Cockroaches as pests often are difficult to get rid of. Here is an article throwing some light on why this is the case.
They've been around for the past 300 million years, outlasting the dinosaurs and teaming up with evolution to outsmart our attempts to get rid of them. Now, Japanese researchers at Hokkaido University have revealed yet another reason why we have been unable to put a dent in their populations: female solidarity.
Cockroaches, along with termites, snakes and sharks, have long been known to be capable of "virgin birth" or parthenogenesis, a form of asexual reproduction that occurs without fertilization. What is less known are the factors that trigger this process. Is the absence of male cockroaches the only condition necessary for asexual reproduction to take place or does the social environment play a part too? Given that cockroaches are social creatures that live in groups, the Hokkaido University researchers believed that there had to be factors other than male-absent conditions.
To test their hypothesis, the researchers conducted 11 sets of experiments with different groups of American cockroaches, a common pest. The control group comprised a male and female that were allowed to mate. Others comprised virgin females that were kept in isolation; in groups of up to five; and with castrated males. In addition, the researchers also added female sex pheromones – which are secreted in greater quantities by virgin females than those that have already mated – to containers housing single roaches to see if they would regard it as a male-absent signal and produce more eggs as a result.
What they found was that group-housed females, especially those with three or more insects, produced egg cases faster than any other group. In addition, the egg cases were produced in a synchronized manner. Bizarrely enough, this behavior was shared even by those kept in different containers. Furthermore, the group-housed females also produced their second batch of egg cases at shorter intervals than those kept alone (an average of 18 versus 27 days).
On the other hand, the presence of the castrated males and female sex pheromones did little to boost the production process. The researchers had included the former to find out what effect (if any) cohabitants of a different sex would have on the egg-laying process and discovered that it took the female cockroaches that were grouped with the castrated males almost the same amount of time to produce egg cases as the isolated specimens, thus suggesting that the promotion of asexual production depends on the females being able to discern the cohabitants' sex.
There was also a difference in the viability of the eggs. Only 30 percent of those laid asexually hatched, compared to around 47 percent of the ones produced by sexual reproduction. This could explain why the egg production process ramps up when virgin female cockroaches are grouped together, say the researchers. Synchronizing egg production in grouped females might result in their offspring hatching at around the same time. The nymphs would be able to increase their fitness by aggregation and the sharing of resources, which could counter the lower hatching rate of the asexually produced eggs.
According to the scientists, the female solidarity exhibited in this experiment is consistent with other observations of roach behavior. Rarely do fights ever break out among unmated females that are housed in the same container. Instead, they are often found huddling close together, whereas unmated males paired together will often fight until the antennae of both individuals are amputated.
Males? We don't need no stinking males
That said, while the hatchability rate of asexually produced eggs is generally lower than those laid via conventional means, the roaches that hatch from these eggs are nevertheless still able to form and maintain a colony for at least three generations without a male's input, as evidenced by the colony that formed when the researchers placed 15 random adult females in a container. Just over three years later, it had grown to comprise more than 300 females with nymphs and adults of different ages. Since they were kept in optimal conditions in the lab, the researchers estimate that some of the roaches may have even reached the fifth generation.
The all-female cockroach colony that spawned from the 15 females that Japanese researchers placed together in a container (Credit: Kato K. et al., Zoological Letters)
"Our study shows that female cockroaches promote asexual egg production when they are together, not alone," says researcher Hiroshi Nishino. "This is consistent with the fact that progenies produced by fifteen females in a larger container have maintained a colony for more than three years, whereas those produced by one female die out fairly quickly. In addition to the increased fecundity of group-housed females, the synchronized egg production could also assure higher survival rates via the aggregation of similar-aged larvae."
While this may be an impressive feat of female solidarity in the insect world, it does not bode well for human societies. Given that female American cockroaches already have several advantages over males that allow them to adapt to new habitats – for a start, they have longer lifespans and their larger body size protects them from environmental changes – their ability to reproduce asexually and maintain colonies for several generations makes them a health threat to be reckoned with, given the way they transfer disease. Hence the importance of understanding how they reproduce so that more effective cockroach traps can be built, say the researchers.
"The traps utilizing sex pheromones to attract only male cockroaches are not sufficient," says Nishino. "Understanding the physiological mechanism behind the reproductive strategies should help us find more effective ways to exterminate pest cockroaches in the future."
Originally published in the Zoological Letters.
originally by Lisa-Ann Lee , modified by ACES pest control
It is that time of the year again, when a shout in the middle of the night means my wife spotted one of the most nefarious and vicious insects in the kitchen. But is the cockroach’s reputation and its ability to evoke fear, justified? Here are some myths we dispel about our six-legged visitors.
(i) Can a cockroach survive a nuclear blast? NOPE. This is one of the most common myths to be quoted as a fact. The truth is that a cockroach can withstand ten times more radiation than a person, but they would not survive a nuclear event.
(ii)Will I get cockroaches if I have a spotless house? YUP. German Cockroaches are hitch hikers e.g. come in on a package or gift or flowers. They don't care if your home is clean or not- they just get on with making an infestation. Gisborne cockroaches wander into your house by mistake and can't get out. They don't give too hoots if you house is dirty or not. Once an infestation gets going, access to food (dirty home) will help it along.
(iii)Do roaches live for decades? NAW. Cockroaches can live anywhere between a few months to a couple of years, depending on the species.
(iv)Can cockroaches live without a head? YUP. This one is actually true. A cockroach body can survive without a head for up to a week. This is because cockroaches breathe through small holes in its body segments and have an open circulatory system. Their brain is a long- tube like structure e.g.sausage like, and is inside the head and the throax. So when you remove the head you only take part out. Their balance and wing grooming parts of their brain are left behind. So they can stand on your window sill for a while. Since it does not need its head to breathe, it can survive for about three days. However, without a way to drink water, the cockroach will eventually die of dehydration.
(v)If I stand on a cockroach will I spread its eggs? NAW. This is a myth. If you stand on a cockroach you will kill it and all its eggs ( if it has any). The myth comes from the ability of a female cockroach to shake off and throw away her ootheca -sack of young cockroaches - ( please see image above) to safety. When you stress out a female say for example with fly spray, she will flick her ootheca (young) to safety before dying. But if you stand on her and the ootheca, its curtains for all of them! So go ahead and stand on a cockroach!
It is unfortunate we have been unable to scientifically debunk one last myth: that they are more afraid of you than we are of them! Happy hunting!
edited from original article https://www.timesofmalta.com/articles/view/20180812/life-features/myth-debunked-omg-its-a-cockroach.686637
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New studies show pest allergens in schools and inner-cities worsen the symptoms of asthmatic children.
Asthma is the most common childhood disease in the United States, affecting up to 15 percent of children, mostly in inner-cities. We’ve known for many years that one of the primary causes of asthma in children is the presence of cockroaches. Cockroach droppings, shed skins, dead bodies and egg cases all shed allergens in the form of protein particles, which become airborne and are then inhaled. Some people have an allergic reaction to cockroaches with sneezing and a runny nose. But cockroach allergens can lead to a more serious asthmatic response in sensitive individuals. For inner-city children and the elderly, German cockroaches cause more cases of asthma than pets or dust mites.
Recently, several researchers have looked more closely at the role of house mice in childhood asthma. What they found was surprising. Mouse infestations cause more serious asthma symptoms than cockroach infestations. Mouse allergens are present at some level in most inner-city and low-income households and are common in high-rise apartments, older homes, mobile homes and inner-city schools. The older the structure, the more likely that mouse allergens are present. The allergens are found primarily in mouse urine and in mouse dander (shed skin flakes). Because mice dribble urine droplets as they travel, allergens can be anywhere.
In the most recent study, 284 children with asthma in a northeastern U.S. city were followed for one year. Dust samples were taken from their inner-city homes and their schools to analyze for various allergens. In schools, dust mite levels were low and cockroach and rat allergens were almost undetectable. However, mouse allergens were present in almost 100 percent of the school samples and at significantly higher concentrations than in the homes. The children with higher exposure to mouse allergen in schools had increased asthma symptoms and lower lung function. A related study of children in the Bronx, N.Y., found that children allergic to mice were more likely to have had at least one emergency department visit in the past year compared to children not allergic to mice.
WHAT CAN SCHOOLS DO? Asthma attributed to pest infestations in schools is a problem for the parents of asthmatic children since they have little control over the school environment where their children spend much of their day. In the home, bedding can be washed to reduce dust mites. Pet dander can be controlled and, presumably, cockroaches and mice can be eliminated. Should schools be routinely tested for allergens, and if so, how would levels be reduced? Because mice are active mostly at night, would most schools even know that they have a mouse problem?
Some national, state, city and non-governmental organizations have developed school-based asthma management programs that primarily rely on education to manage symptoms and reduce asthma-related school absences. The use of classroom HEPA air filters has been studied. What seems to be largely missing is a proactive integrated pest management approach in schools aimed at reducing the pests (now, mice) that are responsible for many asthma symptoms in schoolchildren.
WHAT CAN PMPs DO? If you have school accounts, you can understand the importance of thoroughly inspecting for and controlling mice. Too often, mouse management isn’t begun until mice are spotted in an account. Schools are prime candidates for preventive measures such as rodent-proofing of doors and openings around utility lines that enter the building.
Don’t limit your intensive mouse inspections to school accounts through. Give extra effort to mouse inspections in homes with asthmatic children or adults. Similar inner-city asthma studies in homes have found mouse allergens present in 95 percent of the homes tested. Allergens were found most often in kitchens, but also in children’s bedrooms. This means children are exposed to mouse allergens at school during part of the day, and then continue to be exposed at home during the remainder of the day, although generally at lower levels than at school.
REMOVING ALLERGENS. Unfortunately, eliminating the pests causing asthma doesn’t necessarily eliminate the symptoms for everyone. Allergens accumulate over time and are very difficult to remove from an environment, particularly when they are from pests that live (and die) in hidden places like wall voids or cracks and crevices.
Studies on cockroach allergen deposits in homes found that after successful elimination of the cockroaches, even the most thorough, professional cleaning did not eliminate all the hidden allergens. Enough allergen residue remained to still cause reactions in very sensitive people. This emphasizes the importance of not allowing cockroaches or mice to become problems in the first place. Prevention is key.
adapted from an article by Sandra Kraft and Larry Pinto http://www.pctonline.com/article/choking--on-air/
Are cockroaches RADIATION proof?
Reputation: Yuck. Cockroaches are filthy, immortal scavengers that are unaffected by radiation. In a post-apocalyptic world, it will be these dirty little critters that survive. We would be better off without them.
Reality: There are almost 5,000 species of cockroaches, of which only around 30 have any pest-like tendencies. These few malign a group of insects that boasts an astonishing, enriching diversity of forms. Cockroaches are pretty well toasted by radiation.
The sight of a cockroach scuttling across the kitchen floor is distinctly unsavoury. This emotional truth has led most of us to believe that all cockroaches must be similarly repugnant.
But not George Beccaloni, curator of orthopteroid insects at the Natural History Museum in London, UK. He is on the side of the cockroaches. "People have a very biased view of the group," he says.
Cockroaches are found on all continents apart from Antarctica, from rainforests to deserts
Less than 1% of the 4,800 known species of cockroach cause humans any bother, yet few of us give the 99% a second thought. This is manifestly unfair, says Beccaloni.
He points out that there are about as many cockroach species as there are mammals. So writing off all cockroaches, based on our dislike of 30 or so species, "is like encountering a mouse or a rat and then branding all mammals as disgusting vermin," he says.
I take the point, but remain unconvinced. Mammals are spectacularly diverse. I think back to a childhood holiday in Sardinia, where our flat was plagued by cockroaches. How different can the rest of cockroaches be? Beccaloni takes the next half hour to enlighten me.
For a start, they live in a huge range of habitats.
"Cockroaches are found on all continents apart from Antarctica, from rainforests to deserts," says Beccaloni.
The appealingly-named Megaloblatta blaberoides boasts a whopping wingspan of over 7in (18cm)
The abundance of species is greatest in the tropics, and at low altitudes where temperatures are high. However, there are those can cope with extremes. Eupolyphaga everestiana is a montane specialist that lives on Mount Everest at well over 16,400ft (5,000m) above sea level.
Since they live in so many diverse environments, it is not surprising that cockroaches should come in many different shapes and sizes.
The smallest species on record is the ant cockroach, which lives in the nests of leaf-cutter ants in North America. At just a few millimetres long, it is dwarfed by its hosts.
In contrast, the appealingly-named Megaloblatta blaberoides boasts a whopping wingspan of over 7in (18cm).
Larger still is the giant burrowing cockroach from Queensland, Australia. It is wingless, about 3in (8cm) long, and can weigh over 1oz (30g).
Cockroaches of the Perisphaerus genus can roll up into an armadillo-like defensive ball
This cockroach, which would easily occupy most of your palm, might sound alarming. But it could not care less about humans. "The huge rhinoceros cockroach only feeds on bark and dead leaves," says Beccaloni.
Most cockroaches have taken on similar ecological roles, feeding on decaying organic matter and thus making nutrients available to other organisms. "There are indications that the ecological significance [of cockroaches] is massive," says Beccaloni.
For many species, even some humans, cockroaches are also a sought-after snack. This helps explain why many in the group have evolved nifty ways to avoid being eaten.
The banana cockroaches (Panchlora) have opted for a simple camouflage approach: they are green and this helps them to blend in.
Cockroaches of the Perisphaerus genus can roll up into an armadillo-like defensive ball.
The females churn out perfect clones of themselves without any need for males or copulation
The Prosoplecta species have evolved the same distasteful red-and-black colouration as ladybirds. In order to achieve the rounded shape of a ladybird, Beccaloni says, each of their hind wings rolls up at the ends "like an umbrella around itself".
Some species can fire out a defensive spray, like the Pacific beetle cockroach.
Others, like the Madagascan hissing cockroach, make startling noises when disturbed, presumably to unsettle any would-be predators.
Perhaps inevitably, cockroaches have also come up with a plethora of ways to make more cockroaches.
"Cockroaches as a group are one of the most if not the most varied of all insect groups, in terms of their reproductive biology," says Beccaloni.
A few species appear to be wholly parthogenetic. The females churn out perfect clones of themselves without any need for males or copulation. In others, the females can flip between sexual and asexual modes of reproduction depending on the conditions.
The nymphs have razor-sharp mandibles, which they use to slice into her cuticle and feed on her blood
However, in most species the female produces an egg sac. Some simply lay it and move on, but others incubate the egg case in a brood pouch in their body, effectively giving birth to live young.
Pacific beetle cockroaches have abandoned egg cases altogether. The female deposits eggs directly into her brood pouch. There she nurtures them on a milk-like secretion – "the most nutritious energy-rich protein that's yet been discovered," according to Beccaloni – before giving birth to live, well-developed young.
If this sounds familiar, it should. "It's a very similar situation to the placenta of a mammal," says Beccaloni.
In a few cases, the female even cares for her offspring after birth.
For instance, a Thorax porcellana mother carries her babies huddled beneath her forewing. It sounds almost cute, until you learn that the nymphs have razor-sharp mandibles, which they use to slice into her cuticle and feed on her blood. "They are like little vampires," says Beccaloni.
With so many extraordinary adaptations, it would not come as much of a surprise to find that cockroaches really could survive a nuclear blast. But tolerance of radiation is one talent they lack.
There are about as many cockroach species as there are mammals
"It's mostly an urban myth," says Beccaloni.
A human will usually be killed outright by a dose of 10 Grays. "Cockroaches are only about five times more resistant," says Beccaloni.
At first glance that might sound impressive, but it actually means they "are at the lower end of radiation tolerance for insects," he says. Other species can survive doses of radiation ten times as intense, or even higher
By Henry Nicholls
ACES pest control fields calls from customers every week about these cockroaches. While Simon is right that they do not "infest" houses like German Cockroaches, ACES commonly find the full life cycle inside homes. They are different to the German Cockroaches as they prefer it cooler. But are often still found in kithens in the cooler parts such as the back of cupboards. Mostly people dont like the look of them as they can get quite large. They are not a health risk.
It’s native to Western Australia and has been found as far away as Gisborne, New Zealand. But never in Tasmania. Until now.
The drymaplaneta communis, or the Gisborne cockroach, has arrived.
Simon Fearn is the Collections Officer at QVMAG and has been the first to document the new roach's presence. In February, Simon's colleague, Judy Rainbird, brought one in she'd caught in her West Launceston backyard.
"People in the museum are always on the lookout for things so Judy caught the cockroach and brought it in, and because I'd spent quite a few years on the mainland collecting insects, I recognised the thing straight away."
Finding a single cockroach doesn't mean an established population, though, since one could have arrived through freight or another means, but then the specimens kept coming.
"Over the next few months, she started finding more and more and they were turning up in her neighbour's yard, and then another colleague at work just recently happened to mention that she's also seen some strange cockroaches and she sent through a photo."
You guessed it, the Gisborne cockroach again.
"It was the same type of roach and she lives about 1.1km away from where Judy lives so we've got quite a few specimens now, we've got females with egg cases, so it looks like we've got a new Tasmanian roach."
It's not just Launceston, though.
"Just the other day, one turned up in Sandy Bay in Hobart. Our colleagues at TMAG have been very helpful in getting that one identified and it's the same type of roach."
Again, one roach doesn't necessarily mean they've spread that far, but Simon Fearn would appreciate your help.
"We would really, really like members of the public, if they see anything strange, to bring them into the museums."
Here's what to look for:
- large roach, 25-30mm
- dark, chocolatey brown body
- a clear white band along the outer edge of both sides of its body
"We're urging anyone who sees a large roach with a white or cream band down each side of its body, if they could drop it into the museum please."
If you're wondering how to do that, he adds, "the best way is to put it in the freezer, then it just goes to sleep."
GOOD NEWS: Simon Fearn adds that they don't seem to live in people's houses.
Perhaps with New Zealand being cooler than Australia they are more able to live our houses. Definately a winter issue over here in NZ.
adapted from http://www.abc.net.au/radio/hobart/programs/your-afternoon/cockroaches/8653054, by Simon Fearn
for more information on services offered by ACES pest control please click here for our services for rodents please click here for services for ants please click here and for cockroaches please click here
Flying Cockroaches! Heat Sends Your Favorite Pests Soaring
The summer heat may give American cockroaches like this one enough energy to take to the skies.
Summer weather can make for hot, sticky and uncomfortable days. And if staying cool and keeping hydrated aren't enough to worry about, heat waves could cause cockroaches to take to the skies. Yes, you read that right. Flying cockroaches.
"Cockroaches, like all insects, are cold-blooded, meaning their activity rate increases with temperature," said Jules Silverman, an entomologist and professor at North Carolina State University, in an interview with Live Science. (Cold-blooded creatures are ectothermic, which means they depend on external heat to keep their bodies warm.)
This also means that the species of cockroach that are able to fly (and most of them are capable) are probably more likely to do so in warmer places, said Silverman. [Alien Invaders: Photos of Destructive Invasive Species]
If you think that flying cockroaches are especially horrific, you probably live somewhere with a colder climate and a denser human population. Flying cockroaches in the subways of New York have garnered some headlines, but "flight of the cockroach" is not so common up north, said Michael Bentley, staff entomologist for the National Pest Management Association. People in the southern states are likely to miss what all of the fuss is about. "Down in Florida, they fly a lot more," Bentley told Live Science. "They have to cover a greater distance to find food."
In big cities, these insects have ample access to food that doesn't require aerial travel. As a result, the muscles the roaches use to fly aren't as primed. Sweltering summer heat, however, can give them enough energy to spread their wings. They may fly for various reasons, including to find mates, to find food or to escape a predator (or a stomping foot).
No matter where you live, don't expect cockroaches to fill the skies. They aren't exactly ace flyers. "It's relatively controlled, but not as graceful as something like a butterfly," said Bentley. What they do is more of a controlled glide, although their wings do flap. The distance and heights they reach are more akin to those of a cricket than a bird, according to Bentley.
Another important point, said Silverman, is that the cockroaches with which many people are most intimately acquainted can't fly. The small roaches that often live in homes, called German cockroaches, have wings, but they are unable to get airborne. American cockroaches, a less common and much bigger pest, can fly.
If you have a run-in with a flying roach, don't get too concerned: Although it's unnerving, they aren't trying to attack you. "There is nothing dangerous about flying cockroaches, other than an irrational fear driving people to distraction," said Silverman.
by Taylor Kubota