The Difference Between Organic and Conventional Cultivation on Biodiversity Activity of Spiders (Araneae) in Chamomile and Chrysanthemum in Fayoum Governorate, Egypt

Citation: Egypt. Acad. J. Biolog. Sci. (A. Entomology) Vol.9 (4)pp. 8395 (2016) Egyptian Academic Journal of Biological Sciences is the official English language journal of the Egyptian Society for Biological Sciences, Department of Entomology, Faculty of Sciences Ain Shams University. Entomology Journal publishes original research papers and reviews from any entomological discipline or from directly allied fields in ecology, behavioral biology, physiology, biochemistry, development, genetics, systematics, morphology, evolution, control of insects, arachnids, and general entomology. www.eajbs.eg.net Provided for non-commercial research and education use. Not for reproduction, distribution or commercial use.


INTRODUCTION
The organic farming systems are the extreme expression of low-input agriculture in the UK (Feber et al., 1998).Such systems could potentially sustain longer or more diverse spider communities than more intensive farming systems because of the absence of agrochemical use and the typically more complex crop rotations within the system.For example, Gluck & Ingrish (1990) showed that intensively farmed fields had fewer spider species, and lower activity of Lycosidae, than bio-dynamic fields.
Chamomile [Matricaria chamomilla] and Chrysanthemum [Calendula officinalis] are considered medically beneficial plants, and they have many medical benefits for humans.The active substances extracted from them are used in the pharmaceutical, food, detergent, perfume and cosmetic industries.These plants are considered the most dominant medicinal and aromatic plants cultivated in Fayoum Governorate, the first producer of these crops in Egypt.According to the latest registered data of 2015, the "feddan" area cultivated in Fayoum yields (ton/fed.)0.830 & 15.373 and production (ton) 7308 & 7256 for Chamomile and Calendula, respectively.
Our study aimed to characterize the spider communities of organic and conventional Chamomile and Calendula in Fayoum (Egypt) and quantify the differences which might exist between the spider assemblages of the two systems.
We discuss the implications of any differences for spider conservation in contrasting arable systems.

Study area:
A field experiment of 2400m 2 in two different regions in Fayoum Governorate for organic and conventional management was conducted.Each region was divided into two equal plots (600m 2 each) cultivated with two medicinal plants, Chamomile, Matricaria chamomilla, and Chrysanthemum, Calendula officinalis.
The organic plots were fertilized with compost and no sprays were used, while the conventional plots were treated with inorganic fertilizers and sprayed with pesticides when appropriate.

Sampling method:
Spiders were sampled in organic and conventional fields at each site after two weeks of transplantation, using pitfall trap method as described by Slingsby & Cook (1986) and Southwood and Henderson (2000).Although experiments have shown that pitfall trap catches can be affected by a number of factors such as differing activity rates and habitat structure (Topping, 1993;Topping & Sunderland, 1992), pitfall trapping is nonetheless a valuable and widely used method of investigating the activity of surface-dwelling invertebrates (e.g., Luff & Eyre, 1988;Merrett & Snazell, 1983), as long as the results are interpreted in terms of catch size and composition rather than mean densities.
Pitfall trapping was conducted at the end of October in two seasons and continues to the last week of March .Ten pitfall traps (plastic cups of 7 cm diameter, 8 cm deep) were placed in each of the fields under study, these traps were left for 24 hours.Samples were taken every ten days, stored in a 70% ethanol solution with some droplets of glycerin during sorting and identification to species level as much as possible.

Frequency and abundance values:
The frequency values of the most abundant species were classified into three categories according to the system adopted by Weis Fogh (1948); "Constant species" (C) more than 50% of the samples, "Accessory species" (Ac) 25-50 % of the samples and "Accidental species"(A) less than 25%.

Species diversity:
The biodiversity of ground spiders fauna collected were estimated by using equilibrium.Diversity of collected spiders was determined for samples pooled over two seasons by two different patterns of fertilization.It was measured by diversity index that reflected the number of species (richness) in the samples.
Two common indices were computed, Shannon-Wiener index "H" and Simpson index "S", and i calculated as described by Ludwig & Reynolds (1988).
Where ni is the number of individuals belonging to the i th of "S" taxa in the sample and "n" is the total number of individuals in the sample."H" is more sensitive to changes in number of species and diversity, while "S" is a dominance index gives more weight to common or dominant species (Ludwig & Reynolds, 1988); it highly suggests that the two individuals drawn at random from the population belong to the same species.If the result is high then the probability of both individuals belonging to the same species is high, and as a result the diversity of the community samples might be low.

Sørensen quotient of similarity:
To allow a comparison of the two samplings between microhabitats of the two cultivation systems, Sørensen's quotient of similarity (Sørensen, 1948) was used to determine the similarities of spider species composition among the communities, it is: QS = 2 C / A + B.
Where A and B are the number of species in samples A and B, respectively, and C is the number of species shared by the two samples; QS is the quotient of similarity and ranges from 0 to 1.
The Gnaphosidae were well represented by Micaria dives and Zelotes laetus.The recorded numbers were 92 and 50 individuals during the study, respectively.
When both sampling data were combined, one species, Dictynid sp.1 (Dictynidae), was not recorded in first season.
Also in Table (2) results show that a total of 97 & 118 spider individuals were caught in the Chamomile conventional cultivation in two seasons, respectively.These species were classified in 9 & 8 families and 15 & 15 species in two seasons, respectively.Juveniles comprised 6.2% & 18.6%, while adults averaged 93.8% & 81.4% in two seasons, respectively.
When both sampling data were combined, one species, Dictynid sp.1, disappeared in first Chamomile conventionally farmed field, also in second season in the same field, one species, Nurscia albomaculata, was not recorded.
When both sampling data were combined, one species, Cheiracanthium sp., disappeared in first season, also one species, Dictynid sp.1, was not recorded in second season.When both sampling data were combined, one species, Nurscia albomaculata, was not collected in first season, also one species, Ballus sp., disappeared in second season.

Monthly fluctuation of spider population "Catch size":
In March, more spiders were caught in each of organic and conventional Chamomile,35 & 26 individ.,and 34 & 23 individ. in two seasons respectively, Tables (5-6).
The total number of spiders collected from organic Calendula were 157 & 197 individ. in two seasons respectively, while 126 & 171 individ.were collected in Calendula conventional respectively, in the period between October and May in first season and last week of April in second season.Feber et al. (1998) indicated this result, they mentioned that in late May more spiders were caught in all three organic farms than in all three conventional farms.Also, they indicated that significantly more spiders were caught in the organic fields than the conventional fields.
Unlike, spiders caught in winter were lower in both organic and conventional cultivations (Tables 5-6).Several researchers reported that the winter was the lowest abundance for spiders while in summer the population density of spiders increased (Rizk et al., 2012).Furthermore, Rizk et al. (2015) indicated this result and reported that monthly counts of spiders collected from the organic and conventional cultivations in the period between Octobr and first week of May occurred in high abundance in March and recorded 109 individuals with 3 egg sacs for the organic while respective numbers in conventional cultivation was 88 individuals and one egg sac.
Similar results were reported by Mushtaq et al. (2000); they recorded that maximum number of foliage spider species were recorded in monthly sample of May.
These results agree with Ghallab (2013) who indicated that total monthly counts of spiders collected from Croton trees occurred in high abundance in early summer during May and the lowest numbers were recorded during February, also she found that the highest number of spiders on Lantana plants were collected in May & June while the lowest numbers of spiders were recorded during December, January, and February.

Frequency and abundance values:
Table (3) showed the frequency and abundance values of the most abundant spiders in organic Chamomile and Calendula during two seasons 2014/2015 & 2015/2016.According to"Weis Fogh system" family Lycosidae was considered "accessory" 46.72% in organic Chamomile in first season and "constant" 69.39% in second season.Also this family was considered "constant" in the organic Calendula with 50.32 & 59.39% in two seasons, respectively.Members of family Lycosidae: Hogna sp., Pardosa sp., and Wadicosa fidelis ranged between "dominant" and "eudominant" (according to Weigmann classification of dominance) (Table 4).Our results agreed with the results which were obtained by Shuang-Lin and Bo-Ping ( 2006) who indicated that Lycosidae was the dominant family and occupied more than 60% of individual's community.Moreover, Rizk et al. (2012) indicated that members of Lycosidae were represented by three common species: Wadicosa fidelis, Pardosa injucunda and Pardosa sp. and all their developmental structures were collected by pitfall traps below the four plants: Spearmint, Castorbean, Roselle (Karkadi) and Red pepper.Similar results were reported by Rizk et al. (2015) who found that members of Lycosidae in the three cultivated plants: Wormwood, Daisy and Spearmint were Wadicosa fidelis, and Pardosa sp.ranged between "eudominant" and "dominant" according to Weigmann classification of dominance.
Thanatus albini (Philodromidae), was "subdominant" in all cultivations, except for organic Chamomile in first season and conventional Calendula in second season being "recedent".Whereas, Sengletus extricatus (Linyphiidae) in the conventional Chamomile and Calendula cultivation was "subdominant" in the first season and "recedent" in the second season, while in organic Chamomile and Calendula it was "recedent" in the two seasons.This result was in accordance with that of Eyre et al. (2008) who stated that linyphiid species preferred plants in conventional cultivation, while larger lycosid, philodromid and gnaphosid species favoured the organic cultivation.

Species diversity:
Table ( 7) compared the biodiversity of collected spiders in different vegetation between organic and conventional cultivations in two seasons by using Shannon-Wiener "H" and Simpson "S" indices of diversity.According to Shannon-Wiener "H" index the Calendula conventional cultivation recorded the highest value (2.47) in first season in contrast to that the Calendula organic cultivation recorded the lowest value (2.36) in the same season.In the second season, the Calendula organic cultivation, in contrary to the first season, recorded the highest value (2.23) while the Chamomile organic cultivation recorded the lowest value (2.05).Also, this result revealed that the highest "H" value recorded in conventional Calendula in the first season while the lowest "H" value recorded in organic Chamomile in the second season (Table 7).
Consequently, these values demonstrated that in first season the organic Chamomile harbored more of spider number but less diverse and occur than the conventional Chamomile while the organic Calendula harbored more spider number and diverse but less occur than the conventional Calendula.
In the second season, the organic Chamomile harbored more spider number and diverse but less occur than the conventional Chamomile while organic Calendula harbored more spider number, diverse and occur than the conventional Calendula (Table 7).
According to Simpson "S" index, which reflect the measure of dominance, it was found the highest value recorded in the organic Calendula (0.121), however the lowest value recorded in the organic Chamomile (0.108) in the first season.In contrast to that, the organic Chamomile recorded the highest value (0.199), however the organic Calendula recorded the lowest value (0.149) (Table 7).

Similarity of species:
The number of collected spiders throughout study period from organic farming was more than the members collected from conventional farming (623 and 512 individ.),respectively.However, the same number of spider species was obtained in the organic and conventional Chamomile (16 species of each), whereas the disparity obtained between organic and conventional Calendula (17 & 16 species, respectively).Therefore, according to Sørensen's quotient of similarity (QS) no difference was observed between spider communities for both organic and conventional Chamomile (QS=1) while inconsiderable difference was observed between spider communities for both organic and conventional Calendula (QS=0.97)with percentage of similarity reached 98.5 %, so it can be concluded that insignificant difference was found between both communities.Relation between type of vegetation, spider abundance and spider species richness: Tables (1-2 ) showed that Calendula plants harbored a higher abundance of spiders (354 & 297 individ.) in organic and conventional vegetation respectively while Chamomile had (269 & 215 individ.) in organic and conventional vegetation, respectively.This result indicated that vegetation type may influence spider abundance.
Tahir & Butt (2009) indicated that the spider densities vary with phenology of crops.In general, the density of the spiders in the fields increase with the increase in plant size and complexity, thus smaller plant host fewer spiders than tall ones (Liu et al., 2003).The higher spider densities in the present study in organic field suggested it favorable habitat for spiders (Schmidt et al., 2005).It is argued that organic systems are more diverse and therefore more stable, resulting in lower incidences of pest and disease problems and increased biodiversity (Lampkin, 1990).
Also, Tahir & Butt (2009) found that high abundance of spiders in the organic field might be due to rapid increase in the population of detritivores and plankton feeders after the addition of organic manure.These organisms serve as alternate prey for ground spiders in the absence of potential prey items in the fields (Settle et al., 1996).Organic field also provide more diverse and complex habitat for spiders (especially Lycosidae) than conventionally farmed fields (Wisniewska & Prokopy, 1997;Feber et al., 1998;Yardim & Edward, 1998;Schmidt et al., 2005).Habashy et al. (2005) indicated that, indirectly, the surface vegetation affects spider population density and biodiversity which is influenced by microclimate of the plant.Where growth dependent on a mosaic of microclimatic conditions is produced with shaded areas interspersed with more open exposed area.These variations in sun and shade have a marked effect on the horizontal distribution patterns of many pests affected directly on the growth rate of spiders.Also, this result agreed with the results which obtained by Ghabbour et al. (1999), who found that the shade of plants and the available humidity expressed as water requirements for each crop in addition to density of plants/acre directly affected abundance of activity density of soil fauna.

CONCLUSION
This study concluded reason is that an increased soil microbe community in the organic fields provides a healthier one more than conventional soil system.
More studies are needed to determine relationship between patterns in the distribution of spider species and management practices.Differences in the community compositions among different management practices should continue to be studied so that we may gain a better understanding of the agricultural practice and habitats are important in determining the spider inhabitants.

Table 1 :
1 Population of spider families and species collected by pitfall traps in organic Chamomile and Calendula during two seasons 2014/2015 & 2015/2016.

Table 2 :
Population of spider families and species collected by pitfall traps in conventional Chamomile and Calendula during two seasons 2014/2015 & 2015/2016.

Table 5 :
Number of spiders collected from Chamomile and Calendula fields by pitfall traps during 2014/2015.

Table 6 :
Number of spiders collected from Chamomile and Calendula fields by pitfall traps during 2015/2016.

Table 3 :
Relative abundance -frequency relationship of spider communities in organic Chamomile and Calendula during two seasons 2014/2015 & 2015/2016.

Table 7 :
Estimation of Shannon-Wiener [H'] and Simpson [S] Indices of spider diversity in organic and conventional farming systems.High numbers of spiders were collected on organic plants, the recorded numbers were 122 & 147 individ. in chamomile and 157 & 197 individ. in Calendula in two seasons respectively.Less numbers were recorded on conventional plants, the numbers were 97 & 118 individ. in Chamomile plants and 126 & 171 individ. in Calendula in two seasons, respectively.