When we talk about microorganisms and insects in the garden, it is quite easy to overlook one type of animal that is not actually an insect. Belonging to the biological classification of arachnids, spiders are predatory creatures that have an important role in controlling populations of pest insects on the permaculture plot. Utilizing either webs to capture prey, or simply striking on the ground or in plants, spiders all have some form of venom with which to kill their prey. All spiders will, once they have made a kill, use enzymes to break down and liquefy the prey in order to consume it. Most spiders will take almost any other insect that happens to come across their path so they will inevitably predate some other beneficial species, but their role in keeping pest populations down should not be underestimated, and permaculture gardeners should view spider sightings on their plot as a good sign indeed.
Every country, bar Antarctica, has its own indigenous arachnids, as well as other species that have been introduced from elsewhere. Here are some of the more common ones that permaculturists in the USA may come across.
Whitebanded Crab Spider
Crab spiders are ambush predators, with the whitebanded among the most common varieties. They tend to sit in the centre of flowers, waiting for insects to come to the bloom to feed on the nectar. Then they strike, seizing the victim in their front two pairs of legs and injecting them with venom. The females of the species are able to change their body coloring between white and yellow to camouflage themselves against the flower. Adult males are much smaller than the females.
There are 13 species of grass spider in the U.S., and all of them look similar and exhibit the same behaviors. Grass spiders are members of the funnel weaving family, creating sheets of silk webbing that stretch between the branches of vegetation and lead to a small retreat at the base. The grass spider’s web is not sticky; the spider is alerted to the vibrations of an insect on the web and rushes out to catch it. Grass spiders have brown and grey markings and can be identified by their three rows of eyes – two on the top, four in the middle and two on the bottom –
Carolina Wolf Spider
Wolf spiders are among the most abundant spider species in U.S. gardens and fields. The Carolina is the largest, with adult females growing up to 35 millimeters in body length. They have brown and white markings on the top half of their body, while the underside is solid black. They do not make web; instead during the day they lurk in their burrows waiting for unsuspecting insects to wander past, while at night they go out to actively hunt.
Orchard Orb Weaver
Orchard Orb Weavers have striking coloration, with white, green, and gold markings on their elongated abdomen. Like other orb weavers it spins a circular web that is positioned horizontally, with the spider hanging beneath it. They build their webs on small trees and low-lying shrubs, and feed predominantly on flying insects.
The Hacklemesh Weaver is actually indigenous to Europe, but through global trading it has established itself in other parts of the world, including China and the U.S. A relative of funnel web species such as the grass spiders, the Hacklemesh differs in that it prefers to spin its web on logs, in crevices and in deep leaf litter, rather than up on vegetation. It has a reddish-brown colour and eight eyes arranged in a kind of ‘smiley’ pattern on the front of the head.
Arguably the spider with the most daunting name, the Black Widow actually gets its moniker from the habit of the female to eat the male directly after mating. The males are small and brown, but the females are identifiable from the crimson spot on their bellies. This species hides in crevices by day, and then comes out at night to hang upside down in its web and catch flying insects like moths.
Ant Mimic Spider
The clue is in the name of this spider species. The Ant Mimic not only has a body shape that looks like an ant’s, it comports itself in an ant-like manner as well, holding its first pair of legs aloft as it moves so that they resemble antennae. This behavior is not, as first might be suspected, so that the spider can prey on ants; rather it is to protected itself from predation, as many ants are not preyed upon due to their pungent taste. Instead the Ant Mimic Spider eats small insects like aphids.
Tan Jumping Spider
Jumping spiders can leap up to forty times their own body length. They are also distinctive for their jerky movement when moving across the ground. The Tan species has grey and black mottling on its legs and body, with a scallop-like design on the abdomen. It hunts bugs and other small insects by patrolling vertical surfaces such as walls and fences, before pouncing on their victims.
Native to Europe, this spider is now found in most temperate countries across the globe. It has an orangey-red coloration, with the body darker than the legs. It uses its long legs to grab prey and turn it over, revealing the soft underside into which the spider can sink its fangs. It does not make a web; rather it runs down its woodlouse prey.
Six-Spotted Fishing Spider
If you have a pond on your permaculture plot, you might see this species sprawled out motionless on the water, with its distinctive white stripes down each side of its body, waiting for aquatic insects to inadvertently come within reach. They also eat tadpoles and, on occasion, small fish. If disturbed, the spider will run across the water to reach shelter in the bank. The spider is also known to dive almost 20 centimeters under the surface to catch prey.
If you are looking to increase the number of spiders on your site, there are a number of things you can do that will create an environment the animals want to colonize. Mulching, particularly with straw, leaf litter and prunings provides the spiders with protection from predators (such as birds) and from strong weather conditions, as well as humidity. A good range of shrubs and plants that will provide sites for web building and nest making are attractive to spiders, while you could also utilize plant species that attract insects the spiders will prey on.