Sunday, July 22, 2007

Southern Pine Sawyer Beetle

I've come across many species of beetles in our neck of the woods, but one of the coolest in appearance are the long-horned beetles, specifically the southern pine sawyer. Named for their long, segmented antenna these beetles can cause the spread of a tree disease found in certain pines (mostly scotch pines) known as pine wilt. They don't cause the disease per se, but in fact carry a small worm inside them know as a pine nematode that is the culprit. The female pine sawyer lays her eggs in dying or rotted pines and nematodes that are present in this wood enter the developing beetle's system during the pupa stage. When the beetle is fully developed it bores its way out carrying along with it its new found friend (or friends). These young maturing beetles who are hungry and preparing for mating feed on the young shoots of healthy pines and introduce the nematode via the "wound" created by its gnawing.
Once in healthy trees the nematode feeds on its living cells near the resin canals and eventually plug the canals causing the tree to die. Eggs are laid by female beetles in the dying tree and the cycle goes round and round. Interestingly enough these nematodes can continue living in the dead rotted wood if a certain fungi is present- blue-stain fungi. This fungi is surprisingly introduced to the wood by another species of beetle- the bark beetle.
Note: If you look close at the photos you'll notice four tiny mites near the antenna. Isn't nature cool..............

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