Discovering Bugs: Meet the Coolest Creepy Crawlies on the Planet
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
however they may weaken them But there is also a deadly form of parasite called a parasitoid Parasitoids grow up feeding on their host and in the process slowly kill it like cicada wasps do to cicadas or like tarantula wasps do to tarantulas THE PAST AND FUTURE OF BUGS Scientists have unearthed an incredible variety of ancient arthropod fossils from the Cambrian Period 540 to 490 million years ago Some of the early arthropods to occupy the oceans included trilobites sea scorpions shellfish and horseshoe crabs Sea scorpions died out about 251 million years ago and trilobites became extinct during the Jurassic period about 200 million years ago Do bugs face extinction now Some species are more vulnerable to extinction than others Some die out due to the loss or damage of their natural habitat Many species depend on one type of plant or one type of prey They can be more vulnerable to extinction than others Unfortunately many arthropods are disappearing before scientists even have a chance to name them Knowledge is an important tool for us to make a difference in our world Scientific research continues to provide information on the history biology and behavior of arthropods but we can also learn so much just from simple observation Bugs play an enormous part in the diversity of life on earth and diversity is the key to maintaining the balance of life as we know it left behind by a newly shed arthropod looks like an empty shell of its former self For arthropods growing up means not only shedding their own exterior but also changing body form This change is called metamorphosis Think of how a butterfly advances from caterpillar larva to pupa to winged adult This progression is called complete metamorphosis Crabs beetles flies and ants likewise hatch from the egg as tiny larvae and will change dramatically as they age A simpler form of metamorphosis happens in some bugs such as grasshoppers true bugs scorpions and spiders The immature stage the nymph looks much like the adult in form BUGS AND HUMANS From a human perspective certain species of bugs are notorious pests They eat our crops damage homes and clothes and bite our flesh But they are also beneficial if they pollinate our crops prey on harmful bugs and beautify our world BUGS IN NATURE In nature bugs serve many roles including as pollinators decomposers and recyclers and producers of silk honey beeswax royal jelly dyes shellac honeydew and various medicines Bugs can be herbivores carnivores or fungivores depending on whether they eat plants meat or fungi respectively Bugs are a large part of the food chain serving as both predator and prey Many birds lizards and other larger animals could not survive without bugs to feed on Some bugs like ticks and fleas are parasites that feed on another creature its host Parasites do not kill their hosts 5
FEATHER TAIL CENTIPEDE ALIPES GRANDIDIERI WHERE Eastern Africa SIZE 15 10 centimeters 6 4 inches LOOK FOR Two long legs on the end of the body that look like feathers or flags at the tips BUG BITE The feather like legs on the back of this bug aren't just for show When the feather tail centipede is threatened it shakes it's back legs to make a hissing noise like a rattlesnake This centipede can also use it's back legs to bite or pinch as defense against predators When a female feather tail centipede lays eggs she will protect the newly hatched centipedes by wagging her back legs to distract an approaching predator Sometimes the back section of her body will break off when she does this 6
CREEPY CRAWLIES Not Not all bugs need to fly Some rely on dozens or even hundreds of legs to move around Some burrow deep into the ground and some will live high up in the trees From the caves of South America to the oceans of Australia there are hundreds of different types of bugs that crawl scuttle wriggle and squirm From centipedes to spiders these are the creepiest crawlers around 7
