Details :

Beekeeping for Sustainable Development of North Eastern Hill Agriculture

 

M. PREMJIT SINGH

Central Agricultural University, Iroisemba

Imphal 795 004 – Manipur

vcofficecau@yahoo.in

 

 

Key words  Beekeeping, northeastern region, bee flora, bee pollination, oilseeds, fruits, vegetables Apis cerana himalaya

 

Abstract  Modern agriculture has come to depend greatly on the bees to fulfill its pollination needs. In the North-eastern hill region, a separate subspecies of Asian honeybee has been reported and named as Apis cerana himalaya which differed from Apis cerana cerana of North West Himalayas and Apis cerana indica of South India. Further, there are three locally adapted populations or ecotypes of the subspecies A.c.himalaya that correspond to geographic distributions (1) the Naga and Mizo hills, (2) Brahmaputra valley and Khasi hills, and (3) the foothills of the northeast Himalayas. Pollen analysis of honey samples collected from North-eastern hill region revealed that the dominant sporomorphs  were of Brassica sp., Solanum sp., Helianthus sp., Wendlandia sp., Ageratum sp., Clematis sp., Adhatoda sp., Mussaenda sp., and Papilionaceous, Rubiaceous, Rutaceous and Zingiberaceous members. Bee flora of North-eastern region was studied and identified 107 bee plants. Available informations on important insect pollinators, foraging behavior and pollination requirements of the new subspecies, A.c. himalaya in relation to yield and quality of important oilseeds, fruits and vegetables of North-eastern hill region are reviewed and discussed.

 

CONTENTS

          INTRODUCTION

          BEE POLLINATION

                   Planned bee pollination : A new agricultural production strategy

 

                   Need for planned pollination by honeybees

                   Honeybees  :  The most efficient pollinators

                   Advantages of bee pollination.

SPECIES OF HONEYBEES USEFUL FOR PLANNED POLLINATION

 

BEE FLORA OF NORTH-EASTERN HILL REGION

 

EFFECT OF HONEYBEE POLLINATION

          Oilseed crops

          Fruit crops

          Vegetable crops

NUMBER OF COLONIES REQUIRED FOR POLLINATION

 

HINTS FOR MAXIMIZING THE EFFICIENCY OF HONEYBEE FOR POLLINATION

 

REFERENCES

 

 

 

 

 

 

 

 

Introduction

Intensive cultivation and the much advocated clean culture has destroyed natural food sources and nesting sites of wild pollinators resulting in depletion of their population. Also indiscriminate use of pesticides often kill a large number of pollinators and reducing their numbers further. Integration of beekeeping with agriculture will not only benefit the farmers with the direct benefits in the form of honey, bees wax, hive products and employment opportunities, but indirectly benefit greatly through increased crop production. It has been established that almost all the agricultural crops depend upon pollinating insects for commercial seed/fruit production (Free, 1993; Deodikar and Suryanaryana, 1975, 1977; Rao et al., 1980). Insect pollination is extremely important as only 5.0 per cent of flowers are self-pollinated and 95.0 per cent are cross-pollinated. Among 95 per cent, 85 per cent of pollination is brought about by insects. Evidently for increased crop production and sustainable agriculture, it is essential to explore the possibility of planned bee pollination. This presents an important dilemma with reduction of native pollinators on one hand and an increased need for bees for crop pollination on the other. So, modern agriculture has come to depend greatly on the bees to fulfill its pollination needs. Beekeeping has also become an important and sustainable source of income generation to the rural poor, landless and marginal farmers and other weaker sections of the population, particularly the tribals of north-eastern region living below the poverty line, improving their status. It is ideal as a programme for development of women and children.

 

Bee pollination

 

Planned bee pollination: A new agricultural production strategy

 

          In order to maximize agricultural production various agricultural scientists have tried to improve the genetic constitution of the crop plants (by systematic breeding), nutrition of crop plants (by analysis of soil and its texture) and health of crop plants (by developing measures of plant protection). As a result several essential inputs such as improved implements for soil preparation, irrigation, fertilizers, improved seeds and pesticides were made available to the growers. These are being used by the farmers for improving productivity but these components when fully exploited may not give even marginal returns and therefore for further improvements in agricultural production, we have to look for other possible strategies. One of such possibilities is the planned pollination through honeybees.

 

          The plants grown with the best agronomic practices bear flowers that open and then fade after which they set fruits or are shed, depends largely on whether or not they were pollinated. This option, if left entirely to chance, can mean the difference between profit and loss to the growers and low agricultural productivity.

 

Need for planned pollination by honeybees

 

          The side effects of the various scientific advancements directed towards growing more vigorous and healthy plants coupled with mechanization of agriculture during the past half a century, have been instrumental in making us realize the importance and hence the need for the increased use of honeybees for pollination. Under the modern system of cultivation, certain localities are favoured and specialized for growing a particular crop which is concentrated on a large area. As such the population of wild pollinators in comparison is left very small leaving only a few pollinators per unit area to do the job. Under such conditions, however favourable other factors involved in the production of seeds/fruits may be, the yields are limited by the lack of sufficient number of pollinators at the critical flowering stage.

 

          Furthermore, intensive cultivation and the much advocated clean culture has destroyed natural food sources and nesting sites of wild pollinators resulting in depletion of their population. Also indiscriminate use of pesticides often kill a large number of pollinators and reducing their numbers further.

 

          Greater need of pollinators is thus felt which can be met immediately by honeybees. A few colonies of them when placed in the field when the crop is in flowering stage, press into service several thousand foragers for pollination. It is for this reason that the importance of beekeeping is being realized as an integral part of crop production.

 

Honeybees: The most efficient pollinators

 

          Honeybees are the most efficient pollinators of several cultivated and wild plants because of the following characteristics:

 

-         body parts are specially modified to pick up many pollen grains

-         floral fidelity and constancy

-         potential for long working hours

-         thorough micro – manipulation of flowers

-         maintainability of high populations when and where needed

-         adaptability to different climates and niches

 

Advantages of bee pollination

 

          As a result of cross pollination by bees, somatic, reproductive and adaptive heterosis or hybrid effects occur in plant progeny either in a single way or in different combinations. Such hybrid effects bring the following qualitative and quantitative changes in the economic and biological aspects of plants:

 

-         stimulates germination of pollen on stigmas of flowers and improves selectivity in fertilization

-         increases viability of seeds, embryos and plants

-         more nutritious and aromatic fruits are formed

-         increases the vegetative mass and stimulates faster growth of plants

-         increases number and size of seeds and yield of crops

-         enhances resistance to diseases and other adverse environmental conditions

-         increases nectar production in the nectaries of plants

-         increases fruit set and reduces fruit drop

-         increases oil content in oilseed crops

 

Species of honeybees useful for planned pollination in the North-eastern hill region

 

          Five species of honeybees are available in the north-eastern hill region namely, the small honeybee, Apis florea, the rock bee, Apis dorsata, the giant honeybee, Apis laboriosa, the Asian honeybee, Apis cerana and the European honeybee, Apis mellifera. The former three species cannot be domesticated and therefore, fall under the category of wild insect pollinators. Since no human control can be exercised on them for augmenting their pollination on a particular crop or locality, they are not considered useful for planned pollination. The latter two species are hive bees and can be kept in wooden hives. These species are quite industrious and are amenable to human handling. They can be shifted to different places in required number whenever needed. Both the species show remarkable similarity in pollination behavior. The efficiency of honeybee depends upon the colony strength, number of colonies and their time of shifting, placement and distribution of colonies in the field, weather conditions, presence or absence of competing crops and attractiveness of the crop to them.

 

          In the North-eastern hill region, a separate subspecies of Asian honeybee, Apis cerana himalaya exists, which differed from Apis cerana cerana of North-west Himalayas and Apis cerana indica of South India. Further, there are three locally adapted populations or ecotypes of the subspecies A. cerana himalaya that correspond to geographic distributions in (1) the Naga and Mizo hills, (2) Brahmaputra valley and Khasi hills, and (3) the foothills of the northeast Himalayas. (Singh et al., 1990; Singh and Verma, 1992). These ecotypes differ from each other in several biological and economic characters. Due to outbreak of Thai sacbrood disease on A. cerana himalaya in the north-eastern hill region (Meghalaya, Assam and Nagaland) during 1978, exotic European honeybee, A. mellifera was introduced in Assam and Meghalaya for commercial beekeeping.

 

Bee flora of North-eastern hill region

 

          The north-eastern hill region has great potential for the development of beekeeping because of its richness in forests, agricultural and horticultural crops. Unfortunately this industry has not tremendous progress so far, possibly due to lack of knowledge on modern bee management technology and the honey plant resources. Pollen analysis of honey samples collected from north-eastern hill region revealed that the dominant sporomorphs were of Brassica sp., Solanum sp., Helianthus sp., Wendlandia sp., Ageratum sp., Clematis sp., Adhatoda sp., Mussaenda sp. and Papilionaceous, Rubiaceous, Rutaceous and Zingiberaceous members. The minor pollen sources were Litsea sp., Ocimum sp., Caesalpinia sp., Parkia sp., Bauhinia sp., Senecio sp., Polygonum sp., Acer sp. and members of families Asteraceae, Bignonaceae, Euphorbiaceae, Lamiaceae, Lauraceae, Malvaceae, Myrtaceae, Papilionaceae, Polygonaceae, Ranunculaceae, Rosaceae, Rubiaceae, Rutaceae, Scrophulariaceae and Zingiberaceae (Singh et al., 1994; Singh, 1999).

 

 

For the success of beekeeping programme in any area, it is of utmost importance to know about the major pollen and nectar sources of that area and about the time of the year when there is abundance of flora. In the north-eastern region, bee flora was studied by Rahman, 1990; Kumar, 1993; Singh et al., 1994 and Singh, 1999 and identified a total of 107 bee plants/flora.

 

Effect of honeybee pollination on increasing sustainable agricultural productivity in the North-eastern hill region.

 

          Only a few attempts have been made in the north-eastern hill region to identify important insect pollinators and to assess the pollination requirements of agricultural and horticultural crops. Available information of this region on important insect pollinators of crops, foraging behavior of bees and effect of bee pollination on increasing agricultural productivity has been reviewed and discussed below crop-wise:

 

 

 

 

 

 

 

 

 

Oilseed crops

 

          Rapeseed and mustard: Surveys conducted at twenty oilseed growing localities belonging to six districts of Manipur showed that the Asian honeybee, Apis cerana himalaya and flower fly, Episyrphus balteatus were the main pollinators of rapeseed and mustard, which constituted 72 and 26 per cent, respectively of the total pollinators population. Other visitors were rock bee, Apis dorsata, bumble bee, Bombus tunicatus, cabbage butterfly, Pieris brassicae, housefly, Musca sp. and alkali bee, Nomia curvipes, however, they do not visit the crop in sufficient numbers (Singh et al., 1993;  Singh et al., 1998b). A.c. himalaya was observed to start its foraging activity at 0800 hours and ceased at 1600 hours. The peak population of foraging bees was observed between 0900 and 1100 hours. The bees spent an average of 6.4 seconds per flower with foraging rate of 10 flowers per minute. During the hours of the day, the number of nectar collector’s increased from morning to evening, whereas the trend was reverse for pollen collectors. The average duration of single foraging trip was 8.6 minutes with maximum pollen load of 9.6 mg/bee at 1200 hours (Singh et al., 1998b).

 

          The rapeseed crop pollinated by bees caused 586% and 9% higher yield than self-pollinated and pollinated by natural insects, respectively under Manipur condition (Singh et al., 1998a). Similarly, Mahanta and Rahman (1997a) found 437.5% higher yield of rapeseed in Assam in bee pollinated as compared to self-pollinated crop. Further, Singh and Devi (1997) reported that in rapeseed at least five bee visits per flower are required for good pollination. The crop pollinated by bees enhanced siliqua setting, length of siliqua, number of seeds per siliqua and seed weight. Interestingly, the oil content in seeds of bee pollinated plants increased to the extent of 21.3% and 4.1% as compared to self-pollinated and pollinated by natural insects, respectively. Germination of seeds from bee pollinated plants was also 50.9% higher than from self-pollinated and 2.5% higher than from pollinated by natural insects (Singh et al., 1998a) (Table 1).

 

Table 1. Quantitative and qualitative effects of Apis cerana himalaya pollination on rape seed

 

Yield  parameters

Control (PWI)

Open-pollinated (OP)

Bee-Pollinated (BP)

CD at 5%

% increase over             PWI

% increase Over             OP

Siliqua set (%)

20.67

68.42

70.23

 

239.77

2.65

 

(26.39)

(56.01)

(57.34)

(5.00)

 

 

Siliqua length (cm)

3.94

4.16

4.52

 

14.72

8.65

(2.11)

(2.12)

(2.24)

(0.07)

 

 

No. of seeds per siliqua

9.12

11.65

13.73

 

50.55

17.85

(3.14)

(3.52)

(3.80)

(0.24)

 

 

Wt. of 1000 seeds (gm)

2.01

2.31

2.36

 

17.41

2.16

(1.66)

(1-75)

(1-76)

NS

 

 

Seed yield (q/ha)

1.96

12.37

13.45

2.90

586.22

8.73

Seed

Germination (%)

55.00

81.00

83.00

 

50.90

2.50

(47.93)

(65.98)

(66.02)

(5.21)

 

 

Oil content (%)

33.25

38.75

40.33

 

21.30

4.10

 

(35.18)

(38.48)

(39.41)

(0.81)

 

 

Figures in parentheses are transformed values

 

 

 

 

Sunflower: Under the agro-climatic conditions of Manipur, the Asian honeybee, Apis cerana himalaya and rock bee, Apis dorsata were the predominant pollinators of sunflower, which constituted 46 and 42 per cent, respectively of the total pollinators population. Other insect visitors were little bee, Apis florea, bumble bees, Bombus haemorrhoidalis and B. tunicatus, carpenter bee, Xylocopa aestuans, alkali bee, Nomia curvipes, leaf cutter bee, Megachile umbripennis, sweet bee, Halictus albescens,drone flies, Ischiodon scutellaris and Episyrphus balteatus and cabbage butterfly, Pieris brassicae, however , they do not visit the crop in sufficient numbers. A.c himalaya was observed to start its foraging activity at 0519 hours and ceased at 0608 hours during winter. Bees foraged throughout the day, but the peak foraging activity was observed between 0600 and 0900 hours and spent an average of 53 seconds per flower head with foraging rate of 2 flower heads per minute. During the hours of the day, the number of nectar collectors increased from morning to evening, whereas, a reverse trend was observed for pollen collectors. The average duration of foraging trip of bees was 3.4 minutes with maximum pollen load of 5.8 mg/bee at 1400 hours (Singh et al., 1998b).

 

The sunflower crop pollinated by bees enhanced 801% and 12% higher seed yield than self-pollinated and pollinated by natural insects, respectively. The seed setting in bee-pollinated plants was also observed 2343% and 18.3% higher than self-pollinated and pollinated by natural insects, respectively. The oil content in seeds and seed germination rate could also be increased in the seeds pollinated by bees (Singh and Singh, 1993; Singh et al., 1998a) (Table 2).

 

Table 2. Quantitative and qualitative effects of Apis cerana himalaya pollination on sunflower

 

Yield  parameters

Control (PWI)

Open-pollinated (OP)

Bee-Pollinated (BP)

CD at 5%

% increase over             PWI

% increase Over             OP

Seed set (%)

2.93

60.50

71.58

 

2343.00

18.31

 

(9.84)

(51.13)

(57.81)

(2.20)

 

 

Weight of 1000 seeds (gm)

50.32

64.29

54.88

3.26

9.06

17.15

No. of seeds per gm

20.87

16.58

17.04

2.77

 

 

(4.63)

(4.13)

(4.19)

(0.37)

 

 

Seed yield (q/ha)

2.06

16.60

18.55

1.47

800.49

11.75

Seed germination (%)

69.88

86.50

91.13

 

30.41

5.35

(56.78)

(68.80)

(74.55)

(11.94)

 

 

Oil content (%)

35.96

46.79

43.70

 

21.52

7.07

 

(36.85)

(43.16)

(41.38)

(1.32)

 

 

Figures in parentheses are transformed values

 

 

Niger: Among the bee species, Apis cerana, A. dorsata, A. florea, A. mellifera and Chalicodoma lanata were found pollinating niger crop in Assam. Peak foraging activity of A. cerana was observed between 1000 and 1200 hours. The time required to collect pollen ranged from 4.89 to 7.23 seconds per capitulum and the number of foragers visiting flowers was directly related to the temperature and sunshine intensity. There was 120.2 per cent increase of seed yield in bee pollinated plots and five A. cerana colonies per ha were recommended (Rahman, 1993).

 

 

 

 

 

Fruit crops

 

Citrus: Bhuyan and Bhattacharyya (2002) studies the foraging activity of honeybee on Assam lemon and concluded that the duration of their visits was more in the morning hours in comparison to mid day, while individual honeybee visited more frequently in the morning and decreased subsequently towards evening. Citrus species and varieties greatly vary in their pollination needs. Sweetlime and mandarin oranges are generally benefited  from cross pollination. Bhuyan and Bhattacharya (2002) studies the effect of honeybee on Assam lemon and found 77 per cent fruit set in honeybee pollinated trees as compared to 46 per cent in naturally pollinated ones. They recorded 52.2% yield increase in Assam lemon due to bee pollination and recommended four A. cerana colonies per ha for optimum yield. A study conducted by Gogoi et al. (2007) on Assam lemon pollinated by A. cerana also revealed that the crop pollinated by bees gave 52.17% fruit set as compared to 40.80% in open pollinated and 27.35% in self pollinated plants. Due to A.cerana pollination, 214.79 per cent increased yield was recorded over self-pollinated treatment. The average fruit length, girth, weight and juice content in A. cerana pollinated plants were 12.93 cm, 17.40 cm, 199.46 gm and 655.99 cc, respectively, which were significantly higher than fruits of open pollinated and self-pollinated plants.

 

Litchi : Litchi is a popular fruit plant in sub Himalayan region as known for its expensive fruit. It blooms in February-March and is rich source of nectar to bees. Wind pollination does occur but fruit set is higher by insect pollination and little or no fruit set is obtained under selfing. Honeybees and stingless bees comprise more than 90% of the flower visitors. The study made by Mahanta and Rahman (1997b) on litchi found that A. cerana visit was maximum during 0900 to1100 hours of the day. The average number of bees was highest during 1000 to 1100 hours and frequency of flower visit was highest during 1500 to 1600 hours of the day. Five colonies of A. cerana per ha gave optimum yield of litchi with 123.97% increase in yield against self-pollination.

 

Vegetable crops

 

Cucumber : Islam (2007) studied the foraging behavior of A. cerana on cucumber and its role on fruit set and yield in Assam. Pollinators visiting the cucumber flower consisted of Asian honeybee, Apis cerana, European honeybee, Apis mellifera, rock bee, Apis dorsata, carpenter bees, Xylocopa leucothorax and X. fenestrata, wasps, Polystis habrious and Vespa magnifica, peacock pancy, Junonia almanaa, lemon butterfly, Papilio demoleus, grey count, Euthalia lepidae, housefly, Papilio demoleus, grey count, Euthalia lepidae, housefly, Musca domestica and ant, Oecophylla smaragdinae. Among theses, A. cerana was found to be the predominant pollinator which constituted 51.4% of the total pollinators population. The peak foraging activity of A. cerana was observed during 0800 to 0900 hours of the day.

 

          The cucumber crop pollinated by A. cerana enhanced 25.21% and 48.6% higher fruit yield than self-pollinated and pollinated by natural insects, respectively and recommended seven A. cerana colonies per ha for optimum yield. Similarly, maximum fruit set (19.2%) was also observed in bee pollinated plants against self-pollinated (5.5%) and pollinated by natural insects (12.8%).

 

 

 

 

 

 

Number of colonies required for pollination

          The number of hives needed for effective pollination depend on several interrelated factors i.e., species cultivated, time of flowering and the development of the colonies at the time of flowering. When the days are short during winter, many hives will be required. In the mid summer, for example on sunflower, a small number of well populated colonies will be sufficient, since the bees forage at this time nearly everyday and throughout the day. A large number of bees increase the time involved in searching for a foraging sector. It is precisely during this phase of its life that a forager visits one plant after another and in this manner carries pollen from one flower to another. On the other hand, if the number of bees is few, they immediately find an abundant supply of nectar, they only visit a few nearby flowers on the same branch of a plant. They will not adequately fertilize plants that need cross pollination. Hence, it is recommended that as many colonies as needed be placed so that in a single flight each bee visits different plants, some of which provide pollen for the others.

 

          Per hectare requirements of bee colonies for pollination in important crops of north-eastern hill region are estimated to be:

 

Sl. No.

    Crop

Pollination requirements

(No. of hives/ha)

1.

Apricot

2-5

2.

Apple

2-3

3.

Citrus

2-4

4.

Coconut

2-3

5.

Cucumber

5-7

6.

Guava

2-3

7.

Litchi

3-5

8.

Mango

2-3

9.

Niger

3-5

10.

Papaya

2-3

11.

Peach

2-5

12.

Pears

2-5

13.

Plums

3-5

14.

Pumpkin

2-3

15.

Rapeseed & mustard

3-5

16.

Sesamum

2-3

17.

Sunflower

2-4

18.

Watermelon

1-5

 

Hints for maximizing the efficiency of honeybees for pollination

·        Place the required number of full size colonies per hectare in the centre of the field requiring pollination.

·        Move colonies to the crops needing pollination when flowers in some of the plants have already starting opening.

·        Soak some flowers in sugar syrup (1:1 sugar-water ratio) and feed it to the bee colonies on the previous night before actually transporting them for pollination.

·        The colonies which are shifted for pollination should have sufficient brood so that the colonies do better pollination collecting pollen from the crop.

·        Pollen traps, if available, may be attached to the colonies for better results.

 

 

 

 

 

 

References

 

Bhuyan, M. and Bhattacharyya, P.R. 2002. Foraging of honeybee upon Assam lemon (Citrus acida Roxb.) under agro-climatic condition of Jorhat, Assam, India. Geobios 29 : 33-36.

Deodikar, G.B. and Suryanaryana, M.C. 1975. Bee enhances crop yields. Indian Farming 23 : 31-36.

Deodikar, G.B. and Suryanaryana, M.C. 1977. Pollination in the service of increasing farm production in India. Advances in Pollen Spore Research 2 : 67-87.

Free, J.B. 1993. Insect pollination of crops. Second Edition. Academic Press, London.

Gogoi, B., Rahman, A., Rahman, S. and Deka, M.K. 2007. Foraging behavior and effect of Apis cerana pollination on fruit set and yield of Assam lemon (Citrus lemon L. Burn). Indian Journal of Agricultural Sciences 77(2):120-122.

Islam, N. 2007. Role of Apis cerana (Hymenoptera, Apidae) on fruit set and yield of cucumber, M.Sc. thesis, Assam Agricultural University, Jorhat, pp. 47.

Kumar, R. 1993. Bee pasturage of Khetri. Indian Bee Journal. 55(1-2):40-42.

Mahanta, M. and Rahman, A. 1997a. Pollination studies on honeybees (Apis cerana indica) on rapeseed, Brassica campestris var. toria. Plant Health 2 : 66-69.

Mahanta, M. and Rahman, A. 1997b. Studies on pollination of litchi (Litchi chinensis Sonn.) by honeybee (Apis cerana F.) Indian Bee Journal. 59(2):74-75.

Rahman, A. 1990. Bee forage plants of Jorhat (Assam, India). Indian Bee Journal.                 52(1-4):47-50.

Rahman, A. 1993. Role of honeybee, Apis cerana indica F. in pollination and seed set of niger. In : Pollination in Tropics (Eds. G.K. Veeresh, R. Uma Shankar and K.N. Ganeshaiah). IUSSI – Indian Chapter, Bangalore, pp. 212 – 214.

Rao, G. Mohan, Suryanarayana, M.C. and Thakur, C.V. 1980 Bees can boost oilseed production. Indian Farming. 29:25-26.

Singh, M.P. 1999. Melissopalynology and survey of the bee plants in North-eastern hill region. Indian Journal of Hill Farming 12(1 & 2):79-83.

Singh, M.P. and Devi, C.S. 1998. Effect of repeated flower visitation by Apis cerana Fab. on pod and seed setting in rapeseed. Insect Environment 3(2):40.

Singh, M.P. and Singh, K.I. 1993. Effect of bee pollination on the yield of sunflower.               In : Pollination in Tropics (Eds. G.K. Veeresh, R. Uma Shankar and K.N. Ganeshaiah). IUSSI – Indian Chapter, Bangalore, pp. 226 – 228.

 

 

 

 

 

 

Singh, M.P., Singh, K.I. and Sarangthem, A.K. 1993. Studies on the effect of bee pollination on the yield of rapeseed. In : Pollination in Tropics (Eds. G.K. Veeresh, R. Uma Shankar and K.N. Ganeshaiah). IUSSI – Indian Chapter, Bangalore, pp. 215 – 217.

Singh, M.P., Singh, K.I. and Devi, C.S. 1998a. Role of Apis cerana himalaya pollination on yield and quality of rapeseed and sunflower crops. In : Asian Bees and Beekeeping: Progress of Research and Development (Eds. M. Matsuka, L.R. Verma, S. Wongsiri, K.K. Shrestha and U. Pratap) Oxford and IBH Publishing Company, New Delhi, pp. 186 – 189.

Singh, M.P., Singh, K.I. and Devi, C.S. 1998b. Foraging behavior of Apis cerana himalaya on sunflower and rapeseed. In : Asian Bees and Beekeeping: Progress of Research and Development (Eds. M. Matsuka, L.R. Verma, S. Wongsiri, K.K. Shrestha and U. Pratap) Oxford and IBH Publishing Company, New Delhi, pp. 199 – 202.

Singh, M.P., Verma, L.R. and Daly, H.V. 1990. Morphometric analysis of the Indian honeybee in the North-east Himalayan region. Journal of Apicultural Research                29(1):3-14.

Singh, M.P. and Verma, L.R. 1992. Morphometric comparison of three geographic populations of the Northeast Himalayan Apis cerana. In : Asian Apiculture (Eds. T. Rinderer, A. Sylvester, S. Wongsiri and L.J. Connor) Wicwas Press, Chesire, USA, pp. 67 – 80.

Singh, M.P., Verma, L.R. and Mattu, V.K. 1994. Pollen spectrum of some honeys of the North-east Himalayas as deterimant of honeybee forage. Indian Bee Journal                56(1-2):37-52.

 

 


Source: OUAT Souvenir