Insect

Author: Chris Meadon (UK) and translated by Shen Yingli
Translator: Shen Yingli / Country:
Publisher:
Publish Date: 2003-08-01
Features:
■ Bugs or Insects
When people say "bug," they often mean "insect." But strictly speaking, "bug" is a very different kind of animal in the eyes of insect scientists (or entomologists, which is their actual title). This is because among more than 30 insect species (cockroaches, beetles, ants, two-winged insects, and so on), there is a category called "bug," scientifically known as Hemiptera, and all insects in this category are "true bugs." True bugs (Hemiptera—), such as aphids or bedbugs, have no teeth and no chewing mouthparts. They have a proboscis that looks like a straw and is sharp like a needle. This doesn't mean they sit around all day sipping drinks. What they do is pierce a hole in their food with their proboscis and then suck out the juice. The "food" they suck juice from can be plants, animals, or humans—if these insects happen to be blood-sucking bedbugs.
■ Counting the Number of Legs
A correct way to distinguish insects is to count their legs. But first, you need to make the little creature stay still for a long time so you have enough time to count how many legs it has. If you're using the leg-counting method to determine if it's an insect, remember that any insect has only 6 legs. Many people mistake spiders for insects, but if you check the number of legs, you'll find spiders have 8 legs, proving they are not insects. Centipedes with 14 legs are also not insects. Centipedes with at least 30 legs (but no more than 100) are not insects either. Other worms and snails are not insects either; they don't have legs at all. Most insects live a nomadic life, moving from place to place. As long as they can find food, mates, and shelter, they are satisfied. They are not lazy; they just don't need a home like we do. Some insects spend time building nests to protect their eggs and young, while others are communal insects, living together in groups.
■ Communal Living
Communal insects include termites, ants, and certain wasps and bees. Each colony has a queen that is responsible for producing all the eggs. The other "residents" are the queen's offspring, most of whom are workers who take care of the nest and larvae and are responsible for finding food. There may also be insect soldiers to defend against intruders. They live together like a big family.
■ Building a Queen's Family
A big family needs a big home, so there is a lot of construction work to be done. Most of the construction work in beehives is done by worker bees using their mouthparts. But when an ordinary wasp queen wants to start a new colony, she has to do all the dirty work herself because there are no worker wasps to help her. In the spring, the wasp queen chews wood fibers and turns them into a pulp-like liquid, which is her building material. First, the queen builds a support rod, then she covers it with an umbrella-shaped cap. Under the umbrella cap, she builds a hive with several chambers, where she lays her eggs. While waiting for the eggs to hatch, she adds layers of paper-like shells to the outside of the hive to protect it from wind and rain. When the young wasps grow into workers, they continue to build the hive to expand it for the next generation. The hive grows quickly and eventually becomes as big as a basketball. When the construction is finished, the hive can accommodate 500 wasps at once. But heavy labor also takes a toll—during one spring and summer, a single hive may have housed 10,000 worker wasps, but many of them die young from exhaustion.
■ Solitary Wasps and Bees
Most wasps and bees prefer not to live alone; they prefer to live in busy colonies with others. In fact, some solitary bees pay no attention to the larvae they hatch from their eggs. Just to show they still care about their offspring, they build nests for their larvae in abandoned caves, hollow plant stems, rotten trees, or even snail shells. Some wasps and bees go to more effort when building nests. Sand wasps dig a hole in the sand and place a meal for their offspring inside, such as an egg or a fat caterpillar. They seal the hole tightly with sand and then fly away.
■ Attracting Mates
When men and women want to make themselves more attractive, they spray perfume. Something similar happens in the insect world—butterflies and moths are masters of using scent magic. Some male butterflies spray sweet-smelling powder onto female butterflies as they fly past them, using this method to find a mate. (Sweetness is relative to butterflies.) This scent is very magical; the female butterfly will immediately, as if under a spell, fly down and wait motionlessly for the male to come for mating. For moths, it's the females that emit the romantic scent. The female emperor moth emits a scent so irresistible that even male emperor moths from several kilometers away cannot resist the temptation. As soon as the male detects the scent of the female with his antennae, he will fly at full speed, ignoring any obstacles, to the moth that is emitting the scent to express his romantic love.
■ Love Songs
The chirping of crickets or the loud singing of cicadas is the insect version of a love lullaby. The louder their calls, the more attractive they are to potential mates who can hear them. When a male cicada sings loudly, its volume can reach 100 decibels—this is louder than a vacuum cleaner on its highest setting. Cicadas "sing" by rapidly tapping the drum-like chambers on the sides of their abdomens.
■ Love Light
Fireflies are true beetles. They are named for the way male fireflies flash their abdomens while flying to seek mates. A female firefly interested in the male sends a signal of acceptance by flashing her own light. Fireflies glow because they have a chemical substance in their bodies that can emit light.
■ Marathon Mating
Once the courtship is over, insects can mate. Most mating insects prefer to finish the process quickly, but dragonflies and damselflies can passionately embrace and tangle together for up to 10 hours, while also performing acrobatic-like movements. If a male in heat finds a willing female, he wraps his abdomen into a circle to "grasp" the female's neck. As they fly, they keep the female's neck locked in place by the male. After a while, they land together. Then the female bends her long body and wraps it around her legs, using a small pouch on her abdomen to collect sperm.
■ Insect Mimicry
Many non-venomous insects mimic those that can bite or contain noxious chemicals. This is a smart way to enjoy the benefits other insects get without much effort. This imitation is called mimicry. For example, hoverflies are mimics of wasps and bees. Because they are hard to distinguish from the real thing, few animals dare to attack them. Not all mimics are insects. A weevil in New Guinea found that moving like a spider makes it safer. Although the weevil has six legs while spiders have eight, the weevil still runs like a spider, keeping its legs in a spider-like posture, which increases its chances of survival.
■ Scary Tactics
Sometimes, it's better to stop the deception immediately than to stay still and hope not to be noticed. To help escape, some insects have large eye-shaped spots on each wing. If an insect is threatened, it spreads its wings and flashes these spots, scaring the attacker into thinking it has encountered a large, untamable creature, giving the insect a moment to escape.
■ Threatening Postures
Predators often stop attacking if they see their prey (the insect) strike a threatening pose. The caterpillar of the silver-ground clover moth has a red circle and a black spot on the front of its thorax. When threatened, it retracts its head into its thorax, forming a terrifying face-like shape. If a bird sees it raise its tail and sway it like a snake in a threatening manner, the bird will back off, allowing the caterpillar to narrowly escape.
■ Ambush Experts
Such constant movement and fighting are exhausting for some insects. Many predatory stink bugs are experts at ambushes. They like to hide patiently on leaves, bark, or flowers, waiting for insects to come within striking range. Then they grab their prey with lightning-fast speed, inserting their long proboscis into the victim's body to kill it.
■ Trapping Killers
Some patient killers set clever traps to catch their prey. To attract flies that feed on animal feces, rove beetles disguise themselves to look and smell like feces. Once hungry flies come near, they quickly become someone else's meal. Antlions are the larvae of insects similar to dragonflies. To catch prey, they dig funnel-shaped pits in sandy soil and hide at the bottom. They then throw sand at passing ants or other insects, causing them to fall into the pit and become the victims of this clever trap.