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Spiders are one of the dominant predatory groups found in agro-ecosystems in South Africa. They have special adaptations towards a predatory way of life. Their distensible abdomens enable them to consume large amounts of food in relatively short periods of time, while their rate of predation may greatly increase during short periods when plentiful supply of food is available.
They have an exceeding high resistance to starvation which enables them to survive and maintain normal reproduction during periods of low prey availability. This is accomplished by an ability to decrease their metabolic rate. During their life which varies from 9 months to 25 years, all instars feed actively as predators. Most spiders are polyphagous and feed on a variety of prey but some are specialists. Predation is not limited to adults only but includes the egg and larval or nymphal stages as well.
Spiders are one of the most abundant groups of predators found in agro-ecosystems in South Africa. They have special adaptations towards a predatory way of life. Their distensible abdomens enable them to consume large amounts of food in relatively short periods of time, while their rate of predation may greatly increase during short periods when plentiful supply of food is available. They have an exceeding high resistance to starvation which enables them to survive and maintain normal reproduction during periods of low prey availability. This is accomplished by an ability to decrease their metabolic rate. During their life which varies from 9 months to 25 years, all instars feed actively as predators. Most spiders are polyphagous and feed on a variety of prey but some are specialists. Predation is not limited to adults only but includes the egg and larval or nymphal stages as well.
Spiders have special adaptations towards a predatory way of life. They are exceptionally well adapted to survive in nature:
Their extensible abdomens enable them to consume large amounts of food in relatively short periods of time, while their rate of predation may greatly increase during short periods when plentiful supply of food is available.
They have an exceeding high resistance to starvation, which enables them to survive and maintain normal reproduction during periods of low prey availability. This is accomplished by an ability to decrease their metabolic rate.
During their lifespan, which varies from 9 months to 25 years, all instars feed actively as predators.
Most spiders are polyphagous and have a diverse prey spectrum.
Predation is not limited to adult’s stages of the prey only, but includes the egg and larval or nymphal stages as well.
Spiders are able to withstand extremes of climate.
They are easily distributed by wind.
Usually present in high numbers, through a process known as ballooning
Usually present throughout the year.
At ARC-PPRI spiders are marketed as the “farmers best friend” especially for the small scale farmer. The use of spiders as biological control agents depends mainly on the conservation and increase in numbers through the use of agricultural practices such as selective spraying rather than on mass rearing and release. The extent to which spiders can contribute to agricultural pest control, is however limited by the disruptive effect of insecticide applications. The selective use of pesticides to prevent elimination of natural enemies; restricting insecticide usage during crucial periods in the life cycle of the pest; limiting spray application to midday when spiders are less active and shelter; application of pesticides as spot treatments to permit spiders to recolonize treated areas immediately are recommended.
Spiders in cotton
Spiders in avocado orchards
Spiders in macadamia orchards
Spiders in citrus orchards
Spiders in pistachio orchards
Spiders in strawberry orchards
Spiders on grapes
Spiders as predators of termites
Spiders as predators of mites
