to test whether slippery perianths prevent floral entry by ants, and whether ant presence inside flowers affects pollination. Scanning electron microscopy observations indicated that the slippery surfaces were coated with epicuticular wax crystals. The perianths lost their slipperiness when wiped with hexane. Artificial bridging of the slippery surfaces using non-slippery materials allowed ants to enter flowers more frequently. Experimental introduction of live ants to the Codonopsis flowers evicted hornet pollinators and shortened the duration of pollinator visits. However, no statistical differences were found in the fruit or seed sets of flowers with and without ants. Slippery perianths, most probably based on epicuticular wax crystals, prevent floral entry by ants that negatively affect pollinator behaviour. Experimental evidence of floral defence based on slippery surfaces is rare, but such a mode of defence may be widespread amongst flowering plants.

Diel scent and nectar rhythms of an African orchid in relation to bimodal activity patterns of hawkmoth pollinators.

The temporal dimensions of floral adaptation to pollinators are not yet well understood, partly because we lack accurate information on the diel rhythms of flower visitation for many pollinators. We investigated whether diel patterns of pollinator visitation to flowers of the African woodland orchid Bonatea polypodantha are synchronized with rhythms of floral anthesis, scent emission and nectar availability. Direct observations and motion-activated cameras were used to identify pollinators of B. polypodantha and to document their activity periods. The timing of pollinaria removal from flowers, emission of scent and availability of nectar was also measured. We found that B. polypodantha is pollinated exclusively by short-tongued hawkmoths. Pollinaria of the orchid are affixed between the labial palps of the moths and brush over the protruding stigmatic arms. The flowers also receive visits by long-tongued hawkmoths, but these act as nectar thieves. Tracking of pollinaria removal from flowers confirmed that pollination occurs only at night. Camera footage revealed a striking crepuscular pattern of foraging by short-tongued hawkmoths with peaks of activity during the twilight periods at dusk and at dawn. In contrast, long-tongued hawkmoths were found to visit flowers throughout the night. Flowers of B. polypodantha exhibit unimodal peaks of anthesis, scent emission (dominated by nitrogenous aromatics) and nectar availability before or around dusk. Flowers of B. polypodantha are pollinated exclusively by short-tongued hawkmoths, which show crepuscular foraging activity at dusk and dawn. Floral phenophases of the orchid are closely synchronized with the peak of pollinator activity at dusk.

Draft genome of Rosenbergiella nectarea strain 8N4T provides insights into the potential role of this species in its plant host.

BackgroundRosenbergiella nectarea strain 8N4T, the type species of the genus Rosenbergiella, was isolated from Amygdalus communis (almond) floral nectar. Other strains of this species were isolated from the floral nectar of Citrus paradisi (grapefruit), Nicotiana glauca (tobacco tree) and from Asphodelus aestivus. R. nectarea strain 8N4T is a Gram-negative, oxidase-negative, facultatively anaerobic bacterium in the family Enterobacteriaceae.ResultsHere we describe features of this organism, together with its genome sequence and annotation. The DNA GC content is 47.38%, the assembly size is 3,294,717 bp, and the total number of genes are 3,346. The genome discloses the possible role that this species may play in the plant. The genome contains both virulence genes, like pectin lyase and hemolysin, that may harm plant cells and genes that are predicted to produce volatile compounds that may impact the visitation rates by nectar consumers, such as pollinators and nectar thieves.ConclusionsThe genome of R. nectarea strain 8N4T reveals a mutualistic interaction with the plant host and a possible effect on plant pollination and fitness.

Deceptive pollination of Calanthe by skippers that commonly act as nectar thieves

AbstractFlowers have developed different strategies to attract pollinators through visual or olfactory signals. Most flowers offer pollinators a reward (e.g. nectar and pollen) for the pollination service. However, one‐third of Orchidaceae have been shown not to provide a reward. Calanthe are terrestrial orchids distributed throughout China, Nepal, Japan and tropical Asia. Despite its high diversity, the pollination biology of Calanthe remains largely unknown, even though it is an important aspect of plant conservation. In the study, through field surveying, there were three Hesperiidae butterflies pollinating two species of Calanthe and the pollination behavior differed between the two species of Calanthe, which might lead to different fruit setting rates. There was no nectar in the flowers of the two species, indicating deceptive pollination. Using a glass cylinder experiment, it was deduced that the two species of Calanthe were most likely to attract pollinators by generalized food deception. Interestingly, Hesperiidae butterflies were traditionally thought to be nectar thieves and generally do not transmit pollinia. However, our findings showed that, in this case, the thieves were deceived by the plants and pollinated them for free.

An unexpected visitor

Inside each long and narrow flower spur of the round-leaved orchid (Platanthera orbiculata), a little bit of sweet nectar lures insects. On July 9 at the Hubbard Brook Experimental Forest in New Hampshire, a geranium plume moth (Amblyptilia pica) was seen visiting a P orbiculata. The slender moth was first found embedded in the floral orifice. The moth then flew to a nearby flower and latched onto its dorsal sepal and column with spurred legs. The plume moth could have been pollinating the flower or merely stealing nectar, since several flowers showed signs of already being pollinated, such as swollen ovaries and missing pollinia (when a pollinator uses its long proboscis to extract a flower's nectar, pollen sticks to its eyes to ensure dispersal). Although there is no empirical evidence, it has been speculated that some noctuid moths are the pollinators of P orbiculata based on the size of their mouthparts. While plume moth species have been recorded as likely pollinators for a closely related orchid (Platanthera sparsiflora) that bears similar flowers, to date there has been no evidence to suggest that they could be pollinators for P orbiculata. Geranium plume moths are also known as flower and seed feeders of several horticultural plants. However, it is uncertain whether P orbiculata could be a larval host because the photographed moth appears to be male. So, is A pica a newfound pollinator, a nectar thief, or a seed predator of P orbiculata?

Foraging ants on the extrafloral nectaries repel nectar thieves but not the effective pollinator of Vigna luteola (Fabaceae) in a Mexican coastal sand dune

While some studies have shown that ants that visit extrafloral nectaries may defend their host plants against potential herbivores, recent researches have shown that such ant-plant mutualism may be broken in some cases. For example, the presence of ants on plants could also drive away pollinators and seed dispersers. However, it is not yet known what mechanisms could favor that ant presence on plants does not affect other mutualistic interactions involving plants. In this work, we performed a series of field experiments to test the hypothesis that the presence of ants on EFNs located at the base of the inflorescences of Vigna luteola (Fabaceae) may have a negative effect on floral visitors but not on potential pollinators in a Mexican coastal sand dune. In general, we found that the presence of ants on the plants decreased the rate of flower visitation. However, we observed that the time of visitation of the effective pollinators the bee (Pseudocentron) sp. on the flowers was less compared to that of other floral visitors. This strategy may allow that ants cannot aggressively scare away the effective pollinators. In summary, we show that the effective pollinators of V. luteola present strategies that allow them to visit the flowers without being aggressively attacked by the ants that visit the extrafloral nectaries (EFNs). Therefore, the presence of ants on plants could have a dual function: protecting plants against potential herbivores as well as, filtering flowers against nectar thieves.

Bird-flower interactions in an urban area: Ceiba pubiflora provides nectar and promotes biodiversity in the city

Urbanization has negative effects on plant-animal interactions by reducing plant richness and increasing resource limitations. However, it is possible to replant these areas, and plant species can be selected based on the resources they provide, as well as their relationships with animals. I observed several trees of Ceiba pubiflora (Malvaceae, Bombacoideae) to identify the bird species interacting with their flowers in an urban area. This plant may be especially important, as it blossoms during the dry season, when the overall flower availability in the study area is low. It may also be important during a short period of decline in the fleshy fruit supply. Even though C. pubiflora was growing in the city and had a low volume of nectar accumulating in its flowers (mean of 1.73 μl; SD = 1.39 μl), it attracted a variety of birds (25 species belonging to six families), some of which are usually regarded as forest dependent. Nectarivorous birds from the family Trochilidae (hummingbirds, n = 12 species) had the highest percentage of visits (64.08%), especially during periods of relatively high nectar sugar concentration and calorie availability (c. 18% and 1.5 cal., respectively). Hummingbirds primarily acted as nectar thieves but also sometimes as potential flower pollinators. In contrast, several nonnectarivorous birds (frugivore-granivores, frugivore-insectivores and omnivores) acted only as nectar robbers or flower predators. Ceiba pubiflora flowers appear to be an important source of energy for birds in the urban area. The data of this study show that C. pubiflora has utility as management tool to promote and conserve biodiversity in cities.

Pollination biology and breeding system in five nocturnal species of Oenothera (Onagraceae): reproductive assurance and opportunities for outcrossing

The capacity to produce seed, both by selfing and outcrossing, or mixed mating strategies, is considered a mechanism for overcoming unpredictable pollinator availability. In the present study, we investigate breeding system, insect visitations and the role of insect visitors in the pollination of five species of Oenothera subsect. Oenothera. Field experiments showed that autonomous selfing occurs at bud stage, prior to the opening of the flower. Control flowers showed similar seed set to hand-pollinated flowers, whereas emasculated flowers and those subject to open pollination set fewer seed. These results are consistent with the hypothesis that the investigated Oenothera exhibit a great capacity for autonomous selfing and that selfing is selected in order to provide reproductive assurance. Although flowers were visited mostly by nocturnal lepidopterans, these insects did not precipitate pollination and are thus considered nectar thieves. Conversely, analysis of pollen loads and behavior during foraging by diurnal insect visitors revealed that honeybees and bumblebees are the probable pollinators. We conclude that production of flowers capable of autonomous selfing at bud stage, followed by anthesis and opportunities for outcrossing, probably improves the invasive potential of these Oenothera in Europe, together with a rapid increase in their populations, even when pollinators are scarce.

Evaluation of the symmetric effect of antagonists in the floral morphs of the distylic shrub <em>Bouvardia ternifolia</em>: a field study

Background: Heterostyly is a genetic polymorphism characterized by a system of sporophyte auto-incompatibility in which the plant populations show two (distyly) or three (tristyly) floral morphs. This reproductive system is known as a promoter of cross-pollination, assuming similar reproductive success between morphs.Hyphothesis: For this assumption to take place, the pollinators must respond in a similar manner to attraction floral traits in both morphs, maintaining a symmetric flow of pollen. We hypothesize that floral damage by antagonists should correspond to similarities or differences in atractiveness among floral morphs.Studied species: We tested this hypothesis in the distylous shrub Bouvardia ternifolia (Rubiaceae).Methods: we evaluated the magnitude of the nectar theft, foliar herbivory, and seed predation by assessing individual plants of both floral morphs throughout their flowering period (June-July 2015) under natural conditions. At the end of the flowering season, we quantified fruit and seed production.Results: The intensity of the herbivore and nectar thieves in this distylous population is similar between morphs, as well as the size of their floral displays. The number of seeds and fruits produced was also similar between morphs.Conclusions: Our study showed that selection pressures imposed by antagonists were similar to both floral morphs in the studied population of Bouvardia ternifolia.

Specialist nectarivorous birds (<i>Cinnyris osea</i>) steal nectar whereas omnivorous birds are pollen transfer vectors of <i>Anagyris foetida</i>

The ornithophilous Anagyris foetida is almost the only shrub in the eastern Mediterranean region that flowers in winter. We assessed the pollination potential of flower visitors by observing pollen loads on trapped animals and contacts with floral parts. Resident and wintering omnivorous bird species, together with honey bees (Apis mellifera), were found to carry the shrub’s pollen throughout its long flowering period in Israel and thus might be legitimate pollinators. Spring-migrating omnivorous birds passing through Israel carried pollen. The Palestine Sunbird (Cinnyris osea) is the only specialist nectarivorous bird in the Middle East. It carries little pollen and is therefore primarily a nectar thief of A. foetida.

Mutualism between co-occurring plant species in South Africa's Mediterranean climate heathland is mediated by birds.

Interactions among plant species via pollinators vary from competitive to mutualistic and can influence the probability of stable coexistence of plant species. We aimed to determine the nature of the interaction via flower visitors between Leucospermum conocarpodendron and Mimetes fimbriifolius, two shrubs in the Proteaceae that share many ecological traits and coexist on the Cape Peninsula, South Africa. To assess the extent of pollinator sharing we analysed nectar properties and recorded the pollinator fauna, their behaviour and contribution to seed set. To test for competition via interspecific pollen transfer, we recorded the movement patterns of pollinators and quantified pollen loads. To determine the effect of co-flowering on visitation rates we recorded visits in stands that varied in the density of the two species. We found that the species produce similar rewards and share pollinating Cape Sugarbirds (Promerops cafer). Interspecific pollen transfer is avoided by placing pollen on different parts of the bird. Both species are visited by nectar-thieving Orange-breasted Sunbirds (Anthobaphes violacea). Insects and autonomous self-pollination contributed little to seed set. Pollinator visits increased with conspecific density in both species, and the slope of the increase was steepest in the presence of high densities of the co-occurring plant species. Nectar thief visits also increased with conspecific density in both species, but the slope declined with increasing density of the co-occurring species. Co-occurrence enhanced pollinator visits and alleviated nectar robbing in both plant species, consistent with mutualisms. Mutualism within a trophic level is unusual, but may help to explain the stable coexistence of ecologically similar species.

Floral and pollination biology, breeding system and nectar traits of Callistemon citrinus (Myrtaceae) cultivated in India

This study reports the influence of habitat on floral (flower and nectar characteristics, phenology) and pollination biology (flower visitors and breeding system) on Callistemon citrinus (syn. Callistemon lanceolatus), an Australian species of family Myrtaceae. In India, this small ornamental tree is cultivated in gardens, avenues and road sides and flowers throughout the year. At Agra (Uttar Pradesh, northern India) this species flowers twice a year (February–May and August–November). Flowers open early in the morning and can be characterized as protandrous for a brief period. Fresh open flowers presented ca. 25% of total produced nectar. Nectar sugar composition consisted of only glucose and fructose. A wide array of visitors (honey bees (Apis dorsata), butterflies, wasps, ants, moth, hover flies, several birds and Indian palm squirrel) visit flowers either for pollen or nectar or for facilitating self- and cross-pollination by their intra- and inter-tree movements. Among these, honey bees are dominant in number and in the amount of pollen on their body, while butterflies, ants, wasps, sunbirds, parrots, oriental white-eye sparrow and squirrels forage only for nectar and can be considered occasional pollinators or nectar thieves. Although flowers are highly visited, nectar in standing crop showed that flower visitors did not consume the total nectar produced. Nectar replenishment decreased with age in both bagged- and exposed flowers, showing the capability of secreting nectar after removal during the entire flower lifetime. Experimental hand-pollinations showed that naturalized C. citrinus fruits matured through autogamy, geitonogamy or xenogamy as was reported for native Australian populations. C. citrinus displays an interesting reproductive strategy, shows phenotypic plasticity of flowering periodicity and interacts with a generalized pollinator system, attracts a wide array of animal species with a conspicuous amount or replenished nectar after removals, and uses both compatibility strategies – xenogamy and autogamy – to ensure successful pollination and seed production at native or naturalized habitats.

Asymmetric competition for nectar between a large nectar thief and a small pollinator: an energetic point of view.

There are two alternative hypotheses related to body size and competition for restricted food sources. The first one supposes that larger animals are superior competitors because of their increased feeding abilities, whereas the second one assumes superiority of smaller animals because of their lower food requirements. We examined the relationship between two unrelated species of different size, drinking technique, energy requirements and roles in plant pollination system, to reveal the features of their competitive interaction and mechanisms enabling their co-existence while utilising the same nectar source. We observed diurnal feeding behaviour of the main pollinator, the carpenter bee Xylocopa caffra and a nectar thief, the northern double-collared sunbird Cinnyris reichenowi on 19 clumps of Hypoestes aristata (Acanthaceae) in Bamenda Highlands, Cameroon. For comparative purpose, we established a simplistic model of daily energy expenditure and daily energy intake by both visitor species assuming that they spend all available daytime feeding on H. aristata. We revealed the energetic gain-expenditure balance of the studied visitor species in relation to diurnal changes in nectar quality and quantity. In general, smaller energy requirements and related ability to utilise smaller resources made the main pollinator X. caffra competitively superior to the larger nectar thief C. reichenowi. Nevertheless, sunbirds are endowed with several mechanisms to reduce asymmetry in exploitative competition, such as the use of nectar resources in times of the day when rivals are inactive, aggressive attacks on carpenter bees while defending the nectar plants, and higher speed of nectar consumption.

Floral biology, nectar secretion pattern and fruit set of a threatened Bignoniaceae tree from Brazilian tropical forest

Zeyheria tuberculosa, a Bignoniaceae tree that occurs in a broad latitudinal range in Brazilian forests, is a threatened species of seasonal tropical forest. It is crucial to enhance the knowledge on this species’ floral biology, since interactions related to reproduction of plants are critical for the long term maintenance of their populations. Thus, we investigated the sexual reproduction and floral biology of Z. tuberculosa, including nectar features, aiming to understand the ecological processes associated to this mutualistic plant-animal interaction in the current modified landscape. For this, we performed experiments under natural conditions and in the laboratory. All the evaluated plants were self-incompatible. Zeyheria tuberculosa was pollinated by Bombus pauloensis, a medium-sized bee, and offered hexose-rich nectar as resource. Flowers were also visited by small-sized bee species, Trigona spinipes, that acted as pollen thief, and Pseudoaugochlora pandora and P. graminae that acted as nectar thieves. These three bee groups exhibited temporal separation in the peak of visits throughout the day. The peak of pollinator visits occurred firstly, which may allow the pollinator to access nectar and pollen loads before they are exploited by thieves. However, bee pollinator visits were scarce, and this fact, associated to the self-incompatibility of Z. tuberculosa, may explain the low fruit set registered in the studied plants. It could be of special concern for this threatened species maintenance in the medium and long term, which depends on the offspring originated by sexual reproduction.