insects everywhere although most people however only notice
them when they bug them. They are generally
considered a pest to be destroyed at any cost without
appreciating their value. The world we know now would not
exist without them. For instance flowering plants including many of our
food crops depend on them for pollination. There are now
one million insect
species classified in the world but the true number can only be estimated
ranging from ten to hundredfold. Especially in the
tropics are they numerous and unfamiliar characteristics
like large size, bright colors, cryptic shapes or strange
behavior await the curious visitor in Ecuador.
The large Morpho butterfly
is famous for its brilliant blue coloration. They are
most easily observed fluttering above water along smaller
rivers overhung by thick vegetation. When resting they usually have
their wings closed showing a dark coloration with eyespots on it.
Beetles are the world's
most numerous insects and that holds also true in Ecuador.
They can be found in all ecosystems feeding on
vegetation, dung, carrion or
preying on other insects. Not far behind in numbers are the
and their close cousins, the cryptic nocturnal moths
(although there are also colorful diurnal species of moths). These
insects are important flower pollinators using their long
proboscis to probe for nectar. Not so
easily seen are the walking sticks resembling parts
of a branch. The praying mantis are ferocious predators
grabbing other insects in rapid movements. Very interesting groups are the
social insects, the ants, bees, wasps
and termites. True bugs are somehow similar to
beetles but have their own important characteristics and
suck plant juices. Grasshoppers
and crickets are often heard for their clicking
sounds. A more rare group of insects are the lacewings
and antlions, which have highly veined wings. Cicadas are noisy flying insects
swarming around trees. Flies are well known and range
from the house fly to mosquitoes, sometimes
carriers of diseases. Other interesting insects not
mentioned are dealt with in the Others chapter.
and flowering plants
benefit from each other and co-evolved
together. Through this mutualism both
diversified greatly in numbers. Flowers make up
presently the majority of plants and insects are by
far the largest group of animals either in
species or individual numbers.
This video of a
small fly and a composite flower was taken at an
altitude of 3600m at Pichincha volcano near Quito.
In it you can surely appreciate this symbiotic
relationship. As the fly feeds on the
nutrient-rich pollen provided by the flower, it gets
covered by it. It will then transport the yellow
pollen to its next flower feeding station. Chances
are good that one of those following flowers will
get fertilized and start to set seed.
Insects play an important role in any ecosystem and
without them "higher" animals would not be able to survive.
Flowering plants depend for them for pollination. The
most important pollinators are the bees followed by beetles
and flies. Other insects help in recycling nutrients
by feeding on dead organic matter. From the human
perspective there are also harmful insects. Some destroy
crops by eating leaves or roots and sucking sap.
Billions are spent on pesticides to control them. Others
like flies and fleas carry diseases and millions of
people get infected worldwide each year.
insect family associated with the hot
tropics are the walking sticks or
stick insects, scientifically known as
Phasmida. Although much more abundant
in the lower tropical regions like the male
stick insect, Orephoetes peruana to
the left, they also can be found in high
altitudes of some 4000m like the one shown
below called Monticomorpha flavolimbata.
They are especially plentiful in the
paramo regions around Cotopaxi, being found
rock crevices and hollow skulls of dead
Insects were among the first animals to
inhabit dry land. The earliest fossil of an insect dates back to
the Devonian era, some 400 million years ago. They
started to diversify taking advantage of the extensive
vegetation of the following geological eras. They were also the
first group of animals to take to flight, long before any
other animal group hit on that evolutionary advantage. At that
time flying insects were considerable larger than today
(fossils of dragonflies 4 times the size of present species are
known). The probable cause for that was a more oxygen rich
atmosphere and no aerial predators. The real explosion in
insect diversity however occurred some 130 million years ago
with the emergence of flowering plants. Both co-evolved together
helping each other's cause. Flowers provide insects with rich food
and get paid back by efficient pollination. Today they comprise
by far the biggest group of animals with over 1 million species
classified worldwide. Estimates of their real numbers however
10 to 100 million more species. In numbers,
total mass or distribution they are the most successful animals
nowadays and animal diversity is basically insect diversity.
Insects belong to the class of Insecta which is part
of the phylum Arthropoda, a major animal phylum
which comprises those invertebrates, which have an external skeleton and jointed appendages
(in contrast to
the vertebrates, which are animals with a backbone). Other arthropods
are the arachnids (spiders, scorpions &
ticks) and crustaceans (shrimps, crabs, etc..).
change over the years and no definite one is established
yet. Below is an older traditional scheme which will serve us well.
Apterygota- wingless insects
Pterygota- winged insects
book lice, bark lice
bird lice, true lice
true flies, mosquitoes
beetles, fireflies, weevils
ants, bees, wasps,
Insects are small animals with a segmented body comprising of
three parts, the head, thorax and abdomen. Most possess 3 pairs of
legs, a pair of antennae and 2 pairs of wings. Arthropods
developed from soft bodied annelid-kind animals but developed
later an external skeleton or cuticle for protection. That skeleton however limits the size of those animals and has to be
shed occasionally for growth reasons and then the animals are
vulnerable.The senses of insects are quite different to those of vertebrates.
function as taste and touch organs and eyes are simple or compound
ones and come in pairs or multiples.
Another very distinct trait is that of metamorphosis.The young or larva differs greatly
from an adult or imago in physical form and behavior. Different
insect families undergo distinct metamorphosis, from complete
ones like in butterflies to
shortened or incomplete ones.