sri-13 mei 2017-480 (Balachandran - Pollinator).cdr POLLINATOR DIVERSITY AND FORAGING DYNAMICS ON MONSOON CROP OF CUCURBITS IN A TRADITIONAL LANDSCAPE OF SOUTH INDIAN WEST COAST C. BALACHANDRAN, M.D. SUBASH CHANDRAN, S. VINAY, NAIK SHRIKANT and T.V. RAMACHANDRA* Energy and Wetlands Research Group, Centre for Ecological Science, Indian Institute of Science, Bangalore, Karnataka 560012, India Received 13 April 2015/Accepted 11 October 2016 ABSTRACT Studies on insect pollinator ecology and dynamics are very rarely carried out in traditional Indian agriculture landscapes. Indiscriminate landscape changes in the rural areas and tendencies towards crop monocultures can have significant effects on pollinator habitats and effectiveness. This study was aimed at observing insect pollinators, their visitation frequencies and timings on monsoon cucurbit crops such as Cucumis sativus L., C. pubescens Willd., Momordica charantia L., Trichonsanthes anguina L. and Luffa acutangula L. (Roxb.), in a coastal Karnataka Village. This study was also aimed at covering the significance of the surrounding landscape elements in sustaining pollinator elements. Bees, such as Apis dorsata, A. cerana and Trigona sp., were major visitors on all cucurbits, except snake gourd which was pollinated mainly by lepidopterans. Insect species were found to partition floral resources of any given crops between them by minimal overlapping in their visitation timings. Natural elements of the landscape around, mainly a village forest and rocky savanna furnished habitats for bees and lepidopterans. Prolifically blooming monsoon herbs on lateritic plateaus, by providing nectar resources for pollinators, presumably play key role in making the case study village well known for monsoon vegetables. Keywords: Agroecosystem, crop pollination, cucurbits, foraging behavior, landscape, laterite INTRODUCTION Zoophilous pollination by diverse animal pollinators is very important in flowering plants. About 87 of 115 important food crops of the world depend on animal pollination (Kevan 1999; Steffan-Dewenter & Westphal 2008). Insects pollinate an estimated 70% of flowering plants (Schoonhoven et al. 1998), of which the bee community (family Apidae) is the most important and efficient pollinators (Danforth et al. 2006). Increased flower visitation rate by insects causes more pollen deposits on the stigma, benefitting higher seed setting and better seed quality (Engel & Irwin 2003). Naturally, peak flowering seasons correspond with the highest densities of pollinator taxa (Wolfe & Barrett 1988). Studies from an ecological perspective reveal landscape level habitat heterogeneity as having strong bearings on sustaining insect pollinators (Verhulst et al. 2004; Roschewitz et al. 2005; Fahrig et al. 2011). Linkages within pollination guilds can be disrupted in crop areas of habitat patches reduction causing increasing distances between nesting and foraging areas (Steffan-Dewenter et al. 2006; Pauw 2007). Most pollinators require a reliable supply of nectar within natural pollinator specific foraging distances to provide sufficient pollinator services including gene flow. Honeybees are known to forage in 1 - 3 km radius from the colony (within 1 km for Apis florea Fabricius, 1.5 km for A. cerana Fabricius and 3 km for A. dorsata Fabricius), although pollination efficiency is at the best between 183 – 275 m (Free 1993; Abrol 2012). Landscape maintenance focusing on better plant-pollinator interactions and on pesticide-free farming will have much significance in ensuring adequate food supplies for the world (Palma et al. 2015). The more we know about pollinators, plant pollination services BIOTROPIA 4 1 7 16 27 Vol. 2 No. , 201 : - DOI: 10.11598/btb.201 .2 . .7 4 1 480 * Corresponding author: cestvr@ces.iisc.ernet.in 16 and the interactions between agro-ecosystems and pollination management, the more we can understand how to conserve them and manage them to maintain biodiversity, ensure ecosystem health and improve human livelihoods (FAO 2016). Cucurbitaceae (118 genera, 825 species), members known as cucurbits, is an important family of food crops used as fruits (melons), salads (cucumber, gherkins, long melon), sweets (ash gourd, pointed gourd), pickles (gherkins), desserts (melons), etc. Although widely distributed, cucurbit diversity is more concentrated in tropics and subtropics with hotspots in Southeast Asia, West Africa, Madagascar and Mexico (Schaefer & Renner 2011). India is rich in cucurbits and their wild relatives (31 genera, 94 species including 10 endemics). Cucurbits genera with the highest numbers of species are Trichosanthes (22 species), Cucumis (11 species), Momordica (8 species) and Zehneria (5 species) (Renner & Pandey 2013). Honeybees are considered the most efficient pollinator for cucurbit (Grewal & Sidhu 1979). This study on cultivation of mixed crop of cucurbits in the monsoon period conducted in Utttara Kannada, district of South Indian west coast, is important because it relates to high production of pesticide free, good quality and wholesome gourds from a relatively small area by indigenous farmers. The undulating terrain borders the foothills of the Western Ghat mountain ranges. The cultivators are indigenous subsistence farmers of Halakkivokkal community which depends on traditional farming techniques, cattle manure and leaf manure. The rural landscape has rich biodiversity despite being in the vicinity of the densely populated town Kumta and nearby villages. Although cucurbits are grown year-round in India, studies on pollination during monsoon are needed in Southwest India when cucurbit cultivation is at the peak. The study was aimed at documenting diversities of pollinator insects, their visitation timings and frequencies on cucurbits i.e. Cucumis sativus Cucumis pubescensL. (cucumber), Willd. (Mangalore gourd), L. (bitter Momordica charantia gourd), L. (snake gourd) and Trichonsanthes anguina Luffa acutangula L. (Roxb.) (ridge gourd). It also aimed at the role of diverse elements of a traditional landscape in sustaining cucurbit pollinators and the synchronism of the pollinators with the varying flowering schedules of respective crops. MATERIALS AND METHODS Study Area Tannirkuli Village (14.45876 ºN and 74.42694 ºE), in the Hegde Panchayat of Kumta Taluk of Uttara Kannada in the South Indian west coast was chosen for the study. Tannirkuli is dominated by Halakkivokkal community farmers who are skilled growers of vegetables using traditional agricultural techniques. During the intense coastal monsoon, the farmers mainly grow cucurbits in a 10 ha well-drained ground, while rice is cultivated in the flooded fields. Groundnut, vegetables and cucurbits constitute the second crop in the post- monsoon fields when the hill slopes are too dry for cultivation (Fig. 1). Pollinator diversity and foraging dynamics on monsoon crop of cucurbits – Balachandran et al. 17 Figure 1 Map of study area: Tannirkuli Village, Uttara Kannada District, Karnataka State, India flowering and continued at weekly intervals until flowering nearly stopped (Belavadi & Ganeshaiah 2013). Numbers of visitor insects were counted species-wise. The frequency of visitation by a species was categorized as very frequent (>50% of the floral visits); frequent (>20% and <50%); and rare (<20%). Insect specimens were collected using a sweep-net and identified using Sampling Design The preliminary studies were carried out from July to early August 2013. Observations on insect visitations on flowers were conducted from mid- August to the end of September. The crops studied were cucumber, bitter gourd, snake gourd, ridge gourd and Mangalore gourd (Fig. 2). The observations on pollination were started at 10% BIOTROPIA Vol. 24 No. 1, 2017 18 Figure 2 Flower and fruit of cucurbits plants Notes: a & b = male flower of Cucumis sativus, c & d = female flower of Cucumis sativus; e & f = male flower of Momordica charantia, g & h = female flower of Momordica charantia; i = male flower of Luffa acutangula, j = female flower of Luffa acutangula, k = Delias eucharis on Trichosanthes anguina, l = fruit of Cucumis pubescens, m = fruit of Trichosanthes anguina, n = fruit of Luffa acutangula, o = fruit of Momordica charantia, p = fruit of Cucumis sativus taxonomic keys (Michener 2007; Belavadi & Ganeshaiah 2013). The specimens were examined using stereo microscope for the presence of pollen and segregated as pollinators and non- pollinators. The pollen grains were matched with the host pollen separately collected before ascertaining the visitor insect as a pollinator of a specified crop, in accordance with Belavadi and Ganeshaiah (2013). The insect specimens were maintained in the Kumta field station of Centre for Ecological Sciences, Indian Institute of Science. Foraging Dynamics Insect foraging behavior was studied between 06:00 and 22:30 hours, at hourly intervals during species-specific blooming times. The observation protocols and frequency of visitors were measured using a hand tally counter and stopwatch following Free (1993). Sampling units 2of 1 m (approximately covering 20 - 30 flowers) were selected and the visitor insects were documented. Each observation period for any crop selected was for 5 minutes, at 3 replications per hour. The foraging patterns were assessed based on the dominant groups of visitor insects and peak foraging times. Landscape Analysis Landscape elements of 3 km radius around the study area were deciphered using remote sensing data from Google Earth and Landsat-8 imageries of 2014. The time series spatial data acquired from Landsat Series Multispectral sensor and thematic mapper sensors were downloaded from http://glcf.umiacs.umd.edu/data. Land Use (LU) analysis involved Preprocessing, Classification and Accuracy Assessment. Land use classification was done using supervised pattern classifier-Gaussian maximum likelihood algorithm through open source GIS i.e. GRASS- Geographic Resource Analysis Support System downloaded from http://ces.iisc.ernet.in/grass (Fig. 3). The classifications were based on derived signatures (training polygons). Classifier performance was assessed considering reference pixels using kappa (κ) statistics (Ramachandra et al. 2013). Figure 3 Method followed for land use assessment Satellite Data Pre Processing Acquisition False Colour Composite Land use classification Accurancy assessment Ground Data, Toposheets, Bhuvan, Google eart 19 Pollinator diversity and foraging dynamics on monsoon crop of cucurbits – Balachandran et al. RESULTS AND DISCUSSION Diversity and Abundance of Insect Visitors on Cucurbits Table 1 lists the spatial extent of landscape elements in the study area. About 25.1% of the area was used for agricultural fields (mainly paddy cultivation), 12.3% was used for horticulture (coconut, areca), 4.4% for forest area, 0.8% for built-up area and 0.5% for vegetable gardens. The overall accuracy of the classified data was 85.32% with kappa of 0.813 (Table 1). Male flowers opened earlier than the female ones in all species. In bitter gourd, cucumber and Mangalore gourd anthesis commenced before sunrise, in ridge gourd towards sunset and in snake gourd after sunset (Table 2). A total of 24 insect species (22 genera, 14 families, 4 orders), visited cucurbit flowers (Table 3). Table 1 Elements of agricultural landscapes with beneficiary resource for pollinators Land Use Classification Area (0-3 km radius) % F N ha Built-up Residential Area, Industrial Area, mixed pixels with built-up area 23.7 0.8 Open Area Open lands, Quarries 212.1 7.5 Open Wetland Aquaculture and wetlands 96.4 3.4 Water River, Drainages 308.8 10.9 Agriculture Agriculture Fields Current Fallow and Sown (Paddy) 709.3 25.1 Cashew Cashew Plantations in scrub jungle 269.6 9.5 + + Forest Evergreen forests, Deciduous and mixed Forests 123.7 4.4 + + Horticulture Areca Gardens, Coconut plantations 349.2 12.3 + Laterite Laterite Quarry, Laterite Open lands 318.5 11.3 + Laterite Acacia Acacia auriculiformis plantation in laterite plateaus 193.8 6.9 Acacia Acacia auriculiformis plantation 210.8 7.5 Vegetable Farm Cucurbit varieties with inter crops like ladies finger 12.8 0.5 + Total area (ha) 2,828.7 100 Overall accuracy of classification: 85.32%; Kappa Statistics: 0.813 Notes: N = Nesting habitats; F = Foraging habitats; + = present Table 2 Anthesis time observed in cucurbits studied (in the monsoon months) Species Common name Male flower Female flower Starting time Full bloom Starting time Full bloom Momordica charantia Bitter gourd 5:20 A.M 5:40 A.M 5:40 A.M 6:30 A.M Cucumis sativus Cucumber 6:10 A.M 6:40 A.M 6:10 A.M 7:10 A.M Cucumis pubescens Mangalore gourd 6:30 A.M 6:55 A.M 7:00 A.M 8:20 A.M Luffa acutangula Ridge gourd 5:20 P.M 6:10 P.M 5:25 P.M 6:30 P.M Trichosanthes anguina Snake gourd 8:20 P.M 8:50 P.M 8:30 P.M 9:25 P.M 20 BIOTROPIA Vol. 24 No. 1, 2017 With 8 species of butterflies and 3 species of moths from 7 families, the Lepidopterans had the highest numbers of pollinators. Hymenopterans followed with 6 species of bees and 3 species of wasps. Bees were the most frequent flower visitors. The Dipterans (flies) and Coleopterans (beetles), with 2 species each, were infrequent visitors and had no notable role in pollination as specimen examination revealed general absence of pollen. Hymenopterans were observed as having the highest visitations on ridge gourd, followed by Mangalore gourd, cucumber and bitter gourd, respectively. Lepidopterans were dominant on snake gourd and frequent on bitter gourd. Bitter gourd was also visited by bees. Coleopterans and Dipterans were infrequent on all cucurbits, except snake gourd. Crop-wise abundance of insect visitors is summarized in Figure 4. A. dorsata had the highest abundance of visits on ridge gourd (70.1%) followed by cucumber (66%), Mangalore gourd (56%) and bitter gourd (38%). A. dorsata was negligible on snake gourd. A. cerana was most abundant on Mangalore gourd (39.6%) and cucumber (31.6%). Ridge gourd and bitter gourd also had good dependence on A. cerana. Trigona sp. more frequently visited bitter gourd than others. Butterflies and moths were predominant Table 3 Insect species found on cucurbit flowers during the monsoon period Family Species Common Name C . s at iv us (c uc um b er ) C . p ub es ce ns (M an ga lo re g o ur d) M . c ha ra nt ia (B it te r go ur d) L . a cu ta ng ul a (R id ge g o ur d) T . a ng ui na (S n ak e go ur d) Hymenoptera Apidae Apis dorsata Fabricius Giant honeybee + + + + Apis cerana indica Fabricius Indian honeybee + + + + Trigona Jurine Stingless bee + + + + Ceratina Latreille Small carpenter bee + + + + Xylocopa Latreille Carpenter bee + Halictidae Halictus Latreille Sweat bee + + Vespidae Vespa cincta DeGeer Yellow banded wasp + + Vespa L. Common wasp + Polistes Latreille Paper wasp + Lepidoptera Nymphalidae Hypolimnas bolina L. Great eggfly + Papilionidae Papilio polytes L. Common mormon + + Graphium agamemnon L. Tailed jay + + Pieridae Catopsilia pomona Fabricius Common emigrant + + Eurema hecabe L. Common grass yellow + Delias eucharis Drury Common jezebel + + Papilionidae Pachliopta hector L. Crimson rose + Hesperidae Borbo cinnara Wallace Rice swift + + + + Sphingidae Cephonodes hylas L. Bee-hawk moth + + + + Arctiidae Amata bicincta Kollar Handmaiden moth + + + Geometridae Dysphania percota Swinhoe Blue Tiger moth + + Coleoptera Chrysomelidae Aulacophora Dejean Leaf beetle + + + Coccinellidae Henosepilachna Li & Cook Ladybird beetle + + Diptera Tabanidae Tabanus L. Horsefly + Muscidae Musca domestica L. Housefly + + + Note : + = present 21 Pollinator diversity and foraging dynamics on monsoon crop of cucurbits – Balachandran et al. on snake gourd. Beetles and flies were the least important pollinators on all crops and did not visit snake gourd. In regards of pollinators visitation on Cucumis spp., 11 insect species visited and 10 C. pubescens species visited (Table 3). was C. sativus A. dorsata observed dominant visitor on spp., 66% Cucumis on Mangalore gourd and 56% on cucumber. A. cerana had 39.6% visitation on Mangalore gourd and 31.6% on cucumber In Dharwad, . neighboring district of Uttara Kannada, Prakash (2002) recorded 27 species of insects pollinated cucumber during post-monsoon season, where honeybees ( and ) as A. dorsata, A. cerana A. florea well as Smith were the Trigona iridipennis dominating visitors, validating our findings on honeybees as prime pollinators of spp.Cucumis Bitter gourd was visited by 13 species in which A. dorsata Trigonaand sp. constituted 80.2%. Nidagundi and Sattagi (2005) recorded 10 insect visitors on bitter gourd in Dharwad i.e. 8 Hymenopterans and 2 Lepidopterans. Hymenopterans T. iridipennis, Halictus gutturosus Vachal and were important pollinators of A. florea bitter gourd (Subhakar 2011). In Bangalore, et al. 78.09% of pollinators on ridge gourd were bees, mainly and A. cerana, A. florea Tetragonula iridipennis (Kuberappa 2008). In our study, the wild bee et al. A. dorsata had the prime role as pollinator (70.1%). The rest of pollinators consisted of other bees, butterflies, flies, beetles and hawk moths. Foraging Dynamics Insect forage is a collective process of individuals, as well as of the group (Traniello 1989). Crop-wise foraging times in our study (Trichosanthes excluded) by different insects are presented in Figures 5 to 8. A. dorsata and A. cerana, visited cucumbers from 06:30 to 16:30 hours, until the flowers wilted (Fig. 5). A. dorsata Peak visit of was during 10:30 hours (18.87 visits/m /5 minutes) and 11:30 hours 2 (20 visits/m /5 minutes). The visits were lesser 2 earlier and later (0.2, 0.4 and 1.2 visits/m / 2 5 minutes at 07:30, 08:30 and 16:30 hours, respectively). Peak foraging by in a A. dorsata Dharwad study was between 11:00 to 12:00 hours (Pateel & Sattagi 2007). Conner-Michigan (1969) reported that 10:00 to 15:00 hours as the most effective time for cucumber pollination in Ohio, in which a flower required at least 8 to 10 visits by bees for satisfactory fruit set. The maximum foraging activity of in our study nearly A. cerana overlapped with that of . Although the A. dorsata flowers bloomed at sunrise, the highest visitation frequency of was at 9:30 hours (8.8 A. cerana visits/m /5 minuntes) and 10:30 hours (9.73 2 visits/m /5 minutes). Visitations declined from 2 11:30 hours (7.71 visits/m /5 minutes), reached 2 minimum at 15:30 hours (0.13 visit/m / 2 5 minutes). sp. was only a minor forager of Trigona cucumber. Other infrequent visitors like butterflies, moths and beetles foraged mainly Figure 4 Bar diagram of insect abundance on different cucurbit plants 22 BIOTROPIA Vol. 24 No. 1, 2017 100% 75% 50% 25% 0% Ridge gourd Cucumber Mangalore gourd Bitter gourd Snake gourd Flies Beetles Moths Butterflies Wasps Other bees A b u n d an ce Figure 6 Foraging patterns of diverse insect visitors on Cucumis pubescens between 07:30 to 10:30 hours. Insect foragers on Mangalore gourd were observed from 06:30 to 17:30 hours (Fig. 6). The highest foraging 2frequency of 13.6 visits/m /5 minutes was observed at 12:30 hours by Apis dorsata and the least was observed at 07:30 hours. Apis cerana had 2peak visitations at 13:30 hours (11.2 visits/m /5 minutes), the lowest was at 08:30 and 17:30 hours 2(0.21visits/m /5 minutes). Trigona sp. foraged 2maximum at 11:30 hours with 2.1 visits/m /5 minutes and was not to be found from 15:30 hours. Figure 5 Foraging pattern of diverse insect visitors on Cucumis sativus 23 Pollinator diversity and foraging dynamics on monsoon crop of cucurbits – Balachandran et al. 2 N o. o f in d iv id u al s / m / 5 m in u te s 2 N o. o f in d iv id u al s / m / 5 m in u te s Apis cerana Apis dorsata Trigona sp Other bees Beetle Moth Flies Straight lines = Primary axis Dot lines = Secondary axis Apis cerana Apis dorsata Trigona sp Beetle Butterfly Moth Straight lines = Primary axis Dot lines = Secondary axis Insects foraged on bitter gourd (Momordica charantia) from 06:30 to 14:30 hours (Fig. 7). The stingless bee Trigona sp. as the major pollinator had peak visitations at 09:30 hours 2 (6.88 visits/m /5 minutes); lesser at 07:30 hours 2 (6.75 visits/m /5 minutes). By midday, Trigona sp. shifted to other cucurbits, mainly to Cucumis spp. Visitations of A. dorsata nearly overlapped with that of Trigona sp. in the 2 morning, peaking at 07:30 hours (7 visits/m /5 2 minutes) and 08:30 hours (6.88 visits/m /5 minutes). A. cerana succeeded reaching 2 maximum at 08:30 hours (3.14 visits/m /5 minutes). The butterflies were infrequent on bitter gourd, the highest at 09:30 hours (1.75 2 visits/m /5 minutes). As bitter gourd flowers bloomed very early in the morning, few moths could be found at 07:30 hours. Study of Subhakar et al. (2011) in Tirupati also showed that Trigona (iridipennis) was the most abundant and frequent 2 visitor on bitter gourd (10.83 visits/m /5 minutes). Ridge gourd Luffa acutangula is an important vegetable in coastal Uttara Kannada. Foraging was observed from 17:30 to 22:30 hours (Fig. 8). Honeybees were major foragers. A. dorsata made 2 13.67 visits/m /5 minutes at 18:30 hours, while 2 A. cerana had 4.67 visits/m /5 minutes at 17:30 Figure 7 Foraging patterns of diverse insect visitors on M. charantia Figure 8 Foraging patterns of diverse insect visitors on Luffa acutangula 24 BIOTROPIA Vol. 24 No. 1, 2017 2 N o. o f in d iv id u al s / m / 5 m in u te s Apis cerana Apis dorsata Trigona BeetleButterfly Moth Straight lines = Primary axis Dot lines = Secondary axis 2 N o. o f in d iv id u al s / m / 5 m in u te s 6:30 7:30 8:30 9:30 11:3010:30 14:3012:30 13:30 Apis cerana Apis dorsata Trigona sp Beetle Other bees Moth Straight lines = Primary axis Dot lines = Secondary axis Wasp hours. Beetles, wasps and other bees were rare visitors. A. cerana, A. florea and Tetragonula iridipennis were reported as main pollinators of Luffa sp. in Bangalore (Kuberappa et al. 2008). Shrivastava (1991) reported sphingid moth as an important pollinator of Luffa sp., an evening bloomer. For snake gourd, a night bloomer with white flowers, moths were the main visitors during night, while butterflies frequented after daybreak. The bee-hawk moth had the highest visitations between 20:30 and 22:30 hours. The rainy nights of Southwest Monsoon hampered further observation in the midnight hours. Elements of the Landscape Insect pollinators are known to rely on diverse elements of landscapes (habitats) for resources like nectar, pollen, nesting materials and species- specific nesting sites. Landscape element analysis of the study area (with 3 km buffer) was done using remote-sensing data and field data (Fig. 9). Forests provide nesting and foraging sites for insect pollinators, ensuring their permanence in the landscape. High proportions of natural or semi-natural habitats close to agricultural area are known to benefit bee diversity, mutualistic interactions and insect foraging movements (Hagen & Kraemer 2010). In the 3 km radius around the vegetable growing area, there were forest, cashew trees (in scrub jungle), horticulture, laterite plateaus and vegetable farm, which provided food for the insects. Only forest and cashew trees in scrub jungle were the main nesting areas for the insects. The presence of almost 100 ha forest patch, within the 3 km radius in the Halkar Village, was of high significance, especially in the vicinity of Kumta, a municipal town. The forest has been under careful protection by the village community for generations and is acclaimed as one of the best examples of community managed forests in India (Chandran 2001). The low laterite plateaus characteristic of Uttara Kannada plays as the key role in providing foraging resources for honeybees and lepidopterans (Balachandran 2014). The et al. forests and scrub on laterite hills provided habitats for Changes in landscape A. dorsata. structure are considered to be the primary cause of limitation in pollination services in agricultural systems (Viana . 2012).et al In retrospect, plants can escape competition by utilizing different pollinator species or guilds, due to species-specific floral morphology and blooming times, favoring resource partitioning, conferring mutual benefits to both hosts and pollinators (Pleasants 1980; Schoonhoven et al. 2005). Bees are prominent among cucurbit pollinators. The foraging schedules on any given species showed minimal overlapping between different foragers. took advantage of A. dorsata, the early morning blooming of bitter gourd, congregated on it from 06:30 to 09:30 hours, and shifted to cucumber and Mangalore gourd as the day progresses, although it continued to forage in lesser frequencies until the flowers ceased by midday. After completing their visits on Cucumis spp. during the rest of the day, extended A. dorsata their foraging activity into the night on ridge gourd, although in lesser frequencies, up to 22:30 hours. The knowledge on foraging activity and local climate is important for carrying out multi- species cropping of gourds and cucumbers to obtain maximum crop production. Figure 9 Land use elements in the landscape (with 3 km radius surrounding) 25 Pollinator diversity and foraging dynamics on monsoon crop of cucurbits – Balachandran et al. CONCLUSIONS Insect pollinators can enhance production without additional inputs other than organic manure. Bees, mainly A. dorsata, A. cerana and Trigona sp. were the major pollinators on all cucurbits, except snake gourd. Traditional landscapes of coastal Uttara Kannada had all the necessary elements for sheltering and feeding of pollinator guilds which co-existed harmoniously with the cropping schedules of the local farmers. 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