This part is gently
corrected in "readable English by Nick Loven - click on image to look
around his webpage
Since we don't notice spiders during the
winter, does this mean that they are summer or autumn animals as there are
many of them during this time? Do spiders have a long or short life?
Generally we can assume that on our
hemisphere, in our regions, the average life of a spider is 1 year. For
our native spiders climate and food supply are the factors that restrict a
spider's life span. In the warmer (tropical) climates, spiders often live
longer than 1 year; bird spiders even between 10-15 years.
As climate and food supply can not be
considered as seperate criteria, the spider has to bridge a "dead"
period (winter). They do so, in well-sheltered places, hidden and often
under a tight woven spinning of silk, in a state where all vital functions
are restricted to the utmost minima, in an absolute condtion of rest also
known as DIAPAUSE.
The spider lives during this "silent"
period upon the body supplies built up during the Summer. The smaller the
survival probabilities of the individual, the greater the number of
offspring produced. Spiders do not give birth to living young, but instead
propagate themselves by means of eggs, which are put down in groups in egg
sacs. In the very tiny round eggs, the first development takes place. As
soon as this has progressed far enough, the teeny-weeny spiderlings break
the egg-wall by means of a kind of egg-tooth (which releases later on) at
the base of the palps; they leave the egg and, after a short while, the
silk of the egg-sac. As the first development-phase isn't quite completed,
the spiderlings are rather helpless. In their abdomen they possess quite
important quantities of stored food (egg yolk) which helps them to survive
before they have to search for prey. The young animals that succeed in
resupplying their energy-stock, survive. The spiderlings are getting
bigger. As the skin is limited in his elasticity, it has to be replaced by
a bigger one: the spider MOULTS.
Before the moulting process (ecdysis)the spider becomes less active. As a first step taken on the road to a new skin, the spider spins itself at the spinnerets and legs with a couple of strong threads to an object or a plant; web-spiders hang themselves. The skin of the cephalothorax slits along the edges and the backskin is flinged; afterwards the skin of the abdomen slits along the edges. Legs and palps are freed from the old skin. A moult has a very huge energy price for the spider; this means that after the moult the spider needs to find food as soon as possible. After each moult the spider is not only bigger, but has also become more "adult". The sexual glands in the abdomen show themselves only as genitals after the last moult. The spider has become an adult.
The female spiders are almost always bigger
and less slim than the adult males. The external parts of the genitals are
so specific for the species that identification of the species is mainly
based on the examination these parts. The females have an
epigyne, the males have quite discrete
genitals, which are not suitable for recognition of the species.
The external characteristic of the male is
not to be located in the region of the genitals, but at the front of the
head at the palps. The last member of the palps is changed in a button or
drop like organ, wherein a a small bubble (the bulbus
genitalis) with a fine opening at a sharp point (the
embolus) is situated. The copulation-organ of a male fits only in
the epigyne of a female of its own species. This sexual differences -
epigyne and copulation-organ - are exclusively visible in
ADULT animals.
One has thus to look first if a spider has
thick button like palp members, if it does then it is a male. If this is
not the case, the spider can be an adult female or an immature, male or
female, animal; to examine this closer, one has to check the ventral side
and look after a clear grown up epigyne. If the epigyne is present, we
know the spider is female; if not, we can not make a judgement about the
sex and we have to assume the spider is an half-grown (juvenile)
animal.
The fertilisation of the female spider does
not happen through direct contact with the genitalia, but on a very unique
manner in the world of the animals: the indirect
sperm transfer. Shortly after the last moult, the male spider spins
a small carpet (sometimes only some threads) somewhere made out of fine
silk. Next he brings his genital opening above this woven carpet and
releases his sperm upon it. Then he makes a turn and sucks the sperm in
the bubbles of the button-like last members of the palps. As soon as these
are filled up - the full swollen bubbles are visible with a magnifying
glass in the bigger species - he takes on a quest to look for a female to
empty his palps in her epigyne.
How can a male spider know if he has to deal
with a female of his own species? Sexually mature females secrete a
perfume not detectable by humans. This sex-perfume (feromone)
is - could it be otherwise - specific for each species. For a male, the
approach of a female is a rather risky and dangerous adventure, all the
more that the female is several times bigger than the male. Therefore the
male does not head straight to the female, but begins very modestly to
attract her attention. From a place close to the web he spins a thread to
the web; from this "lovers bridge" he starts his courtship. This
courtship or love-game has a triple purpose: a. investigate from a safe
distance if the female is prepared to undertake a copulation; b. excite
the female sexually; c. make the female understand that the intruder is
not prey and does not belong to another spider species.
The different groups of spiders have several
copulation rituals which are very fascinating and worth observing. The
egg-laying occurs 2-3 weeks after the mating. The laying of the eggs is
for the females an essential activity. Even if they are not fertilized,
the females shall, may it be later than normal, lay the eggs. Such
non-fertilized eggs do not develop. As soon as the female comes to this
conclusion, she leaves the eggs, which are often sucked empty before the
definite separation. The eggs are almost always layed in groups and are
camouflaged with bits of earth, pieces of plants etc...
Different species show remarkable care for their offspring. Hunting-spiders, which make no webs, show on another manner a moving care for their eggs. They carry their egg-sack always with them, glued by means of silk to their spinnerets or between their jaws.
I WISH YOU A LOT OF PLEASURE WITH YOUR OBSERVATIONS...!!!!!!!
