Terms in this set (76)

The open circulatory system of the crayfish has no veins. Two arteries leave the heart, the abdominal aorta (toward the posterior) and the anterior dorsal aorta (toward the anterior). The open circulatory system is common to molluscs and arthropods. Open circulatory systems (evolved in crustaceans, insects, mollusks and other invertebrates) pump blood into a hemocoel with the blood diffusing back to the circulatory system between cells. Blood is pumped by a heart into the body cavities, where tissues are surrounded by the blood.
Crayfish respire through the exoskeleton and through the gills which are around its legs. As the crayfish walks, the surface area of the gills spread so the water can pass through in order for the crayfish to breath.

The antennal and maxillary glands primarily regulate ionic balance. The total balance of salts and water is also controlled in part by the gut, which can absorb both. The antennal gland also has been shown to reabsorb glucose. Most crustaceans excrete the end product of nitrogen metabolism, in the form of ammonia, through the gills. Some of the more terrestrial forms produce urea or uric acid, which are far less toxic than ammonia. Urea and uric acid may be stored in special large cells near the bases of the legs or excreted without the loss of much water. Both have the same basic structure: an end sac and a convoluted duct that may expand into a bladder before opening to the outside. Antennal and maxillary glands are the excretory filaments in Crustacean. These primarily regulate ionic balance. These are tubular structure of the base of either the maxillae or antennea. These have end sacs called labyrinths which connect to the dorsal bladder via excretory tubes. Hydrostatic pressure forces excrement to move through the labyrinth down the excretory tubules to the bladder. The antennal and maxillary glands also reabsorb nutrients and organic materials.
Crayfish rely upon the tactile input from its second antennae to detect topographical changes in the environment and that such topographical changes can be retained for at least 24 hours.

Through saclike statocyst on the basal segment of each first antenna. These bear sensory setae that serve as statoliths along with grains of sand; animal changes position, so does grain of sand, which stimulate the brain; and the animal adjusts accordingly.
A nauplius is the free swimming microscopic first larval stage of many crustaceans, having an unsegmented body; three pairs of appendages and a single median eye.

Direct and indirect development are terms that describe different processes of animal development. Animal development begins with a fertilized egg. The difference between direct and indirect development lies chiefly in the progression through the juvenile phase of life. The path from conception to a sexually mature adult creature is very different in these two processes. Direct development refers to the process of development in which an animal is born in a smaller version of its adult form. There is no major transition in the form of the animal from infancy to maturity. Animals who experience direct development (Reptiles, birds and mammals) may have a large amount of yolk in order to nourish the young, or the young may be fed directly by the mother's body. Both these methods of nourishing the young require a great deal of energy from the mother. Therefore, the number of offspring must necessarily be small. With indirect development (echinoderms, amphibians and insects undergo indirect development: butterflies, dragonflies, frogs), an animal's birth form is very different from the adult form. The embryo hatches from the egg in a larval form. The larva undergoes a drastic metamorphosis in order to achieve its adult stage. Animals that undergo indirect development lay numerous eggs. Because the eggs are small, they have relatively little yolk. Due to the small amount of yolk, the larva develops and hatches rapidly.
A foul smell or a bad taste is often enough to discourage a potential predator. Stink bugs, for example, have specialized exocrine glands located in the thorax or abdomen that produce foul-smelling hydrocarbons.
These chemicals accumulate in a small reservoir adjacent to the gland and are released onto the body surface only as needed. The larvae of certain swallowtail butterflies have eversible glands, called osmeteria, located just behind the head. When a caterpillar is disturbed, it rears up, everts the osmeteria to release a repellent volatile, and waves its body back and forth to ward off intruders.

Insects that blend in with their surroundings often manage to escape detection by predators and parasites. This tactic, called cryptic coloration, involves not only matching the colors of the background but also disrupting the outline of the body, eliminating reflective highlights from smooth body surfaces, and avoiding sudden movements that might betray location. Obviously, this tactic loses much of its effectiveness if an insect moves from one type of habitat to another. Well-camouflaged insects usually stay close to home or make only short trips and return quickly to the shelter of their protective cover. Many ground-dwelling grasshoppers and katydids, for example, have colors of mottled gray and brown that help them "disappear" against a background of dried leaves or gravel. On the other hand, closely related species that live in foliage are usually a shade of green that matches the surrounding leaves. The larvae of some lacewings improve their camouflage by attaching bits of moss or lichen from their environment onto the dorsal side of their body.

If a distinctive visual appearance is sufficient to protect an unpalatable insect from predation, then it stands to reason that other insects might also avoid predation by adopting a similar appearance. This ploy, essentially a form of "false advertising", was first recognized and described by Henry W. Bates in 1861. Today, it is commonly known as Batesian mimicry. Viceroy butterflies (mostly palatable to birds) are largely protected from predation because they resemble monarch butterflies (very distasteful). Batesian mimicry is usually a successful strategy as long as the model and mimic are found in the same location, the mimic's population size is smaller than that of the model, and predators associate the model's appearance with an unpleasant effect.In 1879, Fritz Müller recognized that two or more distasteful species often share the same aposematic color patterns. Many species of wasps, for example, have alternating bands of black and yellow on the abdomen. This defensive tactic, commonly known as Müllerian mimicry, benefits all members of the group because it spreads the liability for "educating the predator" over more than one species.
Some insects can't see very well, and some live in dark places, so they need a method of communication that doesn't depend on sight. They have to do something that another bug can feel. When an ant is 'following a leader,' it uses its antennae to tap the leader's legs so the lead ant knows that its follower is keeping up with it. Other bugs send vibrations through the plant they are on to warn each other of approaching danger.

Insects have an incredible sense of smell. They can detect just a few molecules of a certain scent in the air. To communicate by smell within a species, insects release chemicals called pheromones. These special chemicals do many things, including marking trails and attracting mates. An ant who finds a food source leaves a pheromone trail as it heads back to the colony. As other ants come across the trail they follow it to the food source and leave another layer of pheromone on their way back. This makes the trail stronger and attracts even more ants. Sometimes pheromones are released into the air, and insects smell them with their antennae. Other times they are released onto something - like a leaf or another insect - in which case the insect can taste the chemical with its feet.

From the buzzing of a bee to the whine of a mosquito to a cricket's chirp, insects can make lots of sounds. Many times, these sounds are higher than human ears can hear. Insects can hear them with sensitive membranes called tymbals located on their abdomen or legs. Here are a few of the ways that insects make their own sounds. Bugs like crickets and grasshoppers make sound by rubbing one part of the body (like a leg) against another (maybe a wing). This is called stridulation. You can think of it as kind of like playing a violin. Some insects, including cicadas, can make a very loud sound by vibrating a membrane on their body (their tymbal). A hollow part of their body cavity acts as a resonance chamber to amplify the sound. This works like a drum. Most insects breathe through tiny pores called spiracles. Some of them use these spiracles to make sounds, too. The Madagascar Hissing Cockroach, for example, pushes air out of its spiracles very fast to make a hissing sound. Bees and mosquitoes buzz when they fly because their wings vibrate fast enough to produce a sound.

Insects have compound eyes, made up of thousands of tiny lenses instead of just one like we have. These lenses don't allow them to see very clearly, but they do make them highly sensitive to light and movement. When you sneak up behind a fly with the fly swatter, chances are it'll see your movement and get out of the way before you can smash it! Insects communicate visually in a passive way by their colorings and markings. After eating the poisonous Monarch butterfly, for example, predators avoid its orange and black coloring. The Viceroy butterfly looks almost identical to a Monarch, so predators avoid it too, even though it is safe to eat. Some moths have a different way of scaring off predators - they have marks on their wings that look like big eyes, threatening would-be attackers.
Caste, in biology, a subset of individuals within a colony (society) of social animals that is specialized in the function it performs and distinguished by anatomical or morphological differences from other subsets.

-The queen bee is the heart and soul of the colony. She is the reason for nearly everything the rest of the colony does. The queen is the only bee without which the rest of the colony cannot survive. Without her, your hive is sunk. A good quality queen means a strong and productive hive.
Only one queen lives in a given hive. She is the largest bee in the colony, with a long and graceful body. She is the only female with fully developed ovaries. The queen's two primary purposes are to produce chemical scents that help regulate the unity of the colony and to lay eggs — and lots of them. She is capable of producing more than 1,500 eggs a day at 30-second intervals. That many eggs are more than her body weight!
-The majority of the hive's population consists of worker bees. Like the queen, worker bees are all female. Workers are smaller than the queen, their abdomens are shorter, and on their hind legs they possess pollen baskets, which are used to tote pollen back from the field. Like the queen, the worker bee has a stinger. But her stinger is not a smooth syringe like the queen's. It has a barb on the end. The barb causes the stinger, venom sack, and a large part of the bee's gut to remain in a human victim. Only in mammals does the bee's stinger get stuck. The bee can sting other insects again and again while defending its home.
-The only male bee in the colony, drones make up a relatively small percentage of the hive's total population. At the peak of the season their numbers may be only in the hundreds. You rarely find more than a thousand. He is larger and stouter than a worker bee. But his shape is in fact more like a barrel (the queen's shape is thinner, more delicate and tapered). The drone's eyes are huge and seem to cover his entire head. He doesn't forage for food from flowers, and he has no pollen baskets. He doesn't help with the building of comb, because he has no wax-producing glands. Nor can the drone bee help defend the hive — he has no stinger and can be handled by the beekeeper with absolute confidence. An organ inside the queen called the "spermatheca" is the receptacle for the sperm. The queen will mate with several drones during her nuptial flight. After mating with the queen, the drone's most personal apparatus is torn away, and it falls to its death.

-Each termite lives in a nest or colony with hundreds, thousands, or even millions of its brothers and sisters. In fact, the termite colony is really a large, extended family. Within this family, various groups of individuals have different functional roles according to a "caste system". The worker caste is the largest group. It consists entirely of immatures, both males and females. These soft-bodied, wingless individuals perform all of the hard labor in the colony: they clean, maintain, and repair the nest, gather food and water, care for the young, and construct new tunnels and galleries as the colony grows. These juveniles all have the genetic capacity to undergo additional molts and become soldiers or reproductives, but most will spend their entire lives as workers.
-Members of the soldier caste are larger in size but fewer in number than the workers. They are also wingless, but they have large heads with powerful jaws. Their job is to guard the nest site and protect it from attacks by ants or other invaders. In some species the soldiers lack jaws but have a large gland in the head that shoots defensive chemicals through a nozzle at the front of the head. The soldiers are unable to care for themselves so they must be fed and groomed by the workers.
-The reproductive caste always includes a king (male) and a queen (female) who are the parents of the termite family and founders of the colony. Some species also have a few supplemental reproductives who share the egg laying duties. These are the only adult insects in the colony. The queen lays large numbers of eggs which develop into more workers and soldiers as the family grows. In every mature colony, there also develops an annual population of young winged reproductives that swarm from the parent nest for a short mating flight. After flight, the delicate wings break off, and the new king and queen set out to find another nest site and start a new colony. Large colonies with multiple reproductives may also split into two or more daughter colonies, a process known as "budding".
The termite's caste system is regulated by pheromones. The king and queen each produce special pheromones that circulate throughout the colony and inhibit workers of the same sex from molting into reproductive adults. A death in the royal family (or an increase in the size of the colony) results in a lower concentration of the corresponding pheromone and, subsequently, one or more workers will molt into replacement reproductives. Likewise, the concentration of sex-specific soldier pheromones regulate the numbers of male and female soldiers to fall within an optimal range based on colony size. Excess numbers of soldiers or reproductives may be killed and eaten by the workers.
-Chewing insects have two mandibles, one on each side of the head. The mandibles are positioned between the labrum and maxillae. They are typically the largest mouthparts of chewing insects, being used to masticate (cut, tear, crush, chew) food items. They open outwards (to the sides of the head) and come together medially. In male stag beetles, the mandibles are modified to such an extent that they do not serve any feeding function, but are instead used to defend mating sites from other males. In ants, the mandibles also serve a defensive function (particularly in soldier castes). In bull ants, the mandibles are elongate and toothed, used as hunting (and defensive) appendages. In bees, which feed primarily by use of a proboscis, the primary use of the mandibles is to manipulate and shape wax, and many wasps have mandibles adapted to scraping and ingesting wood fibres.
-Situated beneath the mandibles, paired maxillae manipulate food during mastication. Maxillae can have hairs and "teeth" along their inner margins. At the outer margin, the galea is a cupped or scoop-like structure, which sits over the outer edge of the labium. They also have palps, which are used to sense the characteristics of potential foods.
-The labium is a quadrupedal structure, although it is formed from two fused secondary maxillae. It can be described as the floor of the mouth. With the maxillae, it assists manipulation of food during mastication or chewing or, in the unusual case of the dragonfly nymph, extends out to snatch prey back to the head where mandibles can eat. In the honey bee, the labium is elongated to form a tube and tongue, and these insects are classified as having chewing and lapping mouthparts.
-The hypopharynx is a somewhat globular structure, arising from the base of the labium. It assists swallowing.

-This section deals only with sucking insects, not those that pierce prior to sucking. The typical example is the moths and butterflies, although as is always the case with insects, there are variations. Some moths have no mouthparts at all. All but a few adult Lepidoptera lack mandibles (the mandibulate moths have fully developed mandibles as adults), with the remaining mouthparts forming an elongated sucking tube, the proboscis. The proboscis is a long tube that is formed by heavily modified maxillae, specifically the galea.

Piercing and sucking
-A number of insect orders (or more precisely families within them) have mouthparts that pierce food items to enable sucking of internal fluids. Some are herbivorous, like aphids and leafhoppers, while others are insectivorous, like assassin bugs and mosquitoes (females only). The defining feature of the order Hemiptera is the possession of mouthparts where the mandibles and maxillae are modified into a proboscis, sheathed within a modified labium, which is capable of piercing tissues and sucking out the liquids. For example, true bugs, such as shield bugs, feed on the fluids of plants. Predatory bugs such as assassin bugs have the same mouthparts, but they are used to pierce the cuticles of captured prey. In female mosquitoes, all mouthparts are elongate. The labium encloses all other mouthparts like a sheath. The labrum forms the main feeding tube, through which blood is sucked. Paired mandibles and maxillae are present, together forming the stylet, which is used to pierce an animal's skin. During piercing, the labium remains outside the food item's skin, folding away from the stylet. Saliva containing anticoagulants, is injected into the food item and blood sucked out, each through different tubes.

-The housefly is the typical sponging insect. The labium gives the description, being articulate and possessing at its end a sponge-like labellum. Paired mandibles and maxillae are present, but much reduced and non-functional. The labium forms a proboscis which is used to channel liquid food to the oesophagus. The housefly is able to eat solid food by secreting saliva and dabbing it over the food item. As the saliva dissolves the food, the solution is then drawn up into the mouth as a liquid. The labellum's surface is covered by minute food channels, formed by the interlocking elongate hypopharynx and epipharynx, which form a tube leading to the oesophagus. The food channel draws liquid and liquified food to the oesophagus by capillary action.
Tracheae open to the outside through small holes called spiracles. The spiracles can act as muscular valves in some insects. The network of tracheae equalized pressure throughout the system.

Gas exchange occurs at the cellular level; no need for respiratory pigment because the tracheoles that carry fresh air come in direct contact with almost every cell.

The circulatory system functions in oxygen transport in some aquatic immature insects; hemolymph consists of plasma and amebocytes for lymphatic system and immune/cellular house keeping. Body parts are bathed in hemolymph.

Insects have a unique respiratory system that is separated from the circulatory system. This respiratory system is composed of slender tracheae that enter the hemocoel from spiracles. Insects have an open circulatory system meaning that blood and interstitial fluids move freely throughout the hemocoel, not in vessels that reconnect to the heart. This system typically causes organisms to have bursts of movement followed by oxygen deprovation. Insects counter this by the means of a separate tracheal system in which oxygen flows in through the spiracles into slender tracheal tubes. These tracheal tubes function like air ducts in a house, starting from being relatively large, and becoming more slender as they spread throughout the hemocoel. This eventually leads to capillary like endings called tracheal end cells which are fluid filled cells at the end of the trachea. These transport oxygen directly to the surrounding tissue, thus providing a constant flow of oxygen to the tissue. This allows insects to have incredibly high endurance for example houseflies are able to beat their wings non stop 24/7 and turn upside down and beat their wings until they starve to death.
Eurypterids - extinct; giant water scorpions; 3m in lenth; spike like telson, large crushing claws; lived in marshy habitats; crawled on land for short distances
-Xiphosura aka Horseshoe crabs - unsegmented carapace; long point telson; book gills; hinged between cephalothorax and abdomen; crustaceans; did well 400 mya as organisms began to move on land (Debonian); gestation of eggs is in a tidal cycle; move in on highest tide of the month, plant eggs in sand and cover them, then ride back out; 28 days later, the babies hatch and release into the water; what comes out of the egg is called a trilobite larva; over time grows and feeds; successful strategy; only 4 or 5 species compared to so many, years ago. Limulus (Atlantic horse shoe crab) are successful due to sandbar stability.
-Pycnogonida - Sea spiders can get very large (70inches); sort of live like the tick like existence except life on Cnidarians, clams and starfish as well; stick proboscis in the organism and feed; overall in most organisms in the world the parents do not usually protect the eggs but females are primary or evolved; seahorse and sea spiders males are the primary role in reproduction; females live for multiple years; females release all of her eggs at one time; males with as many mates as they can; males glue the eggs on the arms or ovitures and carry them; sometimes 15-20 egg masses; larval stage is...; sea spiders have an epistostoma abdomen which is smaller than land spiders which have a larger abdomen that carries most of the organs.
Black widow - more systemic, general inflammation around the body, mild diarrhea, pain at site of wound; meter readers are more susceptible to black widows; rarely come in the home; solitary; females are more of a threat; venom is neurotoxic; acting on nervous system and affects breathing, muscle contraction, heart pumping; 5/1000 bites are fatal
- Brown recluse - by far the most risk to health; brown recluse are in the homes; find the moults of the shells; sinks or bathtubs; stay in places that are moist; reclusive spider; shoes or clothes on the ground left overnight, brown recluse hides in clothes, feels threatened and bites; cause selling and lead to necrosis; venom causes necrosis and splitting of tissue; antibiotics are given to avoid secondary infection; venom is hemolytic.
-Hobo spider is found throughout the Pacific Northwest. It is large and brown with a distinct pattern of yellow markings on its abdomen. Unlike many other similar looking spiders, hobo spiders do not have dark bands on their legs. To catch their prey, hobo spiders build funnel webs in holes, cracks, and recesses. They may be found in outdoor workplaces with retaining walls, and in foundations, window wells, and stacks of firewood and bricks. Indoors, they can nest between boxes or other storage items, on window sills, under baseboard heaters or radiators, behind furniture, and in closets. Hobo spiders do not climb like most spiders but are fast runners. These spiders are much more likely to attack if provoked or threatened. The bite of a hobo spider may go unnoticed; however a moderate to severe, slow-healing wound will develop.
trilobite - an extinct marine arthropod that occurred abundantly during the Paleozoic era, with a carapace over the forepart, and a segmented hind part divided longitudinally into three lobes.
-Horseshoe crab - a large marine arthropod with a domed horseshoe-shaped shell, a long tail-spine, and ten legs, little changed since the Devonian.
-Chelicerate - an arthropod of the large group Chelicerata; an arachnid, sea spider, or horseshoe crab.
- mandibles - the jaw or a jawbone, especially the lower jawbone in mammals and fishes; half of the crushing organ in an arthropod's mouthparts.
-pedipalps - each of the second pair of appendages attached to the cephalothorax of most arachnids. They are variously specialized as pincers in scorpions, sensory organs in spiders, and locomotory organs in horseshoe crabs.
- Eurypterids - an extinct marine arthropod of a group occurring in the Paleozoic era. They are related to horseshoe crabs and resemble large scorpions with a terminal pair of paddle-shaped swimming appendages.
- sea spider - a spiderlike marine arachnid that has a narrow segmented body with a minute abdomen and long legs.
- ovigers - In Pycnogonida, one of a pair of legs, located behind the palps and in front of the walking legs, used for grooming and, in the male, for carrying eggs. In females of some species the ovigers are reduced or absent.
- protonymphon - second instar in mites; early nymph instart of arthropod lifecycle
- green gland - excretory antennae gland in some Crustaceans
- Malpighian tubule - a tubular excretory organ, numbers of which open into the gut in insects and some other arthropods.
- gills - aquatic arthropods respire with these
- antennae - either of a pair of long, thin sensory appendages on the heads of insects, crustaceans, and some other arthropods.
- telson - the last segment in the abdomen, or a terminal appendage to it, in crustaceans, chelicerates, and embryonic insects.
- biramous - appendages with two distinct branches
- coxal glands - modified nephridia that opens at the base of the first and third walking leg
- acari - ticks and mides order of arachnida
- chitinous exoskeletons - A tough, semitransparent substance that is the main component of the exoskeletons of arthropods, such as the shells of crustaceans and the outer coverings of insects. Chitin is also found in the cell walls of certain fungi and algae.
- abdomen - the posterior part of the body of an arthropod, especially the segments of an insect's body behind the thorax.
- myriapod - centipede or millipede; many legs
- cephalothorax - the fused head and thorax of spiders and other chelicerate arthropods.
- Arthropoda - phylum with chitin exoskeleton; an invertebrate animal of the large phylum Arthropoda, such as an insect, spider, or crustacean.
- millipede - a myriapod invertebrate with an elongated body composed of many segments, most of which bear two pairs of legs. Most kinds are herbivorous and shun light, living in the soil or under stones and logs.
- entomology - study of insects
- book lungs - respiratory structure of chelicerates where many thinwalled air pockets extend into a blood filled chamber in the abdomen
- tracheae - any air tube of insects
- uniramia - uniramous arthropod subphylum
The males need to be stealthy, strong, and quick; typically seen as food to females, sex then eaten; males dance by grabbing on to her claws; stinger isn't as quick as most think, plant front legs and then swing the stinger over the head; male grabs females claws and retreat, female pushes forward, male deposits sperm mass on ground and tries to line up the spermatophore with the female, male thrusts forward forcing the female to crack the sperm mass hoping the sperm fertilize the female, male runs away; when fertilized the babies climb on the mothers back, if fall off moms do not recognize the baby as their own anymore and may eat it.

Scorpions have their own special mating ritual in which the male will use his pinchers to grab the female's pinchers and pull her along in what can only be classified as a "courtship dance". In some species the male will even sting the female, however, this does not cause her any harm. During this "dance" the male will drag the female along the ground until he has found a good spot to lay his seeds (usually on a twig or rock). After the male has lain his seeds, he will then drag the female through them and she will secrete them into her body through an opening in her abdomen.
The eggs will stay within the female for several months to a year depending upon species. The young are born live and fall into the mother's legs which she especially folds up for this occasion, creating a sort of basket and means for them to climb up to her back. A female Scorpion carries her babies (usually 25-35) on her back for 10 to 15 days before they go off on their own and are fully independent.