If you have seen spiders in the corner of your room using their legs to fight off each other, then you may have just seen their courtship display.
Spiders use a complex display of signals to identify themselves, including sounds, pheromones, vibrations, visual effects, tactile interactions, and even jumping displays. Courtship depends on whether they are web-builders, clear-sighted hunters, or poor-sighted hunters.
Spider courtship is a fascinating subject, and I hope you read on so that next time you see two spiders together, you will know what they are up to.
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How Spiders Use Courtship
Spider courtship can be a complex and lengthy affair as the smaller, more submissive male may spend an entire day attempting to approach, excite and seduce the female, who may be more likely to regard him as a potential meal rather than a mate.
Courtship in spiders is a ritualized form of behavior preparatory to mating, and it is common that animal species mate with such preliminaries between the sexes. The courtship of spiders includes behavior that is advanced compared with most other invertebrates.
Much of it involves signals used to identify themselves, but spiders also exhibit types of behavior that are almost seductive, devious, or pre-emptive.
For the male spider, these first steps are essential if he is to avoid being mistaken for prey. As females are much larger individuals, it helps to pacify their predatory instinct and also provides stimulation necessary for copulation.
The exchange of information between the two sexes can be very complex, with simultaneous actions and signals which include sounds, pheromones, vibrations, visual effects, and tactile interactions. In order to find members of their own species, the combined effect of these interactions is unique.
Interesting Approach To Impregnation
For most spider species the male seeks out the female. However, the female may have tried to attract a male by emitting pheromones into the air or onto webs trailed behind her which help the male to track her down.
Once they reach breeding age, the male spider usually loses interest in prey, leaves his web, and spins a tiny sperm web. On to this, he ejaculates a drop of semen which he draws into organs in his palpi, a pair of elongated segmented appendages near the mouth. He then searches for a partner and attempts to inject the semen into her genital apertures.
Courtship On The Web
Spider courtship techniques can be grouped depending on whether they are web-builders, clear-sighted hunters, or poor-sighted hunters.
Courtship among web builders usually involves the male moving and vibrating the web threads with his legs and drumming with his palps. When the female has allowed his approach, he will stroke her body.
Males are not always successful with their courtship, and many can be seen towards the end of the mating season with only three legs left.
Males of some species will wait in the outskirts of the female’s web until she is busy with an insect before approaching. A few hours may pass without any movement, however, once an insect is caught in the web and the female begins to feed, the male advances and strokes her with out-stretched legs.
They grapple, then break, and while she returns to the meal, he trails a mating thread over her, ready to begin his vibrations which, if he is lucky, will eventually interest her in mating.
Courtship In Clear-Sighted Species
Among clear-sighted hunting spiders, males often perform a visual display before approaching the female. Wolf spiders and lynx spiders wave their palps up and down or vibrate them.
The common wolf spider’s courtship involves an elaborate display in which the male stands as tall as possible and holds his palps out sideways, alternately raising one and lowering the other as he slowly advances on the female.
The most extrovert courtship displays are performed by jumping spiders, known for their highly developed eyesight. In an elaborate dance, the males perform to show off their color pattern to the best effect.
The large semi-aquatic raft spider has a wolf spider-like courtship, with the male stretching out his palps and rapidly vibrating his front legs, although he often waits until the female eats something before advancing.
In some species, the male first catches an insect, wraps it in silk, and then hands it to his partner before attempting to mate. The nursery web spider Pisaura mirabilis sometimes cheats by wrapping up the empty carcass of a fly or even by running away with the carcass at the end of the mating ceremony.
Courtship In Short-Sighted Hunting Spiders
Short-sighted hunting spiders walk about with their forelegs stretched out ahead, and their courtship is extremely brief. Because they are unable to use web vibrations or visual signals, their meeting is an immediate and frenzied interplay of legs, the male attempting to reach the mating position while still using tactile stimulation.
The woodlouse spider spends much time in closed silken cells and this is where the male usually finds a female. On arriving at the cell, the male introduces himself by rubbing the silk using his legs. He tears open the cell with his fangs, places his first two pairs of legs through the hole, and walks in. The female meets him, opening her gaping fangs, but he taps and strokes her body to calm her down.
In the large, fierce Drassodes lapidosus, males reach maturity earlier than females. They take possession of an immature female by enclosing her in a silken cell and mating with her immediately after her final molt, just before she gains full strength. Several crab spider males will seize the female by a leg and hold on until her struggle ceases or until the female attacks.
Too Many Males
Encounters between male spiders are frequent, especially where population density is high, as with wolf spiders. When two male wolf spiders meet in the presence of a female, they assume threat postures and may begin to fight.
The dominant male, established in previous fights, is likely to be the winner, and he turns his attention to the female, circling her and waving his palps in a courtship ritual.