Spiders Honor

Nature Study

Requirements

1. What are the main characteristics of spiders? What are the main differences between spiders and insects?

   Answer: 1) MAIN CHARACTERISTICS OF SPIDERS: a body divided into 2 parts (cephalothorax + abdomen); 8 legs; they have chelicerae for injecting venom; they produce silk through glands (spinnerets) on the abdomen; they breathe through book lungs; they have no antennae or wings. 2) MAIN DIFFERENCES BETWEEN SPIDERS AND INSECTS: spiders have 8 legs, insects have 6; spiders have 2 body parts, insects have 3 (head + thorax + abdomen); spiders have no antennae, insects have 2; spiders never have wings, most insects do; spiders have chelicerae (not present in insects). — Spiders belong to the class Arachnida (along with scorpions and mites), insects to the class Insecta. About 50,000 spider species have been catalogued. Only ~3% have venom dangerous to humans (black widow, Brazilian wandering spider, brown recluse). Chelicerae (modified jaws) inject paralyzing venom and digestive enzymes. The web is a silk protein stronger than steel by weight.

2. What use is the web to spiders? What use is the spider web to human beings?

   Answer: FOR SPIDERS: capturing prey (flying and crawling insects); protecting offspring (egg cocoons); locomotion (a safety line when dangling); shelter (galleries and tubular nests). FOR HUMANS: biological silk threads used in medical research (sutures, prostheses), experimental production of super-strong fabrics (5x stronger than steel by weight), and inspiration for bioengineering. — Spider silk has a tensile strength 5x greater than steel for an equivalent mass — the strongest known biological material. Companies such as Bolt Threads and AMSilk produce artificial silk in the laboratory. In medicine, spider threads are researched for neural sutures and prostheses. Bulletproof vests, parachutes, and technical ropes are future applications inspired by the spider web.

3. Make a drawing of a spherical web.

   Answer: You should draw a SPHERICAL (orb) WEB: a center with a hub and radii coming out of it (usually 8-12 radii); concentric threads forming a spiral from the center outward; the threads are radial (structural) and spiral (sticky, for capturing). Use a pencil and white paper; you may add a small spider in the center. Present the drawing to the Pathfinder honor instructor. — The orb web is the classic wheel-shaped web — produced by spiders of the families Araneidae and Tetragnathidae. The construction follows a pattern: the spider casts a pioneer thread, builds the frame, the radii, and then the sticky spiral. It does this in 30-60 minutes. Each web is discarded and rebuilt daily, using silk protein absorbed and recycled from the previous day.

4. Describe other types of web that exist besides the spherical or orb web

   Answer: 1) FUNNEL WEB (Agelenidae) — a tubular funnel with a flat extension, the spider waits at the bottom; 2) SHEET WEB (Linyphiidae) — horizontal and smooth, in vegetation; 3) TANGLE WEB (Theridiidae) — a chaos of threads with no pattern (black widow); 4) CRIBELLATE WEB (Uloboridae) — small, with decorative threads; 5) TRAPDOOR (Ctenizidae) — a hole in the ground with a movable lid. — The diversity of webs reflects different hunting strategies: the funnel for crawling insects (the spider feels the vibration and attacks quickly); the tangle web captures flying insects that ricochet off it; the trapdoor intercepts walking prey. Some spiders (tarantulas) make no web — they hunt actively. About half of the 50,000 species use a web for hunting.

5. What do spiders feed on? Observe spider webs and list the prey found.

   Answer: Spiders are CARNIVORES — they feed on insects (flies, mosquitoes, grasshoppers, cockroaches), small arthropods, and sometimes small vertebrates (small lizards, owlets). Large spiders such as tarantulas eat mice. They use paralyzing venom and external digestive enzymes, sucking out the nutritious liquid. Observe webs and list the prey found (usually flies, mosquitoes, wasps). — Spiders digest their prey EXTERNALLY — they inject enzymes that dissolve the insect's internal tissues, then suck out the liquid. That is why the insect's 'shell' stays intact in the web. Large tarantulas (Theraphosa blondi, ~30 cm) can eat small birds and rodents. Spiders control insect populations — a single web captures 1,000+ insects per year.

6. What are the main predators of spiders? Besides its predators, what is the spider's main enemy and why?

   Answer: PREDATORS: spider wasps (Pompilidae) that paralyze them to feed their larvae; birds (great kiskadee, thrush); lizards; toads; other spiders (cannibalism); humans. MAIN ENEMY: MAN — destroys their habitat, kills them out of fear (even though only 3% of the ~50,000 species are dangerous), and uses pesticides that indirectly poison spiders in every city. — Spider wasps (Pepsis grossa, the tarantula hawk) paralyze spiders with a sting and lay eggs in the abdomen — the larva hatches and devours the spider alive. Urban pesticides (Baygon, Raid) kill hundreds of spiders in the vicinity of each application. Most spider deaths caused by humans are unnecessary — only the black widow, the Brazilian wandering spider, and the brown recluse currently pose a real risk to human health.

7. What is the largest spider in the world?

   Answer: The largest spider in the world is the GOLIATH BIRDEATER (Theraphosa blondi), native to the Amazon. It reaches a 30 cm leg span and weighs up to 175 g (more than an adult rat). It lives in burrows on the forest floor and feeds on insects, lizards, mice, and even small birds. It has urticating hairs on its back as a defense — despite its size, its venom is weak for humans. — The Goliath is so large that it can eat small birds (hence the name 'bird-eater' in English), although this is rare in nature. When threatened, it rubs its hind legs to release urticating hairs that cause intense itching on the mucous membranes. It lives 15-25 years in captivity. Despite its impressive size, its bite is equivalent to that of a wasp for healthy humans without an allergy.

8. Do one of the following:
   • Collect, identify, and preserve at least 16 species of spiders. Each jar must contain a label with the location and date of capture, the name of the collector, and the name of the spider. (When fulfilling this requirement, be sure you are not breaking any law of your country).
   • Draw and identify at least 16 species of spiders, in their natural colors and life-size or enlarged.
   • Take color photographs and identify at least 16 species of spiders known in your region or country.

   Answer: You should do 1 of the options: 1) COLLECT and preserve 16 species in labeled jars (name, location, date, collector) — be mindful of environmental laws; 2) DRAW 16 species in their natural colors, at real size or enlarged, with identification; 3) PHOTOGRAPH 16 species in color and identify them by scientific name. Present the organized material to the Pathfinder honor instructor. — Collecting spiders in Conservation Units (UCs) requires authorization from ICMBio. Drawing allows for an in-depth study of the anatomy. Photographing is the most ethical and modern option — a good camera with a macro lens allows for identification. Sites such as iNaturalist.org help identify species from a photo. Each region of Brazil has dozens of species — São Paulo has more than 500 catalogued.

9. Write a description of at least 40 words about a spider species known in your region or country.

   Answer: You should write a description of at least 40 words about a species known in your region. Example: 'The Brazilian wandering spider (Phoneutria nigriventer) is native to Brazil, measures 5 cm, and has a 17 cm leg span. Brown with light stripes, it is aggressive when threatened. It hunts at night on the forest floor. Its potent neurotoxic venom makes it one of the most venomous in the world.' Present it to the instructor. — The Brazilian wandering spider is responsible for many accidents in Brazil — common in banana plantations and woodpiles. The scientific name Phoneutria means 'murderess.' Other Brazilian species worth describing: the brown recluse (Loxosceles intermedia), the small tarantula, the garden spider, and the white tarantula. The description should cover the habitat, habits, feeding, reproduction, and distinctive characteristics of the chosen species.

10. How many species of venomous spiders are there in the world? And in your region? What should you do in case of a spider bite?

    Answer: ALL of the ~50,000 spider species have venom (they hunt with it), but only ~30 are dangerous to humans. IN BRAZIL: the black widow (Latrodectus), the Brazilian wandering spider (Phoneutria), the brown recluse (Loxosceles), and the goliath birdeater. BITE: wash the area, do NOT squeeze it, do NOT suck it, do NOT apply a tourniquet; take the person to the hospital with the spider (if possible) for the specific anti-arachnid serum. Time is critical in severe cases. — Brazilian toxicology centers (Cetox) have specific anti-arachnid sera for the Brazilian wandering spider (anti-phoneutria), the brown recluse (anti-loxoscelic), and the black widow (anti-latrodectic). The brown recluse's bite causes a necrotic lesion that can take days to appear. The Vital Brasil Hospital in São Paulo is a world reference in antivenom sera. Capturing the spider carefully helps in the correct identification for treatment.

11. How can spiders be beneficial to humans? How can spiders be harmful to humans?

    Answer: BENEFICIAL: 1) natural pest control (mosquitoes, cockroaches) — one web captures 1,000+ insects per year; 2) silk in medical research (sutures, prostheses); 3) venom in pharmaceutical studies (potent painkillers). HARMFUL: 1) bites from venomous species (3% of the ~50,000 species) can cause serious injuries; 2) some invasive species disturb local habitats. — Spiders are crucial natural predators in the control of urban pests (Aedes aegypti, cockroaches) — without them, insect populations would explode. The venom of Phoneutria nigriventer is being researched to treat erectile dysfunction and chronic pain. Medical research with spider silk is advancing in sutures for delicate tissues. Only 3% of spiders are truly dangerous to humans — the rest are completely harmless.

12. Find 2 biblical references to spiders and their webs.

    Answer: Two biblical references to spiders and their webs: 1) JOB 8:14 — the trust of the wicked is compared to a spider's web: "his hope will be cut off, and his trust will be like a spider's web," a symbol of something fragile that cannot hold. 2) ISAIAH 59:5-6 — about those who do evil: "they weave the spider's web; their webs will not serve as clothing, nor will they cover themselves with their works," denouncing useless human works that are worthless before God. In both texts, the web is a metaphor for spiritual fragility and uselessness. — The Bible uses the spider's web as a powerful metaphor: an imposing appearance but essential fragility. In Job 8:14, Bildad compares the trust of the wicked to a web that breaks at the touch. In Isaiah 59:5-6, the prophet denounces that human works, without God, are like useless webs. Proverbs 30:28 (in some translations) also mentions the spider among the 'small but wise' creatures of the animal kingdom.