What insects live in families?

Some insects merely drop their eggs and fly away.Others the social insects build elaborate homes where colonies of relatives nurse eggs and young and defend them from enemies.Between these extremes lies a wide range of insects family behaviour.

        Many species lay eggs where hatchlings have the best chance to survive.on food plants or in buried balls of food.A few insects live for a time in small family units-usually only a female and her offspring-in which the female keeps her clean and safe.but in several kinds of beetles,the males also share in the rearing of offspring.as in the bess beetle,dung beetle,and bark beetles.

Home in the log:
                Bess beetle tunnel into fallen trees,where they live in colonies.The male and female,shiny black and anout 3 cm long.mix rotten wood with saliva to feed their grubs.

Buried with food:
                     Many dung beetles bury balls of mammal dung.The female lays an egg inside,giving the larva a safe place to grow and plenty of food.In some species the parents stay with the larva until it becomes an adult.

Bark tunnellers:
              Bark beetle bore into the soft tissue under the bark of living or dead trees.There they mate and lay eggs.The female feeds the young on fungus grown in the tunnels,while the male guards the main entrance.

Leafy den:
             Australian cockroach 7 and a half cm long pull leaves into their burrow to feed their young.Adults repel predators such as centipedes.


A wide range of family behaviour:

*The migratory grasshopper lays clumps of eggs in small holes in the soil.After laying the eggs,the female abandons them.

*The swallowtail buttetfly also lays eggs and then leaves.but she lays eggs only on plants .the young can use for food.

*The 1 and a one forth cm long female stink bug lays large groups of barrel-shaped eggs,then stays to defend them against predators.

Feeding and protecting young:

*Dung beetle prepare a nursery for their young.The female lays eggs in a ball of dung and oversees the feeding of the growing grubs.

*Burying beetles shape decaying flesh into balls to roll into their burrows.The young will hatch there,tended by the female.

*Honeybees,true social insects live in large families.The queen lays the eggs and workers bees care for her and the young.

What kind of colonies do ants form?

All ants live in social groups.but ant colonies vary greatly.In adapting to almost every environment on earth ,ants estimated with many different ways of life.Some species from colonies containing only a queen,a dozen or so workers,and a few males.In such colonies all the ants look much alike and may share jobs.At the other extreme,a colony of african drivers ants may have  upto 100 queens laying eggs continously and as many as 22 million workers.They cooperate so well that the colony seems almost like a superorganism' a single huge living thing.Many complex colonies contain several specialized kind of workers ,each doing a different job.

*Storage:
             Desert-dwelling honey ants gather nectar and carry it back to the nest in their crops.Some workers become living honeypots,storing liquid food in their greatly distended abdomens.They hang from the roof of their nest and let ordinary workers feed from them during periods of drought.

*Slavemaker:
                  Several ant species, such as those of  Polyergus  genus,capture the young of other ants to raise and keep as servants.Some species of so called slavemakers can not survive without their captives to feed them and care for their young.

*Stitchers:
                  Most ants nest underground but some build high in the trees.First living bridges of ants pull leaves together.Then workers sew the leaves.using larvae to lay down threads of the same silk they spin for cocoons.



*Farmers:
               Leaf-cutting ants grow their food in huge underground nest.workers cut bits of leaves and carry them to the nest,where they compost leaves and dropping.A special fungus grows on the compost.All life stages eat only this fungus.

*Warriors:
                Australian bulldog ants,more than 2 and a half centimetres long with huge jaws,bits and hold on while they jab with a stinger over half a centimetre long.They can jump neary 30 cemtimetres while protecting a nest or chasing prey.Their colonies contain no more than 2000 ants and the queens receive no special attention.

How do dragonflies mate?

Ancient evolutionery terms,dragonflies,in the order of Odonata , were among the first insects to fly.Fitted with two sets of lacy wings and brilliantly coloured bodies,they flit and hover over ponds and streams.At mating time,they couple either while airborne or perched on a plant stem.
Some spend a few seconds,others several hours,in the air mating in a wheel position.with the female hanging upside down from the male's abdomen.Often after a female's eggs have been fertilized,the male continous fly with her until the eggs are deposited,which guards against mating attempts by other males.Eggs hatch into aquatic larvae,which may take as long as five years to mature.

Mating of dragonflies begins when a male flies over an airborne female and grasps her with his legs.

A male's claspers operate like pliers.In some species,females have indentations behind the head that help hold claspers in place.

In a skilled aerial manoeuvre,the male takes the female by the neck with his tail claspers and unloosens his legs.The pair move along together.

Having previously filled a genital pouch at the front of his abdomen with sperm from reproductive organs at the tip of his tail,the male steers the female to a suitable spot for mating at the pond's edge.

Having obtained from the male's pouch a store of sperm,which fertilizes the eggs she holds in an egg sac,the female disengages to lay her eggs under the pond's surface.Meanwhile ,the hovering male may mate with other female nearby.

While the male holds on to a blade of grass,The female wraps her legs around him and bends her abdomen to touch his sperm-filled pouch.


The male may remain attached to the mated female.while she releases her eggs into the water.

A female goes on alone after mating poking her tail into deposit the eggs.

Diving underwater the pair cling to a plant where the female affixes her eggs.

How do spiders capture prey?

Some of the world's 30000 species of spiders capture prey by stalking it or ambushing their victims on the ground but most spin web to capture prey in the air.The silk with which they build the webs comes from special organs in their abdomens called spinnerets.Each spider species spins only one kind of web.Some species like the orb weaver,coat some of their silk with droplets of sticky liquid.Other species use hundreds of threads of dry silk to build a bewildering maze in which insect lose their way.
Different spider tactics are shown below.

*Stuck:
              A butterfly is caught in the sticky web of orb weaver Argiope bruennichii.This spider can trap insects as large as grasshoppers.

*Sticky Liquid:
                         Drops of gluey liquid dot the spiral threads but not the spokes of an orb web.Spiders walk on the spokes.

*Types of spider webs:
                             Scientist classify spider web by shapes,some of which are shown below.

*

Spider webs vary greatly from a simple line web to the complex,every-which way jumble of the cobweb.but all are effective for capturing prey.

*Orb Webs:
                    These best known spider webs are spun by three spider families:
1-The Araneidae
2-Tetragnathidae
3-Uloboridae

*Funnel Web:
                        Seen on hedges and trees,this web has a maze to trap insects,which then fall into the flat main web below it.

*Sheet Web:
                    Plate-shaped, flat as a sheet,or domed,these webs are spun among roadside grasses or on the tips of tree branches.

*Cobweb:
                  The strand of a cowweb may seem haphazard but the web is actually fairly regular.Some parts are sticky.

*Vertical line web:
                      The Episinus affinis spider spins two strands and holds them apart,trapping insects on the sticky lower ends.

*Line web:
                    This simple web is a line suspended on several threads between tree
branches.Some species use sticky thread,others do not.

*Spring trap:
                       The triangle spider builds a triangular web,holds the mooring thread,and hauls in the net when prey is caught on it.

How does a leaf roller make a nest ?

We often see in forest or in orchards throughout the world hang small objects that look like cigars or spring rolls.
They are the work of leaf-rolling weevils,small beetles that deposit their eggs inside rolled-up leaves.The females of many species of weevil roll leaves in a certain way after cutting the leaf in precise spots,which makes the job easier.The tightly rolled leaves provide both a safe place for the eggs to develop and a ready source of food when the weevils hatch.some species place many eggs in a roll,while others create a nest for only one egg.

*A common leaf-roller female starts by cutting a notch on side of a beech leaf.

*The leaf roller makes the same cut on the opposit side,stopping at the centre.

*The leaf wilts in a few minutes,allowing the weevil to begin the rolling process.

*The weevil walks the lenght of the leaf pressing the two halves together.

*Winding begins at the tip.The weevil uses its legs to pull the leaf toward its body.

*The weevil makes a slit and lays an egg inside,then winds the leaf further and seal it.

*The weevil bites the leaf to make winding easier.Its left legs pull the leaf toward its body,its right legs wind the leaf into a roll.

*Using its legs on one side,the weevil starts to cover the end of the roll.

*The weevil completes the nest by tucking the final piece in place.

*The finished nest is tightly rolled and sealed.The same nest cut in half reveals a single egg inside.when the larva hatches from the egg,it eats its way through the many layers of the leaf.

*The weevil moves to a new leaf to start another nest.

*Leaf-rolling weevils show a variety of techniques for building their nest.Some cut leaves in such a way that the leaves roll themselves into the proper shape.
Other use vines to tie the roll together.
Certain species secrete a glue that they use to keep the nest from unwinding.

How do ants fight?

Ants are well equipped for combat ,armed with a pair of powerful mandibles and an arsenal of poisonous chemicals.

Not only do they fight and kill the small insect on which they prey,ants must also defend their colonies against those that prey on them,including birds,lizards,termites and some mammals.

The tiny warriors most common opponents,however,are other ants.As a colony expands,its workers must venture increasingly farther from the nest to collect enough food for the growing population.Sooner or later,they are bound to trespass on another colony's territory.The resulting territorial battles can pit armies of different species or the same species often end with a fight to the death.Sometimes the victors even carry their dead enemies back to the nest for food.

Black carpenter ants from warring nest confront each other by displaying their mandibles and raising their thoraxes.

During territorial battles,so many ants are killed that their bodies lie in heaps after the fight.

Twice the size of its attackers,a black mountain ant struggles in vain against several red ants as they bite it to death.The smaller ants' superior numbers prevent their larger victim from retailiating effectively.

Yellow tail ants spray a sticky poisonous liquid,secreted by Dufour's gland,at their enemies.The ant's swivelling abdomen allows it to aim the venom.

The ant's mandibles of jaws are among its most effective weapons.Varying in shape and size from one species to the next.mandible can hold or pinch an enemy in a vicelike grip.Some mandibles are sharp enough to slice through an enemy's skin or shell,other can crush or even clip off a limb.

Poison also play a major role in ant combat.

Some families of ants are equipped with stingers in the tip of their abdomen.These powerful attack weapon inject venoms potent enough to kill other insects.So fierce is the sting of some species,such as those of the Paraponera genus of south America,that it can be crippling even to humans.

Other ants have no stingers but eject their poison as a spray.The venom's main ingredient,formic acid,causes burning and itching in humans and is particularly effective against small animals.

Nesting in mounds of fallen larch needles,the Formica yessensis ant is particularly adapt at repelling its foes with formic acid.As soon as an enemy approaches the ant hill,the insect assumes battle posture,thrusting its abdomen upward between its hind legs.when the invader is 18 centimetres away or closer,the ant squirts it with a stream of formic acid the tip if its abdomen.Small insects are easily killed by the acid defence.

Not all predators,however are so easily deterred.A bear for example,can break up an ant hill and lick up tens of thousands of its inhabitants before the insect even begin to respond to the attack.

Do bees have a language?

Though honeybees make a vatiety of sounds,they communicate by other means.A worker that finds a patch of nectar-rich flowers can tell other workers how to get there without using sounds.

It dances to tell its audience how far away the flowers are and in which direction  they must fly.

Workers dance only in nests full of other workers,the other crowd round,sometimes joining the dance.because the hive is dark inside,the "watching 'workers get information by feeling the dancer with their antennae and from vibrations through the honeycomb.

Honeybees use three basic dances.One is a wide figure eight called the waggle dance,in which the dancer shakes its abdomen from side to side.The other dances are a round dance and a busy,buzzing dance.

Only the waggle dance tells workers how to find a certain spot.

The round dance excites them to hunt for food near the nest and the workers do the buzzing dance to regulate two different colony activities,foraging and swarming.

Scout bees in a swarm also use the waggle dance to tell about new nesting sites they have seen.

Foraging bees indicate direction,distance and quality of a food source by dancing.
Dancers normally perform on vertical surface in the dark hive.using gravity to stand for the Sun when they tell direction.

If a food source lies towards the sun the dancer waggles  straight up.if the food is off to the right of the sun the bee angles its waggle.It can also convey the distance from the hives to the food,measured by how hard it worked to get there.

To indicate hard work and long distance,the bees adds more waggles and slow the whole dance down.

A lacklustre dance indicates a poor food source,where as an excited one tells of a treasure-trove.

Workers may watch five or more dances before trying to find the food.Even then,fewer than half succeed.

In last spring honeybee nests become crowded with workers,and the cells of the comb fill up with honey and eggs.The old queen leaves the hive with a swarm of workers.They alight on a tree and surround the queen with a temporary shelter that is made entirely of worker bees.

Then workers begin scouting out sites to build a new nest.
The scouts will communicate the location of a potential nest site through a dance.

A worker that has discovered food more than 90 metres away gives specific direction with a waggle dance.It circles halfway around,crosses the circle with a waggle,then completes the circle.
Other workers may dance with it.
When a scout find a food source less than 90 metres.from the hive it danced in a circle.This round dance excites other workers to search nearby but the dance gives no more information about direction or distance.

How do woodlice tend their young?

Woodlice or pill bug are not insects.Although they are part of the arthropod phylum,which includes insects,they belong tto the crustacean class,which includes creatures such as lobsters and crabs.

Woodlice can be found worldwide from steamy jungles to arid desert,in mountains as well as low lying coastal areas.
Although highly adaptable ,they retain remnants of their oceanic origins,requiruing water to live.

Many species gravitate to damp forest floors or rocky shorelines.Some even breathe through gills.

The essential chore of woodlouse parents is to provide helpless offspring with moisture.
Females carry eggs on the underside of their abdomens in a fluid filled sac until hatching.

The young,closely resembling adults,break free and almost immediately behin scavenging for food.

The tender white bodies of newly hatched woodlice are highly vulnerable.To keep them from harm,the mother woodlouse watches over her young for a short time after they hatch.

If threatened,woodlice roll into a ball.This defensive posture has the added benefit of conserving moisture.

woodlice are efficient scavengers,if we do an experiment of wood lice to keep it with a dead leaf ,

Woodlice begin feeding on a dead leaf as they decimate the leaf  and digest the material,their droppings are the first step in recycling matter.In nature,these droppings would be further broken down by microbes until they resembled soil.

Through these digestive processes,woodlice play a vital role in soil formation.

An overturned woodlouse mother reveals a mass of white eggs carried in an abdominal
Pouch.The eggs hatch after about two weeks and the young break through the transparent membrane to emerge.
Their miniature bodies resemble those of adults.

Some land -based woodlice have gills must be kept moist with a thin film of water.

What do mosquito larvae eat ?

Adult female mosquitos spend much of their time looking for a meal of blood.while the males eat flower nectar.Their young however are water dwellers,hatching from eggs laid in ponds and puddles.
The larvae hang head downward from the surface of water,breathing air through tubes near the tip of their abdomen.

A developing mosquito eats nothing during its brief pupal stage,as it prepares to emerge as an adult.but during its earlier larval stage it "filter feeds"
When the larva draws water into its mouth constantly moving cilia-brush like hair,filter out microscopic food stuff.

Mosquito larvae eat algae,moulds,bacteria,pollen small dead water fleas,and planktons.
A few species also eat other mosquito larvae.

In some mosquito species,larvae eat the larvae of other mosquito species and other aquatic insects.

But these mosquitos do not sting, their larvae store enough food energy to lay eggs as adults without ever eating again.

Mosquito life from egg to adult:
Eggs of the house mosquito are laid on the water's surface in a raft.

The eggs hatch the following day and the larvae begin the first of four larval stages.in which they will moult three times.

The larval period lasts about 10 days in water temperatures of 25 `Celsius or warmer.At the end of the fourth larval stage,the shell cracks open and the pupa emerges.

The pupa continues to live in water .The pula eats nothing while the mouth changes from filter-feeding structure of the latva to the sucking structure of the adult.
After three or four days ,the adult emerges and flies away.

Large antenna and compound eyes nearly fill the mosquito larva's head.with its fuzzy cilia the larva draws water into its mouth and strains out the edible matter.The cilia
flutter between 180 and 240 times per minute,depending on the temperature.

Eating habits

The first insects,developing 350 million years ago,were probably scavengers,nibbling on the remains of dead animals and plants.

Their older relatives,the spiders ,which go back 400 million years,probably have been predacious from the start.

But since then,insects and spiders have diversified enormously.

The more than one million insect species and 30,000 spider species have become highly specialized in the foods they eat and the ways in which they get their food.
   
   Most spiders entrap their victims.Most insects are plant eaters,but some hunt or stalk prey,and other lurk in ambush.

Even ants may be hunters,sharing their prey with their nest mates through a system of scent communication.

Certain mosquito larvae simply turn and gobble up other mosquito larvae.

In many insects,such as the dragonfly larva and praying mantis,body parts have evolved into tools for seizing prey.

The larva of fungus gnats,called glow-worms,not only set traps for their prey but lure their victims with a blue light.

Some fireflies send false signals that trap other fireflies and one family of insect,the termites,uses other organisms to help them digest the wood they eat as they carve out their homes in trees and timber.

This chapter looks at these and other diverse methods the insects and spiders have found to feed themselves.

Although they are both arthropods, these animals capture their food in different ways.

The spider spins a net called an orb web and then waits to capture the insects that stray onto its threads.

The dragonfly nymph flips out its lower lip with surprising speed to seize its prey.

How do insects make sounds?

On a warm summer night,back yards can erupt in a virtual symphony of insect sounds.These sounds are not mere noise.
They are the male insect's way of attracting potential female mates and warning off rivals and predators.

Crickets (below) make sounds by rubbing the ridged edges of their wing covers together.

Grasshoppers rub ridges on their hind legs against other ridges on their abdomen or wing covers.

A grasshopper seeking a mate may make his sound as often as 50 million times in a summer.

Both crickets and grasshoppers rub their wings faster in warmer weather.

The male cicada (below) has a sound organ on his abdomen,along with a hollow resonating chamber that amplifies the sound.

The long horned beetle (below) uses a special sound organ located at the joint between the thorax and abdomen,with it .he makes loud noises intended to warn off potential enemies.

On meeting an enemy,the long horned beetle produces a loud,threatening sound with a sound organ between his thorax and abdomen.

He makes this sound by rasping the thorax across the ridges of the sound.

Vigorous vibration creates a sound loud enough to warm off potential predators.

This beetle also makes other,quieter sound by rubbing together other joints of its body.

What are antennae used for ?

Although they do not look like noses,an insect's antennae serve mainly to detect odours.Flies and mosquitoes,for example,smell their food with their antennae.

Many female insects,such as butterflies,use their antennae to check for competing insect's eggs on the plants where they intend to lay their eggs.

Females and males of many families including honeybees,long horned beetles and moths use their antennae to detect the pheromones-scent molecules,that are released by potential mates.Their antennae also tell them which of their companions
 have already mated.

Cockroaches find water or each other by detecting scents with their antennae.

Antennae have several other uses too.

Honeybees and ants touch antennae to distinguish between nest mates and intruders and to spread news about food sources and danger.

Mosquitoes antennae can also detect sound.

Scarab beetles,like the cockchafer sport multibranched antennae blades that spread widely apart during flight,determining wind direction and detecting any smells that would lead them to a food source.on the ground the beetle closes its antenna into a thin branch.

1.Identity Check:
                               Workers bees often touch antennae ,communicating by smell.

2.Food Alert:
                       A bee dances to announce a new source of nectar to nest mates and passes along a sample of the nectar.

3.Measurement:
                              Honeybees use their antennae to measure wall thicknesses as they build the hexagonal cells of their nests.

4.Flower Check:
                            Honey bees gather nectar from flower as a carbohydrate source and pollen as a protein source to raise the young.

5.Anatomy:
                    Bee antennae are two-part jointed stalks,containing several types of sensilla,or sensory organs.