Black & Yellow Garden Spider
In order to enjoy spiders one must come to grips with their inner fears. I overcame my fear young in life once I realized the spider really has no desire to "attack" anything much larger than itself and most species are pretty much harmless. Respect is key and understanding their behavior goes a long way to avoid any issues. Of course, like any wild creature if you in inadvertently threaten the animal it may react in a negative manner, and that goes for humans as well.
Spiders have their place in the environment so I will talk about that aspect in regards to this species the Argiope Aurantia, or common Black Yellow Garden spider. There are a ton of information on these spiders already on the internet. In this article I will describe my 3 year study of the species, their growing or declining numbers in the areas I find them. Each year I pay multiple visits to check on their status and have tracked at least 20 individuals into the winter months.
Life-cycle: My observations indicate females may at times survive through a mild winter but I have never observed a male late into the year which indicates the males have one main purpose in their life cycle - to find a female and mate. Males are much smaller than the colorful female and normally build their webs in close proximity of the females. Like most spider mating rituals the female must be enticed by the male who plucks the strands of web of the female spider. If all goes as planned the male can make a slow approach and will be allowed to mate, otherwise the female can attack and kill the male.
Local Living: The Black and Yellow Garden Spider species are found to remain close to the area they are born. My observations show that populations depend on availability of food and survive-ability of the nest, and extreme cold, plus the young spiderlings become prey items for other animals, like birds. In a cycle of 3 years I found the density of the populations vary from year to year, In this last season, their numbers increased significantly as opposed to last year where only a few offspring emerge to the same spots. Over the distance of 4 miles that have open trails with sunlight and bushy growth, I found 1-2 webs every 100 or so feet, possibly more beyond the easy viewing area from the trail. The correlation of the numbers I believe are related more to weather than other factors, in the years of heavy extended cold spells with snow - normally resulted in lower number the next season, and probably why spider will have hundreds of offspring these spiders may have close to a 1000 in a sac, with only a hundred or so that survive until mid summer.
Eggsacs: The egg sacs of the female are built and placed close to the main web and has extra web layers to ensure the spiderlings surviveability and protection from the elements. As the eggs mature the eggsac stretches and expands to accommodate the growing embryos until their hatching, which remain in the sac for about one day then emerge. Spiderlings quickly thin out due to predation with only a few ultimately surviving into summer.
Activity: Like most all web bound spiders they will capture any prey item that happens into the web and is too weak to escape, this includes Dragonflies, grasshoppers, and or other similar sized prey. I have never personally observed these spiders at night and can not attest to their nocturnal nature, but in the daytime, they have periods of activity which involves making repairs to the web, and adding to the web. I have observed the Black and Yellow Garden Spider moving to the extremes edges of the web, and if something strikes the web, the spider rushes to the source to investigate. While the spider moves about a anchor line is always in place to allow the spider a way to control any falls. These spiders have tiny hooks and the ends of their legs used to manipulate the web strands and hold themselves in place, The spider also has very fine hairs extruding around the body mostly on the legs that facilitate movement and vibrations. These spiders rely more on "movement" and vibrations than their limited eyesight. Webs are sometimes taken down by the spider and re-built, I have observed the shape and pattern of the web changed over the course of a week - indicating this was the case. It is believed the spider eats the old web and re-uses the silk, I have not witnessed that aspect of the behavior, but It is a fact the webs are replaced from time to time.
Impact to humans: These spiders are considered harmless to humans and provide a beneficial control of other insects that may inflict garden damage to crops, such as grasshoppers. Although the females are large and colorful, they rarely bite and are non aggressive. No reports of humans suffering any long term health issues in regards to this species.
These species are a wonderful spider species to study due to their size, non aggressive nature and allowing people to come close to the web without the spider retreating. I personally enjoy the later summer months and spotting these spiders along the paths and trails.