Goldenrod crab spider / Cvjetni pauk

These spiders may be yellow or white, depending on the flower in which they are hunting; younger females (hunting on flowers such as daisies and sunflowers) may change color "at will". Older females require large amounts of relatively large prey to produce the best possible clutch of eggs. Color occurs by secreting a liquid yellow pigment into the outer cell layer of the body. On a white base, kynurenine and 3-hydroxykynurenine are transported into lower layers, so that inner glands, filled with white guanine, become visible. The color change from white to yellow takes between 10 and 25 days, the reverse about 6 days. My spotting however although yellow did not wanna be unseen in the yellow backgroung so it gave me the opportunity to shot a beautiful picture on a purple-blueish background of a lavander flower :)