Common Household Pests March 26, 2009 · Posted in Pest & Vermin Control  Garden Ants (Lasius niger) Mating Flights Mating / nuptial flights of Lasius Niger usually occur around June to September throughout the species- range; in North America flights usually occur during the autumn, whereas in Europe they generally take place during the hot summer months of July and August. Flights can contain thousands of winged males and females. Disparities between local weather conditions can cause nuptial flights to be out of phase amongst widespread populations of L. niger. During long-lasting, hot summers, flights can take place simultaneously across the country, but overcast weather with local patches of sunshine results in a far less synchronised emergence of alates (winged individuals). Once the queens have mated they will land and discard their wings and begin to find a suitable place to dig a tunnel. Meanwhile the males generally only live for a day or two after the mating flights and will then die. The New Nest Once the tunnel has been completed a queen will block the entrance and retreat to the bottom. Subsequently the queen will begin to dig out a small chamber, this will serve as the founding chamber of the new colony. Generally a queen will begin to lay eggs immediately after the construction of the chamber, the eggs will hatch after 8-10 weeks. Until the eggs hatch and grow to maturity a Lasius Niger queen will not eat relying on the protein of her wing muscles to be broken down and digested. In some cases a Lasius Niger queen may eat her own eggs in order to survive. Egg to Ant Lasius Niger have 4 stages of development egg, larva, cocoon and adult. Lasius Niger lay tiny, white kidney shaped eggs with a smooth sticky surface which helps them to be carried in a group instead of one by one. After hatching Lasius Niger proceed onto the larva stage resembling tiny maggots. The larva need to be fed by the queen (or workers in the case of an established colony) if they are to mature, as they feed the larva grow shedding their skin, doing so usually three times in total. With each molt the larva grow hooked hairs which allows them to be carried in groups. When Lasius Niger larva reach the last molt they are generally too big to be carried as part of a group and so are carried singularly. Once the larva grows big enough it spins a cocoon around itself. To aid this process a queen (or workers) may bury the larva so that it can spin its cocoon undisturbed, and begins a process of metamorphosis. Once the process is complete the Lasius Niger worker emerges from the cocoon, at this stage Lasius Niger is completely white but will darken over the course of an hour until it has turned black. Colony Established The first workers that emerge are very small compared to later generations. At this point the workers immediately begin to expand the nest and care for the queen and brood, they eventually remove the seal from the entrance to the nest and begin to forage above ground. This is a crucial time for the colony as they need to gather food quickly to support future growth and particularly to feed the starved queen, who would have lost around 50% of her body weight. From this point on the queen-s egg laying output will increase significantly, becoming the queen-s sole function. The later generations of worker ants will be bigger, stronger and more aggressive, reason being dependent on the amount of nutrition Lasius Niger receives at the larva stage. The initial brood being fed only by the scarce resources available to a queen will be much smaller than brood supported by a team of foraging and nursing workers. Provided workers are able to find food at this stage the colony will see an exponential rise in population. After several years once the colony is well established the queen will lay eggs that will become queens and males.In the garden This type of ant is a problem for some gardeners. They will farm aphids for the honeydew they excrete by bringing them inside the nest and bringing them back out again when necessary. The ants will also eat ripe fruits, especially fruits like strawberries that lack a thick protective skin. Often they can be found on discarded chewing gum. Lasius niger also feed on insects and spiders, and other small invertebrates. In Ireland they are usually referred to as pismires, an archaic term for an ant. In the home Black garden ants often explore their surroundings quite extensively during early summer months in an effort to increase the food supply to their queen and her young, and also as a way of testing new ground in preparation for the nests- summer flight. In some cases, these explorations lead to a burrowing through mortar and brick. The usual response from humans when they see several ants in their house (usually the kitchen) is to try to kill them using insecticide powder. A better method of eradicating ants from the house is to leave insecticide bait that ants take back to their nest, since ensuring all surfaces are clean and free from food, sugar and sweet substances that may tempt the ants frequently to return for food may be impossible. Even in flight, the ants will soon realize that they have chosen the wrong place to start their mating flight. If left alone, the colony will nearly always choose an external wall to use as their official take off. Black ants will often make large nests with extensive tunnel connections. These ants may bite a human that disturbs their nests, but it is rare for them to do so. Bed Bugs (Cimex lectularius) The common bedbug (Cimex lectularius) is the species best adapted to human environments. It is found in temperate climates throughout the world and feeds on human blood. Other species include Cimex hemipterus, found in tropical regions, which also infests poultry and cats, and Leptocimex boueti, found in the tropics of West Africa and South America, which infests bats and humans. Cimex pilosellus and Cimex pipistrella primarily infest bats, while Haematosiphon inodora, a species of North America, primarily infests poultry.[1] Oeciacus, while not strictly a bedbug, is a closely related genus primarily affecting birds. Adult bedbugs are reddish-brown, flattened, oval, and wingless, with microscopic hairs that give them a banded appearance. A common misconception is that they are not visible to the naked eye. Adults grow to 4-5mm (1/8th - 3/16th of an inch) in length and do not move quickly enough to escape the notice of an attentive observer. Newly hatched nymphs are translucent, lighter in color and become browner as they moult and reach maturity. In size, they are often compared to lentils or apple seeds. A recent paper by Professor Brian J. Ford and Dr Debbie Stokes gives views of a bedbug under various microscopes. Bedbug 4 mm length 2.5 mm width (Shown in a film roll plastic container. On the right is the sloughed off skin, which this bedbug just recently wore during its nymph form) Feeding habits Bedbugs are generally active just before dawn, with a peak feeding period about an hour before sunrise. However, they may attempt to feed at other times, given the opportunity, and have been observed to feed at any time of the day. They climb the walls to the ceiling and jump down on feeling a heat wave (in wooden houses). Attracted by warmth and the presence of carbon dioxide, the bug pierces the skin of its host with two hollow tubes. With one tube it injects its saliva, which contains anticoagulants and anesthetics, while with the other it withdraws the blood of its host. After feeding for about five minutes, the bug returns to its hiding place. The bites cannot usually be felt until some minutes or hours later, as a dermatological reaction to the injected agents, and the first indication of a bite usually comes from the desire to scratch the bite site. Because of their dislike for sunlight, bedbugs come out at night. Although bedbugs can live for a year or as much as eighteen months without feeding, they typically seek blood every five to ten days. Bedbugs that go dormant for lack of food often live longer than a year, well-fed specimens typically live six to nine months. Low infestations may be difficult to detect, and it is not unusual for the victim not to even realize they have bedbugs early on. Patterns of bites in a row or a cluster are typical as they may be disturbed while feeding. Bites may be found in a variety of places on the body. Bedbugs have been erroneously associated with filth in the mistaken notion that this attracts them. Bedbugs are attracted by exhaled carbon dioxide and body heat, not by dirt, and they feed on blood, not waste. In short, the cleanliness of their environment has an effect on the control of bedbugs but, unlike cockroaches, does not have a direct effect on bedbugs as they feed on their hosts and not on waste. Good housekeeping in association with proper preparation and mechanical removal by vacuuming will certainly assist in control. Biscuit Beetle The Biscuit beetle (Stegobium paniceum) (also known as the Bread beetle or Drugstore beetle) is a tiny, brown beetle that can be found infesting a wide variety of products, and is among the most common non-weevils to be found there. Various figures of the beetle They have a worldwide distribution and can be more commonly found in warmer climates. They are similar in appearance to the Cigarette beetle (Lasioderma serricorne), but are slightly larger (adults can be up to 3.5 mm in length). Additionally, Drugstore beetles have antennae ending in 3-segmented clubs, while Cigarette beetles have serrated antennae (notched like teeth of a saw). The Drugstore beetle also has grooves running longitudinally along the elytra, whereas the Cigarette beetle is smooth. Their larvae are small, white grubs, and they can be distinguished from the grubs of the Cigarette beetle by their shorter hair. The female can lay up to 75 eggs at once, and the larval period lasts up to several months depending on the food source. It is the larvae that are responsible for most of the damage that this species can cause. As their name suggests, Drugstore beetles have a tendency to feed on pharmalogical products, including prescription drugs. They will also feed on a diverse range of dried foods and spices, as well as hair, leather, books, and museum specimens. They can bore into furniture, and in some cases tin foil or sheets of lead. The Drugstore beetle lives in obligatory symbiosis with a yeast fungus, which is passed on to the offspring by covering the eggs with it. Pest control The most effective method of ridding your home of these pests is to try and discover the source of the infestation. Once this has been found, efforts can be made in removing the root of the problem - which is usually related to bird nests, food and high humidity levels. Therefore steps will have to be taken in removing any birds nest from the premises (if this is the situation then ideally specialist advice should be sought), food residues and any food which has been left open; these steps should be followed by adopting measures to decrease the humidity levels; perhaps by way of a dehumidifier. Once satisfaction has been reached in removing the main cause of the infestation, the immediate area of the outbreak should be cleaned thoroughly with a vacuum cleaner, paying special attention to small cracks and crevasses; ideally the area should be treated with an effective insecticide, too. Cockroaches The German cockroach, Croton bug or Steam fly (Blattella germanica) is a small species of cockroach, measuring about 1.3cm (0.51in) to 1.6cm (0.63in) long. It can be tan through brown to almost black, and has two dark parallel streaks running from the head to the base of the wings. Although it has wings, it is unable to sustain flight. The German cockroach is one of the most common and prominent household cockroaches in the world, and can be found throughout many human settlements. These insects are particularly fond of inhabiting restaurants, food processing facilities, hotels, and nursing homes. In colder climates, they are found only near human habitats, since they are not very tolerant to cold. However German cockroaches have been found as far north as Alert, Nunavut[1]. The German cockroach is originally from Asia and very common in Russia, not in Germany. It is very closely related to the Asian cockroach, and to the casual observer they appear nearly identical and may be mistaken for the other. This cockroach can be seen in the day occasionally, especially if there is a large population or if they have been disturbed. However, sightings are most commonly reported in the evening hours as they are most active at night. Varied Carpet Beetle The varied carpet beetle (Anthrenus verbasci) is a 3mm-long beetle that can be a serious household pest. It feeds on natural fibers and can damage carpets, furniture and clothing. The larval form is known as a woolly bear, a name it shares with the larvae of Pyrrharctia isabella. A. verbasci was the first insect to be shown to have an annual circadian rhythm and to date remains a classic example of circannual cycles in animals. Larval form of Anthrenus verbasci (4.6 mm long) The larval form of A. verbasci are roughly 4-5 mm in length. The body is covered in a pattern of alternating light- and dark-brown stripes. The body is usually wider at the back than at the front and also bears 3 pairs of hair tufts along its rear abdomen that can be used for self-defense. Adult A. verbasci range from 1.7 to 3.5 mm in length. Their dorsal surface has scales of two colours, whitish and yellowish-brown. White scales are condensed along the lateral margins of the pronotum. In addition, their antennae are 11-segmented with a club of 3 segments The Flea The Flea is the common name for insects of the order Siphonaptera which are wingless insects whose mouthparts are adapted for piercing skin and sucking blood. (some authorities use the name Aphaniptera because it is older, but names above family rank need not follow the ICZN rules of priority, so most taxonomists use the more familiar name). Fleas are external parasites, living by hematophagy off the blood of mammals and birds. Genetic and morphological evidence indicates that they are descendants of the Scorpionfly family Boreidae, which are also flightless; accordingly it is possible that they will eventually be reclassified as a suborder within the Mecoptera. In the past, however, it was most commonly supposed that fleas had evolved from the flies (Diptera), based on similarities of the larvae. In any case, all these groups seem to represent a clade of closely related insect lineages, for which the names Mecopteroidea and Antliophora have been proposed. Some well known flea species include: Fleas are small (1/16 to 1/8-inch (1.5 to 3.3mm) long), agile, usually dark colored (for example, the reddish-brown of the cat flea), wingless insects with tube-like mouth-parts adapted to feeding on the blood of their hosts. Their bodies are laterally compressed (human anatomical terms), permitting easy movement through the hairs or feathers on the host-s body (or in the case of humans, under clothes). Their legs are long, the hind pair well adapted for jumping (vertically up to seven inches (18cm); horizontally thirteen inches (33cm) - around 200 times their own body length, making the flea one of the best jumpers of all known animals (in comparison to body size), second only to the froghopper. The flea body is hard, polished, and covered with many hairs and short spines directed backward, which also assists its movements on the host. Its tough body is able to withstand great pressure, likely an adaptation to survive attempts to eliminate them such as scratching. Even hard squeezing between the fingers is normally insufficient to kill the flea; it may be necessary to capture them with adhesive tape, crush them between the fingernails, roll them between the fingers, or put them in a fire-safe area and burn them with match or lighter. They can also be drowned. Fleas lay tiny white oval shaped eggs. Their larvae are small and pale with bristles covering their worm-like body. They lack eyes, and have mouthparts adapted to chewing. While the adult flea-s diet consists solely of blood, the larvae feed on various organic matter, including the feces of mature fleas.In the pupal phase the larvae are enclosed in a silken, debris-covered cocoon. Life cycle and habitat Fleas are holometabolous insects, going through the three life cycle stages of larva, pupa, and imago (adult). The flea life cycle begins when the female lays after feeding. Adult fleas must feed on blood before they can become capable of reproduction.Eggs are laid in batches of up to 20 or so, usually on the host itself, which easily roll onto the ground. As such, areas where the host rests and sleeps become one of the primary habitats of eggs and developing fleas. The eggs take around two days to two weeks to hatch. Flea larvae emerge from the eggs to feed on any available organic material such as dead insects, feces, and vegetable matter. They are blind and avoid sunlight, keeping to dark places like sand, cracks and crevices, and bedding. Given an adequate supply of food, larvae should pupate and weave a silken cocoon within 1-2 weeks after 3 larval stages. After another week or two, the adult flea is fully developed and ready to emerge from the cocoon. They may however remain resting during this period until they receive a signal that a host is near - vibrations (including sound), heat, and carbon dioxide are all stimuli indicating the probable presence of a host.Fleas are known to overwinter in the larval or pupal stages. Once the flea reaches adulthood its primary goal is to find blood - adult fleas must feed on blood in order to reproduce.Adult fleas only have around a week to find food once they emerge, though they can survive two months to a year between meals. A flea population is unevenly distributed, with 50 percent eggs, 35 percent larvae, 10 percent pupae, and 5 percent adults.Their total life cycle can take as little as two weeks, but may be lengthened to many months if conditions are favorable. Female fleas can lay 500 or more eggs over their life, allowing for phenomenal growth rates. Adult female rabbit fleas, Spilopsyllus cuniculi, can detect the changing levels of cortisol and corticosterone, hormones in the rabbit-s blood that indicate she is getting close to giving birth. This triggers sexual maturity in the fleas and they start producing eggs. As soon as the baby rabbits are born, the fleas make their way down to them and once on board they start feeding, mating, and laying eggs. After 12 days, the adult fleas make their way back to the mother. They complete this mini-migration every time she gives birth. House Flies The adults are 6-9mm long. Their thorax is gray, with four longitudinal dark lines on the back. The underside of their abdomen is yellow, and their whole body is covered with hair. The females are slightly larger than the males, and have a much larger space between their red compound eyes. Like most Diptera (meaning "two-winged"), houseflies have only one pair of wings; the hind pair is reduced to small halteres that aid in flight stability. Characteristically, the media vein (M1+2 or fourth long vein of the wing) shows a sharp upward bend. Species that appear similar to the housefly include: Life cycle Each female fly can lay approximately 500 eggs in several batches of about 75 to 150, eggs The eggs are white and are about 1.2mm in length. Within a day, larvae (maggots) hatch from the eggs; they live and feed in (usually dead and decaying) organic material, such as garbage or faeces. They are pale-whitish, 3-9mm long, thinner at the mouth end, and have no legs. They live at least one week. At the end of their third instar, the maggots crawl to a dry cool place and transform into pupae, colored reddish or brown and about 8mm long. The adult flies then emerge from the pupae. (This whole cycle is known as complete metamorphosis.) The adults live from two weeks to a month in the wild, or longer in benign laboratory conditions. After having emerged from the pupae, the flies cease to grow; small flies are not young flies, but are indeed the result of getting insufficient food during the larval stage. Darkling beetles Darkling beetles (also known as darkening beetles) are a family of beetles found worldwide, estimated at more than 20,000 species. Many of the beetles have black elytra. Darkling beetles eat both fresh and decaying vegetation. Major predators include birds, rodents, sunspiders, and lizards. The larval stages of several species are cultured as feeder insects for captive insectivores, and include the very commonly known mealworms (Tenebrio molitor) and superworms (Zophobas morio), and the lesser-known mini mealworms (Tenebrio obscurus). Some species live in the dry Namib desert and have evolved modifications that help them collect water from the fog that condenses on their elytra. Raising darkling beetles from larvae through adulthood can be a rewarding biology project for lower school educators. Characteristics This family of beetles may be identified by a combination of features, including: A Coelometopine from India A Platynotine from India A Pitted Darkling Beetle from Namibia Notable species Tenebrio molitor is commonly used as food for terrestrial amniotes kept in terraria. Zophobas morio, or Superworm, is another commonly used live food insect among reptile keepers and is notable due to it being slightly larger and containing smaller amounts of chitin than Tenebrio molitor. Tribolium castaneum is a popular laboratory animal and model organism, especially in studies of intragenomic conflict and population ecology studies. These two, along with other Tribolium species (e.g. T. confusum, T. constructor) and Gnathocerus cornutus, are pests of cereal and flour "c8">silos and other storage facilities. In North America, species of the genus Eleodes are known as darkling beetles, particularly the species called the pinacate beetle or desert stink beetle. Moles A mole-s diet primarily consists of earthworms and other small invertebrates found in the soil. The mole may also occasionally catch small mice at the entrance to its burrow. Because their saliva contains a toxin that can paralyze earthworms, moles are able to store their still living prey for later consumption. They construct special underground "larders" for just this purpose; researchers have discovered such larders with over a thousand earthworms in them. Before eating earthworms, moles pull them between their squeezed paws to force the collected earth and dirt out of the worm-s gut. Mice Mice have been known to humans since antiquity. The Romans differentiated poorly between mice and rats, calling rats Mus Maximus (big mouse) and referring to mice as Mus Minimus (little mouse). Mice can also be kept as pets, and are often sold in petshops. De-coloration in mice was supposedly first noticed in China by 900 BC, where a white mouse was discovered.The "white" gene is a recessive gene which arose from mutation. The word "mouse" and the word muscle are related. Muscle stems from musculus meaning small mouse - possibly because of a similarity in shape.The word "mouse" is a cognate of Sanskrit mus meaning "˜to steal,- which is also cognate with mys in Old Greek and mus in Latin. Characteristics Mice range in size from 12 to 21 cm (4 to 8 inches) long (including a long tail). They weigh from .25 to 2oz (7.1 to 57g). The coat color ranges from white to brown to gray. Most mice have a pointed snout with long whiskers, round ears, and thin tails. Many mice scurry along the ground, but some can hop or jump. Distribution and habitat All species of Mus are native to Eurasia and Africa, where they range from lowlands to mountaintops. The five species in the subgenus Pyromys are found in Sri Lanka, India, Pakistan, and mainland Southeast Asia. Much of their range originally consisted of open grasslands or grassy patches in forests. Reproduction Pups that are just a day old Breeding onset is at about 50 days of age in both females and males, although females may have their first estrus at 25-40 days. Mice are polyestrous and breed year round; ovulation is spontaneous. The duration of the estrous cycle is 4-5 days and estrus itself lasts about 12 hours, occurring in the evening. Vaginal smears are useful in timed matings to determine the stage of the estrous cycle. Mating is usually nocturnal and may be confirmed by the presence of a copulatory plug in the vagina up to 24 hours post-copulation. The presence of sperm on a vaginal smear is also a reliable indicator of mating Female mice housed together tend to go into anestrus and do not cycle. If exposed to a male mouse or the pheromones of a male mouse, most of the females will go into estrus in about 72 hours. This synchronization of the estrous cycle is known as the Whitten effect. The exposure of a recently bred mouse to the pheromones of a strange male mouse may prevent implantation (or pseudopregnancy), a phenomenon known as the Bruce effect. The average gestation period is 20 days. A fertile postpartum estrus occurs 14-24 hours following parturition, and simultaneous lactation and gestation prolongs gestation 3-10 days owing to delayed implantation. The average litter size is 10-12 during optimum production, but is highly strain dependent. As a general rule, inbred mice tend to have longer gestation periods and smaller litters than outbred and hybrid mice. The young are called pups and weigh 0.5-1.5g (0.018-0.053oz) at birth, are hairless, and have closed eyelids and ears. Cannibalism is uncommon, but females should not be disturbed during parturition and for at least 2 days postpartum. Pups are weaned at 3 weeks of age; weaning weight is 10-12g (0.35-0.42oz). If the postpartum estrus is not utilized, the female resumes cycling 2-5 days postweaning. Newborn male mice are distinguished from newborn females by noting the greater anogenital distance and larger genital papilla in the male. This is best accomplished by lifting the tails of littermates and comparing perineums. Rats The best-known rat species are the Black Rat (Rattus rattus) and the Brown Rat (Rattus norvegicus). The group is generally known as the Old World rats or true rats, and originated in Asia. Rats are bigger than most Old World mice, which are their relatives, but seldom weigh over 500 grams (1 lb) in the wild. The term "rat" is also used in the names of other small mammals which are not true rats. Examples include the North American pack rats, a number of species loosely called kangaroo rats, and others. Rats such as the Bandicoot rat (Bandicota bengalensis) are murine rodents related to true rats, but are not members of the genus Rattus. Male rats are called bucks, females are called does, and infants are called kittens or pups. A group of rats is either referred to as a pack, or a mischief. In Western countries, many people keep domesticated rats as pets. These are of the species R. norvegicus, which originated in the grasslands of China and spread to Europe and eventually, in 1775, to the New World. Pet rats are Brown Rats descended from those bred for research, and are often called "fancy rats", but are the same species as the common city "sewer" rat. Domesticated rats tend to be both more docile than their wild ancestors and more disease prone, presumably due to inbreeding. The widely distributed and problematic commensal species of rats are a minority in this diverse genus. Many species of rats are island endemics and some have become endangered due to habitat loss or competition with the Brown, Black or Polynesian rat. The common species are opportunistic survivors and often live with and near humans. The Black Plague is traditionally believed to have been caused by the micro-organism Yersinia pestis, carried by the Tropical Rat Flea (Xenopsylla cheopis) which preyed on R. rattus living in European cities of the day; these rats were victims of the plague themselves. While modern wild rats can carry Leptospirosis and some other "zoonotic" conditions (those which can be transferred across species, to humans, for example), these conditions are in fact rarely found (not true in neotropical countries. Wild rats living in good environments are typically healthy and robust animals. Wild rats living in cities may suffer from poor diets and internal parasites and mites, but do not generally spread disease to humans. The normal lifespan of rats ranges from two to five years, and is typically three years. Silverfish Lepisma saccharina (commonly called the fishmoth, urban silverfish, or just silverfish) is a small, wingless insect typically measuring from a half to one inch (12-25mm). Its common name derives from the animal-s silvery blue colour, combined with the fish-like appearance of its movements, while the scientific name indicates the silverfish-s diet of carbohydrates such as sugar or starches. It belongs to the basal insect order Thysanura, a group estimated to have existed for over 300 million years, at least since the Paleozoic Era. Habitat As with many colorless or nearly colorless invertebrates, silverfish inhabit dark areas like within kitchen cupboards of houses. An eyeless species of silverfish, or a close relative, was discovered in January 2006 in caves in Sequoia National Park, California. Diet The favorite food of silverfish is any matter that contains starch or polysaccharides, such as dextrin in adhesives. These include glue, book bindings, paper, photos, sugar, hair, and dandruff. Silverfish can also cause damage to books, tapestries, and textiles. Silverfish will commonly graze in and around showers, baths, and sinks on the cellulose present in many shampoos, shaving foams and so on. Apart from these cases, the damage caused by silverfish is negligible and they have no direct effect on human health beyond psychological distress to those who are frightened or disgusted by their appearance, or to those whose books have been destroyed by the creatures. Other substances that may be eaten include cotton, linen, silk and synthetic fibers, and dead insects or even its own exuvia (moulted exoskeleton). Dur ing famine, a silverfish may even attack leatherware and synthetic fabrics. In extreme cases, silverfish may live for one year without eating. Silverfish can be found anywhere in homes including, but not limited to, garages, closets, underneath beds, couches, electrical appliances such as keyboards and generally preferring dark areas. Reproduction and growth Silverfish held in bugbox for scale The reproduction of silverfish is preceded by a "love dance", involving three phases, which may last over half an hour. In the first phase, the male and female stand face to face, their trembling antennae touching, then repeatedly back off and return to this position. I n the second phase the male runs away and the female chases him. In the third phase the male and female stand side by side and head-to-tail, with the male vibrating his tail against the female. Finally the male lays a spermatophore, a sperm capsule covered in gossamer, which the female takes into her body via her ovipositor to fertilize the eggs she will lay later on. Young silverfish are white in color. Under laboratory conditions, silverfish may go through between 17 and 66 molts, much more than usual for an insect. Silverfish are one of the rare species of insect that continue to molt after mating. Spider beetles Spider beetles are the approximately 500 species of beetles in the subfamily Ptininae of the family Anobiidae. They are sometimes considered a family in their own right, which is then called Ptinidae. Spider beetles have round bodies with long, slender legs, and lack wings. They are generally 1-5mm long. Both the larvae and the adults are scavengers. They reproduce at the rate of two to three generations per year. Woodlice Woodlice (known by many common names; see below) are crustaceans with a rigid, segmented, long exoskeleton and fourteen jointed limbs. They form the suborder Oniscidea within the order Isopoda, with over 3,000 known species. Woodlice in the genus Armadillidium can roll up into an almost perfect sphere as a defensive mechanism, hence some of the common names such as pill bug or rolly-polly. Most woodlice, however, cannot do this. Ecology Porcellio scaber (left) and Oniscus asellus (centre) living on fallen wood Woodlice need moisture because they breathe through gills, called pseudotrachea, and so are usually found in damp, dark places, such as under rocks and logs. They are usually nocturnal and are detritivores, feeding mostly on dead plant matter. Woodlice then recycle the nutrients back into the soil. In artificial environments such as greenhouses where it can be very moist, woodlice may become abundant and damage young plants. The woodlouse has a shell-like exoskeleton, which it must progressively shed as it grows. The moult takes place in two stages; the back half is lost first, followed two or three days later by the front. This method of moulting is different from that of most arthropods, who shed their cuticle in a single process. A female woodlouse will keep fertilised eggs in a patch on the underside of her body until they hatch into small, pink offspring. The mother then appears to "give birth" to her offspring. Some species of woodlice are able to roll into a ball-like form when threatened by predators, leaving only their armoured back exposed. This ability, or dominant behavior, explains many of the woodlouse-s common names. Metabolic rate is temperature dependent in woodlice. In contrast to mammals and birds, invertebrates are not "self heating": the external environmental temperature relates directly to their rate of respiration. They are not generally regarded as a serious household pest as they do not spread disease and do not damage wood or structures; however, their presence can indicate dampness problems. Woodlice are eaten by a wide range of insectivores, but the only animals known to prey exclusively on woodlice are spiders of the genus Dysdera, such as the woodlouse spider Dysdera crocata Wasps A wasp is a predatory flying stinging insect of the order Hymenoptera and suborder Apocrita that is neither a bee nor an ant. A narrower and simpler but popular definition of the term wasp is any member of the aculeate family Vespidae. Wasps are critically important in natural biocontrol as almost every pest insect species has at least one wasp species that is a predator upon it. Parasitic wasps are increasingly used in agricultural pest control as they have little impact on crops. Taxonomy Wasp stinger, with droplet of venom. A wasp is any insect of the order Hymenoptera and suborder Apocrita that is neither a bee nor ant. The suborder Symphyta, known commonly as sawflies, differ from members of Apocrita by having a broader connection between the mesosoma and metasoma. In addition to this, Symphyta larvae are mostly herbivorous and "caterpillarlike", whereas those of Apocrita are largely predatory or "parasitic" (technically known as parasitoid). The most familiar wasps belong to Aculeata, a division of Apocrita, whose ovipositors are adapted into a venomous stinger, though a great many species do not sting. Aculeata also contains ants and bees, and many wasps are commonly mistaken for bees, and vice-versa. In a similar respect, insects called "velvet ants" (the family Mutillidae) are technically wasps. A much narrower and simpler but popular definition of the term wasp is any member of the aculeate family Vespidae, which includes (among others) the genera known in North America as yellowjackets (Vespula and Dolichovespula) and hornets (Vespa); in many countries outside of the Western Hemisphere, the vernacular usage of wasp is even further restricted to apply strictly to yellowjackets (e.g., the "common wasp"). Categorization The various species of wasp fall into one of two main categories: solitary wasps and social wasps. Adult solitary wasps generally live and operate alone, and most do not construct nests (below); all adult solitary wasps are fertile. By contrast, social wasps exist in colonies numbering up to several thousand strong and build nests-but in some cases not all of the colony can reproduce. In the more advanced species, just the wasp queen and male wasps can mate, whilst the majority of the colony is made up of sterile female workers. Characteristics The basic morphology of a female Yellowjacket wasp The following characteristics are present in most wasps: Wasps are critically important in natural biocontrol. Almost every pest insect species has at least one wasp species that is a predator or parasite upon it. Parasitic wasps are also increasingly used in agricultural pest control as they have little impact on crops. Wasps also constitute an important part of the food chain. Biology Genetics In wasps, as in other Hymenoptera, sexes are significantly genetically different. Females have a diploid (2n) number of chromosomes and come about from fertilized eggs. Males, in contrast, have a haploid (n) number of chromosomes and develop from an unfertilized egg. Wasps store sperm inside their body and control its release for each individual egg as it is laid; if a female wishes to produce a male egg, she simply lays the egg without fertilizing it. Therefore, under most conditions in most species, wasps have complete voluntary control over the sex of their offspring. Anatomy and gender Wasp ocelli (simple eyes) and dorsal part of the compound eyes; also showing fine, unbranched hairs Anatomically, there is a great deal of variation between different species of wasp. Like all insects, wasps have a hard exoskeleton covering their three main body parts. These parts are known as the head, metasoma and mesosoma. Wasps also have a constricted region joining the first and second segments of the abdomen (the first segment is part of the mesosoma, the second is part of the metasoma) known as the petiole. Like all insects, wasps have three sets of two legs. In addition to their compound eyes, wasps also have several simple eyes known as ocelli. These are typically arranged in a triangular formation just forward of an area of the head known as the vertex. It is possible to distinguish between certain wasp species genders based on the number of divisions on their antennae. Male Yellowjacket wasps for example have 13 divisions per antenna, while females have 12. Males can in some cases be differentiated from females by virtue of the fact that the upper region of the male-s mesosoma (called the tergum) consists of an additional terga. The total number of terga is typically six. The difference between sterile female worker wasps and queens also varies between species but generally the queen is noticeably larger than both males and other females. Wasps can be differentiated from bees as bees have a flattened hind basitarsus. Unlike bees, wasps generally lack plumose hairs. They vary in the number and size of hairs they have between species. Diet Sand wasp (Bembix oculata, family Crabronidae) removing body fluids from a fly after having paralysed it with the sting. Generally wasps are parasites or parasitoids as larvae, and feed only on nectar as adults. Many wasps are predatory, using other insects (often paralyzed) as food for their larvae. A few social wasps are omnivorous, feeding on a variety of fallen fruit, nectar, and carrion. Some of these social wasps, such as yellowjackets, may scavenge for dead insects to provide for their young. In many social species the larvae provide sweet secretions that are fed to the adults. In parasitic species, the first meals are almost always provided by the animal that the adult wasp used as a host for its young. Adult male wasps sometimes visit flowers to obtain nectar to feed on in much the same manner as honey bees. Occasionally, some species, such as yellowjackets, invade honey bee nests and steal honey and/or brood.[ Wasp parasitism With most species, adult parasitic wasps themselves do not take any nutrients from their prey, and, much like bees, butterflies, and moths, those that do feed as adults typically derive all of their nutrition from nectar. Parasitic wasps are typically parasitoids, and extremely diverse in habits, many laying their eggs in inert stages of their host (egg or pupa), or sometimes paralyzing their prey by injecting it with venom through their ovipositor. They then insert one or more eggs into the host or deposit them upon the host externally. The host remains alive until the parasitoid larvae are mature, usually dying either when the parasitoids pupate, or when they emerge as adults. Nesting habits Various wasp nests The type of nest produced by wasps can depend on the species and location. Many social wasps produce paper pulp nests on trees, in attics, holes in the ground or other such sheltered areas with access to the outdoors. By contrast solitary wasps are generally parasitic or predatory and only the latter build nests at all. Unlike honey bees, wasps have no wax producing glands. Many instead create a paper-like substance primarily from wood pulp. Wood fibers are gathered locally from weathered wood, softened by chewing and mixing with saliva. The pulp is then used to make combs with cells for brood rearing. More commonly, nests are simply burrows excavated in a substrate (usually the soil, but also plant stems), or, if constructed, they are constructed from mud. Tiphiid wasp, a solitary wasp. Paper pulp type wasp colony on maple tree, photographed near Maple Lake in Cook County, Illinois in October 2008. Solitary wasps The nesting habits of solitary wasps are more diverse than those of social wasps. Mud daubers and pollen wasps construct mud cells in sheltered places typically on the side of walls. Potter wasps similarly build vase-like nests from mud, often with multiple cells, attached to the twigs of trees or against walls. Most other predatory wasps burrow into soil or into plant stems, and a few do not build nests at all and prefer naturally occurring cavities, such as small holes in wood. A single egg is laid in each cell, which is sealed thereafter, so there is no interaction between the larvae and the adults, unlike in social wasps. In some species, male eggs are selectively placed on smaller prey, leading to males being generally smaller than females. Social wasps The nests of some social wasps, such as hornets, are first constructed by the queen and reach about the size of a walnut before sterile female workers take over construction. The queen initially starts the nest by making a single layer or canopy and working outwards until she reaches the edges of the cavity. Beneath the canopy she constructs a stalk to which she can attach several cells; these cells are where the first eggs will be laid. The queen then continues to work outwards to the edges of the cavity after which she adds another tier. This process is repeated, each time adding a new tier until eventually enough female workers have been born and matured to take over construction of the nest leaving the queen to focus on reproduction. For this reason, the size of a nest is generally a good indicator of approximately how many female workers there are in the colony. Social wasp colonies often have populations exceeding several thousand female workers and at least one queen. Polistes and some related types of paper wasp do not construct their nests in tiers but rather in flat single combs. Social wasp reproductive cycle (temperate species only) A young paper wasp queen founding a new colony. Wasps do not reproduce via mating flights like bees. Instead social wasps reproduce between a fertile queen and male wasp; in some cases queens may be fertilized by the sperm of several males. After successfully mating, the male-s sperm cells are stored in a tightly packed ball inside the queen. The sperm cells are kept stored in a dormant state until they are needed the following spring. At a certain time of the year (often around autumn), the bulk of the wasp colony dies away, leaving only the young mated queens alive. During this time they leave the nest and find a suitable area to hibernate for the winter. First stage After emerging from hibernation during early spring, the young queens search for a suitable nesting site. Upon finding an area for their future colony, the queen constructs a basic paper fiber nest roughly the size of a walnut into which she will begin to lay eggs. Second stage The sperm that was stored earlier and kept dormant over winter is now used to fertilize the eggs being laid. The storage of sperm inside the female queen allows her to lay a considerable number of fertilized eggs without the need for repeated mating with a male wasp. For this reason a single female queen is capable of building an entire colony from only herself. The queen initially raises the first several sets of wasp eggs until enough sterile female workers exist to maintain the offspring without her assistance. All of the eggs produced at this time are sterile female workers who will begin to construct a more elaborate nest around their queen as they grow in number. Third stage European paper wasp (Polistes dominula) with a regurgitated droplet of water By this time the nest size has expanded considerably and now numbers between several hundred and several thousand wasps. Towards the end of the summer, the queen begins to run out of stored sperm to fertilize more eggs. These eggs develop into fertile males and fertile female queens. The male drones then fly out of the nest and find a mate thus perpetuating the wasp reproductive cycle. In most species of social wasp the young queens mate in the vicinity of their home nest and do not travel like their male counterparts do. The young queens will then leave the colony to hibernate for the winter once the other worker wasps and founder queen have started to die off. After successfully mating with a young queen, the male drones die off as well. Generally, young queens and drones from the same nest do not mate with each other; this ensures more genetic variation within wasp populations, especially considering that all members of the colony are theoretically the direct genetic descendants of the founder queen and a single male drone. In practice, however, colonies can sometimes consist of the offspring of several male drones. Wasp queens generally (but not always) create new nests each year, probably because the weak construction of most nests render them uninhabitable after the winter. Unlike honey bee queens, wasp queens typically live for only one year. Also queen wasps do not organize their colony or have any raised status and hierarchical power within the social structure. They are more simply the reproductive element of the colony and the initial builder of the nest in those species which construct nests. Social wasp caste structure A wasp gathering wood fibers Not all social wasps have castes that are physically different in size and structure. In many polistine paper wasps and stenogastrines, for example, the castes of females are determined behaviorally, through dominance interactions, rather than having caste predetermined. All female wasps are potentially capable of becoming a colony-s queen and this process is often determined by which female successfully lays eggs first and begins construction of the nest. Evidence suggests that females compete amongst each other by eating the eggs of other rival females. The queen may, in some cases, simply be the female that can eat the largest volume of eggs while ensuring that her own eggs survive (often achieved by laying the most). This process theoretically determines the strongest and most reproductively capable female and selects her as the queen. Once the first eggs have hatched, the subordinate females stop laying eggs and instead forage for the new queen and feed the young; that is, the competition largely ends, with the losers becoming workers, though if the dominant female dies, a new hierarchy may be established with a former "worker" acting as the replacement queen. Polistine nests are considerably smaller than many other social wasp nests, typically housing only around 250 wasps, compared to the several thousand common with yellowjackets, and stenogastrines have the smallest colonies of all, rarely with more than a dozen wasps in a mature colony.