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A Walk in Fern Bluff Park (17 Mar. 2007) pg 4
In a meadow to the right of the
wilderness trail,
several stands of a particularly spiny cactus grows. Not so with the more spiny varieties. Although they are as tasty to deer and cattle as the spineless ones, the price of each meal is much higher.
Part of that price, obviously, is getting pricked by the long, white primary spines, but that's not the worst of the deal. Each areole, or wart, on the cactus pad has two kinds of spines, the primary ones, and tufts of secondary spines as well. The secondary spines are barbed in this species, and don't come out without bringing some of the victim's flesh with them.
Though the two kinds of spines on this cactus protect it from browsing animals, they don't protect it from everything. The cochineal insect (Dactylopius coccus), a scale insect in the suborder Sternorrhyncha, is so small the barbed spines don't bother it. Every areole provides a convenient place for the insect to penetrate the cactus skin and feed on cactus juice; as you might guess, that stunts the host's growth and stresses it, making it susceptible to other insects and diseases; whenever you see a sickly stand of cactus, this insect was the likely cause of its decay, at least initially. But, let us not think unkind thoughts about the cochineal insect. Without them, we'd be very unhappy. Trust me. Like most soft scale insects, D. coccus (the species name I am using is one of the more common species, but other species in the genus Dactylopius also infest cactus of various kinds, and it is difficult to tell them apart) produces a covering of downy web-like, unsightly material that helps protect them from predators. Cochineal insects are prized for the control they exert over native and introduced species of cacti that, without this insect, would proliferate into incredible pests in our wilderness landscapes (just ask the Aussies, who introduced this cactus, absent the cochineal, for soil erosion control only to later have to introduce the cochineal to control the cactus).
Cochineal insects are not immune from predation by other insects, but because their bodies contain large amounts of carminic acid, most predators leave them alone. Centuries ago, the natives of South America discovered that carminic acid, which has a deep red color, makes an excellent dye. They began using it to dye the fibers used in their clothing. Later, the Conquistadores took the dye to the Old World, where it soon became the most popular (and most expensive) red dye available. Synthetic dyes later replaced it, but today--owing to the toxic qualities of most synthetic red dyes in comparison with carminic acid, and the unusual stability of the latter--it is once again a popular dye of textiles, foods, and cosmetics. Archives of previous walks in the park: 12 May 2007, 05 May 2007; 28 April 2007, 21 April 2007, 14 April 2007, 1 April 2007 Easter Egg Hunt; 24 March 2007, 17 March 2007; Nov. 03, 2001; April 04, 2001; March 25, 15, 10-11, 04, 2001; February 24, 18, 10, 2001 * TERMITE ENCOUNTERS * SNAKE ENCOUNTERS * SNAKE BITE FIRST AID * SNAKE EXCLUSION * SPIDER ENCOUNTERS FOR 2008 * SPIDER ENCOUNTERS FOR 2007 * SPIDER BITE FIRST AID * SPIDER EXTERMINATION * PUSS CATERPILLAR ENCOUNTERS * PUSS CATERPILLAR FIRST AID * PUSS CATERPILLAR EXTERMINATION * Assembled & Edited by Jerry Cates. Questions? Corrections? Comments? BUG ME RIGHT NOW! ---- Ph: 512-331-1111 ---- E-Mail ---- Privacy ----BugsInTheNews * --0a0s-- |
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