Journal of Threatened Taxa | www.threatenedtaxa.org | 26 March 2019 | 11(5): 13625–13628

 

Pollinators of Sikkim Mandarin Orange Citrus reticulata (Sapindales: Rutaceae)

 

Urbashi Pradhan 1 & M. Soubadra Devy 2

 

1,2 Ashoka Trust for Research in Ecology and the Environment (ATREE), Royal Enclave, Srirampura, Jakkur, Bengaluru, Karnataka 560064, India.

1 Manipal Academy of Higher Education,Tiger Circle Road, Madhav Nagar, Manipal, Karnataka 576104, India

1 urbashipradhan@gmail.com (corresponding author), 2 soubadra@atree.org

 

doi: https://doi.org/10.11609/jott.4528.11.5.13625-13628  

ZooBank: urn:lsid:zoobank.org:pub:8120DF28-84C5-48D0-B1DF-2F6C8F8312C3

 

Editor: Kannan C.S. Warrier, Institute of Forest Genetics and Tree Breeding, Coimbatore, India. Date of publication: 26 March 2019 (online & print)

 

Manuscript details: #4528 | Received 28 August 2018 | Final received 06 February 2019 | Finally accepted 16 March 2019

 

Citation: Pradhan, U. & M.S. Devy (2018). Pollinators of Sikkim Mandarin Orange Citrus reticulata (Sapindales: Rutaceae). Journal of Threatened Taxa 11(5): 13625–13628. https://doi.org/10.11609/jott.4528.11.5.13625-13628

 

Copyright: © Pradhan & Devy 2019. Creative Commons Attribution 4.0 International License. JoTT allows unrestricted use, reproduction, and distribution of this article in any medium by adequate credit to the author(s) and the source of publication.

 

Funding: Department of Science and Technology, Government of India;

National Mission for Himalayan Studies (NMHS) under the Ministry of Environment,

Forest and Climate Change, Government of India (NMHS/2015-16/HF11/11).

 

Competing interests: The authors declare no competing interests.

 

Acknowledgements: We would like to thank Dr Belavadi, Dr Yashwanth and Dr Arathi at GKVK, Bangalore and Dr Kumar Ghorpade, at University of Agricultural Science, Dharwad for helping us identify our pollinator samples. We are immensely grateful to the people of the study villages for their hospitality and support. The officials of the Department of Horticulture and Cash Crop, especially Mr K.K. Singh, ex- Principal Secretary, Mr Khorlo Bhutia, the present Principal Secretary, Mr P.T. Bhutia and field staffs were all generously helpful. We would like to thank the Forest Department officials, PCCF Mr S.T.Lachungpa and PCCF Dr Thomas Chandy, Mrs Usha Lachungpa (Ex- Scientific officer) for giving the necessary permission to work in Sikkim. We take this opportunity to thank the donors—Department of Biotechnology, Government of India and National Mission on Himalayan Studies(NMHS), The Ministry of Environment, Forest & Climate Change (MoEF&CC)-—who generously funded this research.

 

 

 

 

Sikkim Mandarin Orange (Citrus reticulata Blanco, 1837) is a member of the Rutaceae family and a commercially desirable variety of the mandarin group native to Sikkim.  The Sikkim Mandarin Orange (SMO) growing area lies at an altitudinal range of 700–1,500 m and it is an annual flowering plant. Mandarin orange is dependent on bees for its pollination and pollinators help in higher yield and increased fruit set (ICIMOD 2003). Irrespective of large cardamom yield decline due to pollinator deficiency in Sikkim (Sinu & Shivanna 2007), till date there exists no systematic study on the range of pollinators for SMO.  This study aims to bridge this gap especially when a large proportion of farmers are dependent on the SMO for cash income.

Our study area spanned the East, West and South districts of Sikkim.  The southern part of the state, which lies in the altitude range of 600–1500 m provides an ideal climate for SMO cultivation (DHCCD 2015).  Data was collected across 72 SMO orchards from 2011 to 2013.  These orange orchards were selected within an altitudinal gradient of 700–1,452 m and were spread across 316km2 (Fig. 1).

Pollinator visitation: At each site, 150 flowers were tagged and observed from 08.00–17.00 h to record insect species that visit them.  Intra-floral foraging behavior of each insect species was carefully observed to note whether it is a pollinator or a forager.  SMO bear self-fertile, bisexual flowers and pollen movement is facilitated by pollinators.  Transparent plastic bags were used to trap insects visiting the flowers to avoid any fruit loss during their collection.  Collected samples were preserved in 70% ethanol and subsequently identified in the laboratory.  Insects which were not seen touching the flower reproductive parts were not collected for identification.

We recorded 24 species of insects during the study period (2011–2013).  Common Honey Bee Apis cerana was the most dominant pollinator followed by hoverflies belonging to eight genera, namely, Episyrphus sp., Melanostoma sp., Ischiodon sp., Eristalis sp., Eristalinus sp., Scaeva sp., Episyrphus sp.,and Eupeodes sp. (Image 1,2) .  This was followed by stingless bees (Hymenoptera), seed bug (Hemiptera), and beetles (Coleoptera) that were sparse visitors.  Recorded insects were both pollen and nectar feeders.  Bees (Hymenoptera) and hoverflies (Diptera) visited flowers in groups while most of the beetles and seed bugs visited individually.  All the insects landed on the petal and foraged for pollen placed on top of the flower and nectar at the flower base.  In this process all the insects invariably touch both anther and stigma of SMO flower.  An insect visitor was called a pollinator when the ventral side of insect’s body containing pollen load touched the reproductive part of flowers.

SMO is an evergreen plant showing flowering response to early monsoon shower starting in the mid of February.  Flowering period lasts for a month, from late February to early April.  Orchards in the lower altitude starts flowering earlier followed by orchards in the higher altitudes.  Flowers are white in colour with strong scent attracting a range of insects for pollination.  Highlighting the importance of pollinators of the mandarin orange, in a study conducted by the International Center for Integrated Mountain Development (2003), pollination was seen to increase the yield of mandarin orange  by  four times compared to pollinator excluded flowers.  Honey bee (Apis sp.) has been reported as a major pollinator of different varieties of Citrus sp. from across the world, for example, Mandarin orange Citrus reticulata in Nepal is pollinated by A. cerana, A. dorsata, A. florea, and A. mellifera (International Center for Integrated Mountain Development 2003).  Kinnow Citrus reticulata, a hybrid between mandarin orange and sweet lime, was reported to be pollinated by A. dorsata and A. florea in Pakistan (Manzoorul-Haq et al. 1978).  Results of our study show only A. cerana visited mandarin orange flowers, while A. dorsata or A. florea, which were recorded in other studies, were not observed even outside our experiment sites during the study period.  Hoverflies, although not reported as pollinators of mandarin oranges earlier, are known to pollinate rapeseed oil (Jauker & Wolters 2008), apple (Solomon & Kendall 1970), and strawberries (Kendall et al. 1971). Both bees and flies visited flowers in groups and visited more than one flower at a time, possibly aiding in cross/sexual pollination (Raju et al. 2012).  Visits by other taxa such as butterflies, stingless bees, and beetles to orange flowers were less in comparison to bees and flies.  However, the importance of these wild pollinators in sustaining pollination of SMO needs further exploration.

Table 1. Pollinators of Sikkim Mandarin Orange.

 

 

Order

Family

Sub family

Genus

Species

Altitude range

Forage collected

1

Coleoptera

Coccinellidae

Coccinellidae

Oenopia

kirbyi (Mulsant)

700–1400

nectar + pollen

2

 

Scarabaeidae

Rutelinae

Anomala

sp.

700–1400

nectar + pollen

3

 

 Scarabaeidae

Citoniinae

Clinteria

sp.

700–1400

nectar + pollen

4

 

Chrysomelidae

Eumolpinae

Chrysonopa

sp.

700–1400

nectar + pollen

5

 

Chrysomelidae

Galerucinae

Galerucinae

sp.

700–1400

nectar + pollen

6

Diptera

Calliphoridae

Chrysomyinae

Chrysomya

sp.

1000–1400

nectar + pollen

7

 

 Rhiniidae

Rhiniinae

Rhinia

sp.

0800–1400

nectar + pollen

8

 

Sarcophagidae

Paramacronychiinae

Wohlfartia

sp.

0800–1400

nectar + pollen

9

 

Syrphidae

 Syrphinae

Episyrphus

sp.

0800–1400

nectar + pollen

10

 

Syrphidae

Syrphinae

Melanostoma

sp.

900–1400

nectar + pollen

11

 

Syrphidae

Syrphinae

Ischiodon

scutellaris (Fabricius)

0800–1400

nectar + pollen

12

 

Syrphidae

Eristalinae

Eristalis

tenax (Linnaeus)

0800–1400

nectar + pollen

13

 

Syrphidae

Syrphinae

Scaeva

pyrastri (Linnaeus)

900–1400

nectar + pollen

14

 

Syrphidae

Syrphinae 

Eupeodes

confrater (Wiedemann)

900–1400

nectar + pollen

15

 

Syrphidae

Eristalinae

Eristalinus

taeniops (Wiedemann)

900–1400

nectar + pollen

16

 

Syrphidae

Syrphinae

Episyrphus

Viridaureus

900–1400

nectar + pollen

17

 

Syrphidae

Eristalinae

Eristalis

basifemorata(Brunetti)

700–1400

nectar + pollen

18

Hemiptera

Lygaeidae

Lygaeinae

Spilostethus

pandurus (Scopoli)

700–1400

nectar + pollen

19

 

Lygaeidae

Lygaeinae

Graptostethus

incertus (Walker)

700–1400

nectar + pollen

20

 

Largidae

Physopeltinae

Physopelta

gutta gutta (Burmeister) 

700–1400

nectar + pollen

21

Hymenoptera

Halictidae

Halictinae

Seladonia sp

sp.

700–1200

nectar + pollen

22

 

Halictidae

Halictinae

Lasioglossum

sp.

700–1200

nectar + pollen

23

 

Apidae

Apinae

Apis

cerana

700–1500

nectar + pollen

24

 

Apidae

Apinae

Tetragonula

sp.

800–1200

nectar + pollen

 

 

For figure/image  -- click here

 

References

DHCCD (2015). AgriSkm. Available from: http://sikkimagri.gov.in/General/Eng/CropsDetails.aspx?ID=23. Accessed on 22 September 2015.

ICIMOD (2003). A report:  Cash Crop Farming in Nepal: The importance of pollinator diversity and managed pollination in Citrus.    International Center for Integrated Mountain Development  Jawalakhel, Kathmandu, Nepal, 49pp

Jauker, F. & V. Wolters (2008). Hover flies are efficient pollinators of oilseed rape. Oecologia 156: 819–823. https://doi.org/10.1007/s00442-008-1034-x

Kendall, D.A., D. Wilson, C.G. Guttridge & H.M. Anderson (1971). Testing Eristalis as a pollinator of covered crops. Long Ashton Res Stn Rep 1971: 120–121.

Manzoorul-Haq, M. Rafie-ul-Din & A. Ghaffar (1978). Effect of insect pollination on fruit bearing in Kinnow mandarin (Citrus reticulata), and physical and chemical properties of the fruit. Journal of Apicultural Research 17: 47–49.

Raju, A.J.S., P.V.S. Rao, R. Kumar & S.R. Mohan (2012). Pollination biology of the crypto-viviparous Avicennia species (Avicenniaceae). Journal of Threatened Taxa 4: 3377–3389. https://doi.org/10.11609/JoTT.o2919.3377-89

Sinu, P.A. & K.R. Shivanna (2007). Pollination biology of large cardamom (Amomum subulatum). Current Science 93: 548–552.

Solomon, M.E. & D.A. Kendall (1970). Pollination by the syrphid fly, Eristalis tenax. Available online at http://agris.fao.org/agris-search/search.do?recordID=XE20122001901. Accessed on 17 September 2015.