Why the cockroach is one of nature"s survivors
There are more than 4000 species of cockroach, with 30 of those species associated with human habitations, and four considered to be pests.
Common types of pest cockroach are the American, German, Asian and Oriental species. The cockroach belongs to the order 'Blatteria', and is an ancient insect - cockroach-like species have been on the Earth for over 295 million years.
Compared to some insects the cockroach is quite large - many species are the size of a thumbnail, but some are even bigger. The largest species, the Australian Giant Burrowing Cockroach, can reach 3.5 inches long and, weigh up to 30 grams; the Central American giant cockroach is a similar size, but isn't such a heavyweight.
Cockroaches tend to have flat bodies and small heads. They're known as generalised insects, with few specific adaptations, and in fact, are quite primitive. Physically tough, they have four wings, with the top two acting as a shield for the more fragile lower pair. They also have compound eyes, and flexible antennae.
Using pheromones to attract their mates, cockroaches reproduce after the male has performed a courtship display. Reproduction is through copulation - although some species are known to be able to reproduce without the need for a mate. (This process is known as 'parthenogenesis'.) Eggs are carried by the females, either on or in their bodies, although some species carry live young.
Because of their sturdy looking appearance, it's often suggested that a cockroach would survive a nuclear war, and that the species would inherit the Earth from humans.
A cockroach's fatal dose of radiation might be as much as 15 times higher than ours (although this is not much greater than that of any other insect). This is because the effects of radiation are worse during cell-division, and cockroach cells divide relatively rarely, when it changes its skin (once a week, at most, for juveniles). Human cells are constantly changing and dividing, making us more susceptible to radiation.
Cockroaches are indeed extremely tough insects. They are able to survive on little or no food for up to a month, and require very little in the way of nourishment. They're also able to go without air for extended periods, and some experiments have seen cockroaches recover, after spending as long as half an hour submerged in water. These facts may explain why the roach is sometimes referred to as indestructible.
These insects are found in various environments all over the world. Some species are quite adaptable, but in general, all types of cockroach prefer a warm environment. This may explain why some pest species are drawn to the places we live (although our homes would be considered too cold for some tropical species). In general they're nocturnal, and scatter away from light, with the exception of the Asian cockroach, which is drawn to it.
In terms of behaviour, the cockroach displays a mixture of competitive and co-operative tendencies. Individuals will leave scent trails to lead others to food or shelter, and swarms of cockroaches have been observed to show group decision-making skills.
Where resources like shelter are limited, they are known to manage the situation depending on their numbers - splitting a group between different shelters, in order to accommodate all members, for example.
Although people generally react negatively towards the insect, there have been various depictions of the cockroach in human culture, both positive and negative. A cockroach is the friend and companion of the lonely robot Wall:E, in the Disney/Pixar movie, for example; whereas Franz Kafka's 'Metamorphosis' sees the narrator turn into a roach-like insect, much to his disgust.
Whatever our views might be, the humble cockroach has shown itself to be a survivor, and we're likely to be sharing the Earth with them for many years to come.
Common types of pest cockroach are the American, German, Asian and Oriental species. The cockroach belongs to the order 'Blatteria', and is an ancient insect - cockroach-like species have been on the Earth for over 295 million years.
Compared to some insects the cockroach is quite large - many species are the size of a thumbnail, but some are even bigger. The largest species, the Australian Giant Burrowing Cockroach, can reach 3.5 inches long and, weigh up to 30 grams; the Central American giant cockroach is a similar size, but isn't such a heavyweight.
Cockroaches tend to have flat bodies and small heads. They're known as generalised insects, with few specific adaptations, and in fact, are quite primitive. Physically tough, they have four wings, with the top two acting as a shield for the more fragile lower pair. They also have compound eyes, and flexible antennae.
Using pheromones to attract their mates, cockroaches reproduce after the male has performed a courtship display. Reproduction is through copulation - although some species are known to be able to reproduce without the need for a mate. (This process is known as 'parthenogenesis'.) Eggs are carried by the females, either on or in their bodies, although some species carry live young.
Because of their sturdy looking appearance, it's often suggested that a cockroach would survive a nuclear war, and that the species would inherit the Earth from humans.
A cockroach's fatal dose of radiation might be as much as 15 times higher than ours (although this is not much greater than that of any other insect). This is because the effects of radiation are worse during cell-division, and cockroach cells divide relatively rarely, when it changes its skin (once a week, at most, for juveniles). Human cells are constantly changing and dividing, making us more susceptible to radiation.
Cockroaches are indeed extremely tough insects. They are able to survive on little or no food for up to a month, and require very little in the way of nourishment. They're also able to go without air for extended periods, and some experiments have seen cockroaches recover, after spending as long as half an hour submerged in water. These facts may explain why the roach is sometimes referred to as indestructible.
These insects are found in various environments all over the world. Some species are quite adaptable, but in general, all types of cockroach prefer a warm environment. This may explain why some pest species are drawn to the places we live (although our homes would be considered too cold for some tropical species). In general they're nocturnal, and scatter away from light, with the exception of the Asian cockroach, which is drawn to it.
In terms of behaviour, the cockroach displays a mixture of competitive and co-operative tendencies. Individuals will leave scent trails to lead others to food or shelter, and swarms of cockroaches have been observed to show group decision-making skills.
Where resources like shelter are limited, they are known to manage the situation depending on their numbers - splitting a group between different shelters, in order to accommodate all members, for example.
Although people generally react negatively towards the insect, there have been various depictions of the cockroach in human culture, both positive and negative. A cockroach is the friend and companion of the lonely robot Wall:E, in the Disney/Pixar movie, for example; whereas Franz Kafka's 'Metamorphosis' sees the narrator turn into a roach-like insect, much to his disgust.
Whatever our views might be, the humble cockroach has shown itself to be a survivor, and we're likely to be sharing the Earth with them for many years to come.
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