Nectar Research Articles

Urban environments increase generalization of hummingbird–plant networks across climate gradients

Urbanization has reshaped the distribution of biodiversity on Earth, but we are only beginning to understand its effects on ecological communities. While urbanization may have homogenization effects strong enough to blur the large-scale patterns in interaction networks, urban community patterns may still be associated with climate gradients reflecting large-scale biogeographical processes. Using 103 hummingbird–plant mutualistic networks across continental Americas, including 176 hummingbird and 1,180 plant species, we asked how urbanization affects species interactions over large climate gradients. Urban networks were more generalized, exhibiting greater interaction overlap. Higher generalization was also associated with lower precipitation in both urban and natural areas, indicating that climate affects networks irrespective of habitat type. Urban habitats also showed lower hummingbird functional trait diversity and over/underrepresentation of specific clades. From the plant side, urban communities had a higher prevalence of nonnative nectar plants, which were more frequently visited by the hummingbird species occurring in both urban and natural areas. Therefore, urbanization affected hummingbird–plant interactions through both the composition of species and traits, as well as floral resource availability. Taken together, we show that urbanization consistently modifies ecological communities and their interactions, but climate still plays a role in affecting the structure of these novel communities over the scale of continents.

Phenological mismatch is less important than total nectar availability for checkerspot butterflies.

Changes in phenology are a conspicuous fingerprint of climate change, leading to fears that phenological mismatches among interacting species will be a leading cause of population declines and extinction. We used quantile regression to analyze museum collection data and estimate changes in the phenological overlap of Baltimore checkerspot butterflies and 12 common nectar plant species over several decades in two geographic regions. We combined these museum data with field estimates of each species' flower density and nectar sugar production to estimate changes in resource availability caused by shifts in phenological overlap. Phenological overlap (measured as the proportion of plant flowering during the flight period of an average butterfly) decreased through time, primarily because the flowering period of nectar plants was longer, but the flight period of butterflies was shorter in recent years. Our study was also motivated by the hypothesis that phenological mismatches may be more severe in the southern region due to a midsummer dearth in floral resources, but this hypothesis was not supported by our data. Although phenological overlap was somewhat smaller in the southern region, changes in overlap through time were similar in both regions. When phenological overlap was weighted by nectar sugar production of different species, the overlap increased in the southern region but decreased in the northern region (the opposite of our prediction). Overall, nectar resources were much more abundant at study sites in our northern region than in our southern region, possibly due to differences in land management. Our study demonstrates the complexities of phenological mismatch of interacting species and highlights that phenological changes may have small impacts on population viability.

Vanilla planifolia: Artificial and Insect Pollination, Floral Guides and Volatiles

The natural pollinator of the major species of commercially-grown vanilla, Vanilla planifolia, is unknown, and the crop requires hand pollination to achieve significant levels of fruit set; however, the traditional technique (using a toothpick) is costly, as it requires skilled personnel. To overcome this problem, two native Australian bees, Tetragonula carbonaria and Austroplebeia australis, and the blowfly, Lucilia cuprina, were trialled as pollinators. Three alternatives to the toothpick method were also trialled. The appearance of vanilla flowers under ultraviolet radiation was examined to determine the presence of cryptic pollination guides, and the chemical composition of nectar from extrafloral nectaries and aroma volatiles from the flowers were characterised. None of the three insects effected pollination due to their small size and behaviour; other insect pollinators need to be identified. The alternative mechanical methods of pollination trialled resulted in fruit set; however, the percentages of fruit set were lower than the traditional toothpick method, and the fruit were of inferior quality. The nectar produced predominantly consisted of sucrose and melezitose. Melezitose is a strong attractant of various ant species, which may explain the concentration of ants around the nectaries and the apparent lack of nectar production in part of this study. The aroma volatiles included monoterpenoids, terpenes, sesquiterpenoids, aromatics, nitrogen-containing compounds and fatty acids, the most abundant being a-pinene and eucalyptol. Illumination of the flowers with UV-A radiation revealed fluorescence from the stamens, the column and the callus, which is located on the labellum. These observations may aid the identification and use of potential pollinators.

Dramatic recent declines in the size of monarch butterfly (Danaus plexippus) roosts during fall migration

The conservation status of monarch butterflies in North America is a topic of intense scrutiny and debate. It is clear that winter colonies in Mexico are declining, yet some recent studies suggest that summer breeding populations are relatively stable and similar to historical abundances. One possible explanation for these discordant patterns is that fall migration success has been recently disrupted. Here, we use a relatively unexplored citizen-scientist dataset on the size of monarch "roosts," which are resting aggregations on vegetation, to infer changes in monarch abundance along the fall migration route over the last 17 y. We found that the timing of migration remained relatively unchanged while the flyway has generally become warmer and greener. Warmer and greener conditions were associated with larger roosts, yet we found steady, dramatic declines in roost sizes through time that were independent of climate and landscape factors. Roost sizes have declined as much as 80%, with losses increasing from north to south along the migration route. These findings suggest that failure during the fall migration could explain the apparent drop in monarch numbers from summer breeding to overwintering populations. This in turn suggests that conservation efforts that support fall migration success are most needed, such as providing high quality nectar plants along the migration route or limiting the planting of nonnative milkweeds that enhance monarch parasite loads. Overall, it appears the fall migration of monarch butterflies is under imminent threat, even if the species' overall survival is not.

Contamination profile and hazards of neonicotinoid insecticides in honey from apiaries in Beijing, China.

The residues of neonicotinoid insecticides in honey have raised global concern for their adverse effects on non-target organisms. However, information on the presence of neonicotinoids in raw honey in China is limited. Our study investigated the distribution profiles of neonicotinoids in raw honey samples collected from apiaries in plain and mountainous areas surrounding Beijing City. At least one of four neonicotinoids, imidacloprid, thiamethoxam, acetamiprid, or clothianidin, was found in 46.9% of samples. Neonicotinoids in multi-floral honey in plain areas exhibited higher concentrations and prevalence than in uni-floral honey collected from mountainous areas. These results indicated that neonicotinoid residues in honey were linked to the agricultural ecosystems influenced by geographies, particularly the intensity of agriculture and nectariferous plant types. The dietary risks to adult and children health from neonicotinoid exposure were deemed de minimis, while risks to honeybees at the maximum concentration level require much attention through refined, higher-tier assessments and possible mitigation measures for the use of these products.

Nectar plants visited by hummingbirds in an urban area of southern Brazil

Nectar plants visited by hummingbirds in an urban area of southern Brazil

Recognition of Pleuropterus angulatus (Polygonaceae) as a separate species: evidence from morphological and molecular data

On the basis of morphological and molecular data, we demonstrate that Polygonum multiflorum var. angulatum actually belongs to the genus Pleuropterus. As a consequence, a nomenclatural change (Pleuropterus angulatus comb. et stat. nov.) is proposed. This species is closely related to Pleuropterus multiflorus, but differ from the latter in root tuber color (white vs. yellow-brown in P. multiflorus), vascular strands (absent vs. present), branchlets (densely papillate vs. smooth), and vein (densely papillae vs. non-papillate), and extra-floral nectaries (deeper, thicker around the lips vs. shallow, thin).

New observations on prey scarab beetles and host plants of the green lynx spider, Peucetia viridans (Hentz, 1832) (Araneae: Oxyopidae) in Oaxaca, Mexico

ABSTRACT Peucetia viridans (Hentz), commonly called the lynx spider, is an important predator with a diet that encompasses a wide variety of insects and arachnids, including cannibalism. Although several studies that address aspects related to its ecology and behaviour have been carried out, there is a notable lack of studies focused on the recording of its prey and hosts. This information gap is particularly evident regarding the interaction of the spider with beetles belonging to the family Scarabaeidae. To contribute to the knowledge of the feeding habits and host preferences of P. viridans, observations were made in two localities of the Valles Centrales region of Oaxaca, Mexico. Lynx spiders were observed on Croton ciliatoglandulifer Ortega, Lantana camara Linnaeus, Solanum mitlense Dunal, and Wigandia urens (Ruiz and Pav.) Kunth. Spiders utilise these plants as shelter and to ambush their prey, thereby reducing herbivore populations and protecting the plants. In return, the plants provide the spiders with prey and floral and extrafloral nectaries as food sources. Therefore, spiders and plants have a facultative mutualistic relationship, whereas the relationship between spiders and herbivores is antagonistic. For the first time Diplotaxis trapezifera Bates, Macrodactylus fulvescens Bates, Paranomala discoidalis (Bates), Strigoderma costulipennis Bates, Strigoderma sulcipennis Burmeister, and Euphoria pulchella (Gory and Percheron) as prey, and Wigandia urens, Lantana camara and Solanum mitlense as host plants are recorded. A checklist of host plants for P. viridans is given. Overall, these new observations highlight the importance that tritrophic interactions (plant–herbivore–natural enemy) have in wild systems, which are essential for maintaining ecological balance.

The extrafloral nectary traits of woody plants in Brazil’s Caatinga: describing an ecological spectrum

Abstract Plants use extrafloral nectaries (EFNs) as indirect defence mechanisms against herbivores. These structures contain nectar that is offered to ants in exchange for their protection. EFNs display pronounced functional variation, but it is unknown how this variation comes together in phenotypes. Here, we characterized the main functional traits of EFNs and investigated the associations among them. This work was conducted at a study site in the Caatinga that hosts 14 species of woody plants. We characterized the following functional traits: EFN type, position, arrangement, size, and reducing-sugar level. We observed a marked degree of trait variation (~30%) that was manifested in species-specific trait combinations, giving rise to an ‘ecological spectrum’. At one end were Fabaceae species with large, vascularized EFNs that occur individually on the leaf petiole and/or rachis and that produce high levels of reducing sugars. At the other end were Euphorbiaceae species with small, nonvascularized EFNs that are generally grouped on the leaf blade and that produce low levels of reducing sugars. Despite its limited geographical and phylogenetic scale, this study represents an important first step in describing an ecological spectrum that can inform our understanding of the ecological interactions and evolutionary history of this functionally relevant group of plants.

Fire and ant interactions mediated by honeydew and extrafloral nectar in an australian tropical savanna

Fire is a major disturbance affecting ecosystems globally, but its impact on mutualisms has received minimal attention. Here, we use a long-term field experiment to investigate the impact of different fire regimes on globally important ant–honeydew and ant–extrafloral nectar (EFN) mutualistic interactions in an Australian tropical savanna. These interactions provide ants with a key energy source, while their plant and hemipteran hosts receive protection services. We examined ant interactions on species of Eucalyptus (lacking EFNs) and Acacia (with EFNs) in three replicate plots each of burning every 2 and 3 years early in the dry season, burning late in the dry season every 2 years, and unburnt for > 25 years. The proportions of plants with ant–honeydew interactions in Acacia (44.6%) and Eucalyptus (36.3%) were double those of Acacia plants with ant–EFN interactions (18.9%). The most common ants, representing 85% of all interactions, were behaviourally dominant species of Oecophylla, Iridomyrmex and Papyrius. Fire promoted the incidence of ant interactions, especially those involving EFNs on Acacia, which occurred on only 3% of plants in unburnt plots compared with 24% in frequently burnt plots. Fire also promoted the relative incidence of behaviourally dominant ants, which are considered the highest quality mutualists. Contrary to expectations, frequent fire did not result in a switching of behaviourally dominant ant partners from forest-adapted Oecophylla to arid-adapted Iridomyrmex. Our findings that frequent fire increases ant interactions mediated by honeydew and extrafloral nectar, and promotes the quality of ant mutualists, have important implications for protective services provided by ants in highly fire-prone ecosystems.

Effects of sown and spontaneous inter-row vegetation on weeds and beneficial arthropods in vineyards

The intensification of crop management has resulted in a decline of biodiversity in the last decades, in particular through habitat loss, fragmentation and degradation. Semi-natural habitats within agricultural landscapes such as hedges, grasslands or herbaceous field margins, provide resources and refuge to beneficial arthropods. In vineyards, extensively used inter-row vegetation may be functionally equivalent to such semi-natural habitats and sowing of plant species rich in floral resources may improve habitat functions. In this study, three types of vineyard inter-row vegetation treatments were compared in 15 vineyards of South-eastern France: (1) sowing a high-diversity seed mixture (HD) with a high number of nectariferous plant species, (2) spontaneous vegetation, and (3) tilled inter-rows. We monitored the inter-row vegetation including problematic weeds, the abundance of beneficial arthropods, and the predation of sentinel prey. The invasive weedy grass species Cynodon dactylon showed a lower cover in HD inter-rows than in spontaneous vegetation, whereas no differences were found for the invasive herb Erigeron sumatrensis. Both weed species were still best controlled in tilled inter-rows. Beneficial arthropods were less abundant in tilled than in spontaneously vegetated and sown inter-rows. Day predation was higher in HD inter-rows than in spontaneous vegetation although no significant differences were found for observed predators. Over all treatments, plant species richness, flower and grass cover had a positive influence on several beneficial arthropod groups. Our results highlight the positive effects of species-rich inter-row vegetation on weed control, beneficial arthropod abundance and predation but also showed that further research is needed to improve the efficiency beyond services already provided by spontaneous vegetation.

Fluorescent nectar in non-flying mammal-pollinated plants – observations and considerations in some Asparagaceae

Background and aims – Fluorescence is the emission of light by a fluorophore that has absorbed light of shorter wavelengths. While the role of fluorescence in visual communication has been documented in some animals (budgerigars, gelatinous zooplankton), it is controversially discussed in plants. Floral nectar fluorescence has been mainly found in flowers pollinated by bees. It has been suggested as direct visual cue by which bees can evaluate the available quantity of nectar, thus being important for pollination and foraging efficiency. However, this function has been questioned, since fluorescence is said to be obscured by floral reflections due to low quantum efficiency. The aim of this study was to examine the nectar of plants pollinated by non-flying mammals, namely Eucomis regia, Massonia grandiflora, M. echinata, and M. pustulata (Asparagaceae) from South Africa. Material and methods – To detect possible fluorescence in flowers, the plants were illuminated in a darkened room under UV light and photographed with a camera equipped with a UV/IR cut filter (transmitting at 400–700 nm). Key results – Within the inflorescences, the nectar of all species showed blue to bluish fluorescence and UV absorption. Separated nectar also fluoresced. Conclusion – As fluorescence in flowers occurs not only in bee-pollinated plants but also in plants pollinated by wind, and by nocturnal or crepuscular pollinators (non-flying mammals, bats, moths) for which floral scent is an important attractant, floral fluorescence seems to have no adaptive value for the attraction of flower visitors. We discuss the potential role of fluorescence in flowers as just a by-product of compounds that might have other functions such as visual attraction by reflection (or UV absorbance), protection of genetic material in pollen from UV induced damage, or as a floral filter causing nectar to be bitter, repelling ineffective pollinators but not effective ones.

Revisiting ant-plant-pollinator interactions: plant fitness depends on mutualist identity

Abstract Two species may share a mutualistic interaction if the benefits gained by the interaction outweigh the costs incurred. In this study, we tested experimentally how the identity of ants (pinned) and floral visitors of an extrafloral nectary (EFN)-bearing plant can affect plant fitness. We quantified ant activity and floral visitor visitation overlap over time, floral visitor behaviour, amount of floral resources collected, and plant fitness as influenced by the ant species identity in an EFN-bearing plant from Brazilian Cerrado savanna, Qualea multiflora (Vochysiaceae). We found that: (i) ant activity and floral visitation overlap greatly in time; (ii) floral visitors vary in their response to the presence of ants; (iii) different ant species have different impacts on floral visitors; (iv) ants affected the amount of floral resources collected by pollinators, but their levels were contingent on ant identity; and (v) plant fitness components (fruit production, seed weight, and seed size) were most strongly affected by the largest and most aggressive ant species. Our results suggest that the balance of the trade-off between the beneficial effects of ant protection against herbivorous insects and the negative consequences for plant fitness by deterring pollinators depends on the species identity of both the ants and the floral visitors to the plant.

Ant sharing by plant species bearing extrafloral nectaries has a low impact on plant herbivory in a tropical system

Abstract Plant species bearing extrafloral nectaries (EFNs) may indirectly influence other plant species by sharing protective ants, potentially altering herbivory levels. However, the propagation of indirect effects in this type of mutualism has seldom been investigated. We investigated indirect effects via ant sharing among 21 EFN‐bearing plant species of the tribe Bignonieae distributed on 28 plots in the central Brazilian Amazon. We used an ecological network index to quantify potential indirect effects among plant species through shared dominant and subordinate ant species. Plant species that were more attractive to ants (promoter species) had the highest potential to indirectly influence ant visitation to less attractive plant species (receptor species) in the community, primarily through changes in the attraction of dominant ant species. However, these potential indirect effects did not result in significant differences in herbivory patterns among the studied plants. Ant attendance and herbivory levels were similar among promoter species, neighbouring plants, and non‐neighbouring plants. Unlike other mutualisms involving plants (e.g., pollination), the indirect effects among plant species that share protective ants had limited consequences. The low levels of herbivory and the small foraging areas of shared ant defenders could be responsible for the observed limited impact of indirect interactions among plant species in this system. Synthesis: This study demonstrates that plant species with EFNs can indirectly influence other plant species through ant sharing. The attractiveness of certain plants to ants enables them to affect the ant visitation patterns of less attractive plants in the community. However, these indirect effects did not significantly alter herbivory levels among plants. Overall, this study advances ecological understanding by showing that the sharing of protective ants among plant species can in some cases confer limited costs and benefits, leading indirect interactions to have minimal impact on herbivory patterns.

Assessing pollinator abundance and services to enhance agricultural sustainability and crop yield optimization in the Qilian Mountains

ContextPollination services are critical to crop production and human livelihoods, linking natural ecosystems directly to agricultural production systems. However, pollination services and pollinators are under constant threat from land-use changes and various other environmental pressures. ObjectiveIn this study, employing a case study of the entire Qilian Mountains in northwest China, the distribution of nectar sources in different land use types in the study area was determined through field survey and literature. MethodsBased on 1990–2020 land use data, crop yield data, crop prices, pollinating bee species and nectar plants data. We used the Gross Ecological Product (GEP) accounting and InVEST model of pollination services and assessed the status and trends of pollination services, the risks posed by land use changes and environmental pressures, and suggested potential solutions for mitigating identified risks. Results and conclusionsThe results of the study showed that (1) nectar sources and nesting areas' potential distribution closely correlates with land use types; (2) the Pollinator abundance index (PAI) is above 0.30, a high level, and the Pollination potential index (PPI) is between 0.15 and 0.30, a medium level, with both indices generally increasing over the past 40 years; (3) Human economic activities and land management policies had the most significant impact on pollination services, with 15.57 % and 14.02 %, respectively. Climate change (temperature, precipitation, extreme events) and invasive alien species had relatively minor impacts, accounting for 0.14 % and 0.15 %, respectively. (4) The Qilian Mountains will face a new risk, whether monoculture or the expansion of pollinator-dependent crops could lead to habitat homogenization issues, potentially affecting pollinator abundance and diversity. SignificanceWe recommend that future plans emphasize the provision of pollinator nesting resources along with floral resources, restoration of semi-natural and natural habitats adjacent to crops, adjustment of cropping patterns, and implementation of agricultural diversification, which will help to ensure pollinator diversity and sustainability of agroecosystem pollination services.

Nectar sources of Asian honeybees (Apis cerana Fabricius) in West Bengal: determining by pollen analysis of honey and bee’s crop-nectar

: Understanding nectar sources is crucial for sustainable apiculture with Apis cerana, yet information on these sources remains limited. We conducted pollen analysis of honey and bees’ ingested nectar (mainly crop content) to determine the nectar sources of this honeybee species in West Bengal, India. Diverse pollen types were obtained from honey (33) and crop-nectar samples (47). A few pollen types came from non-nectariferous plants, and most came from actual nectariferous plants. Predominant pollen types in honey samples were Calendula officinalis, Eucalyptus tereticornis, and Peltophorum pterocarpum. The very frequent pollen types obtained from crop-nectar were Eucalyptus tereticornis, Peltophorum pterocarpum, and Tridax procumbens. In conclusion, versatile pollen types (that were obtained from honey and bee’s crop-nectar), indicating that the Asian honeybee (Apis cerana) is a generalist visitor, collect nectar from a large number of plant species. Our results also conclude that pollen analysis of bees’ crop-nectar can provide vital information about their nectar sources (excluding a few pollen types of non-nectariferous plants) in addition to the traditional honey analysis.

Consistent generalization of plant-hummingbird networks despite increasing vegetation cover across a tropical urban landscape

Human activities, particularly urbanization, profoundly impact ecosystems often resulting in biotic homogenization. Whether or not urban landscapes can sustain diverse pollinator and plant communities is an important question to be addressed. Here, we investigated the influence of urbanization on plant-hummingbird interaction networks in a large tropical city, Belo Horizonte, Brazil. We recorded 13198 legitimate interactions between seven hummingbirds and 57 plant species across 12 local networks. Urban landscapes exhibited predominantly generalized networks, maintaining this pattern across varying vegetation cover and floral resource abundance. Although some functionally specialized hummingbirds with long bills were recorded performing more specialized interactions, urban environments did not generally support specialized networks. Nevertheless, network specialization did increase with the proportion of native nectar plants, emphasizing their importance for maintaining some specialized interactions. Furthermore, we observed a positive effect of plant richness, but not of flower abundance, on hummingbird abundance, indicating that it is not only the amount of flowers, but the diversity of floral resources that may be a key factor in maintaining hummingbirds. Therefore, promoting a diverse assemblage of native plants in urban green areas is crucial for sustainable pollinator communities. Our study highlights that while a biodiverse urban landscape will require careful urban vegetation planning considering both floral resource diversity and availability, vegetation cover per se may not be sufficient to mitigate the negative impacts of urbanization. Maintaining a diverse vegetation with different life forms, flowering phenology, and especially of native plants across the urban landscape is needed to create welcoming spaces for pollinators.

Morphoanatomical alterations in extrafloral nectaries of Cedrela fissilis Vell. (Meliaceae), a native species of the Atlantic Forest, in response to simulated acid rain

Acid rain is one of the major contributors to the loss of tropical forest. Although the effects of acid rain in leaf anatomy have been widely studied, its impact on specialized secretory structures remains unknown. The aim of this study was to investigate the morphoanatomical changes in the extrafloral nectaries of Cedrela fissilis in response to simulated acid rain. Each seedling was sprayed with 50 ml of an acidic solution daily for 19 consecutive days. Anatomical and micromorphological changes in the nectaries were described. The treated plants exhibited plasmolysis and disruption of epidermal cells, cell collapse, hypertrophy, plasmolysis, phenolic and starch accumulation in the nectar-secreting cells, and the formation of a wound healing tissue. The results indicate that the nectaries of C. fissilis undergo alterations when exposed to acid rain, which may compromise the functioning of the entire structure and potentially impact plant-insect ecological interactions.

Conserving apollo butterflies: habitat characteristics and conservation implications in Southwest Finland

The conservation of insects, particularly endangered species such as the Apollo butterfly, is a pressing global concern. Understanding the habitat requirements and factors influencing species occupancy is crucial for designing effective conservation strategies. We focused on investigating the habitat characteristics expected to affect the occupancy of the nationally endangered Apollo butterfly in Southwest Finland. We conducted field surveys and GIS analysis to assess the impact of larval host plant and adult nectar resources, habitat encroachment, elevation, connectivity, and spatial variation on Apollo larval occupancy in rocky outcrop habitats. We found that rocky outcrops with abundant host plants and those less isolated from nectar patches play a significant role in supporting Apollo reproduction, whereas encroachment, specifically increased tree volume, negatively affected occupancy. We additionally observed spatial variation in occupancy across different blocks within the study area. Our findings emphasise the importance of resource availability for Apollo butterflies and highlight the dynamic nature of their habitat requirements. Maintaining a network of intact rocky outcrops with suitable resources is essential for the long-term persistence of the Apollo butterfly population in the region.Implications for insect conservation: Our research underscores the critical need to protect and restore habitats for the Apollo butterfly, particularly by addressing threats such as habitat encroachment and construction projects that pose risks to their breeding sites.

Interaction of Capnodium alfenasii with extrafloral nectaries of Azadirachta indica.

Sooty moulds are saprophytic epiphytic fungi that grow mostly on insect secretions, but they can also be associated with plant secretions. In this study, we aimed to describe de interaction of Capnodium alfenasii sooty mould with the extrafloral shoot nectaries of Azadirachta indica. Anatomical and histochemical studies were carried out on serial sections of extrafloral shoot nectaries of A. indica without and with C. alfenasii infestation. The total soluble sugar content of the secreted nectar was determined, and the conidial germination of the fungus in distilled water and in dextrose and nectar solutions was evaluated. The shoot nectaries of A. indica are elongated structures that occur in pairs near the base of the petiole. The exuded nectar contains an average of 534.8µg of total soluble sugars per µL of nectar and provides ideal conditions for conidial germination and fungal growth. C. alfenasii hyphae grow on the nectary, penetrate through breaks in the cuticle, travel under the cuticle and penetrate the secretory tissue by inter- and intracellular routes. The present report is the first to describe the interaction of C. alfenasii with the A. indica nectary, including the penetration of hyphae into nectariferous tissues and the plant defence mechanisms.