Diversity of spiders after spring sowing – influence of farming system and habitat type

Spiders contribute considerably to diversity in agroecosystems and are important components of natural pest control. Farming system and adjacent habitats may influence spider diversity. In this study, diversity of the spider families Lycosidae and Linyphiidae was studied after spring sowing until the time when a common pest (Rhopalosiphum padi) colonizes cereal fields. The spiders were collected with pitfall traps at eight organically or conventionally managed farms around Uppsala, Sweden, in three different habitats at each site: field margin, crop field and the edge between the two. The effects of farming system and habitat type on diversity of lycosids and linyphiids were considered using three different measures (activity density, species richness and composition). The most dominant species of each spider family, Pardosa agrestis (Lycosidae) and Oedothorax apicatus (Linyphiidae), had higher activity density at organic sites, and farming systems also contained different species compositions of both lycosid and linyphiid spiders. Also, linyphiid species richness was higher on conventional sites and linyphiid species composition was influenced by habitat type, in contrast with lycosids. Activity density and species richness of lycosid spiders were, on the other hand, more associated with field margins than linyphiid spiders.     

A 3-year field-scale monitoring of foliage-dwelling spiders (Araneae) in transgenic Bt maize fields and adjacent field margins

Concerns have been raised that genetically modified Bt maize may harm non-target organisms, and there is a general call and need for a risk assessment of Bt maize. Spiders are important pest predators in agroecosystems and in maize, and can be exposed to the Bt toxin by herbivorous or pollen-collecting prey, by active Bt maize pollen feeding, and by ingesting their pollen-dusted webs. The foliage-dwelling spider fauna of Bt maize fields and adjacent margins was monitored and compared to non-transgenic maize fields. The study took place during the vegetation seasons of 2001–2003 in Bavaria, South Germany. Maize fields and adjacent nettle field margins were colonized by a typical spider assemblage, dominated by space-web spiders (Theridiidae and Linyphiidae). Abundance and species richness of spiders was higher in nettle margins than in maize fields. The proportion of hunting spiders tended to be higher in nettle margins, whereas space-web spiders tended to be more frequent in maize fields. Bt maize showed no consistent effect on individual numbers, species richness and guild structure of spiders in maize fields and adjacent nettle field margin strips. The spider abundance was higher in Bt treatments in 2003, whereas in 2001 and 2002 no significant differences were found. The results provide an important contribution for the implementation of case-specific and general surveillance of transgenic plants to be employed due to the regulations of the European Community.     

Spider diversity in cereal fields: comparing factors at local, landscape and regional scales

Aim Factors acting at various scales may affect biodiversity, demanding analyses at multiple spatial scales in order to understand how community richness is determined. Here, we adopted a hierarchical approach to test the contribution of region, landscape heterogeneity, local management (organic vs. conventional) and location within field (edge vs. centre) to the species richness and abundance of spiders in cereals. Location Three regions of western and central Germany: Leine Bergland, Soester Boerde, and Lahn‐Dill Bergland. Methods Forty‐two paired organic and conventional winter wheat fields were compared. Field pairs were located in areas ranging from structurally simple to structurally complex landscapes. In May and June 2003, spiders were sampled using pitfall traps. Linear mixed models were used to determine the relationship of spider diversity and abundance with regional spatial factors and landscape heterogeneity within a 500‐m radius, as well as with local management and within‐field location. Results Within‐field location of the traps and landscape heterogeneity were the best predictors of species richness: more species were found in field edges and in heterogeneous landscapes. Region and local management had no effect on species richness. Activity density was higher in field edges and differed among regions. Main conclusions The diversity of farmland spiders was influenced by differences at two of the spatial scales (edge vs. centre, simple vs. complex landscapes), but not at the two others (field management, region), emphasizing the importance of analyses at a variety of spatial scales for an adequate explanation of patterns in biodiversity. Our study suggests that promoting heterogeneity in land use at landscape scales is one of the keys to promoting spider diversity in agroecosystems.     

Non‐cropped fragments as important spider reservoirs in a Pampean agro‐ecosystem

Agricultural landscapes include patches of cropped and non‐cropped habitats. Non‐cropped fragments are often source habitats for natural pest predators which colonise less suitable agricultural fields. The goals of the present study were: (a) to evaluate the contribution of non‐cropped fragments to agro‐ecosystems as biodiversity reservoirs and ecosystem service providers, by assessing the abundance of spider species and their diversity and (b) to quantify the spatial variation in spider communities across different non‐cropped fragments and crops. We hypothesised that non‐cropped fragments function as spider diversity reservoirs with better conditions for reproduction than crops. We collected spiders from 10 restored fragments having had no disturbance for 20 years and four field edges, along a gradient inside the crop adjacent to each fragment. Overall, we collected 3,591 spiders belonging to 49 species/morphospecies in 14 families. Non‐cropped fragments had a central role in the spider community, as estimated through species–habitat networks. We found differences in the diversity and abundance of spiders between non‐cropped and cropped fragments. However, these differences were only for immature spiders, whose abundance decreased from non‐cropped fragments towards the inside of crops. Our results highlight the importance of non‐cropped fragments in agro‐ecosystems as important source habitat patches, reservoirs of biodiversity and sites where spider reproductive success is possibly higher.     

湖北潜江农田景观中步甲和蜘蛛的群落结构

1995年6～10月在湖北省潜江市郊用陷阱法研究了不同农田景观元素中步甲和蜘蛛的群落结构,结果表明：10类农田景观元素中的五类景观元素,即稻田边缘,农林间作地,不打药的滩田,少打药的旱田和植被丰富的庭院菜地分别在步甲和蜘蛛的贮存上有重要意义。1)稻田边缘步甲和蜘蛛物种的多样性指数和物种数均最高。2)农林间作地步甲和蜘蛛的均匀度居首位,多样性指数位居第二。3)不打药的滩田步甲和蜘蛛的发生数量多,步甲的主要物种为爪哇屁步甲Pheropsophus javanus和耶屁步甲.Jessoensis。蜘蛛的主要物种为星豹蛛Pardosa astrigera。4)少打药的旱田发生的步甲数量多,主要物种为大劫步甲Lesticus magnus。5)植被丰富的庭园菜地发生的蜘蛛数量多,主要蜘蛛物种为沟渠豹蛛Pardosa laura。步甲或蜘蛛物种和景观元素的对应分析表明了优势步甲大劫步甲,爪哇屁步甲,耶屁步甲和优势蜘蛛沟渠豹蛛,星豹蛛,雾豹蛛Pardosa nebulosa,拟环纹豹蛛 P.Pesudoannulata和类水狼蛛Pirata piratoides各自的适生环境,同时也表明了这些景观元 素与常规管理农田(如水稻田,商业性菜地和棉田)之间在步甲、蜘蛛物种上的联系,这为农田景观的合理设计,保证农业的持续发展提供了参考。     

红火蚁入侵对玉米地蜘蛛类群多样性的影响

采用陷阱法和目测法系统研究了红火蚁入侵玉米地对蜘蛛类群多样性的影响.期间共调查到蜘蛛8科16种,其中红火蚁发生区有6科10种,药防区4科5种,对照区8科11种;蜘蛛种类以游猎型为主,隶属于猫蛛科和跳蛛科,优势种包括斜纹猫蛛、乔氏蚁蛛和蚁蛛.在红火蚁发生区,从玉米心叶后期开始红火蚁种群数量不断增加,在玉米抽穗开花期达到最大,为225头,之后缓慢降低,相应的猫蛛属蜘蛛种群数量则逐渐降低,降幅达79.2％;而蚁蛛属蜘蛛的种群数量变化不大.随着玉米植株的生长,红火蚁发生区和药防区的蜘蛛种类、多样性指数和均匀度指数逐渐降低,生态优势度指数却不断升高,而对照区相关指标则相反.表明红火蚁入侵显著改变了玉米地蜘蛛的类群结构.     

Taxonomic and functional characteristics of field edge weed communities along a gradient of crop management intensity

The widespread loss of weed diversity and associated ecosystem functions is raising important concerns. Field edges could play a major role in the maintenance of weed functional diversity in arable landscapes as these habitats still harbour high weed diversity, owing to either a reduced farming management intensity and/or to a spillover of species from adjacent perennial field margins. Here, we investigated the taxonomic and functional characteristics of weed species recorded in surveys of field edges and their associated field cores over six consecutive years in 60 arable fields farmed with five crop management strategies. We found that field edges were richer, with species more functionally diverse and composition more stable over years than field core surveys. The distribution of individual functional traits differed between field edges and field cores, with higher values for seed mass and nitrophily (Ellenberg.N), and a wider distribution of specific leaf area values in field edges. The bimodal distribution of plant height and germination period observed in field edges became unimodal in field cores. Field edges harboured species with ecological strategies associated with field cores (ruderal species) plus a conservative strategy which could be explained by a spillover from the adjacent perennial field margins. Crop management strategies impacted field edge flora, though to a lesser extent than the field core flora whereas the functional differences between the field edge and the field core flora were less marked when crop management intensity was lower. These results indicate that field edges harbour a unique assemblage of species and highly contribute to the maintenance of weed diversity in arable landscapes. Future studies should thus focus on the importance of these specific functional traits to the agroecosystem functioning.     

农田边界生物多样性保护功能的初步研究——以北京东北旺步甲群落多样性研究为例

农田边界是农田间的过渡带 ,包含了树篱、防护林、草皮 (带 )、墙、篱笆、沟渠、道路、作物边界带等景观要素[3] 。许多研究表明 ,农田边界在保护生物多样性方面有着重要的作用。Ｄｅｎｎｉｓ等[7] 的研究表明 ,通过为节肢动物提供多样、稳定的栖息地和越冬场所 ,增加农田中节肢动物的多样性。Ｈｏｌｌａｎｄ等[12 ] 的研究也表明 ,林地边界在农业生态系统中能起到保护生物多样性的作用 ,这种作用不仅使林地中有较高的多样性 ,而且还使相邻农田生物多样性增加。同时 ,多样化的农田生态系统比纯作系统具有更为丰富和多样的害虫天敌[6 ] 。国…     

人为活动对地表节肢动物多样性的影响——以沈阳市北陵公园地表蜘蛛为例

为了解人为活动对地表节肢动物多样性的影响,2010年9月至10月,采用陷阱法对沈阳市北陵公园地表蜘蛛多样性进行了调查.共采集蜘蛛标本737头,经鉴定隶属于9科15属23种.调查发现,沈阳市北陵公园地表蜘蛛物种多样性较低,狼蛛和密蛛是该地区的优势类群,其中类奇异獾蛛Trochosa ruricoloides和拟吉小密蛛Mysmenella pseudojobi为优势种.从公园的边缘到内部,蜘蛛群落组成及多样性相似,各多样性指数间均无统计学差异.研究结果表明,由于北陵公园开放程度较高,公园内锻炼、游憩的人数众多,频繁的人为干扰对地表蜘蛛造成较大影响,地表蜘蛛物种组成单一、群落结构简单以及物种多样性从边缘到内部无明显差异,这说明人为活动是影响市区开放式公园内节肢动物多样性的重要因素.     

不同生境条件与管理方式对茶园蜘蛛群落结构及多样性的影响

蜘蛛在茶园的生态控制和生物防治中起到重要的作用,为了解不同生境条件和管理方式的茶园蜘蛛群落结构差异和多样性变化,于2011年3月份—2011年10月份,运用振落承接和过筛法对3种不同类型茶园的蜘蛛群落组成与多样性进行了调查。结果表明:(1)3种类型茶园蜘蛛群落组成:3种类型茶园蜘蛛群落在科、属、种的组成及个体数量上,均表现为有机茶园高,无公害茶园次之,普通茶园低,且在物种数和个体数存在显著差异。管巢蛛科和狼蛛科是3种类型茶园的优势类群,球蛛科、跳蛛科、狼蛛科、皿蛛科的物种优势度大于10%。(2)蜘蛛群落物种多样性的多重分析结果表明,有机茶园蜘蛛群落的个体数、物种数、物种多样性指数、物种丰富度指数和均匀度指数均高于无公害茶园和普通茶园,普通茶园最低,且达到显著水平(P0.05)。(3)多元数据分析结果表明,有机茶园蜘蛛群落组成与普通茶园差异较大,无公害茶园与普通茶园蜘蛛群落组成差异较小;3种类型茶园的茶丛蜘蛛群落个体数、物种数及物种多样性指数、丰富度指数和均匀度指数均高于地表,且表现为机茶园多,无公害茶园次之,普通茶园最少。蜘蛛的功能群采集发现,在3种茶园中结网蜘蛛少,而主要是游猎蜘蛛。(4)不使用化学农药的茶园,因其周边生境结构复杂(竹林、小灌木及杂草),植被丰富,形成植被缓冲带,改善了茶园小气候环境,增加了茶园土表覆盖度,可明显提高茶丛和地表游猎蜘蛛的物种数和个体数量。综合研究结果表明,在生态条件好、干扰少的有机茶园中的蜘蛛物种数量、群落多样性明显高于受损生态系统和人为干扰强的普通茶园。     

Plant functional diversity in agricultural margins and fallow fields varies with landscape complexity level: Conservation implications

A consensus has been established that functional traits rather than taxonomic diversity play a fundamental role in linking biodiversity with ecosystem processes and associated services. This study from Finland addressed an issue of relative values of fallow and field margin biotopes in conservation of plant functional diversity (based on six functional traits of relevance to ecosystem services, and diversity of multiple traits) in agricultural landscapes differing in their structural complexity. Relative covers of plant species were surveyed in sampling plots located in perennial fallow fields and three types of perennial margins (margins between crop fields, along forest edges and by river) in three types of landscape context (simple, intermediate and complex). Fallow fields significantly contributed to the total functional diversity only in simple landscapes. The river margins provided the greatest functional diversity, especially in reproduction and regeneration traits while crop margins were consistently characterized by the lowest functional diversity. Substantial functional diversity of fallow patches in simple landscapes was due to high abundance of functional species, while that of river margins stemmed from presence of unique species. The plant functional diversity progressively declined with agricultural landscapes becoming simplified. The study indicates non-cropped biotopes having complementary roles in ensuring multifunctionality of agro-landscapes and confirms importance of biotope mosaic for functional diversity.     

农田蜘蛛群落结构及其多样性研究

本文对南宁地区农田自然蜘蛛群落和旱地狼蛛亚群落结构及其多样性进行了研究。 1.农田区蜘蛛群落有14科、41属、80种。主要成分是食虫瘤胸蛛、拟环纹狼蛛、拟水狼蛛、奇异獾蛛和豹蛛属种类,个体数以食虫瘤胸蛛最多。旱地狼蛛亚群落主要成分是奇异獾蛛和豹蛛属种类。 2.稻田区蜘蛛群落多样性指数以田埂杂草群落最高,早稻田群落最低。多样性、均匀度和种类丰富度时间格局是早、晚稻皆随时间序列增加。平均多样性、均匀度和个体数,晚稻均高于早稻。狼蛛更群落多样性和均匀度以草地最高。 3.应用群落比例相似性和聚类分析表明,拟环纹狼蛛与拟水狼蛛和奇异獾蛛与豹蛛属种类是组成当地农田区的水田和旱地生境具有代表性的两个狼蛛亚群落主要成分。 本文试图揭示农田生态系统中的稻田蜘蛛,在不受化学农药干扰下群落结构及其多样性变化,并以狼蛛亚群落为代表,比较农田区内不同生境的群落结构及多样性与生境生态特征的关系,为害虫防治和动物资源的利用提供参考。     

单季稻田的蜘蛛群落及其与褐飞虱的相关性研究

通过对南京地区４种不同类型单季稻田蜘蛛群落的结构及其与褐飞虱的相关性研究,结果表明,该地区蜘蛛群落由１０科２１种组成,其中草间小黑蛛、食虫瘤胸蛛、拟水狼蛛为优势种。物种丰富度、多样性化防田低于生防田,而均匀性则施药田大于不施药田。不同移栽时间的稻田,丰富度、多样性、均匀性迟栽田低于早栽田。蜘蛛与褐飞虱各发育阶段的相关性分析表明,蜘蛛与褐飞虱长翅成虫相关性好,而与低龄若虫相关性差;蜘蛛与褐飞虱的相关性主要由褐飞虱田间第１次若虫高峰时的蜘蛛量和蛛虱比决定,模拟的回归方程为：ｒ＝ － ０．１９９７＋ ０．００７５６ｘ１＋ ０．３３７１ｘ２（Ｆ＞ Ｆ０．０２３）。     

中国蜘蛛物种多样性分析

基于2011年1月更新的世界蜘蛛名录第11．5版,本文对中国蜘蛛的物种多样性进行了统计和分析：（1）目前中国共记述蜘蛛67科670属3667种,种数占世界蜘蛛的8．72％,仍有许多物种尚待发现;（2）目前中国特有蜘蛛物种共计2376种,占中国蜘蛛种数的64．79％、世界蜘蛛种数（42055种）的5．65％,表明中国蜘蛛特有物种极为丰富,为中国生物多样性的保护、环境及气候的历史演变和蜘蛛的系统演化研究起到重要作用;（3）已知蜘蛛物种数最多的省份为云南（728种,占19．85％）、湖南（612种,占16．69％）、四川（454种,占12．38％）等,一定程度上表明上述各省生物多样性丰富,但这一结果也与各地蜘蛛多样性研究不均衡有关。蜘蛛各科名录及统计数据可参见“中国蜘蛛特有物种网”。     

城市化对本土植物多样性的影响——以廊坊市为例

虽然城市化对生物多样性影响的研究在发达国家是一个重要的研究领域,但是在发展中国家这方面的研究不多。通过案例研究,分析本土植物多样性沿着城市化梯度的变化,及其与生境土壤因子的关系。在廊坊市,中国北部一个快速城市化的地区,沿着中心城区、城区、郊区、远郊区城市化梯度,每个梯度选取6个样地进行本土植物多样性调查,记录种类数、多样性和种类组成,并分析了多样性指数。与远郊区相比,中心城区失去了88%的物种,物种多样性下降了78%,城区物种多属于禾本科、藜科等耐践踏、耐土壤紧实度的物种。远郊区的本土植物属于45个科,科数大于城区物种。相似性指数表明,城区和郊区大部分物种相同,但是远郊区差异较大。DCCA分析表明,土壤总氮、有机质含量是影响物种城市化分布的主要因素。城市化促进了物种分布的匀质化。     

How to catch foliage-dwelling spiders (Araneae) in maize fields and their margins: a comparison of two sampling methods

The foliage‐dwelling spider fauna was collected in maize fields and on stinging nettles in adjacent margins in Bavaria, South Germany. Two different sampling methods were evaluated: drop cloth sampling and suction sampling. The overall catch was dominated by juvenile spiders, web‐building spiders, and spiders of the families Theridiidae, Linyphiidae, Tetragnathidae and Araneidae (in decreasing order). Field margins harboured more species than maize fields, whereas the total spider abundance was higher in the maize crop. Web‐building spiders such as Theridiidae and Linyphiidae were prominent in maize by individual numbers. Suction sampling with a small suction device proved to be a more efficient and consistent sampling method for foliage‐dwelling spiders than drop cloth sampling. Density and species richness of foliage‐dwelling spiders in maize was shown to be fairly high, implying that spiders of higher strata may play a more important role in biological control than suspected up to now.     

Contrasting trends of butterfly species preferring semi-natural grasslands,field margins and forest edges in northern Europe

Indicator classifications help us to focus on the most relevant groups of species in monitoring the effects of land use changes on biodiversity. We studied changes in distribution area of 74 butterfly species preferring one of the three common habitats of boreal agricultural landscapes: semi-natural grasslands (35 species), arable field margins (7) and forest edges (32). Using extensive atlas data from four time periods during the last 50 years in Finland, we quantified trends in the occupancy of the species in 10 km grid squares, and classified them into four classes: declining (23), stable (17), increasing (27) and fluctuating (7) species. Trends among the species favouring three habitats were different: 60% of the species of semi-natural grasslands had declined, whereas 86% of the species typical of open field margins had increased. An increase also predominated in species associated with forest edges. Declining and increasing species differed in three ecological characteristics: increasing species were more mobile, utilized a wider range of habitats and, based on their larval host plants, lived in more eutrophic habitats than declining species. Species overwintering as adults showed more positive trends in occupancy than species overwintering as eggs, larvae or pupae. Observed trends in occupancy are in good agreement with long-term changes in land use and habitat availability in Finland: a long-continued decrease in the area of semi-natural grasslands and an increased amount of open forest edges and clearings due to modern forestry during the past 50 years.     

Butterfly diversity at the ecotone between agricultural and semi‐natural habitats across a climatic gradient

Aim Understanding the response of species to ecotones and habitat edges is essential to designing conservation management, especially in mosaic agricultural landscapes. This study examines how species diversity and composition change with distance from semi‐natural habitats, over ecotones into agricultural fields, and how within‐site patterns of community transition change across a climatic gradient and differ between crop types. Location A total of 19 sites in Israel where semi‐natural habitats border agricultural fields (wheat fields or olive groves) distributed along a sharp climatic gradient ranging between 100 and 800 mm mean annual rainfall. Methods  We performed butterfly surveys in 2006. We analysed species richness (α‐diversity), diversity, community nestedness and species turnover (β‐diversity) within sites and between sites (γ‐diversity). We also assessed where species of conservation concern occurred. Results In wheat sites, richness and diversity declined abruptly from ecotones to fields and remained homogenously poor throughout the fields, regardless of climate. In olive sites, despite the sharp structural boundary, richness and diversity remained high from the semi‐natural habitat to the grove margins and then declined gradually into groves. Species of conservation concern occurred across all habitats at olive sites, but none were found inside wheat fields or at their ecotones. The contrast in community structure between semi‐natural habitats and fields was affected by both climate and field type. Irrigation in arid regions did not augment species diversity. Main conclusions Our results indicate that consideration of crop type, within a climatic context, should receive high priority in biodiversity conservation in agricultural areas. In ‘hostile’ crops, such as wheat, we suggest favouring a combination of high‐intensity management and wide margins over less intensive management without margins, which may merely aid generalist butterfly species. The scarcity of butterflies in arid irrigated fields suggests a need to carefully assess the effects of irrigation and agrochemicals on species’ communities.     

植被边界带对相邻麦田地表步甲和蜘蛛分布及蚜虫发生的影响

通过管理半自然生境提高农田中天敌多样性及农田害虫的生物控制效率是当前生态农业研究的基本问题之一。为探讨不同类型半自然植被边界带对相邻麦田地表天敌的发生以及对小麦蚜虫生物控制潜力的影响,在北京顺义区赵全营镇采用陷阱法调查了不同类型植被边界带（人工林地、人工种植草带、自然演替草带）相邻的小麦田中,距离边界0,15 m和30 m处步甲和蜘蛛两类重要地表天敌的多度分布及小麦田蚜虫发生情况,同时分析了边界带植被群落结构对步甲和蜘蛛群落分布的影响。结果表明：人工林地相邻的小麦田中维持了显著较高的步甲、蜘蛛和蚜虫发生密度;不同类型植被边界带相邻小麦田中步甲和蜘蛛群落组成显著不同,植被边界带宽度以及乔木层盖度是影响相邻麦田步甲和蜘蛛群落分布的主要因子;距离植被边界带不同取样界面处,不同迁移方向的步甲和蜘蛛的活动密度无显著性差异;与林地相邻的麦田中,蜘蛛活动密度从农田边界向农田内部处依次降低,与人工种植草带以及自然演替草带相邻的麦田中,农田边界处蜘蛛的活动密度显著高于农田内部。研究显示,半自然植被边界带与麦田交界处维持了较高的蜘蛛活动密度,并具有向农田内部扩散的趋势,然而,并非高天敌密度就意味着低害虫发生率,深入研究天敌群落与害虫发生关系及其影响因素是未来天敌保护和害虫生物防治的重要方面。同时,因为不同类型植被边界带维持的天敌群落具有高度异质性,未来的研究需要充分考虑不同类型植被边界带对天敌维持的作用,以及不同类型生境界面地表天敌的活动规律。     

Species composition,seasonal abundance and population dynamics of predatory spiders from cotton field plots of irrigated and semi-arid regions of Punjab,Pakistan

The purpose of the current study was to document the variety of predatory spider species present in the cotton fields of two major cotton-producing districts in Punjab, Pakistan, as well as the population dynamics of those spiders. The research was carried out between May and October 2018 and 2019. Manual picking, visual counting, pitfall traps, and sweep netting were the procedures used to collect samples on a biweekly basis. A total of 10,684 spiders comprising 39 species, 28 genera, and 12 families were documented. Araneidae and Lycosidae families contributed a major share to the overall catch of spiders, accounting for 58.55 percent of the total. The Araneidae family's Neoscona theisi ) was the most dominating species, accounting for 12.80% of the total catch and being the dominant species. The estimated spider species diversity was 95%. Their densities were changed over time in the study, but they were highest in the second half of September and the first half of October of both years. The cluster analysis distinguished the two districts and the sites chosen. There was a relationship between humidity and rainfall and the active density of spiders; however, this association was not statistically significant. It is possible to increase the population of spiders in an area by reducing the number of activities detrimental to spiders and other useful arachnids. Spiders are considered effective agents of biological control throughout the world. The findings of the current study will help in the formulation of pest management techniques that can be implemented in cotton growing regions all over the world.