Biology: Spiders vs Insects

Spiders vs. Insects

• Spiders have four pairs of walking legs, while insects have three pairs.
• Spiders have two body segments, whereas insects have three.
• Spiders breathe through gill-like structures called book lungs, whereas insects breathe through holes in their bodies.
• Spiders have simple eyes, while insects have both simple and compound eyes.
• Spiders lack antennae, whereas insects have a variety of antennae.
• Most spiders have poisonous fangs that quickly paralyze their prey, a trait shared by only a few insects.

Spider Characteristics

• Spiders breathe through book lungs, which resemble the pages of a book.
• Each "page" (lamella) is separated from the next by pillar-like columns, creating a space for air to flow.
• Blood circulates through the pages, absorbing oxygen from the air flowing between the pages.

Spider Legs

• Spiders do not repair broken legs; they replace them.
• A new leg grows, often shorter than the original, during the next molting process.
• Only immature spiders can grow new legs.
• Mature spiders that lose a leg remain handicapped.

Spider Senses

• Spiders have eight simple eyes.
• They hear and taste with their feet, which have "listening slits" with extremely sensitive nerves.
• These nerves respond to vibrations, triggering immediate responses.

Spider Hunting and Eating

• Spiders use tiny hairs on their legs to examine prey and determine edibility.
• They cover edible prey with digestive juices before chewing, softening the meal.
• The enzymes in these juices are strong, allowing the spider to suck in the softened meal.

Spider Reproduction

• Garden spiders lay eggs in the fall, wrapping 300-800 eggs in an oval, silken cocoon.
• The eggs hatch the following June, with the spiderling emerging by breaking through the egg sac with an egg tooth.
• The spiderling absorbs the remaining yolk into its own body for nutrition.