Floral Visitors Research Articles

Contribution of pollinators to production and reproduction of neglected and underutilized food species in family farming systems in Patagonia

ABSTRACT Many of the species used in family farming systems (FFS) in Patagonia belong to the group known as neglected and underutilized species (NUS), which promote biocultural diversity and contribute to food sovereignty. Due to the scarce attention paid to NUS by agronomic sciences, little is known about their biotic pollination, although it is a well-studied aspect for commercially important plants. We evaluate the contribution of animal pollination to NUS managed by Patagonian FFS. We present a literature review of the NUS used and aspects related to their pollination and floral visitors, for which 725 papers were reviewed. FFS use 426 NUS (414 angiosperms, 10 gymnosperms and 2 ferns). Most NUS (86.7%) depend to some extent on animal pollination, either for the production of fruits or seeds that are harvested for consumption (direct dependence, 35%) or for obtaining seeds (indirect dependence, 65%), which in many cases are necessary for reseeding. Gathering and cultivation are the most common management practices for these species. Hymenoptera and Diptera are the animals that contribute most to NUS biotic pollination. Our results show that animal pollination is a key contribution of nature to sustain cultural aspects and food sovereignty of FFS in Patagonia.

Role of Insects in Cross-Pollination and Yield Attributing Components of Fenugreek

Fenugreek (Trigonella foenum-graecum) is a self-pollinated crop however insect pollination can improve the seed and fruit set. The present study was carried out at the agricultural research farm of The Islamia University of Bahawalpur, Pakistan to enlist the pollinator community of fenugreek, their foraging behavior, and identify the most effective pollinator species in terms of plant reproductive success. The floral visitor community of fenugreek was comprised of six bees, four flies, one moth, and one butterfly species. The highest visitation frequency was observed for Apis florea (3.86 individuals/meter2/120 seconds) and the visitation rate for Apis dorsata (19.90 flower/120 seconds). The highest stay time on a single flower was observed for Ceratina smaragdula (3.94 seconds/flower). The maximum pod weight, pod length, and seed weight were recorded in C. smaragdula pollinated pods. Results suggest that C. smaragdula is an efficient pollinator of fenugreek in Bahawalpur in terms of plant reproductive success. Future studies should focus on the conservation of C. smaragdula and other allied bee species for enhanced crop pollination.

Ancient tea gardens play important role on in situ conservation of epiphytic orchids in southwest Yunnan, China

Southwest Yunnan of China is the homeland of famous Pu’er tea and preserved the largest area of ancient tea gardens in the world. The ancient tea gardens keeping a large number of shade trees have prevailed for hundreds of years persist and formed typical agroforestry systems. To assess the potential of the ancient tea gardens for in situ orchid conservation, in this study, three typical ancient tea gardens located at different elevations, JiNuo Mountain ancient tea garden (JNM, 1150 m asl.), JingMai Mountain ancient tea garden (JMM, 1345 m asl.), and LaoBanZhang ancient tea garden (LBZ, 1787 m asl.), were selected to investigate species diversity and composition, and conservation status of all orchids. Floral visitors, reproductive success, and seedling recruitment of selected epiphytic orchids were also investigated from 2019 to 2021. We identified 88 orchid species (85 epiphytic and 3 terrestrial orchids) in 33 genera in the three ancient tea gardens, including one critically endangered species (CR), four endangered species (EN) and 16 vulnerable species (VU). Although the orchid species diversity was not significantly different, the species composition varied greatly among the three ancient tea gardens. For the randomly selected 40 epiphytic orchid species, all species could set fruits naturally, and the natural fruit-sets ranged from 1.11 ± 6.0% to 62.07 ± 15.4% with great variations among species and years. For 60 epiphytic orchid species observed, seedling recruitment for 26 species (43.3%) were observed and confirmed. Among 42 insect visitors observed, 21 species including bees, flies and ants, were confirmed as effective pollinators to 16 epiphytic orchids. These results revealed that the ancient tea gardens maintained high species diversity of epiphytic orchids and provided pollinator services for reproductive success and suitable micro-environment for seed germination and seedling recruitment. We strongly suggested that the ancient tea gardens in the area could serve as important supplements for in situ conservation of epiphytic orchids.

Benefits of Cross-Pollination in Vegetable Soybean Edamame

Dependence on cross-pollination varies widely among wild and cultivated plant species. Even among crops that are less dependent on outcrossing, such as soybean (Glycine max L.), cross-pollination can improve fruit quality and commercial value. There is a growing body of literature regarding the role of insect pollination in soybean; however, there is a knowledge gap on the intersection between the reproductive system of soybean and its pollination ecology. To address this gap, we first sought to characterize the reproductive system of vegetable soybean (edamame) in terms of benefits and reliance on outcrossing using three traditional experimental pollination scenarios in field conditions: open pollination, automatic selfing (pollinator-exclusion), and hand cross-pollination (controlled crossing). We also tested whether proximity to floral supplements planted on one edge of the field affected its reproductive outputs, and surveyed the floral visitors of the crop. Overall, we found a significant increase in fruit weight among open-pollinated plants compared to those in the automatic selfing treatment, with this effect accentuated with proximity to the flower strip. Despite open pollinated flowers having 30% higher flower abortions rates compared to automatic selfing, the number of developed seeds per fruit was similar among these treatments, with open-pollination having a greater proportion of commercial grade-A fruits. Additionally, grade-A fruits in open-pollination and hand cross-pollination treatments were similar in weight, both of which were significantly heavier than those in the automatic selfing treatment. Although edamame can automatically self, our results suggest that reproductive outputs including fruit weight and number of commercial grade-A fruits are positively affected by cross-pollination and proximity to floral supplements.

A silk-floss tree (Ceiba speciosa) provides an oasis for floral visitors in an otherwise hostile suburban-farmland environment

ABSTRACT Keystone components in green urban spaces can make a big difference in supporting either impoverished or rich animal communities. Trees that produce thousands of flowers at densities higher than that of herbs and produce much more nectar than the latter can be such keystone structures. However, there is a lack of specific information on trees, both native and alien, and their flower visitors in urban/suburban contexts, which blurs the conservation role that such species can perform. In 2019 and 2020, we thoroughly recorded the flower visitors to a silk-floss tree in suburban Guadalajara, Mexico. To our knowledge, this is the first comprehensive inventory of silk-floss tree flower visitors. We documented 79 species/morphospecies of insects; eight of birds, and one of mammals visiting the flowers. All, except two, are native to the region; three are endemic/quasi-endemic to Mexico. Besides direct and indirect floral resources, the silk-floss tree offered perches, resting/hiding cover, nesting substrate, and seed fibres used by several birds, and feeding substrate for gleaning insectivorous birds. Four species are on one or more conservation listings: monarch butterfly (endangered), pink-spotted swallowtail (vulnerable), sparkling-tailed hummingbird (threatened), and lesser long-nosed bat (near-threatened). Our data supports that small patches can enhance the quality of urban green spaces, and that rather than geographic origin, flower output drives visitation. Alien trees can be pollination enhancement ‘devices’ for imperilled pollination networks. Silk-floss trees are a potential option for conservation-oriented urban greening, as well as to contribute to enhancing human enjoyment of nature, and provide opportunities for public outreach.

Chemical Insect Attractants Produced by Flowers of Impatiens spp. (Balsaminaceae) and List of Floral Visitors.

The study of the semiochemicals produced by the flowers of Impatiens spp. is an important topic that may explain the reason for the rapid expansion of some species in this genus. Impatiens L. belongs to the Balsaminaceae family, which includes several species considered to be invasive plants in Europe. This study aimed to characterize the phytochemistry of four naturally occurring plant species in Poland, including three invasive alien taxa (Impatiens parviflora, I. glandulifera, and I. capensis) and one native species (I. noli-tangere). Gas chromatographic techniques were used to assess phytochemical profiles of chemical attractant cues in their pollination biology. We detected differences in the scent profiles of the investigated species. All the examined Impatiens species produce various alcohols, i.e., heptacosanol, octacosanol, aldehydes (e.g., octadecanal, eicosanal, etc.), and fatty acids, as well as long-chain hydrocarbons such as dodecane, tricosane, petacosane, hexacosane, and farnesene. Impatiens parviflora, I. glandulifera, and I. capensis produce geraniol and linalool, which attract members of the Apidae family, including bumblebees and honeybees. Impatiens parviflora also produces linalool-derived monoterpenes (linalool oxide and 8-hydroxylinalool), which are a strong attractant for Diptera; this may clarify why the species is mainly visited and pollinated by syrphid flies. A list of insect visitors to the Impatiens species under study can be found in the article.

Fruit production in coffee (Coffea arabica L.) crops is enhanced by the behaviour of wild bees (Hymenoptera: Apidae)

AbstractChanges in floral visitors' diversity and community composition have been reported to affect coffee production, which optimal growing conditions are cool to warm tropical climates found in the coffee belt. However, few studies have focused on understanding how insects' foraging behaviour (e.g., contact with floral reproductive organs) relates with coffee production. Thus, it is important to consider floral visitors' foraging behaviour, as this can influence the transfer of conspecific pollen required for plant fertilisation, the efficiency of floral visitors and improve the pollination service provided. Here, we assessed how foraging behaviour of honeybees and stingless bees affects coffee fruit set and fruit weight in conventional and agroecological managed crops. We quantified local floral resources and recorded diversity, abundance and behaviour of floral visitors at eight pairs of sites with agroecological and conventional management systems to assess how foraging behaviour of honeybees and stingless bees affects coffee fruit set and fruit weight in both types of managed crops. We found that the managed honeybee Apis mellifera and three wild bees Tetragonisca angustula, Scaptotrigona mexicana and Partamona bilineata are the principal floral visitors of coffee crops in Guatemala, whose total abundance but not richness was higher in agroecological areas. Regarding their behaviours, we observed that the average number of flowers visited by P. bilineata and its behaviour of touching the nectaries of coffee flowers were positively related to fruit set, while only the percentage of A. mellifera carrying pollen was positively related with fruit weight, suggesting that although A. mellifera is found in large quantities, wild bees are also efficient pollinators of coffee in the region. Our findings also suggest that in other tropical regions where coffee is grown and honeybees have been observed as a primary pollinator, wild bees may play an important role when considering their behaviour. In the same way, coffee farms in Guatemala are a representation of the diversity of agroecosystems found worldwide, and thus, the study of foraging behaviour of managed and wild bees and the conservation of wild bee species in different coffee agroecosystems should be emphasised to improve the production of coffee and other cash crops.

Floral Visitation, Phytochemical and Biological Activities of Bioproducts from Tetragonisca angustula (Hymenoptera, Apidae, Meliponini): A Review.

Tetragonisca angustula (Latreille, 1811) is an indigenous neotropical stingless bee, popularly known as "Jataí", with a wide distribution in the Brazilian territory. T. angustula produces other derivatives such as propolis, geopropolis, fermented (saburá pollen), cerumen and resins, which are important in folk medicine. In this review, the objective was to gather research on the main plant species visited by T. angustula, as well as studies that verified the chemical composition and biological properties of T. angustula bioproducts. The bibliographic review was performed by searching the Scopus, Web of Science, ScienceDirect, and PubMed databases for publications from 2003 to February 2023. We found 78 studies that analyzed the interactions between T. angustula and floral species, with species from the botanical families Fabaceae, Asteraceae, Malvaceae, Bignoniaceae, Solanaceae, Myrtaceae and Lamiaceae being the most reported as the main food sources for this species. The presence of compounds belonging to the class of flavonoids, phenolic acids, terpenoids and alkaloids has been identified by studying the chemical composition of honey, propolis, geopropolis and fermented pollen (saburá) in 21 studies. The data collected in the literature emphasize that these T. angustula products have remarkable biological properties, especially their antibacterial and antioxidant activities.

Pan traps: An effective tool for monitoring phenological changes in insect floral visitors and their relationship with floral resources in a coastal Mediterranean forest

Precise monitoring of insect floral visitors and their relationship with floral resources throughout the flowering season provides baseline information to help us understand long-term changes in plant-pollinator interactions and improve pollinator conservation strategies. Pan traps are one of the methods most used for monitoring insect floral visitors and several studies have already linked the abundance and richness of these floral visitors with floral resources. However, less research has been conducted into the effectiveness of pan traps for monitoring phenological changes in the floral visitor community with regard to floral resources. We used pan traps to study the species composition and the abundance of insect floral visitors and their relationship with flower richness in a coastal forest throughout the entire flowering season for two consecutive years. Captures were confirmed to be floral visitors through field survey studies. Pan traps were effective for revealing changes in the abundance and species composition of floral visitor communities during and between years that correlated with changes in floral richness and species composition. Changes in floral visitor abundance showed a different bias in their association with floral richness. Thus, while Hymenoptera and Diptera abundance tended to be negatively correlated with floral richness, Coleoptera abundance tended to be positively correlated, although such correlations could change from year to year. There were two significantly different groups of flowering plant and floral visitor species: one in spring and the other in summer. Each period was characterized by unique overlap between some floral visitors and their floral resources, suggesting that to monitor floral visitors effectively both communities need to be considered. Interestingly, the floral phenology in this coastal forest extended longer than that of more inland communities, so reliable monitoring of floral visitors throughout the floral season may help us to better understand the role of coastal plant communities in the stabilization of the pollinator networks of more inland communities. Overall, phenology patterns need to be taken into account for pan trapping to become an effective methodology for monitoring floral visitor communities, considering both intra-year (spring and summer communities) and inter-year variations.

Pollinators of Arisaema nambae (Araceae), endemic to Okayama and Hiroshima prefectures, western Japan

Effective pollinators of Arisaema nambae Kitam., endemic to western Okayama and eastern Hiroshima prefectures, western Japan, were determined, and 113 insects from 24 spathes of A. nambae in three populations in Okayama Prefecture were collected. Most floral visitors were fungus gnats (Mycetophilidae and Sciaridae). Their maximum body width was less than the internal diameter (ca. 2 mm) of the exit at the bottom of the staminate spathe. Pollen grains of Arisaema attached to the bodies of fungus gnats collected from pistillate spathes provided evidence that they visited the pistillate spathe after escaping from staminate spathes. Based on their visitation frequency, size compatibility between their body and the exit from the staminate spathes and the pollen loads they carry, fungus gnats appear to play an important role in the pollination of A. nambae.

Floral visitors of three species of <i>Corallorhiza</i> in Monte Tláloc, Texcoco, Estado De México, Mexico

Corallorhiza is a genus of mycoheterotrophic orchids that includes 12 species, most of them restricted to North and Central America. In Mexico, there are seven taxa, distributed throughout the country, except for seven of the 32 Mexican states; in Estado de México all of them are present. The Orchidaceae is known for its diversity of pollination syndromes; however, for the more than 200 species of mycoheterotrophic orchids, little has been studied about their floral visitors and pollinators, and for the Mexican species of Corallorhiza nothing is known to date. Our goal was to document photographically and identify all the floral visitors of three sympatric species of the genus in Monte Tláloc, municipality of Texcoco, Estado de México. We observed individuals of Araneae, Coleoptera, Diptera, Hemiptera, and Hymenoptera visiting flowers of Corallorhiza macrantha, C. macrantha × C. maculata, C. maculata, and C. striata. Only Ocyptamus coeruleus and Platycheirus sp. (Diptera: Syrphidae) were found carrying pollinaria on their thorax. These are the first records of potential pollinators for the genus Corallorhiza in Mexico.

The effects of pesticides on tomato pollinators depend on application practices and floral visitor assemblage

AbstractPesticide use affects biodiversity and ecosystem service provision. Yet, such effects may vary between pesticides, dosage, application timing and pollinator assemblage in the study area. Understanding such diversity of effects is essential to enable integrated pest management practices that minimize negative impacts on pollinators. Here, we use a controlled experiment to compare different strategies of pesticide application in tomato crops: no application, low‐intensity applications (every 7 days) and high‐intensity application (every 3–4 days) with the last being the usual practice used by farmers in the study region. We focus on imidacloprid that is a neonicotinoid insecticide commonly used in Brazil. We show the negative effects of imidacloprid on the pollinator visitation rate of tomato flowers varied between flower visitor species. While the bee Paratrigona lineata was negatively affected by the imidacloprid application, no effects were detected when analysing all other bees as a group, indicating a null net effect. Although some studies have shown this insecticide is extremely harmful to bees' health, others showed that some bees do not avoid it, which may explain our results. However, the visitation rate recovery for P. lineata was only detected in the less than the more intensive treatment after imidacloprid applications ceased. The fact that no differences in fruit production were detected between treatments (including control blocks) could result from a null net effect of the negative effects on pollinators and positive effects on pest control. Further studies would be needed to disentangle the two effects.

Manipulating network connectance by altering plant attractiveness.

Mutualistic interactions between plants and their pollinating insects are critical to the maintenance of biodiversity. However, we have yet to demonstrate that we are able to manage the structural properties of these networks for the purposes of pollinator conservation and preserving functional outcomes, such as pollination services. Our objective was to explore the extent of our ability to experimentally increase, decrease, and maintain connectance, a structural attribute that reflects patterns of insect visitation and foraging preferences. Patterns of connectance relate to the stability and function of ecological networks. We implemented a 2-year field experiment across eight sites in urban Dublin, Ireland, applying four agrochemical treatments to fixed communities of seven flowering plant species in a randomized block design. We spent ~117 h collecting 1,908 flower-visiting insects of 92 species or morphospecies with standardized sampling methods across the 2 years. We hypothesized that the fertilizer treatment would increase, herbicide decrease, and a combination of both maintain the connectance of the network, relative to a control treatment of just water. Our results showed that we were able to successfully increase network connectance with a fertilizer treatment, and maintain network connectance with a combination of fertilizer and herbicide. However, we were not successful in decreasing network connectance with the herbicide treatment. The increase in connectance in the fertilized treatment was due to an increased species richness of visiting insects, rather than changes to their abundance. We also demonstrated that this change was due to an increase in the realized proportion of insect visitor species rather than increased visitation by common, generalist species of floral visitors. Overall, this work suggests that connectance is an attribute of network structure that can be manipulated, with implications for management goals or conservation efforts in these mutualistic communities.

Forest restoration treatments indirectly diversify pollination networks via floral- and temperature-mediated effects.

In North American conifer forests, a variety of federally initiated thinning programs are implemented to restore pre-European settlement forest structures, but these changes may impact ecosystem function via impacts on sensitive biotic communities. Across the wildland-urban interface of the Front Range region of Colorado, agencies associated with the Collaborative Forest Landscape Restoration Program (CFLRP) have implemented thinning treatments across thousands of hectares of ponderosa pine forest; here we leverage these treatments as an experimental framework to examine thinning effects on a pollinator community. We measured variation in forest structure and sampled bee community assemblages using multiple methods (trapping and netting) to compare bee biodiversity and patterns of floral visitation by bees (bee-flower networks) between mechanically thinned stands that were 3-10 years after treatment and nonthinned stands. Three key findings emerged: (1) Native bee abundance, richness, and diversity were 120%, 53%, and 37% greater, respectively, in thinned stands. In addition, nestedness, richness, and abundance of bee-flower interactions were all substantially higher in thinned stands, and there was increased functional redundancy in bee assemblages after thinning. (2) Structural equation modeling indicated that variation in temperature and floral abundance were mediated by canopy openness and correlated with bee richness and abundance, thereby indirectly driving variation in bee-flower interactions. (3) Four floral species (Penstemon virens, Cerastium arvense, Erysimum capitatum, and Geranium caespitosum) were identified as key connectors in bee-flower interaction networks, though these were not necessarily the most abundant flowering plants. Our analyses indicate that native bee α-diversity and bee-flower interactions positively responded to thinning treatments, and these effects were indirectly driven by canopy removal. We conclude that CFLRP treatments have conservation value for native bee communities. Further monitoring is warranted to evaluate the longevity of these effects.

Distinct diurnal and nocturnal flower visitor communities provide pollination services in urban gardens

Abstract Urban gardens are considered a key tool for mitigating biodiversity and plant‐pollinator interaction loss due to their ubiquity in urban landscapes and the variety of resources they provide. To date, most urban garden pollination research has focused on diurnal pollination, omitting a potentially important group—nocturnal pollinators. To assess the diversity and pollination activity of both diurnal and nocturnal flower visitors in urban gardens, I monitored arthropods on focal inflorescences of Eupatorium perfoliatum, a common Michigan‐native species, for 24‐h cycles and recorded the number and duration of visits. I also measured diurnal and nocturnal communities' pollination services using a temporal floral visitation exclusion experiment. Flowers averaged nearly twice as many visits during the day as compared with night within 24‐h cycles, but nocturnal visit durations were 2.5‐fold longer on average. Day and night floral visitor communities were distinct, with day visits being dominated by Diptera, ants and other Hymenoptera, and night visits being carried out most frequently by ants, Dermaptera and Hemiptera. In the floral visitor exclusion experiment, plants open to only nocturnal visits produced larger seeds, whereas plants open to only diurnal visits trended towards producing more seeds, signalling a potential trade‐off between seed quantity and size among visitor communities. Overall, diurnal and nocturnal floral visitor communities were distinct, and nocturnally pollinated plants had reproductive output comparable to diurnally pollinated treatments. Given the emphasis on diurnal pollinators in most pollination studies, it is possible that relevant plant‐pollinator interaction information may be missed in cases where anthesis spans both day and night.

Pollinator Diversity and Foraging Behaviour of Insect Pollinators in Aonla

This study is on the diversity, abundance of floral visitors, foraging rate and speed of major pollinators in aonla orchard. Aonla flowers were observed with 22 floral visitors belonging to the Hymenoptera, Diptera, Lepidoptera and Coleoptera. Tetragonula iridipennis was the most abundant floral visitor followed by Apis cerana indica and A. dorsata. Number of flowers visited by A. cerana indica (13.46 flowers/ min) and T. iridipennis (8.26) was maximum during 1100-1200 hr. The time spent by A. cerana indica (6.24 sec/flower) and T. iridipennis (6.20) was also maximum during 1100-1200 hr.

Floral, reproductive, and pollination biology of Floral, reproductive, and pollination biology of Eugenia myrcianthes Nied.

Studies on species of the family Myrtaceae are mostly related to floristic surveys, reproduction involving large plant communities, and family taxonomy. Thus, the objective of this study was to elucidate aspects of the floral and reproductive biology, as well as floral visitors of ubajai (Eugenia myrcianthes Nied.). Studies were conducted on floral morphology and morphometry, identification of nectaries and structures attractive to floral visitors, characterization of floral visitors, stigma receptivity, and androecium maturation, pollen storage, in vitro viability testing, and characterization of the reproductive system. Ubajai flowers open at approximately 6:00 a.m., and their anthers are the main attractive structure to floral visitors. The main floral visitors and effective pollinators of ubajai are honeybees (Apis mellifera). The addition of 40% sucrose to the culture medium, using fresh pre-anthesis pollen, allows for a 90% germination rate. Ubajai pollen is recalcitrant, thus, it loses viability before 30 days of storage, even when stored in a refrigerator, freezer, liquid nitrogen, or natural environment. Ubajai can be considered a self-compatible plant; however, fertilization of flowers through cross-pollination also occurs, and apomixis does not occur.

Glosophagine bats (Chiroptera: Phyllostomidae) as floral visitors of Stenocereus huastecorum (Plantae: Cactaceae) in the Jaumave Valley, Tamaulipas, Mexico

The objectives of the present work were to determine the species of bats as floral visitors of Stenocereus huastecorum Alvarado-Sizzo, Arreola-Nava & Terrazas, 2018 in the Jaumave Valley, the night activity patterns of these floral visitors, their abundance within the flowering periods of 2018 and the comparison of effectiveness of nocturnal and diurnal pollinators. During March-May and August-October 2018, 12 nights were sampled per flowering period using three mist nets of 12 x 2.6 meters. Bats captured were identified, samples of pollen were taken from them which was processed by Erdtman's acetolysis. Three different treatments were applied to evaluate pollination effectiveness (nocturnal exclusion, diurnal exclusion, and control), selecting three flowers in 19 individuals. Leptonycteris yerbuenae (Martínez & Villa, 1940), L. nivalis (Saussure, 1860) and Choeronycteris mexicana (Tschudi, 1844) were the nocturnal floral visitors of S. huastecorum during its two flowering periods, the first species being the most frequently recorded throughout the night. Although this species has flowers with chiropterophilous characteristics, no significant differences were found in the effectiveness of diurnal, nocturnal and control pollinators. Very little is known about the nocturnal floral visitors of S. huastecorum and the effectiveness of its pollinators in the north of its distribution. Since this species is very important for the economy of rural communities due to the sale of its fruits, this research provides basic information for the conservation and use of this species.

Assessing the biodiversity and the impact of pollinators on carob production.

As the current climate crisis intensifies, drought resistant crops are becoming more important due to their ability to withstand the increasingly hotter and drier summers. Such crops are valuable for pollinators as they provide food resources for wild and managed species. The carob tree (Ceratonia siliqua L.) represents an example of a heat- and drought- resistant crop, able to grow in dry areas with practically no inputs. The current study assessed over two growing seasons the diversity of wild bees and other pollinators relying on carob flowers, as well as the contribution of animal pollination to carob production. Carob flowers were subjected to two treatments: Open pollination, where inflorescences were left untreated, and wind pollination, where inflorescences were bagged in a mesh during blooming. Weekly observations during blooming showed that Apis mellifera was the most frequent floral visitor followed by wild bees and wasps. Carob flowers were visited by at least 10 different wild bee species. Open-pollinated flowers produced significantly more pods, with the benefit ranging from 4 to 16 times higher production, depending on the region. Open pollination led to pods with greater weight, length and number of seeds compared to pods derived from wind pollination. The results of the current study highlight the importance of animal pollination to carob production, as well as the significance of carob trees to wild bee conservation.

The breeding systems and floral visitors of two widespread African dry forest species of ethnobotanical significance.

Forest products derived from woody trees, such as fruits, seeds, honey, wood and others, are important resources for supporting rural livelihoods. However, little is known about the breeding systems or floral visitors of trees that provide these resources, often due to the difficulty of accessing tree canopies. This study addresses key knowledge gaps from a data poor region, providing information on the breeding systems and contribution of biotic pollination to two trees abundant in south-central Africa, that provide forest product supports for rural livelihoods: Julbernardia paniculata (Benth.) Troupin and Syzygium guineense (Willd.) subsp. barotsense F. White (Fabaceae and Myrtaceae respectively). The breeding systems of these species were assessed by conducting controlled pollination experiments, and then measuring the effects on reproductive success to determine the degree of self-compatibility and pollen limitation. Floral visitors and their behaviour were observed to provide preliminary information on possible pollinator groups. S. guineense appeared to be self-compatible, while J. paniculata showed signs of both self-incompatibility and pollen limitation. Floral visitors of both species were dominated by bees, with native honeybees (Apis mellifera) providing the highest visitation rates. These insights provide the first steps for understanding the reproductive ecology of these key tree species and can help to inform sustained management and conservation aimed at protecting forests and supporting rural livelihoods, as well as broaden the understanding of the floral visitors, and contribution of biotic pollination to forest tree reproductive success.