Diversity Of Spider Fauna In Backyard Rice AgroecosystemSumana Saha1a, Ampita Bhadra1b, and Dinendra Raychaudhuri2c

1Post Graduate Department of Zoology, Barasat Government College, 10, K.N.C. Road, Barasat, Kolkata – 7000124, India 2IRDM Faculty Centre, Department of Agricultural Biotechnology, Ramakrishna Mission Vivekananda University, Narendrapur, Kolkata – 700103, India

IntroductionPaddy is grown mostly in the warm and humid environment under diverse culturalconditions over a wide geographical range (Dale, 1994). It is distributed in different parts of the world from 39oS (Australia) to 50oN latitude(China). In India, it extends from 8oN to 34oN latitude under varying climatic conditionsranging from below the sea-level as in Kuttanad region of Kerala to altitudes above2000m as in parts of Jammu & Kashmir. Depending on the pattern of rainfall distribution, it is cultivated as rain-fed uplandcrop in Jharkhand, Chhattisgarh, Orissa and parts of West Bengal. On the contrary, it is also grown in shallow (upto 30 cm), semi-deep (30-100 cm)and deep water (1-6 cm) ecosystem in eastern Uttar Pradesh, Bihar, West Bengal,Assam and Orissa.A tropical rice land offers a biologically diverse and dynamic environment formicrobial, floral, invertebrate and even vertebrate populations to flourish shortly afterfields are flooded and continuing well after canopy enclosure (Settle et al., 1996;Schoenly et al. 1998). Insect pests are recognized as major biotic stress responsible for significantreduction in yield in different system zones of India (Chelliah et al., 1989). There are over 1400 insect species attacking paddy in the world (Grist & Lever,1969), of which 20 species are of major importance and of regular occurrence (Dale,1994). Usage of different chemical pesticides in various agricultural systems like rice landsis rather a common practice across the globe. This is supposed to be the most effective measure of pest control as of today despiteknowing their ill effects.In a stable ecosystem, the natural enemies particularly predators are recorded aspotential weapon to regulate the rice insect pest (Baltazar, 1963; Gabriel 1978 andChandra 1979). The predators are responsible to bring 95% mortality on plant hoppernymphs (Anonymous, 1979).

Different growth stages of rice

Seedling bed Plantation Tillar

FloweringPanicle FormationMaturity

Spiders as a Biocontrol Agent in Paddy Fields

Spiders, the predatory fauna in rice fields act as biocontrol agents in regulation ofinsect pests (Lee & Kim, 2001; Vinothkumar , 2012; Anitha & Vijay, 2016; Joseph &Premila, 2016; Chandra & Singh, 2017; Bao, 2018; Basu, 2019).It is reported that 80% of the total predatory community is represented by the spidersin the rice fields (Wang, 1985).They are the magical gift of nature to farmers for suppressing the insect-pestpopulation in rice fields (Singh et al., 2005).Spiders are obligate carnivores and hold the unique position of being the only largepart of the predatory arthropod fauna of rice ecosystem and prey upon plant and leafhoppers, dipterans mainly whorl maggot and stem borer (Barrion & Litsinger, 1980;Pantua et al., 1980).

Spiders are omnipotent or ubiquitous

Numerous and dominant

Generalist predators in both agricultural and natural ecosystem

Exert considerable top down control

Potential to both lower and stabilize pest population

Special features of predatory behaviour

Ability to kill prey even in their absence, by the web only

Mortality of non-consumed prey in the web

Wasteful killing or partial consumption of prey by hunting spiders

Specific adaptations for matching with the background such as-leaves, flowers,

twigs, grass, bark, etc.

Weekly survey is conducted during August to November, 2019 (kharif season) in therice fields of the study area.

▶ Sampling is done by hand picking, bush beating, sweeping & using inverted umbrella.

▶ Samples are killed and preserved in 70% alcohol as per recommendation of Tikader

(1987) and Barrion & Litsinger (1995).

▶ The materials are studied using Stereo Zoom Binocular Microscope, model Olympus

SZX-16. The measurements are in millimeters, made with an eye piece graticule.

▶ Materials are in the deposition of Post Graduate Department of Zoology, Barasat

Government College, Barasat, Kolkata.

SAMPLING TECHNIQUES

Inverted umbrella

Visual search

Hand picking Bush beating Foliage, trunk & Branch sampling

Sweeping

0

1

2

3

4

5

6

2 2

1

6

1 1

4

7. 44%

6.37%

3.19% Ambushers

Ground Runners

Orb Web Weaver

Different functional guilds of spider taxa recorded from study areas

Families Guilds

Araneidae,

Tetragnathidae

Orb Web Weavers

Clubionidae, Oxyopidae,

Sparassidae, ThomisidaeAmbushers

Salticidae Ground Runners

Results

No. of spider taxa recorded from study area

No. of Family - 7No. of Genera – 16No. of Species – 17

No. of Individuals – 66(♀) + 6(♂)

Why Spiders ?

Aim of Study

To generate data-base on the diversity spectrum of spiders in the rice agroecosystem

Materials & Methods

Study Area

Ramakrishna Mission Vivekananda Educational & Research

Institute (22.44°N Latitude, 88.4° E Longitude)

Till date the survey resulted in the record of a total of 17 species under 16 generadistributed over 7 spider families.Spiders are encountered in the field during maturity stage of paddy when pests attaintheir peak.Among spiders family Salticidae is the most dominant group.Analysis of their zoogeographical distribution reveals that the fauna apart from beingOriental also includes some Ethiopian (17.65%), Australian, Neotropical and Palaearctic(each 11.76%) and Nearctic (5.88%) elements.Dominant guild is constituted by the Ambushers (7.44%) followed by Ground Runners(6.37%) and Orb Web Weavers (3.19% ).Ranking sequence of most abundant four species are [in descending order] : Oxyopesshweta (34.72%) > Plexippus paykullii (13.89%) > Camaricus formosus (12.50%) > Rhenedecorata (9.72%).Sex ratio (♀ : ♂) is around 11 : 1. Availability of food/season and/or cannibalism maybe the factors for female dominated society.It is presumed that foraging and competition compel the spiders to float across the longdistance in air by ballooning and gets rehabilitated to begin the life cycle afresh.Therefore, flow of the wind may determine the richness, diversity and distribution of the spider fauna at large.

Acknowledgements

The authors express their deep sense of gratitude to The Hon’ble Vice Chancellor, Ramakrishna Mission Vivekananda Educational and ResearchInstitute (RKMVERI), Narendrapur and The Principal, Barasat Government College for necessary logistic support.

Family-wise richness of species

Observations

Rice pests encountered during field survey for spiders

Egg mass of Rice Stem Borer [Scirpophagaincertulas (Walker)]

Rice Gandhi Bug [Leptocorisa

varicornis (Fabricius)]

Caterpillar of Rice Stem Borer [Scirpophagaincertulas (Walker)]

Rice Weevil

Adult Click BeetleRice Grasshopper Nymph

Spiders encountered during field survey

Spiders encountered during field survey

Summary

Literature Cited1.Anitha, G. & Vijay, J. 2016. Quantification of the abundance and diversity of predatory spiders in rice ecosystem of Rajendranagar, Telangana, India. J. Appl. Nat. Sci. 8 (2): 1010 –1014.2.Barrion, A.T. & Litsinger, J.A. 1980. Taxonomy and bionomics of spider in Philippine rice agro ecosystem: foundations future biological concept effort. Paper presented at the 11thannual conference of the pest control council of Philippine Cebu city, Philippines. April 23 -26; 1980 pp.3.Bao, L., Ginella, J., Cadenazzi, M., Castiglioni, E., Martínez, S., Casales, L., Caraballo, M., Laborda, Á. & Simo, M. 2018. Spider assemblages associated with different crop stages ofirrigated rice agro ecosystems from eastern Uruguay. Biodiversity Data Journal 6 : e24974.4.Chelliah , S., Bentur, J.S. & Rao, P. S. 1989. Approaches in rice pest management - Achievements and oppurtunities. Oryza, 26 : 12-26. 5.Lee, J. H. & Kim, S.T. 2001. Use of Spiders AsNatural Enemies to Control Rice Pests in Korea. Vol 501 of Extension bulletin : Ya-Tai-Liangshi-Feiliao-Jishu-Zhongxin, Publ. : Food and Fertilizer Yechnology Centre : 13 pp.5. Pantua, P., and Litssinger, J.A. 1980. Comparison of insect pest and natural enemy abundance in weekly and biannual rice cropping systems. IRRI Saturday Seminar, May 31, 1980.Los Banos Philippines. 21 p.6.Schoenly , K.G., Justo, H.D., Barrion, A.T., Harris, M.K. & BoHrel, G.D. 1998. Analysis of invertebrate biodiversity in Phillippines farmers irrigated rice field. Environ. Entomol., 27 :1125-1136.7. Settle, W.H., Ariawan, H., Triastute, E., Cahyana, W., Hakrin, A.L., Hindyana, D., Srilestari, A., Pajarningsin, S. 1996. Managing tropical rice pests through conservation of generalistnatural enemies. Ecology, 77 : 1975-1988.8. Singh, R.B., 2005. Prevalance and compositions of different spiders and of land rice ecosystems. J. Plant Prot. Envrion, 2(1):41-45.9. Swaminathan, M.S., and Siddiq, E.A. 1991. Rice pest management in India. Shell Agric., 10:30-33.10.Tikader, B. K. 1987. Hand book of Indian spiders. Ed. Director Zool. Surv. India, Calcutta : 251 pp.11. Vinothkumar, B. 2012. Diversity of spider fauna in upland rice agroecosystem at Gudalur valley in Tamilnadu. J. Biol. Control, 26 (3): 222–229.12. Wang, J.G., 1985. A preliminary investigation of spiders in paddy fields in Shoanxi. Natural Enemies insects, 7(4):189-91(c. f. Rice Abstr, 10(6): 273, 1987).

Clubiona sp. 1 ♀ Clubiona sp. 2 ♂

Oxyopes shweta (Tikader) ♀

Family : Oxyopidae

Family : Clubionidae

Family : Araneidae

Cyclosa spirifera Simon♀ Neoscona theisi (Walckenaer)♀

Hyllus semicupreus(Simon) ♀

Plexippus paykulii(Audouin) ♀

Rene decorata Tikader ♀

Family : Salticidae

Phintella vittata (C.L.Koch) ♀Carrhotus viduus (C.L.Koch) ♀

Thiana bhamoensis Thorell♀

Runcinia insecta (L.Koch) ♀ Thomisus sikkimemsisTikader♀

Xysticus sp.♀

Family : Sparassidae

Olios sp.♀ Leucauge decorata(Walckenaer) ♀

Family : Tetragnathidae

Family : Thomisidae

Camaricus formosusThorell ♀

Family : Thomisidae

Ground runnerOrb -weavers

Ambusher