Spiders have been collected over a period of ten years in five cotton-growing areas in South Africa. Thirty-one families, represented by 92 genera and 127 species were recorded. The Thomisidae were the richest in species (21) followed by the Araneidae (18) and Theridiidae (11). The most abundant species were Pardosa crassipalpis (Lycosidae), Enoplognatha sp. (Theridiidae), Eperigone fradeorum (Linyphiidae), and Misumenops rubrodecoratus (Thomisidae). The wandering spiders constituted 61.5% of the spider fauna collected and the web-builders 38.5%. Spiders are common and occur in high numbers in cotton fields and prey on a variety of cotton pests. Although spiders may be incapable of controlling major pest outbreaks by themselves their role in a complex predatory community may be important in regulating pest species at low densities early in the season and in between peaks of pest species activity. They therefore could play an important role in keeping pests at endemic levels and preventing outbreaks. This survey forms part of the South African National Survey of Arachnida (SANSA) in agro-ecosystems.

Read more in:
Dippenaar-Schoeman, A.S., Van den Berg, A.M. & Van den Berg, A. 1999.
Spiders in South African cotton fields: species diversity and abundance (Arachnida: Araneae). African Plant Protection 5: 93-103.

Van den Berg, A.M., Dippenaar-Schoeman, A.S. & Schoonbee, H.J. 1990. The effect of two pesticides on spiders in South African cotton fields. Phytophylactica 22: 435-441.
[The effect of two pesticides on spiders in South African cotton fields.pdf]

Van den Berg, A.M. & Dippenaar-Schoeman, A.S. 1991. Spiders, predacious insectsand mites on South African cotton. Phytophylactica 23: 85-86. [1991.Cottonspiderspredaciousinsectsandmites.pdf]


Spiders in Bt-cotton

Bt-cotton, containing and expressing genes from the soil bacterium Bacillus thuringiensis, is specifically toxic to lepidopteran larvae but little is known about the impact on predators such as spiders. A survey to determine the effect of Bt-cotton and endosulfan applications on spider populations was conducted over two cotton growing seasons (2001/2002 and 2002/2003) at Marble Hall, South-Africa. Plant dwelling spiders (n=227) were counted while scouting the plants, but not identified during both seasons. Ground dwelling spiders (n=3775) were collected with pitfall traps (n=180) during both seasons and identified to species level. The ground dwellers were represented by 21 families, 49 genera and 54 species. During the first season a total of 2431 spiders were collected from the pittraps: 945 spiders from Bt-cotton and 1486 from non Bt-cotton (control) plots, while in the second season a total of 781 were collected, 416 from Bt-cotton and 365 from the non Bt-cotton (control) plots. A total of 563 spiders were collected from the endosulfan sprayed non-Bt-cotton fields during the second season. The Lycosidae (n=2359) comprises 62.5% of all spiders collected in the pittraps, followed by the Theridiidae (n=757) with 20.1% and Linyphiidae (n= 342) with 9.1%. Steatoda erigoniformis (Theridiidae) (n=744) were the most abundant species representing 19.7% of all the spiders collected followed by Pardosa clavipalpis (Lycosidae) (n=624) with 16.5%, an undetermined Trabea sp. (Lycosidae) (n=592) with 15.7% and another lycosid Pardosa crassipalpis (n=543) with 14.4%. Neither Bt-cotton nor the application of endosulfan had apparent negative effects on ground or plant dwelling spiders in the field. Spiders should therefore be able to continue playing a role in biological control in Bt-cotton fields.

Read more in:

Mellet, M.A., Schoeman, A.S. & Dippenaar-Schoeman, A.S. 2006. The effect of Bt-cotton cultivation on spider populations in Marble Hall, South Africa. African Plant Protection 12: 40-50. [The effect of Bt-cotton cultivation on spider populations.pdf]

Theridiidae: Enoplognatha sp.

Lycosidae: Pardosa sp.

Spiders in Agro-Ecosystems

Spiders in avocado orchards

Spiders in macadamia orchards

Spiders in citrus orchards

Spiders in pistachio orchards

Spiders in strawberry fields

Spiders on grapes

Spiders as predators of termites

Spiders as predators of mites


Theridiidae: Steatoda sp.