An online resource based on the award-winning nature guide

Posts tagged “Argiope aurantia

What’s Inside A Spider Egg Sac This Time of Year May Surprise You

10-2-17 black and yellow argiobe egg sac2 IMG_5913

Some species of spiders (including wolf and jumping spiders) overwinter as young adults and mate/lay eggs in the spring. Many spiders, however, mate in the fall, after which they lay eggs and die. Their white or tan egg sacs are a familiar sight at this time of year. One might assume that these species overwinter as eggs inside their silken sacs, but this is rarely the case as spider eggs can’t survive being frozen. Spider eggs laid in the fall hatch shortly thereafter and the young spiders spend the winter inside their egg sac.

Although egg sacs provide a degree of shelter (the interior is packed with very fine, very soft silken threads), the newly-hatched spiderlings do have to undergo a process of “cold hardening” in the fall in order to survive the winter. On nights that go down into the 40’s and high 30’s, these young spiders start producing antifreeze compounds, which lower the temperature at which they freeze. By the time freezing temperatures occur, the spiders are equipped to survive the winter inside their egg sac – as spiderlings, not eggs.  (Photos:  Black-and-Yellow Argiope, Black-and-Yellow Argiope egg sac, Black-and-Yellow Argiope spiderlings inside egg sac)


What’s Inside A Spider’s Egg Sac This Time Of Year May Surprise You!

10-2-17 black and yellow argiobe egg sac2 IMG_5913

Some species of Northeastern spiders (including wolf and jumping spiders) overwinter as young adults and mate/lay eggs in the spring. Many spiders, however, mate in the fall, after which they lay eggs and die. Their white or tan egg sacs are a familiar sight at this time of year. One might assume that these species overwinter as eggs inside their silken sacs but this is rarely the case, as spider eggs can’t survive being frozen. Spider eggs laid in the fall hatch shortly thereafter and spend the winter as young spiders inside their egg sac.

Although egg sacs provide a degree of shelter, the newly-hatched spiderlings do have to undergo a process of “cold hardening” in the fall in order to survive the winter. On nights that go down into the 40’s and high 30’s, these young spiders start producing antifreeze compounds, which lower the temperature at which they freeze. By the time freezing temperatures occur, the spiders are equipped to deal with them throughout the winter – as spiderlings, not eggs.  (Photo: Black-and-Yellow Argiope (Argiope aurantia) egg sac)

 


Silk Rainbow


Spider Spinnerets

All spiders are capable of spinning silk, regardless of whether they use it to spin webs and trap prey or not.  Egg sacs, drag lines (so they can find their way home), drop lines (to catch them if they fall) egg cases and transportation (young spiders disperse by “ballooning” as the wind catches their silk and carries them off) are some of the other functions silk plays in the life of a spider. Silk is extruded through nozzles called spinnerets located near the tip of the abdomen. Typically a spider has two or three pairs of spinnerets.  Each one is the exterior tip of an interior silk gland and has a valve which can control the thickness and the speed with which the silk is extruded.  The different glands produce different kinds of silk used for different purposes. The spinnerets work independently for some functions, and together for others.  In the photograph, the black and yellow argiope is turning her grasshopper prey around and around as she produces a sheet of silk in which she wraps it.  Most, if not all, of the spinnerets are in use.