species distribution of spiders in barpeta district of assam: a diversity measure

E-International Scientific Research Journal, VOLUME – IV, ISSUE- 1, 2012, ISSN 2094-1749

47

SPECIES DISTRIBUTION OF SPIDERS IN BARPETA

DISTRICT OF ASSAM: A DIVERSITY MEASURE.

Suruchi Singh 1, A. Borkotoki

2 and C. K. Sarmah

3

1. Assistant Professor, Dept. of Zoology, B.H. College, Howly, Barpeta, Assam.

2. Retd. Professor, Dept of Zoology, Gauhati University, Assam.

3. Assistant Professor, Dept. of Statistics, B. H. College, Howly, Barpeta, Assam.

Author for Correspondence: [email protected]

ABSTRACT:

The study of spider fauna of state Assam has not been comprehensively carried out. Our present

work has been an attempt to provide relevant information regarding spiders, which would be the

baseline documentation for the future studies in the state Assam or for Northeastern part of the

nation. The study area, Barpeta district of the state Assam, lies between Latitudes 2605’ N to

26049’ N and Longitudes 90

039’E to 91

017’E covering an area of 3245 sq Km. A survey was

carried out during June 2008 to May 2011 in different ecosystem of this area to assess the spider

diversity. Many specimens were collected by visual search methods and preserved in 70% ethyl

alcohol .The specimens were identified in Zoological Survey of India, Kolkata. This paper has

been started with the spider distribution in the district and concluded with the alpha, beta and

gamma diversity estimation. It is documented that 69 spider species from different habitats of the

different blocks of Barpeta District.

Keywords: Barpeta, spider distribution, diversity estimation, web.

INTRODUCTION:

Northeastern region of India is one of the richest hotspots of the world, has remained poorly

explored, and much of its diversity is being lost without any record. Spiders, of class Arachnida,

order Araneae under Phylum Arthropoda, vary considerably in size, shape and behavior. The

basic characteristics shared by them are- body divided into cephalothorax and the abdomen,

presence of eight legs (made up of seven segments each) and pedipalps, capacity to produce silk

and possess no antenna. They are identified for their webs and web silk with future prospects. All

spiders can make silk but many don’t spin web, they may use the silk to wrap the prey, to hang

from and to make egg sacs and nests. They are ubiquitous in terrestrial ecosystems and abundant

in both natural and agricultural habitats (Turnbull, 1973; Nyfeller & Benz, 1987). They play a

significant role in the regulation of insect and other invertebrate populations in most ecosystems

(Wise, 1993; Russell-Smith, 1999; Raghavendra, 2001).Spider surveys may provide an effective

means for measuring the impact of habitat degradation or land use change on biodiversity.

Baseline studies involving spiders as biological indicators have been conducted elsewhere; e.g.

Allred (1969) and Allred & Gertsch (1976) documented spider diversity in Arizona and Utah

after new power plant installations and in Nevada at the Nevada Nuclear Test Site. In spite of


48

several applied values, spiders have received cursory attention. In conservation efforts, often

“charismatic” species like birds and mammals draw most attention and ecological significant

groups like spiders are often neglected. Ironically, the spider diversity in Assam is still not fully

explored or understood. Manoranjan Barman (Barman, 1975, 1979) has done a work on spider of

Khasi and Jantia hills of Meghalaya, N.E. region in seventies of last century. B.K.Tikader

(Tikader,1970) and B.K.Biswas (Biswas,2000a,b,2003,2004,2006,2007) also collected some

information on diversity of spiders of Northeastern states like Tripura, Meghalaya, Sikkim ,

Manipur, Arunachal Pradesh and Mizoram except Assam. As spiders species of Assam are

poorly documented & no research has been done so far for the applied use of spider & its related

product in this region. The proposed study was carried out with the objectives to document the

spider diversity of Barpeta District of Assam.

Objective:

The present study has been carried out with the objective of documentation of the spider fauna of

Barpeta District of the state Assam through quantification of spider density and diversity

estimation.

Study Time:

The study was carried out during the year June 2008 to May 2010. The year was divided into

four seasons - June to September, October to November, December to February and March to

May. Most collection were made between the hours of 9 A.M. to 6 P.M. Sampling occurred

under suitable weather conditions for spider collection, temperatures between 15–38 °C.

Sampling:

Visual search sampling methods used by Sebastian et al. (2005) was adopted in this study to

sample the spider fauna from selected study sites. Random sampling was done from the same

selected study sites in all the seasons. A total of 36 hours was spent in each site across the four

seasons. We have taken all 10 political blocks of the district and in each block’s 3 plots were

selected. As a whole, we have divided whole district in 30 different plots. Each plot is again

divided into 4 different types of habitat i.e. Grassland cum bushy, Marshy, Residential and

agricultural area.

COLLECTION METHODS:

The following collection methods carried out according to Coddington et al. (1991); Toti et al.

(2000) -

1) Aerial hand collection i.e. collecting spiders found above knee level for that a sweep net was

used to capture spiders seen high in the vegetation.

2) Ground hand collection i.e. collecting spiders found below knee level in the vegetation or leaf

litter.


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3) The beat-sheet method of collection performed by stretching out a light-colored cloth under

the tree branch or other low vegetation and grabbing the branch and shaking it vigorously.

Spiders resting or nesting in this vegetation fall onto the cloth.

Preservation technique:

The spiders collected from each site was preserved together in 70% ethyl alcohol with proper

labeling of locality, date of collection and other notes of importance.

Identification:

The preserved specimens were observed under a stereo-zoom microscope for some of its minute

characteristics. The spiders were identified to the species level except the immature ones, which

could be identified only to the generic level. All specimens were identified in Zoological Survey

of India, Kolkata and with the help of available literature like Handbook of spiders’ by

B.K.Tikadar(1987) and ‘Spiders of India’ by P.A.Sebastian and K.V.Peter(2009).

RESULTS AND DISCUSSION:

The percentage distribution of spider family in the Table 1 tells us that the Araneidae spider

family is found significantly in Barpeta district contributing 28.14% of the total spider family

found in the district, whereas the spider family Hersilidae being almost rare in the district. From

the Table 2 we observed that Barpeta Block of the district consist of large number of individuals

of spider i.e.14.20% and Bhabanipur showing only 6.02% of individual 0f observed spider.

From the Table 3 of percentage distribution of spider species found in Barpeta district, we have

observed that Argiope pulchella, the spider species are significantly available covering 11.96%

of the total spider population in the entire district. On the other hand the spider species like

Asemonea tenuipes, Olios milleti, Argyrodes argentatus, Argyrodes gezedes and Misumena

chrysanthemi are found to be almost rare in the district just covering 0.09% contribution to the

spider families. The Pie diagram (refer to Figure 1) given below shows that more than half of the

total species observed in the Barpeta district are web less spider. Almost one/3rd

of the observed

spiders is Orb weaver.

Table 4 reveals that spider of Araneidae family are found in large number as residential habitat.

Whereas the families Tetragnathidae, Lycosidae etc are found widely as wild spider in the

district Barpeta. More over a few numbers of marshy spiders are also found in the district. From

the Figure 2 (bar diagram) shown below we have observed that wild spiders are found in large

scale than domestic spiders and a few no. of marshy spiders are found in the district.

From the table 5 we have found that Aerial collecting method of spider is more significant than

all other trapping techniques. By Aerial method, we have collected more than half of the sample

spiders in our study.


50

From the table 6, we found that maximum families and species were abundant during the

summer season and least during monsoon and winter. Thus, clarifies that they are more active

during summer.

Alpha diversity usually expressed as species diversity or number of species (diversity) of a

particular area or ecosystem. The table 7 shows that Block 2 (Rupsi) is rich in spider species with

alpha diversity as 56 whereas the Block 3(Bajali) and Block 4 (Bhabanipur) consist of least

spider species with alpha diversity calculated as30 and 29 respectively. Beta diversity is the total

number of species unique to each area or ecosystem, when compared with between them. The

table 8 shows that the beta diversity is more when comparison is done between Block 2/3

(Rupsi/bajali) i.e. 28 and least in Block 6/7(Mandia and Jamaphulbari) with 6. Table 9 below

shows that Gamma diversity is the measure of overall diversity of the region i.e. the total number

of spider species in the Barpeta District of Assam is 69.

Table 10 shows that the number of species found per sample unit are 0.58, which shows workers

effectiveness.

CONCLUSION:

From the results and data, a preliminary status of spiders in Barpeta district of Assam is much

clear. The study documented 69 species of spiders and highest of Araneidae family with Argiope

pulchella as the dominant species. The largest individuals collected were in summer season. The

spider weaving orb webs are in majority among web weavers. Rupsi block recorded highest

number of species. There is an urgent need for updating the database. Exploration of species

diversity understanding the habitat ecology, behaviour, etc. culminating into a database for the

Assam is an imperative.

Acknowledgement:

Our sincere thanks to the Director, Zoological Survey of India, Kolkata for granting permission

to do the taxonomic works with Dr. A. K. Sanyal, S. Talukdar and Dr. B. K. Biswas, utilizing the

facilities there.

REFERENCES:

Allred, D.M. 1969. Spiders of the National Reactor Testing Station. Great Basin Naturalist

29:105-108.

Allred, D.M. and W.J. Gertsch. 1976. Spiders and Scorpions from northern Arizona and

northern Utah.Journal of Arachnology 3: 87-99.

Barman, M. (1975).Studies on Spider fauna of Khasi and Jantia Hills.(Aranea:Arachnida),

PhD Thesis, Department of Zoology, Gauhati University.


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Barman, M. (1979). Studies on some spiders of the genera Tegenaria and Agelena from

Khasi and Jaintia hills,India (Araneae: Agelenidae).Journal of the Bombay Natural History

Society. 75:454-457.

Biswas, B. & S.C.Majumder 2000a. Arachnida: Araneae. Fauna of Tripura (Part-2), State

Fauna Series7, Zoological Survey of India. 113-122.

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Fauna Series 4, Zoological Survey of India. 93-128.

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Series 9, Zoological Survey of India. 67-100.

Biswas, B. & K. Biswas 2004. Araneae: Spiders. Fauna of Manipur, State Fauna Series 10,

Zoological Survey of India. 25-46.

Biswas, B. & K. Biswas 2006. Araneae: Spiders. Fauna of Arunachal Pradesh, State Fauna

Series 13(Part-2), Zoological Survey of India. 491-518.

Biswas, B. & K. Biswas 2007. Araneae: Spiders. Fauna of Mizoram, State Fauna Series 14,

Zoological Survey of India. 455-475.

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testing sampling protocols to estimate biodiversity in tropical ecosystems. Pp. 44–60. In The

unity of evolutionary biology: Proceedings of the Fourth International Congress of

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Oregon.

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Entomology 103:321–329.

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dissertation, Department of Applied Zoology, Mangalore University.

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Mkomazi: The ecology, biodiversity and conservation of a Tanzanian savanna. Royal

Geographical Society, London.

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Journal of Arachnology 33:247–255.

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64:1-83


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Tikader, B .K. 1987. Handbook of Indian Spiders, Zoological Survey of India, Calcutta,

India.

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Entomology 18:305–348.

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(Proceedings of the Oklahoma Academy of Science. Volume 56— 1976)

Table 1: Percentage distribution of spider on the basis of their family

Sl.No. Family Percentage abundance of different families

1. Araneidae 28.14

2. Hersiliidae 0.17

3. Linyphiidae 1.98

4. Lycosidae 11.45

5. Nephilidae 0.95

6. Oxyopidae 12.65

7. Philodromidae 0.34

8. Pholcidae 10.24

9. Pisauridae 4.22

10. Salticidae 17.82

11. Sparassidae 4.39

12. Tetragnathidae 4.39

13. Theraphosidae 0.26

14. Theridiidae 2.32

15. Thomicidae 0.34

16. Uloboridae 0.34

Total 100


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Table 2: Percentage distribution of the individual spider by block of the district.

Sl.No. Name of the Block Percentage of the individual

1 Gobardhana 13.08

2 Rupsi 15.49

3 Bajali 9.90

4 Bhabanipur 6.02

5 Paccabetbari 7.74

6 Mandia 7.5

7 Jamaphulbari 8.7

8 Chenga 7.05

9 Sorukhetri 10.32

10 Barpeta 14.20

Table 3: Percentage distribution of spider species found in Barpeta Dist.

Sl.no. Species % of

species Sl.no. Species

% of

species

1 Araneus mitificus 1.72 36 Smeringopus pallidus 0.34

2 Araneus inustus 3.18 37 Uthina atrigularis 0.17

3 Argiope aemula 2.15 38 Perenethis venusta 1.98

4 Argiope anasuja 1.38 39 Polyboea vulpine 0.34

5 Argiope catenulate 0.34 40 Thalassius albocinctus 1.89

6 Argiope pulchella 11.96 41 Asemonea tenuipes 0.09

7 Cyclosa bifida 0.17 42 Carrhotus viduus 0.86

8 Cyclosa confraga 0.34 43 Epeus tener 0.52

9 Cyclosa

hexatuberculata 0.6 44 Hasarius adansoni 3.1

10 Cyclosa spirifera 0.52 45 Hyllus semicupreus 0.26

11 Cyrtophora cicatrosa 0.52 46 Menemerus bivittatus 0.52

12 Cyrtophora moluccensis 0.6 47 Phidippus yashodharae 0.6

13 Gasteracantha kuhli 0.6 48 Plexippus paykulli 5.16

14 Neoscona mukerjei 3.79 49 Plexippus petersi 4.32

15 Parawixia dahaanii 0.26 50 Telamonia dimidiate 2.41

16 Hersilia savignyi 0.17 51 Heteropoda leprosa 0.69

17 Lepthyphantes sp. 1.03 52 Heteropoda nilgirina 1.8

18 Lynyphia striata 0.95 53 Heteropoda venatoria 1.8

19 Lycosa mackenziei 2.84 54 Olios milleti 0.09


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20 Lycosa tista 1.64 55 Leucauge decorate 2.75

21 Pardosa birmanica 3.18 56 Leucauge tessellata 1.12

22 Pardosa

pseudoannulata 1.46 57 Tetragnatha javana 0.17

23 Pardosa sumatrana 2.32 58 Tetragnatha

andamanensis 0.17

24 Herrennia multipuncta 0.26 59 Tetragnatha mandibulata 0.17

25 Nephila kuhlii 0.34 60 Ischnocolus khasiensis 0.26

26 Nephila pilipes 0.34 61 Achaearanea 0.17

27 Oxyopes birmanicus 3.96 62 Argyrodes andamanensis 0.26

28 Oxyopes javanas 2.15 63 Argyrodes argentatus 0.09

29 Oxyopes lineatus 1.81 64 Argyrodes flavescens 0.09

30 Oxyopes shweta 2.5 65 Argyrodes gezedes 0.09

31 Oxyopes sunandae 2.24 66 Theridion manjithar 1.64

32 Tibellus elongates 0.34 67 Camaricus formosus 0.26

33 Artema Atlanta 2.32 68 Misumena chrysanthemi 0.09

34 Crossopriza lyoni 6.11 69 Uloborus danolius 0.34

35 Pholcus phalangioides 1.3 Total 100

Table 4 : Proportion distribution of spider families

on the basis of their habitat

Family

Habitat Proportion of

observed

individuals residential agricultural jungle marshy

Araneidae 0.40 0.17 0.34 0.09 0.281

Nephilidae - - 1.0 - 0.009

Tetragnathidae 0.08 0.31 0.55 0.06 0.044

Uloboridae 1.0 - - - 0.003

Hersiliidae - - 1.0 - 0.002

Oxyopidae - 0.56 0.44 - 0.127

Philodromidae - - 1.0 - 0.003

Thomicidae 1.0 - - - 0.003

Pisauridae 0.04 0.12 0.41 0.43 0.043

Salticidae 0.21 0.27 0.41 0.11 0.178

Sparassidae 0.55 - 0.45 - 0.044

Lycosidae 0.10 0.11 0.64 0.15 0.114

Theraphosidae - - 1.0 - 0.002

Theridiidae 0.07 - 0.93 - 0.023

Pholcidae 0.54 0.03 0.43 - 0.103

Linyphiidae 0.26 - 0.74 - 0.021

Total - - - - 1.00


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TABLE 5: NUMBERS OF INDIVIDUALS, ADULTS AND SPECIES OF ADULT

SPIDERS ACCORDING TO THE COLLECTING METHOD.

Collecting

Methods

No. of

sampl

e

units

No.of

adults

Mean no.

of adults

per sample

unit

% of

total

adults

No.of

species

Mean No.

of species

per

sample

unit

% of

total

species

Aerial 120 525 4.375 45.18 39 0.33 56.52

Ground 120 477 3.975 41.05 28 0.23 40.58

Beating 120 160 1.333 13.77 26 0.22 37.68

Total 120 1162 9.683 100 69 0.58 100

Table 6: Status on different collecting seasons

Sl.

No.

Collecting

Seasons

No. of

families

% of

family

No. of

species

% of

species

No. of

Observed

individuals

% of

individuals

1 Monsoon 11 68.75 26 37.68 84 7.23

2 Post-

Monsoon

15 93.75 57 82.61 430 37.00

3 Winter 10 62.5 23 33.33 63 5.42

4 Summer 16 100 69 100 585 50.34

TOTAL - - - - 1162 100

Table 8: Beta diversity estimates of spider species in the Blocks of Barpeta district.

Diversity

Indices

Blocks of Barpeta District

1 2 3 4 5 6 7 8 9 10

Beta

Diversity

1/2=17 2/3=28 ¾=11 4/5=15 5/6=16 6/7=6 7/8=10 8/9=11 9/10=16 10/1=17

Table 9: Gamma diversity estimates of spider species in the Blocks of Barpeta district.

Diversity

Indices


1 2 3 4 5 6 7 8 9 10

Gamma Diversity 69

Table 7: Alpha diversity estimates of spider species in the Blocks of Barpeta district.

Diversity

Indices


1 2 3 4 5 6 7 8 9 10

Alpha Diversity 54 56 30 29 36 36 34 34 37 46

E-International Scientific Research Journal, VOLUME

Figure 1: Showing proportion of spider on the basis of web characteristics

52%

Diagram represents spider proportion on

the basis of web characteristics

Table 10 : Worker’s Effectiveness

No. of

sample

unit

No. of adults

collected

120 1162

Scientific Research Journal, VOLUME – IV, ISSUE- 1, 2012, ISSN 2094

proportion of spider on the basis of web characteristics

34%

2%

12%

Diagram represents spider proportion on

the basis of web characteristics

Orb weaver

Sheet weaver

Irregular weaver

Webless

Table 10 : Worker’s Effectiveness

No. of adults No. of

species

No. of adults per

sample unit

No. of species per

sample unit

69 9.7 0.58

1, 2012, ISSN 2094-1749

56

proportion of spider on the basis of web characteristics

Orb weaver

Sheet weaver

Irregular weaver

Webless

No. of species per

sample unit

E-International Scientific Research Journal, VOLUME

Figure 2: Represents the proportion of spider families in different habitat.

Scientific Research Journal, VOLUME – IV, ISSUE- 1, 2012, ISSN 2094


1, 2012, ISSN 2094-1749

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species distribution of spiders in barpeta district of assam: a diversity measure

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