Life Cycle

The Life Cycle of a Butterfly As carefree as the butterfly may seem, its life is preoccupied by the purpose of reproduction. That is not as simple as it may sound. The first step of course is to find a congener of the opposite sex to mate with. To accomplish that, the females sit in between plants or in some other strategic spots and release an aromatic substance to attract the males. As butterflies mainly recognise each other merely by their external appearance, the male butterfly throws himself practically at every female that resembles the female of his own species. Every butterfly species do have a characteristic odour, and as the female butterfly can only smell her own congeners, not of the other species, she will court and mate with only those that she can smell. Others will be chased away. When the suitable candidates for mating have approached one another, the courting and mating takes place. The mating usually takes several hours, depending on the species. After the mating the males go looking for other females while females will seek suitable plants to lay her eggs on. Butterflies have a strong preference for particular plants, some of them even having one single food plant, which can make this stage difficult as well. The caterpillar that in time will crawl out of the egg can only utilize its natural food plant - not any others. Luckily the female butterfly can recognise the suitable plant with the sensilla of her legs. Thus solely by standing on a plant the female can judge whether the plant fulfils its purpose as a food plant or not.

The Egg - the Birth The embryo develops inside the egg. A typical time for this process would be from two to three weeks, however there are species that overwinter at this stage, and thus remain in this state from the summer to the following spring. The eggs vary in shape, pattern and colour, all of them carrying certain characteristics of the species in question. Once the caterpillar is fully formed, it is able to pierce the eggshell and it will eat a hole just large enough for emerging from the egg.

The Caterpillar or Larva - the Growth This is a vital stage in the life cycle of a butterfly: this is when the growth occurs. Utilizing its food plant, the caterpillar absorbs a large quantity of food. As the caterpillars do not have elastic skin, they need to shed their skin four times. The new skin is much larger than the previous one, thus enabling the growth. As with eggs and the adult butterflies, caterpillars are unique in their appearance. This stage usually lasts from one to two months, but some species overwinter as caterpillars. The caterpillars are vulnerable to predators, and are often well camouflaged to blend in with their food plant or habitat.

The Pupa - the Transformation How an active caterpillar becomes a pupa with no ability to move is one of nature's great wonders. At the end of the caterpillar's final instar (an interval between the moults) there is one more skin change, in which the skin splits to reveal a wet, glistening creature that looks like a hunched-up caterpillar. In a couple of hours the pupal characters become prominent and once the outer layer dries and hardens the pupal stage is fully formed. Before this final transformation the caterpillar seeks a place where to pupate. Generally butterflies do not spin cocoons to protect the pupa. However, many of them use their silk for fastening themselves in a plant. The pupae are astutely camouflaged by form and colour, which protects them during this vulnerable stage. Inside the pupal

the metamorphosis takes place. From the minute initial stages of adult features, cells grow to produce the recognisable adult characters. The duration of this stage is usually about two weeks, however, some species overwinter as pupae.

The Butterfly - the miracle: the End, the Beginning When the metamorphosis is completed, the adult butterfly breaks the pupal case, pulls itself out and hangs upside down with its wings wet and limp. It begins immediately expanding its wings by forcefully pumping blood into the veins of its wings. Once the wings have reached their definite measurements, the butterfly lets them dry and harden up. When that is accomplished, the butterfly pumps the blood back out of its wing veins. Now the wings are light and strong, and the butterfly is ready to take a flight for the first time. The freshly emerged, beautiful butterfly will fly to seek nourishment and then congeners to mate with, thus creating new beauty in the world. To fulfil this task the butterfly will have to brave the weather, the unsettled environmental conditions, and of course it has to be always wary of its predators. Now, with this newly emerged butterfly, the cycle is to start from the very beginning—

Butterflies are popular, well-known insects with large, colorful wings covered with tiny scales. Together with moths, butterflies make up the order Lepidoptera, which contains over 150,000 species or kinds. Scientists estimate that about 15,000 butterfly species exist worldwide. During its life cycle, a butterfly undergoes a complete metamorphosis (pronounced met-uh-MOREfuhsiss) during which it changes from a leaf-eating caterpillar to a nectar-sipping butterfly.

Beauty with a purpose

Butterflies are one of our very favorite insects. The fact that they do not sting or bite, are brightly colored, and do not become pests in people's homes has something to do with why most people enjoy seeing them fly around and would seldom think of killing one (as one might do with other insects thought of only as "bugs"). Most people think that butterflies simply make the world a prettier place. However, like other life forms in the world, they have a place and serve a purpose. For the plant world, butterflies pollinate or carry pollen from plant to plant, helping fruits, vegetables, and flowers to produce new seeds. From the animal point of view, butterflies are near the bottom of the food chain and provide food (especially in their caterpillar stage) for birds, mammals, and other insects. It is thought that the word butterfly may have originated in England when people started calling the yellow Brimstone or the English sulfur a "butter-colored fly" because the pretty insect reminded them of the color of butter. Eventually it was shortened to "butterfly." The scientific name of its order, Lepidoptera, means "scaly wings" in Latin. This is a correct description since their wings and their bodies are covered with tiny scales. Butterflies and moths are the only insects that have scales. Moths and butterflies are mainly different in their appearance and activities. Moths fly mostly at night and usually have a dull color. Butterflies are active during the day and are brightly colored. Their bodies are thin and hairless, while most moths have plump and furry bodies.

Words to Know Chrysalis: A soft casing, shell, or cocoon protecting the dormant pupa of insects during metamorphosis. Metamorphosis: A complete change of form, structure, or function in the process of development. Pupa: An insect in the nonfeeding stage during which the larva develops into the adult.

Butterflies are everywhere Butterflies are found nearly everywhere in the world except Antarctica. They have lived on Earth for at least 150 million years and range in size from the Western Pygmy Blue, which is smaller than a dime and found in North America, to the Queen Alexandra's Birdwing of Papua New Guinea, which has a wingspan of up to 11 inches (28 centimeters). Although some tropical butterflies can live up to one year, the average life span of a butterfly is at most two months. Butterflies display every color of the rainbow in their wings, and no two butterflies are exactly alike. This coloring serves many purposes: from attracting a mate, to blending in with its surroundings, to warning its enemies that it is poisonous and should be avoided.

Unique life cycle One of the most interesting things about butterflies is their unique life cycle. When a butterfly changes from a slow-moving, fat caterpillar to a colorfully winged, beautiful flying insect, one of nature's most magical events occurs. This metamorphosis happens to most insects, but not as dramatically as it does to a butterfly (the word metamorphosis is Greek for "change in form"). There are four stages in a butterfly's metamorphosis. Every butterfly begins life as an egg. After mating, the female lays her eggs (she actually "glues" them) in small clusters on the leaves of a certain plant. Each species selects its own plant, and the eggs of each are different in shape and markings. In many species, the female dies shortly after doing this. When the egg hatches, the larva emerges. Actually a tiny caterpillar eats its way out the egg, and then proceeds to eat the

eggshell. This caterpillar is a true eating machine, and it continues to eat the leaves of the plant where its mother laid her eggs. Caterpillars have one goal—to eat as much as possible—and in their short lifetimes they may eat as much as twenty times their own weight. Caterpillars naturally grow quickly with all this eating, and since their skin cannot stretch, it splits and is shed. This is called molting and it happens several times as the caterpillar gets fatter and fatter. It is at this slow-moving stage that many a caterpillar is devoured by a hungry bird. Still, many protect themselves by using their colors to blend in with their environment. Other have sharp spines or prickly hairs on their bodies to deter predators, while still others have circles or spots on their skin that trick their predators into thinking that the caterpillar is really a larger animal than it is.

Caterpillar to chrysalis to butterfly If the caterpillar survives and reaches its full size, it attaches itself to a stem from which it hangs upside down. It then sheds its skin one last time, and the old skin hardens almost immediately and becomes a tough shell called a chrysalis (pronounced KRIS-uh-liss). The caterpillar has now become a pupa (pronounced PEW-puh) inside a chrysalis, and its body parts are broken down into a thick liquid that will feed special, pre-programmed cells that have lain dormant in the caterpillar. These cell clusters start to form specialized body parts, like wings, legs, and eyes of a new creature. This process goes on for days, weeks, and sometimes months, according to the type of butterfly that will emerge. The final stage occurs when an adult butterfly finally pushes itself out of its chrysalis, looking nothing like the caterpillar that it was. When the butterfly breaks through the now-soft shell, its wings are wet and crumpled and it must rest while it expands its wings and pumps them full of blood. Continued flapping makes them strong, and soon the adult butterfly is ready to fly away and begin this cycle all over again by looking for a mate. Every adult butterfly is covered with millions of tiny scales that help it to control its body temperature. They also can help it escape from a predator's grip since they rub off easily. It is these scales that give but terflies their beautiful colors. A butterfly's body is made up of three parts: head, thorax, and abdomen. On its head are two long antennae, which it uses as feelers to touch and to smell things. They also have two large compound eyes, which means that each is really thousands of eyes formed together. This allows a butterfly to see in all directions at once. They also have a long hollow tube called a proboscis (pronounced pro-BOSS-siss), which they use like a straw to sip the energy-rich, sugary liquid called nectar produced by flowering plants.

Amazing fliers A butterfly's wings are its most important part since they enable it to move about for food, shelter, a mate, and all the other things it needs. Its wings are very strong, and they are supported and shaped by a network of veins, just like those in a leaf. Different species have differentshaped wings that make each fly in a different manner. Those with large wings flap and make long glides, while those with wide wings flutter and flit or move with short bursts. Those with long, thin wings fly the fastest, and those with short, triangular wings can zigzag and dart about quickly. No matter how they move about, butterflies are incredible fliers, and some migrate over 3,000 miles (4,800 kilometers) to spend the winter in a warmer place. The well-known Monarch butterfly flies to Mexico from North America before the autumn chill arrives. Those living east of the Rocky Mountains fly the longest, traveling over 2,000 miles (3,200 kilometers) to get to the same spot in Central America. Some scientists believe that they find their way by using the position of the Sun as a compass, while others think that they are able to detect changes in light

waves that are filtered through the clouds. However they do it, millions make the journey south every year, and their offspring make their way north again the following spring. The ancient Greeks are said to have believed that when people die, their souls leave their bodies in the form of a butterfly. Their symbol for the soul was a young girl named Psyche who had butterfly wings. Today, we know that real butterflies are extremely sensitive to changes in their environment. More and more, as their habitats are being destroyed and endangered by pollution, pesticides, and other human activity, butterflies are threatened. Some rare species may have already become extinct.

The Life Cycle of a Mosquitoes There are over 2500 different species of mosquitoes throughout the world of which 150 species occur in the United States. 52 species occur in California, and 19 species occur in Alameda County. In the course of the District's operation about 10 species are commonly found in the County. Eight of the species account for over 99% of complaints from the public. Each of the species has a scientific name that is latin, such as Culex tarsalis. These names are used in a descriptive manner so that the name tells something about this particular mosquito. Some species have what is called "common names" as well as scientific names, such as Anopheles freeborni, the "Western malaria mosquito". All mosquitoes must have water in which to complete their life cycle. This water can range in quality from melted snow water to sewage effluent and it can be in any container imaginable. The type of water in which the mosquito larvae is found can be an aid to the identification of which species it may be. Also, the adult mosquitoes show a very distinct preference for the types of sources in which to lay their eggs. They lay their eggs in such places such as tree holes that periodically hold water, tide water pools in salt marshes, sewage effluent ponds, irrigated pastures, rain water ponds, etc. Each species therefore has unique environmental requirements for the maintenance of its life cycle.

The feeding habits of mosquitoes are quite unique in that it is only the adult females that bite man and other animals. The male mosquitoes feed only on plant juices. Some female mosquitoes prefer to feed on only one type of animal or they can feed on a variety of animals. Female mosquitoes feed on man, domesticated animals, such as cattle, horses, goats, etc; all types of birds including chickens; all types of wild animals including deer, rabbits; and they also feed on snakes, lizards, frogs, and toads. Most female mosquitoes have to feed on an animal and get a sufficient blood meal before she can develop eggs. If they do not get this blood meal, then they will die without laying viable eggs. However, some species of mosquitoes have developed the means to lay viable eggs without getting a blood meal. The flight habits of mosquitoes depend again on the species with which we are dealing. Most domestic species remain fairly close to their point of origin while some species known for their migration habits are often an annoyance far from their breeding place. The flight range for females is usually longer than that of males. Many times wind is a factor in the dispersal or migration of mosquitoes. Most mosquitoes stay within a mile or two of their source. However, some have been recorded as far as 75 miles from their breeding source. The length of life of the adult mosquito usually depends on several factors: temperature, humidity, sex of the mosquito and time of year. Most males live a very short time, about a week; and females live about a month depending on the above factors.

Mosquito Life Cycle

The goes separate stages of its they are as Larva, adult. Each stages can recognized special There are groups of living in the They are Anopheles, Culiseta.

mosquito through four and distinct life cycle and follows: Egg, pupa, and of these be easily by their appearance. four common mosquitoes Bay Area. Aedes, Culex, and

Egg : Eggs are laid one at a time and they float on the surface of the water. In the case of Culex and Culiseta species, the eggs are stuck together in rafts of a hundred or more eggs. Anopheles and Aedes species do not make egg rafts but lay their eggs separately. Culex, Culiseta, and Anopheles lay their eggs on water while Aedes lay their

eggs on damp soil that will be flooded by water. Most eggs hatch into larvae within 48 hours. Larva : The larva (larvae - plural) live in the water and come to the surface to breathe. They shed their skin four times growing larger after each molting. Most larvae have siphon tubes for breathing and hang from the water surface. Anopheles larvae do not have a siphon and they lay parallel to the water surface. The larva feed on microorganisms and organic matter in the water. On the fourth molt the larva changes into a pupa. Pupa: The pupal stage is a resting, non-feeding stage. This is the time the mosquito turns into an adult. It takes about two days before the adult is fully developed. When development is complete, the pupal skin splits and the mosquito emerges as an adult. Adult: The newly emerged adult rests on the surface of the water for a short time to allow itself to dry and all its parts to harden. Also, the wings have to spread out and dry properly before it can fly. The egg, larvae and pupae stages depend on temperature and species characteristics as to how long it takes for development. For instance, Culex tarsalis might go through its life cycle in 14 days at 70 F and take only 10 days at 80 F. Also, some species have naturally adapted to go through their entire life cycle in as little as four days or as long as one month. The following pages show a typical mosquito egg raft, larva, pupa, and adult, and explains more about each stage.

Mosquito Egg Raft

Culex mosquitoes lay their eggs on the surface of fresh or stagnant water. The water may be in tin cans, barrels, horse troughs, ornamental ponds, swimming pools, puddles, creeks, ditches, or marshy areas. Mosquitoes prefer water sheltered from the wind by grass and weeds.

Culex mosquitoes usually lay their eggs at night. A mosquito may lay a raft of eggs every third night during its life span. Culex mosquitoes lay their eggs one at a time, sticking them together to form a raft of from 200- 300 eggs. A raft of eggs looks like a speck of soot floating on the water and is about 1/4 inch long and 1/8 inch wide.

Tiny mosquito larvae emerge from the eggs within 24 hours. Notes: Anopheles mosquitoes lay their eggs singly on the water, not in rafts. Aedes mosquitoes lay their eggs singly on damp soil. Aedes eggs hatch only when flooded with water (salt water high tides, irrigated pastures, treeholes, flooded stream bottoms, etc.).

Mosquito Larva Mosquito larvae, commonly "wrigglers", must live in water on water temperature.

called "wigglers" or from 7 to 14 days depending

Larvae must come to the intervals to obtain oxygen called a siphon. The larva organisms which live in the water.

surface at frequent through a breathing tube eats algae and small

During growth, the larva molts (sheds its skin) four times. The stages between molts are called instars. At the 4th instar, the larva reaches a length of almost 1/2 inch. When the 4th instar larva molts it becomes a pupa. Note : Anopheles are unlike Culex and Aedes larvae since they do not have a breathing tube, they must lie parallel to the water surface in order to get a supply of oxygen through a breathing opening.

Mosquito Pupa

Mosquito pupae, commonly called "tumblers", must live in water from 1 to 4 days, depending upon species and temperature. The pupa is lighter than water and therefore floats at the surface. It takes oxygen through two breathing tubes called "trumpets". When it is disturbed it dives in a jerking, tumbling motion and then floats back to the surface. The pupa does not eat. The metamorphosis of the mosquito into an adult is completed within the pupal case. The adult mosquito splits the pupal case and emerges to the surface of the water where it rests until its body can dry and harden.

Mosquito Adult

Only female animals and drink mosquitoes do not bite, but feed on the nectar of flowers.

mosquitoes blood.

bite Male

Aedes mosquitoes are painful and persistent biters, attacking during daylight hours (not at night). They do not enter dwellings, and they prefer to bite mammals like humans. Aedes mosquitoes are strong fliers and are known to fly many miles from their breeding sources. Culex mosquitoes are painful and persistent biters also, but prefer to attack at dusk and after dark, and readily enter dwellings for blood meals. Domestic and wild birds are preferred over man, cows, and horses. Culex tarsalis is known to transmit encephalitis (sleeping sickness) to man and horses. Culex are generally weak fliers and do not move far from home, although they have been known to fly up to two miles. Culex usually live only a few weeks during the warm summer months. Those females which emerge in late summer search for sheltered areas where they "hibernate" until spring. Warm weather brings her out in search of water on which to lay her eggs. Culiseta mosquitoes are moderately aggressive biters, attacking in the evening hours or in shade during the day. Anopheles mosquitoes are the only mosquito which transmits malaria to man.