Discovering Bugs: Meet the Coolest Creepy Crawlies on the Planet

Discovering Bugs: Meet the Coolest Creepy Crawlies on the Planet — page 1
INTRODUCTION Darlyne Murawski author of The Ultimate Bugopedia WHAT IS A BUG What does the word bug mean to you We often refer to a small critter or creepy crawly as a bug But the word has many meanings There are true bugs insects that scientists place in the order Hemiptera If you get sick you might have caught a bug a virus or bacterium If someone bugs you that person is being annoying A bug can also be a listening device to record conversations secretly So let’s get specific In this book we use the term bug to mean any arthropod or small animal with jointed legs a segmented body and a hard exoskeleton That includes the following l insects l crustaceans crabs lobsters shrimp barnacles wood lice whale lice and related species l myriapods millipedes and centipedes and l chelicerates spiders scorpions sea spiders and horseshoe crabs to name a few Bugs are found the world over on all continents from the warm tropics to the frigid polar regions and from coastal shores to the deep sea They may be small but they rule the earth with their spectacular diversity About 84 of all animals are arthropods That includes more than a million named species of insects alone and many more species await scientific description PARTS OF A BUG Arthropods have either two or three body sections Most have three a head a thorax and an abdomen Spiders scorpions ticks and horseshoe crabs have two sections a fused head and thorax called a cephalothorax and an abdomen Arthropods pump blood from their heart into open body cavities where their internal organs and tissues get bathed in blood This open circulatory system is different from the closed system of arteries and veins that we have Early arthropods could see with compound eyes made up of many facets that work together to form a picture This gave them the advantage of seeing more detail than could be seen with simple eyes Today’s arthropods have either compound or simple eyes and some like many insects have both types If you take a look at a grasshopper or a cicada it has two large compound eyes and in between them three tiny simple eyes By comparison all spiders have simple eyes A rigid exoskeleton external skeleton supports an arthropod’s body and protects it from predators and dehydration Unlike the smooth gradual growth of vertebrates arthropods are invertebrates that grow in stages by molting or shedding their outer shell The newly molted animal is soft bodied at first until it expands in size and the cuticle gradually hardens The thin exoskeleton 4