Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
American Cockroach - Periplaneta americana
American Cockroach - Periplaneta americana

[Image: DSCF0003b_zps297841a2.jpg]

Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Blattodea
Family: Blattidae
Genus: Periplaneta
Species: Periplaneta americana

The American cockroach (Periplaneta americana), also colloquially known as the waterbug, but not a true waterbug since it is not aquatic, or misidentified as the palmetto bug (see Florida woods cockroach for the differences), is the largest species of common cockroach, and often considered a pest. It is also known as the ship cockroach, kakerlac, and Bombay canary.

Despite the name, none of the Periplaneta species are endemic to the Americas; P. americana was introduced to the United States from Africa as early as 1625. They are now common in tropical climates because human activity has extended the insect's range of habitation, and are virtually cosmopolitan in distribution as a result of global commerce.

Cockroaches date back to the Carboniferous period. Cockroaches are thought to have emerged on the supercontinent Pangaea, or on Gondwana, the daughter continent of Pangaea. The cockroach made many adaptations over the years to be able to survive the major die offs to which many species succumbed.

American cockroach adults grow to an average length of around 4 cm (1.6 in) and about 7 mm (0.28 in) tall. They are reddish brown and have a yellowish margin on the body region behind the head. Immature cockroaches resemble adults except they are wingless.


The cockroach is divided in three sections; the body is flattened and broadly oval, with a shield-like pronotum covering its head. A pronotum is a plate-like structure that covers all or part of the dorsal surface of the thorax of certain insects. They also have chewing mouth parts, long, segmented antennae, and leathery fore wings with delicate hind wings. The third section of the cockroach is the abdomen.

The insect can travel quickly, often darting out of sight when someone enters a room, and can fit into small cracks and under doors despite its fairly large size. It is considered one of the fastest running insects.

In an experiment carried out at the University of California, Berkeley in 1991, a Periplaneta americana registered a record speed of 5.4 km/h (3.4 mph), about 50 body lengths per second, which would be comparable to a human running at 330 km/h (210 mph).

It has a pair of large compound eyes, each having over 2000 individual lenses, and is a very active night insect that shuns light.

[Image: cockroach_zpseae633dd.jpg]

Risk to humans
The odorous secretions produced by American cockroaches can alter the flavor of food. Also, if populations of cockroaches are high, there will be a strong concentration of this odorous secretion. Cockroaches can pick up disease-causing bacteria, such as Salmonella, on their legs and later deposit them on foods and cause food infections or poisoning. House dust containing cockroach feces and body parts can trigger allergic reactions and asthma in certain individuals.

American cockroaches generally live in moist areas, but can survive in dry areas if they have access to water. They prefer warm temperatures around 29 °C (84 °F) and do not tolerate cold temperatures. In residential areas, these cockroaches live in basements and sewers, and may move outdoors into yards during warm weather. These cockroaches are common in basements, crawl spaces, cracks and crevices of porches, foundations, and walkways adjacent to buildings.

Life cycle
American cockroaches have three developmental stages: egg, nymph, and adult. Females produce an egg case (ootheca) which protrudes from the tip of the abdomen. On average, females produces 9-10 ootheecae. Cockroach is paurometabolous. After about two days, the egg cases are placed on a surface in a safe location. Egg cases are about 0.9 centimetres (0.35 in) long, brown, and purse-shaped. Immature cockroaches emerge from egg cases in 6 to 8 weeks and require 6 to 12 months to mature. After hatching, the nymphs feed and undergo a series of 13 moultings or ecdysis Adult cockroaches can live up to an additional year during which females produce an average of 150 young.

American cockroaches are omnivorous and opportunistic feeders that eat a great variety of materials such as cheese, beer, leather, bakery products, starch in book bindings, manuscripts, glue, hair, flakes of dried skin, dead animals, plant materials, soiled clothing, and glossy paper with starch sizing. It is particularly fond of fermenting foods. They have also been observed to feed upon dead or wounded cockroaches of their own or other species.

[Image: 100_6_zps18f0679f.jpg]

Due to their large size and slow development, large infestations of these insects are not common within houses. However, during certain times of the year, these cockroaches may move inside a house from outside. In cold weather these cockroaches may move indoors, seeking warmer temperatures and food. Cockroaches may enter houses through sewer connections, under doors, around plumbing, air ducts, or other openings in the foundation. Cockroach populations may be controlled through the use of insecticides. It is also wise to cover any cracks or crevices through which cockroaches may enter. Also, always clean any spills or messes that have been made so that the cockroaches will not be attracted to the food source. Another way to prevent an infestation of cockroaches is to thoroughly check any material that is brought inside. Cockroaches and egg cases can be hidden inside or on furniture, in boxes, suitcases, grocery bags etc. 
[Image: wildcat10-CougarHuntingDeer.jpg]
Parasitic Wasp Turns Roaches into Zombie Slaves using Neurotoxic Cocktail

By Sana Suri, University of Oxford | June 05, 2014 02:48am ET

[Image: 5kvg2pqd-1401881125_zpsc089ae46.jpg]
Bow before thy master.

This article was originally published at The Conversation. The publication contributed the article to Live Science's Expert Voices: Op-Ed & Insights.

For decades, scientists have tried to understand the complex and gruesome relationship between the parasitic emerald wasp Ampulex compressa and its much larger victim, the common household cockroach Periplaneta americana.

At first glance, this parasite-prey relationship seems much like any other: the female wasp stings the cockroach, lays an egg on its abdomen, and once hatched, the hungry larva feeds on the cockroach. However, while most parasitic insects tend to paralyse their victims with a venomous sting, the emerald wasp instead manipulates the cockroach’s behaviour, essentially transforming it into a zombie slave.

With two stings the cockroach is left with the ability to walk, but is entirely robbed of the power to initiate its own movement. The wasp, now tired after administering two stings, regains its energy by cutting off the ends of the cockroach’s antennae, and drinking its blood. Revitalised, it then latches on to the stung cockroach’s antennae and, much like an obedient toddler being lead to his first day of school, the submissive insect follows the wasp’s orders.

In the meantime the wasp also lays an egg on the cockroach, which hatches after three or four days. The hatched larva chews its way into the cockroach’s abdomen, where it proceeds to eat the internal organs in a precise order. This ensures that the docile victim stays alive for the next four days, until the larva eventually forms a cocoon inside it.

With time, the fully-grown wasp emerges from the host’s body and continues this vicious cycle. Through it all, the stupefied roach, although able to move, shows no desire to struggle, flee, or fight, even as it is being eaten alive from the inside.

How to control a roach

This wasp-cockroach relationship has been documented as early as the 1940s, but it wasn’t until recently that scientists have been able to understand how exactly the wasp pulls off this precise behavioural manipulation.

The first sting, administered to a mass of nerve tissue in the cockroach’s thorax, contains large quantities of gamma amino butyric acid (GABA), and complementary chemicals called taurine and beta alanine. GABA is a neurotransmitter that blocks the transmission of motor signals between nerves, and, together with the other two chemicals, it temporarily paralyses the cockroach’s front legs. This prevents the cockroach from escaping while the wasp inflicts the second, more toxic sting directly into the roach’s brain.

It is the second sting that turns the cockroach into a zombie, and contains what Frederic Libersat and his colleagues at Ben Gurion University refer to as a “neurotoxic cocktail”. The venom of the second sting blocks the receptors for another neurotransmitter called octopamine, which is involved in the initiation of spontaneous and complex movements such as walking.

Libersat has shown that unstung cockroaches injected with an octopamine-like compound show an increase in walking behaviour. Those injected with a chemical that blocks octopamine, however, show a reduction in spontaneous walking, much like the victims of the wasp sting. Zombie cockroaches were also able to recover from their stupor and walk after they were injected with a chemical that reactivates octopamine receptors.

There is a fine distinction between the ability to walk, and the ability to initiate such a movement. The stung cockroaches in this instance are devoid of the latter, while their skills for the former seem intact, demonstrated by the fact that these poor creatures are entirely capable of walking to the wasp’s nest, but only when being led by the wasp.

Libersat and colleagues investigated this interesting phenomenon by placing stung cockroaches in potentially harmful situations and testing their escape reflexes. They found that cockroaches stung by the emerald wasps were soon deprived of any will to escape to safety even when electrocuted or drowned. However, their motor skills, measured by the contractions of their muscles when subjected to these dangers, were the same as unstung cockroaches, suggesting that the venom affects the decision rather than the ability to walk.

However haunting this behavioural manipulation is, one can’t help but appreciate the ingenuity of this tiny parasite, enabling it to incapacitate a much bigger victim. If the wasp were to paralyse the cockroach, it probably would not be able to carry it back to its lair. If it were to kill the cockroach, it would lose its source of fresh food. It has evolved to develop the most complex and precise weapon to overcome these two obstacles: venom that only targets the specific neural circuits which guarantee that its victim will walk obediently to its tomb, and stay alive while it is being devoured. And with no will to escape, these poor roaches help another generation of terrifying emerald wasps to be spawned. 
[Image: wildcat10-CougarHuntingDeer.jpg]
Quote:Here's Why Cockroaches Can Survive Just About Anything

[Image: aHR0cDovL3d3dy5saXZlc2NpZW5jZS5jb20vaW1h...NoLmpwZw==]

The genome of the American cockroach has been sequenced for the first time, revealing why these creepy-crawlies are such tenacious survivors.

The roach (Periplaneta americana) has widely expanded gene families related to taste and smell, to detoxification and to immunity, compared with other insects, according to a new study published March 20 in the journal Nature Communications.

"It makes total sense in the context of the lifestyle," said Coby Schal, an entomologist at North Carolina State University who was part of a team that last month reported an analysis of the genome of the German cockroach (Blattella germanica). Many of the gene families that expanded in the American cockroach were also expanded in the German cockroach, Schal said. That makes sense because both species are omnivorous scavengers that can thrive on rotting food in seriously unsanitary environments.

Discriminating tasters

The American cockroach is a denizen of the sewers. It originally hails from Africa, but was introduced to the Americas in the 1500s. Unlike the German cockroach, which is a major pest found almost exclusively in human dwellings, the American cockroach mostly ventures only into the basements or bottom levels of buildings, Schal said. [Photos: Insects and Spiders That May Share Your Home]

Both roaches, though, are hardy survivors, and their genes hold the keys as to why. In the new study, researcher Sheng Li of South China Normal University and colleagues found that American cockroaches have the second-largest genome of any insect ever sequenced, right behind the migratory locust (Locusta migratoria), though a good 60 percent of the roach genome is made up of repetitive segments. Gene families related to taste and smell were much larger than those of other insects, and the researchers found 522 gustatory, or taste, receptors in the roach. German cockroaches are similarly well-equipped, Schal said, with 545 taste receptors.

"They need very elaborate smell and taste systems in order to avoid eating toxic stuff," Schal said.

Hardy survivors

American cockroaches also had a larger-than-average suite of genes devoted to metabolizing nasty substances, including some of the ingredients in insecticides. German cockroaches have similar adaptations, Schal said. Both species developed these genetic changes long before humans came on the scene, he said. Thanks to their tendency to live among toxin-producing bacteria and to eat plant matter that might hold toxic substances, roaches were "pre-adapted" to the insecticides that humans throw at them, Schal said.

The American cockroach also had an expanded family of immunity genes, likely another adaptation for surviving unsanitary environments and fermenting food sources, Li and colleagues wrote. Finally, the roach had a large number of genes devoted to development, like genes responsible for synthesizing the insect's juvenile hormone or the proteins in its exoskeleton. This made sense, the researchers wrote, since American cockroaches can grow up to 2 inches (53 millimeters) long and molt many times to reach that size.  

A greater understanding of the cockroach genome could help researchers come up with new ways to control pest species, the researchers wrote. One example, Schal said, is the Asian cockroach (Blattella asahinai), a close relative of the pesky German cockroach that lives outdoors and doesn't bother humans much at all. It would be interesting to see if there are any differences between the Asian and German cockroach genomes that might explain why one is dependent on human-made environments and the other is not, Schal said.

"There are 5,000 described species of cockroaches, and now we have two [full] genomes," Schal said. "So we need more."

Quote:Explorer or Wallflower? Study Shines Light on Cockroach Personalities

[Image: American-cockroach-Periplaneta-americana...1000&ssl=1]

Most non-entomologists do not readily discern personality traits among cockroaches, lice, or ants. But a team of entomologists from the Université libre de Bruxelles (ULB) in Belgium, have not only found that members of the family Blattidae (in this case, American cockroaches) have distinct “personalities”; they found that those personalities affect how the insects flee to avoid predators and other hazards.

Michel-Olivier Laurent Salazar, Ph.D., previously a doctoral student at ULB and now a postdoctoral researcher at the University of Ryukyus in Japan, and a team of colleagues at ULB examined the phenomenon of thigmotaxis, the trend of any animal to seek contact with other objects. Positive thigmotaxis involves an animal seeking contact with a wall, crevice, or other object, providing close quarters and therefore protection. The researchers discovered that, at least among the American cockroach (Periplaneta americana), thigmotactic tendencies varied, indicating personality differences. (“Personality” carries a complex meaning in humans; in animals, biologists measure personality as consistent individual behavioral traits.) The researchers’ work was published February 1 in of the open-access Journal of Insect Science.

Since cockroaches generally flee to darker, closer quarters when confronted with light, Laurent Salazar’s team—who have been studying cockroach and other insect behavior for more than 15 years—examined how their responses to light differ among individuals.

The researchers set up a circular arena, with an electric fence on the perimeter to prevent escape, and covered the floor of the experimental arena with white paper, which they changed after each experiment to prevent the possibility of the roaches leaving chemical markings. Plastic rings with two openings constituted shelters. The room was darkened except for one single light bulb that exclusively lit the shelter area.

[Image: cockroach-experiment-setup-diagram.jpeg?w=1000&ssl=1]

Over three days, adult male roaches were tested and kept in darkness until their trials (each had three trials). During the trial, the roach was placed in the shelter for a waiting period. Then, shelter openings were opened and light was shown. Individual behavior was recorded for five minutes or until the cockroach fled the shelter. The researchers measured the position, orientation, and wall contact of each roach before and after turning on the light. They also measured individual reaction times to the light.

The researchers discovered personality differences among roaches even before the experimental light disturbance. Individuals showed preferences toward standing in the center or on the side of the shelter, with some touching the walls with their antennae and others never touching the wall. Over the trial period, 28 roaches expressed “low” thigmotaxis (tendency toward the shelter center) and 44 showed higher thigmotaxis. In addition, higher thigmotactic individuals tended to orient themselves toward the shelter wall.

After the light was switched on, reaction times between “high” and “low” thigmotactic roaches differed greatly. Highly thigmotactic roaches had slower reaction times, of about 27 seconds, while low thigmotaxis roach reaction times was much faster, at about 7 seconds. And, in contradiction with earlier studies, reaction times for an individual were not consistent across the three-day period, indicating that roaches might be reacting to light intensity or that other thigmotactic behavioral reactions are occurring.

The study showed that “thigmotaxis is a quantifiable personality trait in P. americana,” the authors wrote, and will help entomologists and others understand the remarkable ability of the cockroach to withstand inhospitable conditions and even resist pest control attempts. “The presence of personalities within a group has been seen to have an important impact on the performance of the group during collective behaviors. These personalities could be an evolutionary benefit for the collective fleeing response to disturbances.”

I think this is an American cockroach, though I'm not entirely sure:
Quote:Dead cockroach in stairwell gets an amazing memorial from university students

A dead cockroach in the stairwell of Texas A&M's anthropology building has just received a sendoff fit for a king.

The dead roach appeared in the stairwell sometime in the middle of November, according to Imgur user jimmyevil. Since the roach apparently persisted through any building maintenance, someone felt compelled to create a shrine for the little creature on Dec. 3.


In the following days, the simple memorial slowly began to grow.


The cockroach received its very own "Never Forget" poster.


Before long, a teddy bear and various candles appeared at the roach's memorial.


Some thoughtful student even created a tiny little open-casket for the bug.


By Dec. 16, the tokens of remembrance were taking up a substantial corner of the stairwell.


And finally, on Dec. 17, the cockroach was cremated and laid to rest.


It's clear that not only are the students at Texas A&M dedicated to all creatures great and small, but they should probably be given more homework — because obviously they have WAY too much time on their hands.

Forum Jump:

Users browsing this thread: 1 Guest(s)