Brightly colored garden spiders are harmless to humans.
There are nearly 400 identified species of spider in Indiana. Two well-known spider species with orange to yellow backs are the marbled orb spider and the garden spider. Neither spider is considered harmful to humans, and both are believed to be beneficial by gardeners.
Because markings and coloration can differ between individuals of the same species, it may help to identify your spider based on more than color and markings alone. Shape of the abdomen, size of the abdomen and web characteristics can provide additional identification clues.
The Marbled Orb Spider
The marbled orb spider (Araneus marmoreus) is found throughout Indiana. Its abdomen is orange with varying mottled black markings. The female is about 10mm, while males are around 8mm. These spiders are considered harmless and are usually found outside in Indiana during the warm months of the year. They are thought to be nocturnal and to rebuild their web every night.
The Garden Spider
Garden spiders (Argiope aurantia) are native throughout the United States. The females are 19mm to 28mm, while the males are only 5mm to 9mm. The females are more brightly colored, with yellow to orange bands across the legs and bright-colored spots on the back. The female weaves an orb web, with a characteristic zigzag in the center, that can be up to 2 feet wide. Garden spiders are usually found outside but will sometimes make their way into structures during winter.
Other Spiders
Are you still not sure of your spider's identity? Are you concerned that it might be venomous? You may want to proceed by making sure it is not one of Indiana's two poisonous spiders -- the black widow and the brown recluse spiders. These two venomous spiders do not have orange spots on their backs, but the female black widow spider has a yellow or red spot on her abdomen.
Tags: black widow, found outside, Garden spiders, usually found, usually found outside