INTRODUCTION
To date, 35,000 species of spiders have been identified
in the world and a total of 244 species of spiders are known in Iran (Ghavami,
2006a). Most of investigations on spiders are in agricultural ecosystems
in Iran. For instance, some researches were performed on the spider fauna
and abundance of rice fields (Ghavami, 2004, 2007a), olive orchards (Ghavami,
2006d; Ghavami et al., 2007c), Rose fields (Ghavami and Nematollahi,
2006) citrus orchards (Ghavami, 2006b, c) and cotton fields (Ghavami et
al., 2007d; Ghavami, 2007b).
The present study is accomplished for the first time
in Iran but in many countries have been done many studies about them.
Such as, in cotton field in South-eastern Queensland, the spider species
Cheiracanthium mordax L. Koch (Diversum L. Koch), Archaearanea
veruculata (Urquhart) and Lycosa sp. were equally distributed
in the outer, middle and inner portions. However, A. veruculata
was more abundant in the western side of the field late in the season,
apparently in response to a more favorable habitat. In sampling, the variance
was greater than the mean and over dispersion was apparent. C. mordax
and A. veruculata were most abundant in the top and one-third
of plants and Oxyopes mundulus L. Koch was evenly distributed over
plants. Among crop spacing`s, most spiders of 4 species preferred the
highest density (12 plants/m) (Bishop, 1981). Thanatus formicinus
had high population in Tando jam cotton fields. It was one of the most
effective of spider species on pests control in these fields (Rad et
al., 2002). O. salticus was dominant species in Massachusetts
cotton fields. This species were 58% of collected spider species (Bradwell
and Averill, 1997). Philodromus cespitum was one of the most abundance
predators of cotton pests in Cshinese cotton fields (Liu and Niu, 1981).
O. salticus was dominant species in Texas cotton fields (Dean et
al., 1982). C. erraticum and C. pennyi had high population
in German cotton fields (Wolf, 1990).
The aims of the present study were investigation density
of spider`s population and determination dominant spider species in the
Ardebil Golestan, Fars and Tehran provinces during 2003-2004.
MATERIALS AND METHODS
In order to establish the spider abundance of the major
cotton fields (Ardebil, Golestan, Fars and Tehran), spider specimens were
collected every week in spring, summer and autumn during 2003-2004. Localities
of collections were Aghdam, Oltan, Majidabad and Moghan in Ardebil province
and Filestan, Goltapeh, Pakdasht, Pishva, Taghi Abad, Jafar Abad, Ghasem
Abad, Gharchak and Varamin in Tehran province, Estahbanat, Darab, Fasa,
Jahrom and Neyriz in Fars province and Gonbad, Bailar, Hivehchi, Ghareghaj,
Kordkooy and Hashemabad in Golestan province.
Spiders were collected by choose 40 bushes of each cotton
fields and shaking them. The collected spiders counted and determined
rate of frequency of each species and dominant species (Rad et al.,
2002; Bradwell and Averill, 1997). The keys of Anonymous (2002), Barrion
and Litsingerm (1995), Borrer et al. (1989), Kaston (1970) and
Roberts (1985), were used for the species classification.
RESULTS AND DISCUSSION
In the present study, quantity of frequency and dominant
species of spiders inspected in Iranian major cotton fields during 2003-2004.
The examinations executed in cotton fields of 4 provinces, i.e., Ardebil,
Golestan, Fars and Tehran. A total of 632 specimens were classified in
76 species, 59 genera belonged to 19 families. Twenty seven species and
15 genera of them were new records for spider`s fauna of Iran. The abundance
of spiders considered weekly for 7 months (June to December) in each year,
too (Table 1).
The dominant spider species determined in Ardebil cotton
fields by weekly sampling. Cheiracanthium pennyi O.P. Cambridge,
1873 had the most population in these fields. This species assigned as
a dominant species in Ardebil cotton fields. The frequency percent of
that in June to December were 5, 5, 10, 15, 30, 25 and 10 in 2003 and
8, 12, 12, 16, 28, 20 and 4 in 2004 (Table 2, 3).
According to the results, spiders had the highest population
in the Ardebil cotton fields. The highest population of C. pennyi
(dominant species) and X. cristatus were in August, September and
October. These species had synchronized with the highest population of
cotton pest`s in these times. The fewest population of them were in May
and June. The highest population of the other spider species were in July,
August and September and the fewest population were in June and December.
The dominant spider species in Fars cotton fields assigned
by weekly sampling. Aulonia albimana (Walckenaer, 1805) had the
most population in these fields and it determined as a dominant species
in Fars cotton fields. The frequency percent of it was included 5, 5,
10, 15, 35, 15, 10 and 5 in May to December in 2003 and 5.71, 8.57, 11.42,
14.28, 25.71, 17.14, 11.41 and 5.71 in May to December in 2004. Arctosa
sp., Drassodes sp. and Xysticus sp. had high population
after A. albimana in these fields (Table 4, 5).
As per the results, the highest population of A. albimana,
Drassodes sp., Arctosa sp. and Xysticus sp. were in
July to October. These times had contemporary with the highest population
of pests in cotton fields. The fewest population of that were in May and
June. The
| Table 1: |
Quantity of population percent of spider`s species
in Iranian cotton fields during 2003-2004 |
 |
highest population of the other species was in July and
August and the fewest population was in May and June.
The dominant spider species in Golestan cotton fields
ordained by the weekly sampling. Neoscona adianta (Walckenaer,
1802) had the highest population in these fields and it assigned as a
dominant species in Golestan cotton fields. The frequency percent of it
was 23.33, 33.33, 16.66, 13.33, 6.66, 3.33 and 3.33 in May to December
in 2003 and 20, 33.33, 17.77, 15.55, 6.66, 4.44 and
| Table 2: |
Monthly dispersion spider`s species in Ardebil
cotton fields in 2003 |
 |
| Table 3: |
Monthly dispersion spider`s species in Ardebil
cotton fields in 2004 |
 |
| Table 4: |
Monthly dispersion spider`s species in Fars
cotton fields in 2003 |
 |
| Table 5: |
Monthly dispersion spider`s species in Fars
cotton fields in 2004 |
 |
| Table 6: |
Monthly dispersion spider`s species in Golestan
cotton fields in 2003 |
 |
2.22 in May to December in 2004. C. erraticum
(Walckenaer, 1802) and Theridion sp. had high population in these
fields after Neoscona adianta (Table 6, 7).
According to the results, the highest population of dominant
species (N. adianta) and other spider species in Golestan cotton
fields were in June to August. These times had concurrent with the highest
population of pests in cotton fields. The fewest population was in November
and December. The highest population of the other species was in August
to October and the fewest population of them was in December.
The dominant spider species in Tehran cotton fields considered
by weekly sampling. Thanatus formicinus (Clerck, 1757) had the
highest population in these fields and assigned as a dominant species
in Tehran cotton
| Table 7: |
Monthly dispersion spider`s species in Golestan
cotton fields in 2004 |
 |
| Table 8: |
Monthly dispersion spider`s species in Tehran
cotton fields in 2003 |
 |
fields. The frequency percent of it was in May to December
and were included 1.66, 2.11, 5.33, 7.22, 13.45, 7.12 and 3.44 in 2003
and 2.03, 7.45, 10.23, 15.65, 8.38 and 5.34 in 2004, respectively. C.
erraticum, Oxyopes salticus (Hentx, 1802), Philodromus cespitum
(Walckenaer, 1802) and Thyene imperialis (Rossi, 1846) had high
population in these cotton fields after T. formicinus (Table
8, 9).
As per results, the highest population of T. formicinus
(dominant species) and C. erraticum, Oxyopes salticus (Hentx, 1802),
Philodromus cespitum (Walckenaer, 1802) and Thyene imperialis
(Rossi, 1846) in Tehran cotton fields were in September to November. These
times had synchronized with the highest population of pests in cotton
fields. The fewest population of spider species was in July, August and
December. The highest population of the other species was in August and
September and the fewest population was in December.
According to the results, O. salticus had high
population in Tehran cotton fields. Also, it was in Ardebil cotton fields.
This species was one of the dominant species in Texas and Massachusetts
cotton fields too (Dean et al., 1982; Bradwell and Averill, 1997).
T. formicinus was dominant species in Tehran province. It was in
Golestan cotton fields, too. This
| Table 9: |
Monthly dispersion spider`s species in Tehran
cotton fields in 2004 |
 |
species was one the most abundance spider species in
Tando Jam cotton fields (Rad et al., 2002). P. cespitum
had high population in Tehran cotton fields. It was in Ardebil cotton
fields, too. Also, it had high frequency in Chinese cotton fields (Liu
and Niu, 1981).
According to the results, spiders and cotton pest`s were
appearance in the same time and when the pest population was height spider`s
population were height, too. Spiders, specially the dominant spider species
had an important role in reduce of cotton pest`s population.
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