20057--Sneha Latha Nagulapalli 25 May-2020 Indian Journal of Entomology Online published (Preview) DoI No.: INSECT POLLINATORS AND THEIR ABUNDANCE IN WEST BENGAL SNEHA LATHA NAGULAPALLI*, GAUTAM KUNAL, RAKESH DAS AND SHANTANU JHA Department of Agricultural Entomology, Bidhan Chandra Krishi Viswavidyalaya, Mohanpur, Nadia 741252, West Bengal *Email: [email protected] (corresponding author) ABSTRACT Studying pollinator diversity and their abundance is essential to analyze the health of the agroecosystem. This study undertook observations on the number of pollinators visiting the flowers/ 2m for 5 min at randomly selected 10 spots in agroecosystems in West Bengal. The diversity index was measured by Simpson’s Index of Diversity. A total number of 55 individuals of insect pollinators belonging to 19 families and 4 orders were observed of which Hymenoptera were maximum (47.25%) followed by: Coleoptera (24.68%), Lepidoptera (11.26%) and Diptera (8.29%). Simpson’s index ranged from 0 to 1. Maximum species richness was found in Lower Bongbasti, Kalimpong (0.995) and the lowest at AB-Block farm BCKV Kalyani (0.751). Among the surveyed areas, species evenness was found highest in Khelia North 24 Parganas (1.34) and lowest in Jhanti pahari Bankura (0.14). So far pollinator species richness is concerned, it was maximum in hilly terrains of Kalimpong followed by North 24 parganas, Bankura and Nadia. Key words: West Bengal, pollinator diversity, Simpson’s index, Hymenoptera, Lepidoptera, Diptera, Coleoptera, species richness, species evenness, abundance West Bengal is a north eastern of India with The observations were taken based on the number agriculture being its mainstay. In the agroecosystems, of pollinators visiting the flowers/m2 for five minutes animal pollination is one of the key ecosystem services at randomly selected 10 spots within the field and the (Aguilar et al., 2006; Ricketts et al., 2008). More mean data was recorded for the final result. The data was than 75% of the major crops in the world rely on collected at maximum flowering stage of the crops at animal pollinators (Powell and Powell, 1987; Steffan- two hours interval from 7 am to 5 pm viz. 7 am, 9 am, 11 Dewenter and Tscharntke, 1999). The global annual am, 1 pm, 3 pm and 5 pm. Samples of insect pollinators economic value of insect pollination is estimated to were caught by sweep net and preserved into the killing be € 153 billion (Gallai et al., 2009). Currently, these bottle containing ethyl acetate and then stored for services are threatened by habitat destruction and identification process. Identification of the pollinators climate change, as illustrated by marked decreases in was done by matching with previously identified fauna pollinator diversity and abundance in different parts of of pollinators preserved in Insect Museum, Department the world (Kevan, 2003; Memmott, 2007). The loss of of Agricultural Entomology and also from the assistance biodiversity, destruction of habitat and lack of forage of expert teacher. Climatic factors in the fields, i.e. due to monocultures, pests and diseases of bees and bee- temperature, humidity and locations of the field had killing pesticides are particular threats for honeybees been also recorded using GPS tool. Relative abundance and wild pollinators. These declines will have severe which determines the percentage of specimens of a consequences for the ecosystem services provided by given species in the total number of organisms collected, pollinators. Hence, studying pollinator diversity and were calculated based on the observations taken on the their abundance is essentiallyPreview required to analyze the number of pollinators visiting the flowers/m2/5 min, health of the agroecosystem. The present study had using following formula: Relative abundance (%) = been conducted to record pollinator diversity, their (Population of a particular species visiting flower/Total abundance, species richness and evenness in different population of all species visiting flowers) x 100 (Das parts of West Bengal. and Jha, 2019; Padhy et al., 2018). The diversity index to measure the species diversity in a community like MATERIALS AND METHODS Simpson’s Index of Diversity and Simpson’s Reciprocal In different crops, surveys were carried out in Index were worked out based on the methods suggests different locations during July to December 2018 at by Simpson (Simpson, 1949). weekly intervals, of which the details given in Table 1. 2 Indian Journal of Entomology Online published (Preview) Table 1 Location Districts Latitude & Longitude Crops Kachiara village & North 24 Parganas 22°53’08.5’’ N Dolichos bean, Sugar cane, chilli, brinjal, Khelia village 88°32’00.1’’ E & bitter gourd, banana, okra, pointed gourd 22°47’40.4’’ N 88°30’21.4’’ E Teaching farm, Nadia 22°56’39’’ N Sweet potato, rose, tuberose, coconut, goat Mandouri , BCKV 88°30’56’’ E weed, Ixora Central Research 22o95’54’’ N Black gram, guava, brinjal, sweet potato, Farm, Gayeshpur, 88o49’61’’ E parthenium, maize, citrus BCKV AB-Block (BCKV 22°58’46’’ N Dangshen bell flower, night shade, Farm), Kalyani, 88°25’15’’ E parthenium, goat weed C-Block (BCKV 22°59’15.5’’ N Bitter gourd, ridge gourd, cucumber, Farm), Kalyani 88°27’24.1’’ E pointed gourd IARI, Research Kalimpong 27°3’47.89’’ N Cucumber, Siam weed, lantana, Complex & 88°27’31.46’’ E parthenium, mandarin, squash, Gomphrena Bongbasti, sp.,okra, Tridax sp. Jhanti Pahari Bankura 23°21’38.88’’ N Passion flower, Dolichos bean, 86°54’’17.279’’ E pomegranate, Tridax sp., Amaranthus sp., Ixora. RESULTS AND DISCUSSION most predominant (5 insects/ m2, 25.48%). Epilachna sp., though a pest, helps in pollination (Das et al., A total of 55 insect species belonging to 19 families 2009). A total of 15 insect visitors belonging to order from 4 orders i.e. Hymenoptera, Lepidoptera, Diptera Hymenoptera (5) sequentially followed by Coleoptera and Coleoptera were observed as visitors from the (6), Lepidoptera (2) and Diptera (2) were observed in studied plants; Lepidoptera were the maximum with 24 weeds, and the Coleoptera were the abundant (54. 26%) species, followed by Hymenoptera and Coleoptera with of these followed by Hymenoptera (38.48%) followed 16 and 10 species, respectively. List of floral visitors by Lepidoptera and Diptera (3.36 %). On ornamentals are given in Table 2, and the relative abundance (insect 2 to such results were obtained and these are given in fauna/ m / 5 min) observed during the blooming period Table 2, which reveal that during the blooming period, in Table 2. L.niger was the most predominant (4.66 insects/ m2 and These reveal that Lasius niger was the most 25.50%). In ornamentals, a total of 17 insect visitors predominant species with an population of 10 insects/ belonging to order Hymenoptera (6) followed by m2 representing 35.37% of total insect visitors. This Lepidoptera (4), Diptera (4) and Coleoptera (3) were was followed by Epilachna sp., (3.0 insects/ m2 observed, and among the visiting fauna, Hymenoptera constituting 10.61%) and Aulacophora foevicollis were the most abundant (50.92%). (1.66 constituting 5.87%). Though A. foevicollis is Diversity indices analysed from these observations a pest, it is also known to help in pollination (Das reveal that the Simpson’s index ranges from 0 to 1, et al., 2009). Apis dorsata, A. mellifera, Coccinella 2 where the value zero indicates lesser species diversity transversalis and Episyrphus sp. (1.33 insects/ m and one indicates richness of diversity. Diversity index, constituting 4.70%) are thePreview other floral visitors. richness and evenness of different areas are represented A total of 22 insect visitors belonging to order in Table 4. On the basis of Simpson’s index it was found Hymenoptera (8) followed by Lepidoptera (6), that almost all the areas had good richness of pollinators’ Coleoptera (5) and Diptera (3) were found to visit diversity (0.751 to 0.995). Maximum values of species the cultivated crops in surveyed areas. Among them, richness were observed at Lower Bongbasti, Kalimpong Hymenoptera were the most abundant (51.74%). The (0.995), sequentially followed by Upper Bongbasti relative abundance of insect visitors observed in weeds Kalimpong, IARI-RS Kalimpong, Khelia North is also given in Table 3. On the basis of insect visitors 24 Parganas, Jhanti pahari Bankura and Mandouri recorded/ m2, Oecophylla sp. and A. foevicollis were the Teaching farm (0.98), C-Block Farm BCKV Kalyani Insect pollinators and their abundance in West Bengal 3 Sneha Latha Nagulapalli et al. Table 2. List of floral visitors in crop, weed and ornamental ecosystem: HYMENOPTERA 1 European bee Apis mellifera (L.) Apidae 2 Little honey bee Apis florae (F.) Apidae 3 Indian honey bee Apis cerana indica (F.) Apidae 4 Rock bee Apis dorsata (F.) Apidae 5 Stingless bee Tetragonula sp. Apidae 6 Carpenter bee Xylocopa sp. Apidae 7 Small carpenter bee Ceratina sp. Apidae 8 Cuckoo bees Nomada sp. Apidae 9 Blue banded bee Ammegilla zonata (L.) Apidae 10 Blue mud dauber Chalybion bengalense (Dahlbom) Sphecidae 11 Sweet bee Halictus sp. Halictidae 12 Leaf cutter bees Megachile sp. Megachilidae 13 Banded paper wasp Polistes Sagittarius (Saussure) Vespidae 14 Yellow paper wasp Polistes wattii (Cameron) Vespidae 15 Red ants Oecophylla smaragdina (F.) Formicidae 16 Black ants Lasius niger (L.) Formicidae LEPIDOPTERA 17 Grey pansy Junonia atlites (L.) Nymphalidae 18 Five ringed butterfly Ypthima baldus (F.) Nymphalidae 19 Tawny coster Acraea terpsicore (L.) Nymphalidae 20 Striped tiger Danaus genutia