Behavior Of Floral Visitors Research Articles

Floral scent changes in response to pollen removal are rare in buzz-pollinated Solanum

Main conclusionOne of seven Solanum taxa studied displayed associations between pollen presence and floral scent composition and volume, suggesting buzz-pollinated plants rarely use scent as an honest cue for foraging pollinators.Floral scent influences the recruitment, learning, and behaviour of floral visitors. Variation in floral scent can provide information on the amount of reward available or whether a flower has been visited recently and may be particularly important in species with visually concealed rewards. In many buzz-pollinated flowers, tubular anthers opening via small apical pores (poricidal anthers) visually conceal pollen and appear similar regardless of pollen quantity within the anther. We investigated whether pollen removal changes floral scent composition and emission rate in seven taxa of buzz-pollinated Solanum (Solanaceae). We found that pollen removal reduced both the overall emission of floral scent and the emission of specific compounds (linalool and farnesol) in S. lumholtzianum. Our findings suggest that in six out of seven buzz-pollinated taxa studied here, floral scent could not be used as a signal by visitors as it does not contain information on pollen availability.

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 nectar and insect flower handling time change over the flowering season: Results from an exploratory study

In recent decades, hundreds of secondary metabolites have been found in floral nectar and many studies have demonstrated that they can play various roles in modulating the behaviour of floral visitors. However, temporal variations in nectar chemistry over extended flowering seasons have never been substantiated. Moreover, the effects of nectar chemicals on insect behaviour are often studied under laboratory conditions, focusing on few insect species under artificial conditions which may influence insect responses. The aim of this exploratory study was to compare nectar chemistry and the durations of pollinator visits in the early and late summer periods of the long-flowering species Echium vulgare L. in natural populations. Nectar samples were collected in the early and late summer periods and insects were observed for a total of 480 min. The biogenic amine octopamine, sugars and the protein to non-protein amino acid ratio increased as the season proceeded. It remains to clarify whether these changes are determined by biotic and abiotic factors or whether the plant expresses some chemical constraint, however it seems likely that changes in nectar chemistry may be the cause of the longer visits by bumblebees to single flowers at the end of the flowering season. Though not conclusive, these results set a baseline for future research and highlight an interesting question. Since long-flowering plants see changing contexts during their bloom period, do they express chemical constraints to regulate their attractiveness?

Influence of plant domestication on plant-pollinator interactions: floral attributes and floral visitor communities in wild and cultivated squash plants.

Domestication of plant species results in phenotypic modifications and changes in biotic interactions. Most studies have compared antagonistic plant-herbivore interactions of domesticated plants and their wild relatives, but little attention has been given to how domestication influences plant-pollinator interactions. Floral attributes and interactions of floral visitors were compared between sister taxa of the genus Cucurbita (Cucurbitaceae), the domesticated C. moschata, C. argyrosperma ssp. argyrosperma and its wild progenitor C. argyrosperma ssp. sororia in the place of origin. We conducted univariate and multivariate analyses to compare floral morphological traits and analyzed floral reward (nectar and pollen) quantity and quality between flowers of wild and domesticated cucurbits. Staminate and pistillate flowers of all three taxa were video recorded, and visitation and behavior of floral visitors were registered and analyzed. Most floral morphological characteristics of flowers of domesticated taxa were larger in both staminate and pistillate flowers. Staminate and pistillate flowers presented distinct correlations between floral traits and integration indices between domesticated and wild cucurbits. Additionally, pollen quantity and protein to lipid ratio were greater in domesticated cucurbits. Cucurbit pollen specialists, Eucera sp., had the highest probability of visit for all cucurbit taxa. We provide evidence that floral traits of domesticated and wild cucurbit plants experienced different selection pressures. Domesticated cucurbit plants may have more resources invested towards floral traits, thereby increasing attractiveness to pollinators and potentially plant reproductive success. Wild ancestor plant populations should be conserved in their center of origin to preserve plant-pollinator interactions. This article is protected by copyright. All rights reserved.

Diversity of Insect Flower Visitors of Xylopia aromatica (Magnoliales, Annonaceae) in a Brazilian Savanna

Small beetles are important pollinators of Annonaceae whose flower chambers are small and have diurnal and/or nocturnal anthesis. The pollinators of these flowers belong to the families Nitidulidae, Staphylinidae, Chrysomelidae, and Curculionidae. In this study, the first conducted in the Cerrado of Chapada dos Guimarães, Mato Grosso, Brazil, the behavior of the insect flower visitors of Xylopia aromatica was observed, in both the field and the laboratory. The chambers of 253 flowers were collected from 11 plants, and the biological aspects of their visitors were analyzed quantitatively and qualitatively. The most abundant visitors were thrips and beetles. Coleoptera was represented by four morphospecies occurring frequently in the floral chambers (>70% of individuals). Among beetles, one species belonged to Nitidulidae (Cillaeinae, Conotelus sp. 1) and two belonged to Staphylinidae (Aleocharinae sp. 1 and Aleocharinae sp. 2). These three morphospecies of small elongate beetles have setae where pollen may adhere. In addition, they were present on both male and female phases of the flowers, indicating potential cross-pollination. In the study area, X. aromatica possesses mixed pollination promoted by Thysanoptera and small Nitidulidae and Staphylinidae beetles. This study brings the first record of Lamprosomatinae (Chrysomelidae) and, especially, of Conotelus (Nitidulidae) in the flower chambers of X. aromatica, with new information on behavior of floral visitors coupled with their morphological traits that may promote cross-pollination in this plant species.

Testing competing hypotheses about the behaviour of floral visitors in mixed‐flower stands

1. Plants occur in mixed stands and flower simultaneously. Most hypotheses about how flowers affect the visitation rates of conspecific or heterospecific neighbours involve attractiveness. Attractive flowers are thought to monopolise visitors, but also to act as magnets increasing visits to unattractive neighbours. Attractiveness may be density‐dependent: Visitors could profit from focusing on abundant species, sometimes forming search images that make rare flowers less detectable.2. We tested four hypotheses using data on visitation rates by honeybees (Apis melifera) and bee flies (Bombyliidae) to 1072 stands comprising six plant species in different densities. Hypotheses were compared through multi‐model inference using the disc equation (a functional response model) modified for co‐flowering species and density‐dependent attractiveness.3. We found that the most attractive flowers had attributes (colour, position, mobility) that elicit strong responses in the sensory apparatus of each type of visitor.4. Attractiveness usually increased with conspecific floral density, indicating that visitors focus on abundant species. The most attractive flowers strongly reduced the attractiveness of their neighbours, reinforcing visitor monopolisation. However, mildly attractive species increased the attractiveness of less alluring flowers, acting as magnets.5. In bombyliids, flowers increased the attractiveness of same‐coloured heterospecifics but reduced it when colours differed, suggesting search‐image formation. The results were similar for both types of visitors but were weaker and less consistent in honeybees. This suggests that Apis behaviour is not as rapidly adjusted to local densities as that of bombyliids, perhaps because of longer‐term memory or a strong role of sociality in determining individual behaviour.

Extranuptial nectaries in flowers: ants increase the reproductive success of the ant-plant Miconia tococa (Melastomataceae).

Although the production of extranuptial nectar is a common strategy of indirect defence against herbivores among tropical plants, the presence of extranuptial nectaries in reproductive structures is rare, especially in ant-plants. This is because the presence of ants in reproductive organs can generate conflicts between the partners, as ants can inhibit the activity of pollinators or even castrate their host plants. Here we evaluate the hypothesis that the ant-plant Miconia tococa produces nectar in its petals which attracts ants and affects fruit set. Floral buds were analysed using anatomical and histochemical techniques. The frequency and behaviour of floral visitors were recorded in field observations. Finally, an ant exclusion experiment was conducted to evaluate the effect of ant presence on fruit production. The petals of M. tococa have a secretory epidermis that produces sugary compounds. Nectar production occurred during the floral bud stage and attracted 17 species of non-obligate ants (i.e. have a facultative association with ant-plants). Ants foraged only on floral buds, and thus did not affect the activity of pollinators in the neighbouring open flowers. The presence of ants in the inflorescences increased fruit production by 15%. To our knowledge, the production of extranuptial nectar in the reproductive structures of a myrmecophyte is very rare, with few records in the literature. Although studies show conflicts between the partners in the ant-plant interaction, ants that forage on M. tococa floral buds protect the plant against floral herbivores without affecting bee pollination.

The invasive hornet Vespa velutina affects pollination of a wild plant through changes in abundance and behaviour of floral visitors

The Asian hornet (Vespa velutina) is a keen predator of honeybees and other insects. Its success as invasive species threatens the stability of ecosystem services provided by them, such as pollination of wild plants and crops. In this study we analyse their impact as hunters of flower visitors on plant pollination, by studying the hunting behaviour of V. velutina in flower surroundings, the effect of V. velutina hunting on the floral visiting behaviour by insects and its impact on the amount of conspecific pollen deposited on the stigmas of Mentha suaveolens, a native and common herb to southern and western Europe. We made observations and video-recordings in blooming patches with and without the presence of V. velutina and quantified the deposition of conspecific pollen on stigmas in those same patches. Asian hornets were frequent and successful hunters of flower visitors of Mentha suaveolens, inducing changes in the foraging behaviour of several groups of pollinators. The patch visitation rate of European honeybees (Apis mellifera), the flower visitation rate of small hymenopterans and the flower visitation time of bumblebees (Bombus sp.) and syrphids was significantly reduced in patches with presence of the predator. As a consequence, the quantity of conspecific pollen on stigmas of the studied native plant decreased in patches with V. velutina. In this study we demonstrate the negative impact of the invasive hornet V. velutina on pollination services in invaded areas as a consequence of their hunting of pollinators in flower patches.

Effectiveness of native nectar-feeding birds and the introduced Apis mellifera as pollinators of the kangaroo paw, Anigozanthos manglesii (Haemodoraceae)

Plants pollinated by vertebrates are often visited by native and exotic insects foraging for pollen and nectar. We compared flower visitation rates, foraging behaviour, and the contribution to reproduction of nectar-feeding birds and the introduced honeybee Apis mellifera in four populations of the bird-pollinated Anigozanthos manglesii (Haemodoraceae). The behaviour of floral visitors was quantified with direct observations and motion-triggered and hand-held cameras. Pollinator access to flowers was manipulated by enclosure in netting to either exclude all visitors or to exclude vertebrate visitors only. Apis mellifera was the only insect observed visiting flowers, and the most frequent flower visitor, but primarily acted as a pollen thief. Although birds visited A. manglesii plants only once per week on average, they were 3.5 times more likely to contact the anther or stigma as foraging honeybees. Exclusion of birds resulted in 67% fewer fruits and 81% fewer seeds than flowers left open and unmanipulated. Unnetted flowers that were open to bird and insect pollinators showed pollen-limitation and a large variation in reproductive output within and between sites. Although honeybees have been shown to pollinate other Australian plants, compared to birds, they are highly inefficient pollinators of A. manglesii.

Risk-sensitive foraging strategy of flower visitors in Serjania caracasana

Production of nectar can play a fundamental role in the foraging behaviour of floral visitors through its availability and distribution. The aim of this study was to understand the foraging pattern of floral visitors in Serjania caracasana. The field study observed the strategy of nectar production and the foraging behaviour of the floral visitors of Serjania caracasana, carried out through an experiment that evaluated the amount of nectar produced by flowers, species richness and frequency of visits. The data analysis showed that there is no significant correlation between any of the variables analysed. The unstable nectar between the flowers and the unpredictability during the hours of the day suggest a risk-foraging strategy of risk-prone type of the species of floral visitors. The data from this study suggests that Serjania caracasana has potential to understand the theory of risk-sensitive foraging in relation to its reproductive success.

Distribución espacial y temoral de las recompensas florales dentro de los capítulos: el caso de Hyalis argentea (Asteraceae)

Introducción y objetivos: Una asignación diferencial de recursos entre la función de atracción, recompensa y sexual ha sido observada en capítulos de especies derivadas de Asteraceae. Los capítulos heterógamos están compuestos por flores pistiladas, estaminadas o estériles y perfectas, con lo cual las funciones sexual y de recompensa son realizadas por diferentes tipos de flores y en distintos momentos. Esta distribución espacial y temporal de las recompensas dentro del capítulo no es tan clara en especies con capítulos homógamos, donde todas las flores son perfectas y producen polen y néctar. Aquí evaluamos la distribución espacial y temporal de las recompensas florales en los capítulos homógamos de Hyalis argentea. M&M: Comparamos la fenología floral, el número de granos de polen y la concentración y volumen de néctar entre las flores marginales y centrales, y registramos el comportamiento de forrajeo de los visitantes florales. Resultados: Los capítulos tienen un patrón de floración centrípeto y también alterno y son visitados por abejas, hormigas, mariposas, polillas, escarabajos y trips, siendo Apis mellifera su principal polinizador. No encontramos un patrón temporal en la oferta de recompensas dentro de los capítulos, pero sí un patrón espacial en el volumen de néctar que aumenta desde las flores marginales hacia las del centro del capítulo. Conclusiones: Dicha variabilidad espacial en la cantidad de néctar podría afectar el comportamiento de forrajeo de los polinizadores y así aumentar las probabilidades de polinización cruzada, mejorando la reproducción sexual de esta especie autoincompatible.

Floral biology, pollination requirements and behavior of floral visitors in two species of pitaya

The present work aimed to study floral biology, pollination requirements and the behavior of floral visitors in two species of pitaya, Hylocereus undatus and H. polyrhizus, in Northeastern Brazil. The experiment was carried out through diurnal and nocturnal observations and the use of flowers bagged or accessible to visitors. Results showed that flowers of both species are similar both in anatomical and functional traits. They are large, with nocturnal anthesis onset and attract night and daytime flower visitors. The floral visitors found were sphinx moths, ants, wasps and bees, with Apis mellifera accounting for 86.1% of visits to flowers. The H. undatus species is independent of biotic pollination to set and produce large and well-shaped fruits, but H. polyrhizus shows limited self-pollination and requires biotic pollination to set fruits and also to produce larger fruits. In this case, A. mellifera appears as the most likely pollinator. It is concluded that biotic pollination deficit is a limiting factor for the productivity of H. polyrhizus , but not to H. undatus under the conditions studied and that the role of pollinators, especially A. mellifera , in the quality of the fruits produced by both pitaya species needs to be investigated.

Ant-Mediated Nectar Robbing from the Chilean Firetree Embothrium coccineum (Proteaceae): No Effect on Seed Production

Nectar robbing by the ant Camponotus distinguendus was observed in flowers of Embothrium coccineum (Proteaceae), a tree mainly pollinated by hummingbirds. We hypothesized that robbing would reduce the amount of nectar, affecting the foraging behaviour of floral visitors and reducing seed production. Nectar robbing affected one-third of mature tree blossoms and 93.3% of trees. This reduced the amount of nectar to about half. Foraging behaviour of floral visitors included pollinating visits to consume nectar and pollen, primary and secondary nectar robbing, and nectar theft. We found no effect of nectar robbing by C. distinguendus on seed production in E. coccineum, which was sparse and completely dependent on legitimate pollinator visits, mostly performed by the green-backed firecrown Sephanoides sephaniodes. Determining the effects of nectar robbing by ants on the reproduction of plants is important to understand the dynamics of plant-animal interactions in the temperate forests of Chile.

Heavy metals in nectar modify behaviors of pollinators and nectar robbers: Consequences for plant fitness

Plants growing in heavy-metal-rich soils can accumulate metals into their nectar. Nectar chemical composition can alter foraging behavior of floral visitors (including pollinators and floral antagonists) and further affect plant reproductive fitness. The role of nectar heavy metals in deterring pollinators (e.g., shortening foraging time) has been recently studied, but their effects on plant reproduction via changes in behaviors of both pollinators and floral antagonists (e.g., nectar robbers) are less understood. We experimentally manipulated four nectar heavy metals (Zn, Cu, Ni, and Pb) in a native ornamental plant, Hosta ensata F. Maekawa, to investigate the effect of nectar metals on plant reproductive success. We also recorded nectar robbing as well as foraging time and visitation rate of pollinators to assess whether nectar metals could alter the behavior of antagonists and mutualists. Although metals in nectar had no significant direct effects on plant reproduction via hand-pollination, we detected their positive indirect effects on components of female fitness mediated by pollinators and nectar robbers. Matching effects on female plant fitness, nectar robbers responded negatively to the presence of metals in nectar, robbing metal-treated flowers less often. Pollinators spent less time foraging on metal-treated flowers, but their visitation rate to metal-treated flowers was significantly higher than to control flowers. Moreover, pollinators removed less nectar from flowers treated with metals. Our results provide the first direct evidence to date that heavy metals in nectar are capable of deterring nectar robbers and modifying pollinator foraging behavior to enhance plant reproductive fitness.

Pollination, Mating System, Phenology and Characterisation of Medinilla multiflora Merr. (Melastomataceae) on Mt Makiling, Philippines

An investigation into the reproductive biology of Medinilla multiflora Merr. (Melastomataceae) from Mt Makiling, Luzon, is presented. This includes a morphological and distributional examination of the population on the mountain, the documentation of reproductive phenological patterns, a study of the mating system and observations of biotic interactions. Measurements were made of trait variability, reproductive phenology was characterised from field and herbarium observations, stigmatic receptivity was tested by counting pollen germination, insect exclusion and hand-pollination experiments helped determine the mating system and field observations recorded the identity and behaviour of floral visitors. Significant reproductive morphological differences were found between described populations. This identified a need for the recognition of this diversity and further delimitation of the Medinilla multiflora species complex. Although Medinilla multiflora produced flowers and fruit year-round, the population also exhibited cycles of increased reproduction most likely initiated by seasonal low temperatures. Medinilla multiflora was found to require pollination but not cross-pollination. Two major peaks in stigmatic receptivity occurred throughout the day and the majority of pollen was found to be viable. Generalist bees proved to be the primary pollinators of the study population and were most active in the morning depending on weather conditions. Generalist pollinators and self-compatibility are advantageous traits for establishment and persistence in isolated mountain habitats; however, losses of this habitat due to climate change could have profound consequences for the future success of Medinilla multiflora.

Reproductive Biology of Varronia curassavica Jacq. (Boraginaceae)

Varronia curassavica, a subshrubby medicinal species associated with restinga in the Atlantic Forest, has been exploited by local people and the pharmaceutical industry. Indeed, restingas have experienced a continuous process of degradation, and thus, with species and ecosystem both at risk, efforts to support conservation actions are required. The present study aimed to evaluate aspects of V. curassavica reproductive biology. To accomplish this, morphological characterization was performed by monitoring flowering events. The availability of nectar and pollen, as well as the frequency and behavior of floral visitors and dispersers, was also evaluated. This species exhibits both heterostyly and protogyny. Anthesis is diurnal, and flowers last less than a day. The high number of flower and fruit abortions suggests that mechanisms, such as self-incompatibility intra-morphs and easily detached flowers, contribute to reduced fruit production. The high diversity of floral visitors indicate a generalist pollination syndrome. Diptera, Hymenoptera and Lepidoptera were the main pollinators, and nectar was the main resource sought by these insects. Fruits were dispersed by birds and ants. It can be concluded that the interaction of V. curassavica with several species is a key factor in its own survival and for maintaining the biological diversity of restinga.

Beetle pollination and flowering rhythm of Annona coriacea Mart. (Annonaceae) in Brazilian cerrado: Behavioral features of its principal pollinators.

The conservation and sustainable management of Annona coriacea requires knowledge of its floral and reproductive biology, and of its main pollinators and their life cycles. In this work, we analyzed these aspects in detail. Floral biology was assessed by observing flowers from the beginning of anthesis to senescence. The visiting hours and behavior of floral visitors in the floral chamber were recorded, as were the sites of oviposition. Excavations were undertaken around specimens of A. coriacea to determine the location of immature pollinators. Anthesis was nocturnal, starting at sunset, and lasted for 52–56 h. The flowers were bisexual, protogynous and emitted a strong scent similar to the plant´s own ripe fruit. There was pronounced synchrony among all floral events (the period and duration of stigmatic receptivity, release of odor, pollen release and drooping flowers) in different individuals, but no synchrony in the same individuals. All of the flowers monitored were visited by beetle species of the genera Cyclocephala and Arriguttia. Beetles arrived at the flowers with their bodies covered in pollen and these pollen grains were transferred to the stigmata while foraging on nutritious tissues at the base of the petals. With dehiscence of the stamens and retention within the floral chamber, the bodies of the floral visitors were again covered with pollen which they carried to newly opened flowers, thus promoting the cycle of pollination. After leaving the flowers, female beetles often excavated holes in the soil to lay eggs. Larvae were found between the leaf litter and the first layer of soil under specimens of A. coriacea. Cyclocephala beetles were the main pollinators of A. coriacea, but Arriguttia brevissima was also considered a pollinator and is the first species of this genus to be observed in Annonaceae flowers. Annona coriacea was found to be self-compatible with a low reproductive efficiency in the area studied. The results of this investigation provide ecological data that should contribute to the conservation and economic exploitation of A. coriacea.

Flowering Phenology and Floral Visitors in Distylous Populations ofPsychotria carthagenensis(Rubiaceae) in Brazilian Cerrado

Flowering synchrony has a relevant role in pollinator attraction. In distylous species, synchronous blooming between individuals of both morphs means that the chances of intermorph crosses are increased, which is important for the maintenance of the heterostylous system. The aim of the present study was to describe the flowering phenology and the behavior of the floral visitors in three populations of Psychotria carthagenensis Jacq. (Rubiaceae) between January 2008 and January 2010. Flower and pollinator censuses were conducted at three urban forest fragments in Brazil. Psychotria carthagenensis flowering occurred between October and December, with a high degree of synchrony within populations as well as between floral morphs. The exotic Apis mellifera L. (Apidae) was the main pollinator in the three populations. A high degree of similarity was found in the behavior of floral visitors as well as in nectar production. Visitation rates did not differ between floral morphs. Similar floral recompenses (flower availability and nectar) as well as no preference in pollinators' visiting are thought to be contributing to a greater intermorph visitation to pin and thrum flowers in P. carthagenensis.

Flower Pollinator Interactions within Two Tropical Tree Species of Mizoram, North East India

Understanding the interactions between plants and pollinators is vital in exploring the structural and functional dynamics of tropical forest ecosystem. Such interactions are also helpful in resolving issues of regeneration, maintenance of biodiversity and conservation of tropical forest resources. The aim of this study was to understand the foraging behaviour of floral visitors of two valuable forest species in North East India, viz. Schima wallichii Choisy and Lagerstroemia speciosa (L.) Pers. The types and behaviour of pollinators were assessed by counting of the total number of visits by insects during day time (05:00-18:00) per field visit/flower in the peak flowering season, foraging rate (number of flowers visited/minutes) and average time spent per flower. The frequency of pollinator visits was also determined in terms of visits/flower/hour. Ten species belonging to seven families were recorded visiting S. wallichii flowers. The flowers of L. speciosa were mainly visited by three species in the family Apidae and one species in the family Calliphoridae. Various moth and bee species were involved in pollination of S. wallichii flowers. The Xylcopa spp. of bee showed a high level of functional synchronisation with the floral morphology of L. speciosa.

Flower Pollinator Interactions within Two Tropical Tree Species of Mizoram, North East India

Understanding the interactions between plants and pollinators is vital in exploring the structural and functional dynamics of tropical forest ecosystem. Such interactions are also helpful in resolving issues of regeneration, maintenance of biodiversity and conservation of tropical forest resources. The aim of this study was to understand the foraging behaviour of floral visitors of two valuable forest species in North East India, viz. Schima wallichii Choisy and Lagerstroemia speciosa (L.) Pers. The types and behaviour of pollinators were assessed by counting of the total number of visits by insects during day time (05:00-18:00) per field visit/flower in the peak flowering season, foraging rate (number of flowers visited/minutes) and average time spent per flower. The frequency of pollinator visits was also determined in terms of visits/flower/hour. Ten species belonging to seven families were recorded visiting S. wallichii flowers. The flowers of L. speciosa were mainly visited by three species in the family Apidae and one species in the family Calliphoridae. Various moth and bee species were involved in pollination of S. wallichii flowers. The Xylcopa spp. of bee showed a high level of functional synchronisation with the floral morphology of L. speciosa.