ARTWORK
- Somewhat better than the huge ants in "Them," but perhaps not as good as
the CGI in Antman. Now a
museum
exhibit in Sussex, England.
The artwork is based on the incredible Australian Bulldog
ant.
As
anyone knows, ants are some of the most interesting of insects.
They are incredibly industrious engineers, builders of pyramids
made of twigs and leaves. They are amazing biological machines, that can lift
or support, between 20-100 times their own body weight.
In science and technology
- (Myrmecology, Biomimetics, Ant colony optimization algorithms)
Observed by humans since the dawn of history, the behavior of ants
has been documented and the subject of early writings and fables passed
from one century to another. Those using scientific methods, myrmecologists, study ants in the laboratory and in their natural
conditions. Their complex and variable social structures have made ants
ideal model organisms.
Ultraviolet
vision was first discovered in ants by Sir John Lubbock in
1881. Studies on ants have tested hypotheses in ecology and
sociobiology, and have been particularly important in examining the
predictions of theories of kin selection and evolutionarily stable
strategies. Ant colonies may be studied by rearing or temporarily
maintaining them in formicaria, specially constructed glass framed enclosures.
Individuals may be tracked for study by marking them with dots
of paint.
The successful techniques used by ant colonies have been studied
in computer science and robotics to produce distributed and
fault-tolerant systems for solving problems, for example Ant colony
optimization and Ant robotics. This area of biomimetics has led to
studies of ant locomotion, search engines that make use of "foraging
trails", fault-tolerant storage, and networking
algorithms.
The
remains of a giant insect discovered in the Antarctic ice, with a human
skull
RELATIONSHIP
WITH HUMANS
Ants perform many ecological roles that are beneficial to
humans,
including the suppression of pest populations and aeration of the soil.
The use of weaver ants in citrus cultivation in southern China is
considered one of the oldest known applications of biological
control. On the other hand, ants may become nuisances when they
invade buildings, or cause economic losses.
In some parts of the world (mainly Africa and
South America),
large ants, especially army ants, are used as surgical sutures. The
wound is pressed together and ants are applied along it. The ant seizes
the edges of the wound in its mandibles and locks in place. The body is
then cut off and the head and mandibles remain in place to close the
wound.
Some ants of the family Ponerinae have toxic venom and are of
medical importance. The species include Paraponera clavata (Tocandira)
and Dinoponera spp. (false Tocandiras) of South America
and the Myrmecia ants of Australia.
In South Africa, ants are used to help harvest rooibos (Aspalathus
linearis), which are small seeds used to make a herbal tea. The plant
disperses its seeds widely, making manual collection difficult. Black
ants collect and store these and other seeds in their nest, where humans
can gather them en masse. Up to half a pound (200 g) of seeds may be
collected from one
ant-heap.
Although most ants survive attempts by humans to eradicate them, a
few are highly endangered. Mainly, these are island species that have
evolved specialized traits. They include the critically endangered Sri
Lankan relict ant (Aneuretus simoni) and Adetomyrma venatrix of
Madagascar.
It has been estimated by E.O. Wilson that the total number of
individual ants alive in the world at any one time is between one and
ten quadrillion (short scale). According to this estimate, the total
biomass of all the ants in the world is approximately equal to the total
biomass of the entire human
race.
Diagram of a worker ant
(Pachycondyla verenae)
RELATIONSHIPS
WITH OTHER ORGANISMS
Ants
form symbiotic associations with a range of species, including other
ant species, other insects, plants, and fungi. They also are preyed on
by many animals and even certain fungi. Some arthropod species spend
part of their lives within ant nests, either preying on ants, their
larvae, and eggs, consuming the food stores of the ants, or avoiding
predators. These inquilines may bear a close resemblance to ants. The
nature of this ant mimicry (myrmecomorphy) varies, with some cases
involving Batesian mimicry, where the mimic reduces the risk of
predation. Others show Wasmannian mimicry, a form of mimicry seen only
in
inquilines.
Aphids and other hemipteran insects secrete a sweet liquid called,
honeydew, when they feed on plant sap. The sugars in honeydew are a
high-energy food source, which many ant species
collect. In some cases the aphids secrete the honeydew in response
to ants tapping them with their antennae. The ants in turn keep
predators away from the aphids and will move the them from one feeding
location to another. When migrating to a new area, many colonies will
take the aphids with them, to ensure a continued supply of honeydew.
Ants also tend mealybugs to harvest their honeydew. Mealybugs may become
a serious pest of pineapples if ants are present to protect mealybugs
from their natural
enemies.
Myrmecophilous (ant-loving) caterpillars of the butterfly family
Lycaenidae (e.g., blues, coppers, or hairstreaks) are herded by the
ants, led to feeding areas in the daytime, and brought inside the ants'
nest at night. The caterpillars have a gland which secretes honeydew
when the ants massage them. Some caterpillars produce vibrations and
sounds that are perceived by the
ants. Other caterpillars have evolved from ant-loving to
ant-eating: these myrmecophagous caterpillars secrete a pheromone that
makes the ants act as if the caterpillar is one of their own larvae. The
caterpillar is then taken into the ant nest where it feeds on the ant
larvae.
An ant
milking an aphid
Fungus-growing ants that make up the tribe Attini, including
leafcutter ants, cultivate certain species of fungus in the
Leucoagaricus or Leucocoprinus genera of the Agaricaceae family. In this
ant-fungus mutualism, both species depend on each other for survival.
The ant, Allomerus decemarticulatus, has evolved a three-way association
with the host plant, Hirtella physophora (Chrysobalanaceae), and a
sticky fungus which is used to trap their insect
prey.
Ants may obtain nectar from flowers such as the dandelion but are only rarely known to pollinate flowers
Lemon ants make devil's gardens by killing surrounding plants with
their stings and leaving a pure patch of lemon ant trees, (Duroia hirsuta). This modification of the forest provides the ants with more
nesting sites inside the stems of the Duroia
trees. Although some ants obtain nectar from flowers, pollination
by ants is somewhat
rare. Some plants have special nectar exuding structures,
extrafloral nectaries that provide food for ants, which in turn protect
the plant from more damaging herbivorous
insects.
Species such as the bullhorn acacia (Acacia cornigera) in Central
America have hollow thorns that house colonies of stinging ants (Pseudomyrmex
ferruginea) who defend the tree against insects, browsing
mammals, and epiphytic vines. Isotopic labelling studies suggest that
plants also obtain nitrogen from the
ants. In return, the ants obtain food from protein - and lipid-rich
Beltian bodies. Another example of this type of ectosymbiosis comes
from the Macaranga tree, which has stems adapted to house colonies of
Crematogaster ants.
Many tropical tree species have seeds that are dispersed by ants.
Seed dispersal by ants or myrmecochory is widespread and new estimates
suggest that nearly 9% of all plant species may have such ant
associations. Some plants in fire-prone grassland systems are
particularly dependent on ants for their survival and dispersal as the
seeds are transported to safety below the ground. Many ant-dispersed
seeds have special external structures, elaiosomes, that are sought
after by ants as
food.
A convergence, possibly a form of mimicry, is seen in the eggs of stick insects. They have an edible
elaiosome-like structure and are taken into the ant nest where the young
hatch.
Most ants are predatory and some prey on and obtain food from
other social insects including other ants. Some species specialise in
preying on termites (Megaponera and Termitopone) while a few Cerapachyinae prey on
other
ants. Some termites, including Nasutitermes corniger, form
associations with certain ant species to keep away predatory ant
species.
The tropical wasp Mischocyttarus drewseni coats the pedicel of its nest
with an ant-repellant
chemical. It is suggested that many tropical wasps may build their
nests in trees and cover them to protect themselves from ants.
Stingless bees (Trigona and Melipona) use chemical defences against
ants.
Flies in the Old World genus, Bengalia (Calliphoridae), prey on
ants and are kleptoparasites, snatching prey or brood from the mandibles
of adult
ants. Wingless and legless females of the Malaysian phorid fly (Vestigipoda
myrmolarvoidea) live in the nests of ants of the genus
Aenictus and are cared for by the
ants.
Fungi in the genera Cordyceps and Ophiocordyceps infect ants. Ants
react to their infection by climbing up plants and sinking their
mandibles into plant tissue. The fungus kills the ants, grows on their
remains, and produces a fruiting body. It appears that the fungus alters
the behaviour of the ant to help disperse its spores
in a microhabitat that best suits the fungus. Strepsipteran
parasites also manipulate their ant host to climb grass stems, to help
the parasite find
mates.
A nematode (Myrmeconema neotropicum) that infects canopy ants (Cephalotes
atratus) causes the black coloured gasters of workers to
turn red. The parasite also alters the behaviour of the ant, causing
them to carry their gasters high. The conspicuous red gasters are
mistaken by birds for ripe fruits such as Hyeronima alchorneoides and
eaten. The droppings of the bird are collected by other ants and fed to
their young leading to further spread of the
nematode.
John
Storm and Charley
Temple make a disturbing discovery in Antarctica
an
adventure story by Jameson
Hunter.
ETYMOLOGY
Ants
are social insects of the family Formicidae and, along with the related
wasps and bees, belong to the order Hymenoptera. Ants evolved from
wasp-like ancestors in the mid-Cretaceous period between 110 and 130
million years ago and diversified after the rise of flowering plants.
More than 12,500 out of an estimated total of 22,000 species have been
classified. They are easily identified by their elbowed antennae
and a distinctive node-like structure that forms a slender waist.
Ants form colonies that range in size from a few dozen predatory
individuals living in small natural cavities to highly organised
colonies that may occupy large territories and consist of millions of
individuals. Larger colonies consist mostly of sterile wingless females
forming castes of "workers", "soldiers", or other specialised groups.
Nearly all ant colonies also have some fertile males called "drones" and
one or more fertile females called "queens". The colonies sometimes are
described as superorganisms because the ants appear to operate as a
unified entity, collectively working together to support the
colony.
Ants have colonised almost every landmass on Earth. The only
places lacking indigenous ants are Antarctica and a few remote or
inhospitable islands. Ants thrive in most ecosystems and may form 15–25%
of the terrestrial animal
biomass. Their success in so many environments has been attributed
to their social organisation and their ability to modify habitats, tap
resources, and defend themselves. Their long co-evolution with other
species has led to
mimetic, commensal, parasitic, and mutualistic
relationships.
Ant societies have division of labour, communication between
individuals, and an ability to solve complex
problems. These parallels with human societies have long been an
inspiration and subject of study. Many human cultures make use of ants
in cuisine, medication, and rituals. Some species are valued in their
role as biological pest control
agents. Their ability to exploit resources may bring ants into
conflict with humans, however, as they can damage crops and invade
buildings. Some species, such as the red imported fire ant, are regarded
as invasive species, establishing themselves in areas where they have
been introduced
accidentally.
The word ant is derived from ante of Middle English which is
derived from æmette of Old English and is related to the Old High German
āmeiza, hence the modern German Ameise. All of these words come from
West Germanic *amaitjo, and the original meaning of the word was "the
biter" (from Proto-Germanic *ai-, "off, away" +
*mait- "cut"). The family name Formicidae is derived from the
Latin formīca
("ant") from which the words in other Romance languages such as
the Portuguese formiga, Italian formica, Spanish hormiga, Romanian
furnică and French fourmi are derived. It has been hypothetized that a
Proto-Indo-European word *morwi- was used, cf. Sanskrit vamrah, Latin
formīca, Greek myrmex, Old Church Slavonic mraviji, Old Irish moirb, Old
Norse
maurr.
Taxonomy and evolution
The family Formicidae belongs to the order Hymenoptera, which also
includes sawflies, bees, and wasps. Ants evolved from a lineage within
the vespoid wasps. Fossil evidence indicates that ants were present in
the Late Jurassic, 150 million years
ago. After the rise of flowering plants about 100 million years
ago they diversified and assumed ecological dominance around 60 million
years
ago. In 1966, E. O. Wilson and his colleagues identified the
fossil remains of an ant (Sphecomyrma freyi) that lived in the
Cretaceous period. The specimen, trapped in amber dating back to more
than 80 million years ago, has features of both ants and
wasps. Sphecomyrma probably was a ground forager, but some suggest
on the basis of groups such as the Leptanillinae and Martialinae, that
primitive ants were likely to have been predators underneath the surface
of the
soil.
Meat eater ant nest during swarming
During the Cretaceous period, a few species of primitive ants
ranged widely on the Laurasian super-continent (the northern
hemisphere). They were scarce in comparison to the populations of other
insects, representing only approximately 1% of the entire insect
population. Ants became dominant after adaptive radiation at the
beginning of the Paleogene period. By the Oligocene and Miocene ants had
come to represent 20–40% of all insects found in major fossil deposits.
Of the species that lived in the Eocene epoch, approximately one in ten
genera survive to the present. Genera surviving today comprise 56% of
the genera in Baltic amber fossils (early Oligocene), and 92% of the
genera in Dominican amber fossils (apparently early
Miocene).
Termites, although sometimes called white ants, are not ants. They
belong to the order Isoptera. Termites are more closely related to
cockroaches and mantids. Termites are eusocial, but differ greatly in
the genetics of reproduction. That their social structure is similar to
that of ants, is attributed to convergent
evolution. Velvet ants look like large ants, but are wingless
female wasps.
Distribution and diversity
Ants
are found on all continents except Antarctica, and only a few large
islands such as Greenland, Iceland, parts of Polynesia and the Hawaiian
Islands lack native ant
species. Ants occupy a wide range of ecological niches, and are
able to exploit a wide range of food resources either as direct or
indirect herbivores, predators, and scavengers. Most species are
omnivorous generalists, but a few are specialist feeders. Their
ecological dominance may be measured by their biomass and estimates in
different environments suggest that they contribute 15–20% (on average
and nearly 25% in the tropics) of the total terrestrial animal biomass,
which exceeds that of the
vertebrates.
Ants range in size from 0.75 to 52 millimetres (0.030–2.0 in), the
largest species being the fossil Titanomyrma giganteum, the queen of
which was 6 centimetres (2.4 in) long with a wingspan of 15 centimetres
(5.9
in). Ants vary in colour; most ants are red or black, but a few
species are green and some tropical species have a metallic lustre. More
than 12,000 species are currently known (with upper estimates of the
potential existence of about 22,000) (see the article List of ant
genera), with the greatest diversity in the tropics. Taxonomic studies
continue to resolve the classification and systematics of ants. Online
databases of ant species, including AntBase and the Hymenoptera Name
Server, help to keep track of the known and newly described
species. The relative ease with which ants may be sampled and
studied in ecosystems has made them useful as indicator species in
biodiversity
studies.
Leaf Cutter ants:
workers, soldier, male and queen
Morphology
Ants are distinct in their morphology from other insects in having
elbowed antennae, metapleural glands, and a strong constriction of
their second abdominal segment into a node-like petiole. The head, mesosoma, and metasoma are the three distinct body segments. The petiole
forms a narrow waist between their mesosoma (thorax plus the first
abdominal segment, which is fused to it) and gaster (abdomen less the
abdominal segments in the petiole). The petiole may be formed by one or
two nodes (the second alone, or the second and third abdominal
segments).
Like other insects, ants have an exoskeleton, an external covering
that provides a protective casing around the body and a point of
attachment for muscles, in contrast to the internal skeletons of humans
and other vertebrates. Insects do not have lungs;
oxygen
and other gases such as carbon dioxide pass through their exoskeleton
via tiny valves called spiracles. Insects also lack closed blood
vessels; instead, they have a long, thin, perforated tube along the top
of the body (called the "dorsal aorta") that functions like a heart, and
pumps haemolymph toward the head, thus driving the circulation of the
internal fluids. The nervous system consists of a ventral nerve cord
that runs the length of the body, with several ganglia and branches
along the way reaching into the extremities of the
appendages.
Black
ants fighting
Head
An ant's head contains many sensory organs. Like most insects,
ants have compound eyes made from numerous tiny lenses attached
together. Ant eyes are good for acute movement detection, but do not
offer a high resolution image. They also have three small ocelli (simple
eyes) on the top of the head that detect light levels and
polarization. Compared to vertebrates, most ants have
poor-to-mediocre eyesight and a few subterranean species are completely
blind. Some ants such as Australia's bulldog ant, however, have
exceptional vision.
Two antennae ("feelers") are attached to the head; these organs
detect chemicals, air currents, and vibrations; they also are used to
transmit and receive signals through touch. The head has two strong
jaws, the mandibles, used to carry food, manipulate objects, construct
nests, and for
defence. In some species a small pocket (infrabuccal chamber)
inside the mouth stores food, so it may be passed to other ants or their
larvae.
Legs
All six legs are attached to the mesosoma ("thorax"). A hooked
claw at the end of each leg helps ants to climb and to hang onto
surfaces.
Wings
Most queens and the small number of drones in a colony (the male
ants), have wings; queens shed the wings after the nuptial flight,
leaving visible stubs, a distinguishing feature of queens. Wingless
queens (ergatoids) and males occur in a few species,
however.
Metasoma
The metasoma (the "abdomen") of the ant houses important internal
organs, including those of the reproductive, respiratory (tracheae), and
excretory systems. Workers of many species have their egg-laying
structures modified into stings that are used for subduing prey and
defending their
nests.
ALEX WILD
- Is a macro photographer and a biologist based in
Texas specializing in ants. According to his websites he
started photographing insects in 2002 to complement his scientific work
on ant taxonomy and evolution. Alex holds a Ph.D. in Entomology from
the University of California (Davis) and is Curator of Entomology at the
University of Texas, Austin, USA.
You can read more on ants and a macro photography and
photographers media review by clicking on the picture above.
POLYMORPHISM
In the colonies of a few ant species, there are physical
castes - workers in distinct size-classes, called minor, median, and major
workers. Often the larger ants have disproportionately larger heads,
and correspondingly stronger mandibles. Such individuals sometimes are
called "soldier" ants because their stronger mandibles make them more
effective in fighting, although they still are workers and their
"duties" typically do not vary greatly from the minor or median workers.
In a few species the median workers are absent, creating a sharp divide
between the minors and
majors. Weaver ants, for example, have a distinct bimodal size
distribution.
Some other species show continuous variation in the size of workers.
The smallest and largest workers in Pheidologeton diversus show nearly a
500-fold difference in their
dry-weights. Workers cannot mate; however, because of the
haplodiploid sex-determination system in ants, workers of a number of
species can lay unfertilised eggs that become fully fertile, haploid
males. The role of workers may change with their age and in some
species, such as honeypot ants, young workers are fed until their
gasters are distended, and act as living food storage vessels. These
food storage workers are called repletes. This polymorphism in
morphology and behaviour of workers initially was thought to be
determined by environmental factors such as nutrition and hormones that
led to different developmental paths; however, genetic differences
between worker castes have been noted in Acromyrmex
sp. These polymorphisms are caused by relatively small genetic
changes; differences in a single gene of Solenopsis invicta can decide
whether the colony will have single or multiple
queens.
The Australian jack jumper ant (Myrmecia pilosula) has only a single
pair of chromosomes (with the males having just one chromosome as they
are haploid), the lowest number known for any animal, making it an
interesting subject for studies in the genetics and developmental
biology of social
insects.
Meat eater ants
eating a cicada
Development and reproduction
The life of an ant starts from an egg. If the egg is fertilised,
the progeny will be female (diploid); if not, it will be male (haploid).
Ants develop by complete metamorphosis with the larva stages passing
through a pupal stage before emerging as an adult. The larva is largely
immobile and is fed and cared for by workers.
Food is given to the larvae by trophallaxis, a process in which an
ant regurgitates liquid food held in its crop. This is also how adults
share food, stored in the "social stomach". Larvae may also be provided
with solid food such as trophic eggs, pieces of prey, and seeds brought
back by foraging workers and the larvae may even be transported directly
to captured prey in some species.
The larvae grow through a series of moults and enter the pupal
stage. The pupa has the appendages free and not fused to the body as in a
butterfly
pupa. The differentiation into queens and workers (which are both
female), and different castes of workers (when they exist), is
influenced in some species by the nutrition the larvae obtain. Genetic
influences and the control of gene expression by the developmental
environment are complex and the determination of caste continues to be a
subject of
research. Larvae and pupae need to be kept at fairly constant
temperatures to ensure proper development, and so often, are moved
around among the various brood chambers within the
colony.
A new worker spends the first few days of its adult life caring
for the queen and young. She then graduates to digging and other nest
work, and later to defending the nest and foraging. These changes are
sometimes fairly sudden, and define what are called temporal castes. An
explanation for the sequence is suggested by the high casualties
involved in foraging, making it an acceptable risk only for ants who are
older and are likely to die soon of natural
causes.
Most ant species have a system in which only the queen and
breeding females have the ability to mate. Contrary to popular belief,
some ant nests have multiple queens while others may exist without
queens. Workers with the ability to reproduce are called "gamergates"
and colonies that lack queens are then called gamergate colonies;
colonies with queens are said to be
queen-right. The winged male ants, called drones, emerge from
pupae along with the breeding females (although some species, such as
army ants, have wingless queens), and do nothing in life except eat and
mate.
Most ants are univoltine, producing a new generation each year.
During the species-specific breeding period, new reproductives, females
and winged males leave the colony in what is called a nuptial flight.
Typically, the males take flight before the females. Males then use
visual cues to find a common mating ground, for example, a landmark such
as a pine tree to which other males in the area converge. Males secrete
a mating pheromone that females follow. Females of some species mate
with just one male, but in some others they may mate with as many as ten
or more different
males.
Mated females then seek a suitable place to begin a colony. There,
they break off their wings and begin to lay and care for eggs. The
females store the sperm they obtain during their nuptial flight to
selectively fertilise future eggs. The first workers to hatch are weak
and smaller than later workers, but they begin to serve the colony
immediately. They enlarge the nest, forage for food, and care for the
other eggs. This is how new colonies start in most ant species. Species
that have multiple queens may have a queen leaving the nest along with
some workers to found a colony at a new
site, a process akin to swarming in honeybees.
Ants mating
A wide range of reproductive strategies have been noted in ant
species. Females of many species are known to be capable of reproducing
asexually through thelytokous parthenogenesis
and one species, Mycocepurus smithii, is known to be all-female.
Ant colonies can be long-lived. The queens can live for up to 30
years, and workers live from 1 to 3 years. Males, however, are more
transitory, being quite short-lived and surviving for only a few
weeks. Ant queens are estimated to live 100 times longer than
solitary insects of a similar
size.
Ants are active all year long in the tropics, but, in cooler
regions, they survive the winter in a state of dormancy or inactivity.
The forms of inactivity are varied and some temperate species have
larvae going into the inactive state, (diapause), while in others, the
adults alone pass the winter in a state of reduced
activity.
SPIDERS
AND ANTS AS FOOD
South American poison dart frogs in the genus Dendrobates feed mainly on ants, and the toxins in their skin may come from the
ants.
Army ants forage in a wide roving column attacking any animals in
that path that are unable to escape. In Central and South America,
Eciton burchellii is the swarming ant most commonly attended by
"ant-following" birds such as antbirds and woodcreepers. This behaviour was once considered
mutualistic, but
later studies found the birds to be parasitic. Although direct
kleptoparasitism (birds stealing food from the ants' grasp) is rare, the
birds eat many prey insects that the ants would otherwise eat and thus
decrease their foraging
success.
Birds indulge in a peculiar behaviour called anting that, as yet, is
not fully understood. Here birds rest on ant nests, or pick and drop
ants onto their wings and feathers; this may be a means to remove
ectoparasites from the birds.
Anteaters, aardvarks, pangolins, echidnas, and numbats have
special adaptations for living on a diet of ants. These adaptations
include long, sticky tongues to capture ants and strong claws to break
into ant nests. Brown bears (Ursus arctos) have been found to feed on
ants. About 12%, 16%, and 4% of their faecal volume in spring, summer,
and autumn, respectively, is composed of
ants.
NAVIGATION
Foraging ants travel distances of up to 200 metres (700 ft) from
their nest
and scent trails allow them to find their way back even in the
dark. In hot and arid regions, day-foraging ants face death by
desiccation, so the ability to find the shortest route back to the nest
reduces that risk. Diurnal desert ants of the genus Cataglyphis such as
the Sahara desert ant navigate by keeping track of direction as well as
distance travelled. Distances travelled are measured using an internal
pedometer that keeps count of the steps taken
and also by evaluating the movement of objects in their visual
field (optical
flow). Directions are measured using the position of the sun. They
integrate this information to find the shortest route back to their
nest. Like all ants, they can also make use of visual landmarks
when available
as well as olfactory and tactile cues to navigate. Some species of
ant are able to use the Earth's magnetic field for
navigation.
The compound eyes of ants have specialised cells that detect polarised
light from the Sun, which is used to determine
direction.These polarization detectors are sensitive in the
ultraviolet region of the light
spectrum. In some army ant species, a group of foragers who become
separated from the main column sometimes may turn back on themselves
and form a circular ant mill. The workers may then run around
continuously until they die of
exhaustion. Such wheels have been observed in other ant species,
notably when a group has fallen into or been overcome with water,
whereby the group rotates in a partially submerged circle on the surface
of the water. The behavior could allow survival of a brief flooding.
LOCOMOTION
The female worker ants do not have wings and reproductive females
lose their wings after their mating flights in order to begin their
colonies. Therefore, unlike their wasp ancestors, most ants travel by
walking. Some species are capable of leaping. For example, Jerdon's
jumping ant (Harpegnathos saltator) is able to jump by synchronising the
action of its mid and hind pairs of
legs. There are several species of gliding ant including
Cephalotes atratus; this may be a common trait among most arboreal ants.
Ants with this ability are able to control the direction of their
descent while
falling.
Other species of ants can form chains to bridge gaps over water,
underground, or through spaces in vegetation. Some species also form
floating rafts that help them survive floods. These rafts may also have a
role in allowing ants to colonise
islands. Polyrhachis sokolova, a species of ant found in
Australian mangrove swamps, can swim and live in underwater nests. Since
they lack gills, they go to trapped pockets of air in the submerged
nests to
breathe.
COOPERATION
& COMPETITION
Social ants cooperate and collectively gather food.
Not all ants have the same kind of societies. The Australian
bulldog ants are among the biggest and most basal of ants. Like
virtually all ants, they are eusocial, but their social behaviour is poorly developed compared
to other species. Each individual hunts alone, using her large eyes
instead of chemical senses to find
prey.
Bulldog
by name, Bulldog by nature. This is a serious feller, give him, er, her a
wide berth.
Some species (such as Tetramorium caespitum) attack and take over
neighbouring ant colonies. Others are less expansionist, but just as
aggressive; they invade colonies to steal eggs or larvae, which they
either eat or raise as workers or slaves. Extreme specialists among
these slave-raiding ants, such as the Amazon ants, are incapable of
feeding themselves and need captured workers to
survive. Captured workers of the enslaved species Temnothorax have
evolved a counter strategy, destroying just the female pupae of the
slave-making Protomognathus americanus, but sparing the males (who don't
take part in slave-raiding as
adults).
Ants
identify kin and
nest-mates through their scent, which comes from hydrocarbon-laced
secretions that coat their exoskeletons. If an ant is separated from
its original colony, it will eventually lose the colony scent. Any ant
that enters a colony without a matching scent will be
attacked. Also, the reason why two separate colonies of ants will
attack each other even if they are of the same species is because the
genes responsible for pheromone production are different between them.
The argentine ant, however, does not have this characteristic, due to
lack of genetic diversity, and has become a
global pest because of it.
Parasitic ant species enter the colonies of host ants and
establish themselves as social parasites; species such as Strumigenys
xenos are entirely parasitic and do not have workers, but instead, rely
on the food gathered by their Strumigenys perplexa
hosts. This form of parasitism is seen across many ant genera, but
the parasitic ant is usually a species that is closely related to its
host. A variety of methods are employed to enter the nest of the host
ant. A parasitic queen may enter the host nest before the first brood
has hatched, establishing herself prior to development of a colony
scent. Other species use pheromones to confuse the host ants or to trick
them into carrying the parasitic queen into the nest. Some simply fight
their way into the
nest.
A conflict between the sexes of a species is seen in some species
of ants with these reproductives apparently competing to produce
offspring that are as closely related to them as possible. The most
extreme form involves the production of clonal offspring. An extreme of
sexual conflict is seen in Wasmannia auropunctata, where the queens
produce diploid daughters by thelytokous parthenogenesis and males
produce
clones by a process whereby a diploid egg loses its maternal contribution to produce haploid males who are
clones of the father.
Australian Bulldog (Jumper) ants fighting - note sting deployed
BEHAVIOUR
COMMUNICATION
Ants communicate with each other using pheromones, sounds, and
touch. The use of pheromomes as chemical signals is more developed in
ants than in other hymenopteran groups. Like other insects, ants
perceive smells with their long, thin, and mobile antennae. The paired
antennae provide information about the direction and intensity of
scents. Since most ants live on the ground, they use the soil surface to
leave pheromone trails that may be followed by other ants. In species
that forage in groups, a forager that finds food marks a trail on the
way back to the colony; this trail is followed by other ants, these ants
then reinforce the trail when they head back with
food
to the colony. When the food source is exhausted, no new trails are
marked by returning ants and the scent slowly dissipates. This behaviour
helps ants deal with changes in their environment. For instance, when
an established path to a food source is blocked by an obstacle, the
foragers leave the path to explore new routes. If an ant is successful,
it leaves a new trail marking the shortest route on its return.
Successful trails are followed by more ants, reinforcing better routes
and gradually identifying the best
path.
Ants use pheromones for more than just making trails. A crushed
ant emits an alarm pheromone that sends nearby ants into an attack
frenzy and attracts more ants from farther away. Several ant species
even use "propaganda pheromones" to confuse enemy ants and make them
fight among
themselves. Pheromones are produced by a wide range of structures
including Dufour's glands, poison glands and glands on the hindgut, pygidium, rectum, sternum, and hind
tibia. Pheromones also are exchanged, mixed with food, and passed
by trophallaxis, transferring information within the
colony. This allows other ants to detect what task group (e.g.,
foraging or nest maintenance) to which other colony members
belong. In ant species with queen castes, when the dominant queen
stops producing a specific pheromone, workers begin to raise new queens
in the
colony.
Some ants produce sounds by stridulation, using the gaster
segments and their mandibles. Sounds may be used to communicate with
colony members or with other
species.
Honeydew
ants, a living larder
DEFENCE
Ants attack and defend themselves by biting and, in many species,
by stinging, often injecting or spraying chemicals such as formic acid.
Bullet ants (Paraponera), located in Central and South America, are
considered to have the most painful sting of any insect, although it is
usually not fatal to humans. This sting is given the highest rating on
the Schmidt Sting Pain Index.
The sting of Jack jumper ants can be fatal, and an antivenom has been developed for
it. Fire ants, Solenopsis spp., are unique in having a poison sac containing piperidine
alkaloids. Their stings are painful and can be dangerous to hypersensitive
people.
Trap-jaw
ants of the genus Odontomachus are equipped with mandibles called
trap-jaws, which snap shut faster than any other predatory appendages
within the animal
kingdom. One study of Odontomachus bauri recorded peak speeds of
between 126 and 230 km/h (78 – 143 mph), with the jaws closing within
130 microseconds on average. The ants were also observed to use their
jaws as a catapult to eject intruders or fling themselves backward to
escape a
threat. Before striking, the ant opens its mandibles extremely
widely and locks them in this position by an internal mechanism.
Energy is
stored in a thick band of muscle and explosively released when
triggered by the stimulation of sensory organs resembling hairs on the
inside of the mandibles. The mandibles also permit slow and fine
movements for other tasks. Trap-jaws also are seen in the following
genera: Anochetus, Orectognathus, and Strumigenys, plus some members of
the Dacetini
tribe, which are viewed as examples of convergent evolution.
A Malaysian species of ant in the Camponotus cylindricus group has
enlarged mandibular glands that extend into their gaster. When
disturbed, workers rupture the membrane of the gaster, causing a burst
of secretions containing acetophenones and other chemicals that
immobilise small insect attackers. The worker subsequently
dies.
The
world's smallest ant, the Egyptian pharaoh ant
Suicidal defenses by workers are also noted in a Brazilian
ant, Forelius pusillus, where a small group of ants leaves the security
of the nest after sealing the entrance from the outside each
evening.
In addition to defence against predators, ants need to protect
their colonies from pathogens. Some worker ants maintain the hygiene of
the colony and their activities include undertaking or necrophory, the
disposal of dead
nest-mates. Oleic acid has been identified as the compound
released from dead ants that triggers necrophoric behaviour in Atta
mexicana while workers of Linepithema humile react to the absence
of characteristic chemicals (dolichodial and iridomyrmecin) present on
the cuticle of their living nestmates to trigger similar
behavior.
Nests may be protected from physical threats such as flooding and
overheating by elaborate nest
architecture. Workers of Cataulacus muticus, an arboreal species
that lives in plant hollows, respond to flooding by drinking water
inside the nest, and excreting it
outside. Camponotus anderseni, which nests in the cavities of wood in mangrove habitats, deals with submergence under water by switching to anaerobic
respiration.
LEARNING
Many animals can learn behaviours by imitation, but ants may be
the only group apart from mammals where interactive teaching has been
observed. A knowledgeable forager of Temnothorax albipennis will lead a
naive nest-mate to newly discovered food by the process of tandem
running. The follower obtains knowledge through its leading tutor. Both
leader and follower are acutely sensitive to the progress of their
partner with the leader slowing down when the follower lags, and
speeding up when the follower gets too
close.
Controlled experiments with colonies of Cerapachys biroi suggest
that an individual may choose nest roles based on her previous
experience. An entire generation of identical workers was divided into
two groups whose outcome in food foraging was controlled. One group was
continually rewarded with prey, while it was made certain that the other
failed. As a result, members of the successful group intensified their
foraging attempts while the unsuccessful group ventured out fewer and
fewer times. A month later, the successful foragers continued in their
role while the others had moved to specialise in brood
care.
An ant transporting an aphid
NEST CONSTRUCTION - ANT COLONIES
Complex nests are built by many ant species, but other species are
nomadic and do not build permanent structures. Ants may form
subterranean nests or build them on trees. These nests may be found in
the ground, under stones or logs, inside logs, hollow stems, or even
acorns. The materials used for construction include soil and plant
matter, and ants carefully select their nest sites; Temnothorax
albipennis will avoid sites with dead ants, as these may indicate the
presence of pests or disease. They are quick to abandon established
nests at the first sign of
threats.
The army ants of South America and the driver ants of
Africa
do not build permanent nests, but instead, alternate between nomadism
and stages where the workers form a temporary nest (bivouac) from their
own bodies, by holding each other
together.
Weaver ant (Oecophylla spp.) workers build nests in trees by
attaching leaves together, first pulling them together with bridges of
workers and then inducing their larvae to produce silk as they are moved
along the leaf edges. Similar forms of nest construction are seen in
some species of Polyrhachis.
Some ant species build nests in and on buildings. Interior spaces
in walls, windows, and even electric appliances such as clocks, lamps,
and radios in the interior of buildings may be used as sites for nests.
POPULAR INSECTS
Ants Apid Army
Ant Bee Beetles Bulldog
Ant Butterfly Centipede Cockroach Crickets Damsel
Fly Death
Watch Beetle Dragonfly Dung
Beetle Earwig Fly Grasshopper Hornet
|
Ladybird Leafcutter
Ant Locust Mantis,
Praying Maybug Millipede Mosquito Moth Praying
Mantis Scarab
Beetle Stag
Beetle Stick
Insect Termite
Wasp
Water
Boatman
Wood
Ant
Woodlice
Woodworm
|
Global
warming has unexpected consequences for competing
groups
of scientists
each
wanting to take credit for themselves
for the find of the century.
INSECT CLASSIFICATION
Modern insect classification divides the Insecta into 29
orders. Some of the more common orders are:
- Mantodea - praying mantids
- Blattodea - cockroaches
- Isoptera - termites
- Siphonaptera - fleas
- Odonata - dragonflies and damselflies
- Dermaptera - earwigs
- Diptera - flies - mosquitoes
- Lepidoptera - butterflies and moths
- Orthoptera - grasshoppers, katydids, crickets
- Coleoptera - beetles
- Hymenoptera - wasps,
bees,
ants, sawflies,
hornets
A
startling discovery in the ice, sharp jaws protruding from a block of
solid ice.
INSECT FEATURES
- The insect body is divided into three main parts, the head, thorax and abdomen.
- Insects have no internal skeleton, instead they are covered in an external shell (exoskeleton) that protects their soft internal organs.
- No insect has more than three pairs of legs, except for some immature forms such as caterpillars that have prolegs. These are appendages that serve the purpose of legs.
- The typical insect mouth has a pair of lower jaws (maxillae) and upper
jaws (mandibles) which are designed to bite. There are many variations to this structure, as many moths and butterflies have tubular sucking mouthparts, many bugs and other blood-sucking insects have sucking stabbing mouthparts and some adult insects
don't have functional mouthparts.
- Insects have one pair of antennae located on the head
- Most insects have one or two pairs of wings although some insects such as lice, fleas, bristletails and silverfish are completely wingless.
The
artwork is also suitable for use in "Jimmy Watson's Magic
Dinobot."
A proposed network TV serialization, about boy who saves his paper round
money to buy himself a robot for Christmas. Then, when assembled, it
come to life, to become his friend.
Another
title, using the same giant ant special effects artwork as Sectasaur™ is JIMMY
WATSON'S MAGIC DINOBOT. This is a children's Christmas story. Far
removed from high seas adventures and John
Storm (for now).
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