THE BEST LAID PLANS …
The plan was to have PART II of the story about spiders to appear on Halloween. Obviously, that didn’t happen. So, what was the problem? As you probably know, Constant Contact has been sending our More Mesa Updates for many years. For all of those years we used their template; one that worked very well for us. Enter the Smart Phone! Because much of its material is being read on Smart Phones, Constant Contact decided to retire the original template and substitute a new one designed to work especially well for the Smart Phone. My excuse … it took me several days and several desperate calls to Constant Contact staff to learn how to work with the new template. I rest my case. Pretend it’s Halloween and enjoy Part II.
Why are Humans Afraid of Spiders?
Despite the enormous benefit spiders are to us, humans are ambivalent about spiders. Fear of spiders is mostly cultural and not hard-wired into our DNA, as is the fear of snakes. (We talked about this in an earlier Treasure Hunt.) Also fear of spiders is definitely not universal. In warm countries, spiders are welcomed and appreciated since they rid households of less welcomed insects like cockroaches, flies and earwigs … all year long. Colder countries have the fall-winter change we’ll talk more about below. And, some of these colder countries also have less welcome species like Black Widow Spiders and a dangerous species of Funnel Spiders. (In the event you read Part I of Spiders very carefully, be assured that the species of Funnel Spiders on More Mesa is completely harmless. The one from Australia is the one to watch out for.)
Fear of spiders, known as arachnophobia, is so common that it is on the “top ten” list of phobias around the world. Some people think spiders are “creepy” because of their large number of legs (eight) and their habit of scuttling around in dark corners. They do that because dark corners are where they find food; food consisting of other critters you don’t want in your home anyway. Indulge me in another plea for spiders. They rarely bite, and all but a very few are harmless to humans. Yes, in our area, the Black Widow should be avoided, but even a bite from dreaded large Tarantulas produces only slight irritation. Granted they are definitely not cuddly, but maybe you could cut them some slack … given all the they do for us.
Why are Spiders Associated with Halloween?
Here are some current explanations:
- during the Middle Ages belief in witches was rampant; as was the belief that they were at the height of their power in the fall. Somehow spiders became the sidekicks of witches and the same superstitions about witches were attached to spiders as well.
- The colors of fall are typically orange and black and many spiders are black. So, with some sort of crazy logic, spiders were then considered representatives of fall … when Halloween is celebrated.
- An associated legend had it that spiders were thought to have magical powers because they could spin webs.
What’s really going on? Fall is a time when spiders produce young. But more importantly, late fall is a critical time of year for many insects. They are searching for safe and warm havens in which to spend the winter … like your house. When that happens, your house becomes a veritable grocery store for spiders. Not as exciting as witches, magic and supernatural stuff, but more of nature doing what it has to do to adapt to changing weather conditions.
Spider Lifeways Are All About Females
Transitioning from the supernatural to more practical issues, spiders have to make a living, keep from getting eaten and ensure that the species persists. That is where we go from here. So, I started studying about webs, a fascinating subject. But as I learned more and more about webs, I noticed that the pronoun “she” was always used. Then I learned that the world of spiders is all about females and the tremendous amount of hard work they do. All of this was strangely familiar! Following is a typical “To-Do” list for a female spider.
In Part I you might have seen some hints about procuring food when you are a Crab Spider, but when it comes to spider grocery shopping, most of us think of webs. Since spiders are carnivores, webs become perfect butcher shops; places to procure protein; whether it walks in, flies in or otherwise.
A web spider has virtual rope factory inside her. The spinneret glands, located in her abdominal region, squirt liquids that solidify immediately into several different kinds of silk. The tensile strength of spider silk is comparable to that of steel wire of the same thickness. However, as the density of steel is about six times that of silk, spider silk is correspondingly stronger than steel wire of the same weight. Web silk’s unmatched combination of strength and toughness allows it to survive the strongest winds as well as the most frantic attempts of captured prey to escape. And if you are not impressed with the above comparisons, I recalled back in my youth learning that the Norden bombsight used Black Widow silk for the crosshairs … that’s how strong it is!
There are a bewildering array of webs, each species building a fixed pattern, with the talents of different species varying greatly. Webs are not only supermarkets but also serve as a safe retreat from enemies and sometimes as a residence as well. Some webs are crude and some extremely delicate, but the one web usually considered the most beautiful, and the most beloved, is the Orb Spider web. Although web building takes between one and two hours in real time, you can watch the tiny (half inch) Spiny Orb Weaver creating her 12 inch diameter web in a couple of minutes. During the build the spider will coat some of the fibers with a sticky substance that entraps any unwary meal, but leaves other strings of the web clear for her to traverse. If the spider gets tired of waiting for dinner to be collected by the web, and would like to sleep, she drops a single line to a convenient “bedroom location” and keeps it attached to one of her legs. When prey wanders into the dining room, the web will vibrate at specific frequencies that are associated with prey capture. At the call of this dinner bell, she will wake and hurry out to inject killing venom. In this video, watch how she packages up dinner in a silk bag and then enjoys it later.
Preparing Dinner Unlike most humans a spider drinks its dinner. This means that before it can consume prey, it must convert a meal into liquid form. This is accomplished by injecting special digestive enzymes into the prey, waiting for liquification and then sucking up dinner. Its stomach can stretch to hold very large amounts of liquid, so the spider cannot really ever overeat. On the other hand, if times get bad, a spider can survive for extremely long periods of fasting … perhaps up to 1 ½ years.
Recycling And, since the Orb Spider is a tidy, thrifty critter and protein is expensive, she is also an avid recycler; i.e. the protein from the old web is never wasted. When the web is no longer usable, she eats and digests it. The web protein then goes back into the silk glands to be made into a new web. In this way, even if a spider misses a few meals, she can still go on spinning webs!
Taking Out the Garbage Like any good housekeeper the spider tidies up. Since dinner has been liquified and ingested, any prey body parts that are left over need to be cut out of the web and discarded. This same process is used for any extraneous and useless material that is blown into the web by accident … like leaves.
Romance? In Part I we mentioned that female spiders have absolutely no interest in reproduction until their very last molt. As you will see, it is a completely different story for the males. Males are much smaller than the females, do not live as long as the females, are more heavily decorated than the females and have a much shorter “To-Do” list. It has one entry! Their entire lives revolve around a single aspect of their existence … depositing sperm. They are obsessed with this one thing and this one thing only. This singular drive is the reason their webs are messy and badly made. Why? … because males are not territorial and spend their lives moving around looking for girls. Under these circumstances building a good web would not make sense, since they will abandon it as soon as they have accomplished their purpose, and moreover, accomplished it with all the available females in the area. For the males, who are both nomadic, and somewhat dispensable, building a web is an exercise that is more like “pitching a tent” than building a home.
Courting human couples frequently go out to dinner. However to the contrary, males spiders try to make sure that the gals have already eaten. This tactic is imperative because if a female is hungry, she may just eat the potential suitor instead. Further, there is always that danger, even if she has already eaten. That is why the legs of the males are often longer than those of the female. In cases where the date is not going well, this anatomical difference gives the male a chance to escape. (In the photo notice how gingerly the male is approaching.)
A male spider will display several behaviors during courtship, hoping the female will accept his sperm. These behaviors include pulling on the web, rocking his body, pushing the female’s legs, vibrating his abdomen, tapping on the web, making rolling motions with his palps and tapping the female spider. (Reminds me of dance moves I have seen on T.V.) How the sperm gets to the right place is really complicated as I discovered in a really long and graphic article I waded through. (You probably really don’t want to know!
Pregnancy At this point the female has both eggs and sperm in her body. Since she is so good at spinning, she spins a disc of silk and then deposits both eggs and sperm on that disc. This is when fertilization actually occurs. To protect the fertilized and hardening eggs she completes the task by spinning a cover over the disc to form an egg sac. In some species, she carries the sac with her everywhere, and in others she just deposits the sac somewhere safe and guards it, as is shown in the photo. One of the reasons females are so much bigger in some species is the need for her to carry around that heavy burden of the egg sac. Sacs can contain hundreds of eggs that will hatch into spiderlings in 2-3 weeks.
Looking After the Kids Just as mother guarded the eggs, she will guard the newly hatched babies. Once spiderlings fully emerge, they usually settle close to the nest area for several weeks before moving on and staking out their own territory.
Intelligence And for something really unbelievable, we are discovering that the spider possesses genuine ingenuity and inventiveness in both its web design, as well as in many other areas. Recent studies published in National Geographic showed many species of Jumping Spider could plan out intricate routes and detours to reach their prey — a quality usually observed in larger creatures. And almost everything is much larger than the Jumping Spider! It is between 0.125 and 0.750 inches long. And its brain … it’s the size of a poppy seed.
It is all too clear that Stan Lee knew absolutely nothing about spiders when he created Spider-Man in the early 1960s. No self-respecting male spider would be wasting his time as a superhero when he could be mating with thousands of female spiders instead. I guess Lee probably didn’t care, since Spider-Man is often ranked as one of the most popular and iconic comic book characters of all time.
And, of course you knew that I would mention one of the scariest monsters in Harry Potter, Aragog. This giant spider that sired a multitude of giant spiders in the Forbidden Forest, was the size of a small elephant and had legs 18 feet long. Apparently J.K. Rowling did not know much about spiders either, or she would have made Aragog a female.
Stay safe … Valerie