Misumena vatia female

Misumena Vatia


Kingdom:  Animal

       Phylum:  Arthorpoda

           Sub-phylum:  Chelicerata

                Class:  Arachnoidea

                      Order:  Aranea

                                Family:  Thomisidae

                                       Genus:  Misumena

Scientific Name:  Misumena Vatia

Common Name:  Flowering Crab Spider, Goldenrod Spider



The habitat of Misumena Vatia is the world.  Flowering crab spiders, or Goldenrod spiders, are indeed the same arthropod, these are simply different names for different continents.  The spider can be found in Europe and Britain extensively, but is only found in North America near Mexico all the way into the Amazon River.  The Family Thomisidae, which refers to the “crab spiders” (named such for their leg distribution and the side-ways manner of their locomotion), is found all about the world.  Misumena Vatia specific habitat is the local flora.  All crab spiders dwell within or upon plant life.  Flower coloration is a heavy factor of survival to the crab spider and as such most will dwell solely in foliage similar to their pattern of coloration.



                All crab spiders are carnivorous, eating small insects that tend to be attracted to flowering plants.  You see, this is the Misumena Vatia’s strategy:  it waits upon or within a chosen flower, its arms outstretched, until a suitable meal arrives, whatever flying insect it may be.  Like all spiders, the crab spider’s fangs produce venom which paralyzes the victim so it may be dissolved (spiders liquefy the internal contents of their victims) and eventually drained for nutrients.  The fangs also hold and penetrate the victim for feeding purposes.


Defense and Protective Coloration

                Misumena Vatia’s defense from predators is important, as the spider is fed upon by birds and a variety of omnivores and carnivores located within the tropical rain forest.  The poison of the crab spider is potent enough to incapacitate most insects very quickly, despite their size.  However, against larger predators, such as birds, a new strategy must be arranged.  This strategy is evasion.

The crab spiders evade their predators by not being noticed.  Each type of crab spider is camouflaged to match the blooms of the flora in its natural habitat.    By not being noticed the Misumena Vatia can focus its attentions on other matters, rather than actively defending itself from predators.  This coloration is also the main strength of its method of predation. 


Adaptations and. Reproduction

                One of the masked crab spiders’, and all crab spiders’, adaptations is its means of locomotion.  The joints of Misumena Vatia are “like those of a crab,” allowing the spider to move sideways as opposed to straight ahead.  This is primarily due to its terrain and habitat, specifically referring to the fact that its hunting ground is located within flowering plants.  This method of locomotion allows greater movement either inside a blossom or upon the plants surface as it moves  “about” its terrain as opposed to “over” it.  This is also to hold prey, as the legs bend easily to grab prey.  This is different from the strategies of other spiders, who simply use their mandible to hold prey or ensnare them with silk. 

Another adaptation of Misumena Vatia is one very useful ability that allows it to maintain its camouflage even if it migrates to another flower (no other member of the family Thomisidae has this option if there is a necessity to migrate).  The skin tones of the Misumena Vatia mimic the dramatic coloration of the blossom that it inhabits after only 3 to 4 days worth of exposure.  This allows the Misumena Vatia to survive more frequently than other crab spiders, because when other crab spiders must leave their “home” flowering plant, they are easily seen.  Imagine if the spider on the first page had to live on a red rose out of necessity.  It would be easily seen by predators and by prey limiting its ability to feed.

Yet another adaptation of this animal is something common with most spiders.  The Misumena Vatia produces silk from its spinnerets, yet does not use the silk to ensnare its prey.  The silk is used primarily for two reasons.  The first is as a safety cord in case a quick escape must be made off of the plant, or to quickly find ones way back to its native plant.  The other reason is actually involved in the maintaining of the Misumena Vatia’s young.  To protect its eggs, the Misumena Vatia lays its eggs upon a leaf, then rolls and sews up the leaf until it vaguely resembles an “ice cream cone.”  This not only disguises the eggs and protects them, but also guarantees the young will emerge upon a suitable flowering plant and thus increase the chances of survival.

Misumena Vatia produces litters of hundreds of Misumena Vatia’s before sealing them in the leaf as described above.  The mother does watch over her eggs, because the young cannot tear through the “protection” she has created.  After opening the egg sac, she will move on.  This is all the parental care the young can expect to receive, as the spider will not be on friendly terms.  Misumena Vatia is very territorial and will attack its own young if they enter its home (the new home).  Not all the young will survive, which is why Misumena Vatia produces such high numbers.  As far as mating goes, their territorial nature is extreme.  The female Misumena Vatia is literally helpless to the advances of the male due to pheromones after she “comes of age.”  This guarantees many broods of young for the animal.  However, before this coming of age, the female will devour any other spider. 


Evolutionary pressures

When one looks at spiders evolutionarily, ones sees them diversifying to hunt prey everywhere and everyway.  The pressure evolutionarily upon the flowering crab spider focuses on being able to spend most of its time mating.  Most spiders must either hunt or look for a mate, not both.  Because the spider does not travel to its food, but rather lures its food to it, Misumena Vatia does not have to exert as much energy as other spiders toward hunting.  By matching its environment, it does not actively have to avoid predators.  By making mating pheromones absolute in their effectiveness it guarantees the maximum breeding possible.  The adaptations of the flowering crab spider allow it to spend its time increasing its number.  The pressures of predation and defense have both been handled in one stroke: match the environment that attracts those animals which you feed from.   The specialization is completely parallel to that of the flora about it. 


                The Misumena Vatia lives in all environments, from the rainforest to the British countryside.   As man populates the earth, and tears down forests and fields, we are finding fewer and fewer locations for the plant that the spider inhabits.   The spiders are definitely in danger through habitat destruction and pollution, since they are dependent on both the longevity of the local flora and that of bees and other flying insects.  They are far from endangered, due to their widespread base, but if man affects the environment, he is affecting the Misumena Vatia.  The arachnid is one who has no chance of surviving elsewhere, as is the cost with specialization.