Natures wonders: parasite on parasite (Introduction)

by David Turell @, Monday, August 20, 2018, 18:50 (691 days ago) @ David Turell

A vine attacks a wasp induced gall on a tree, which mummifies the adult wasp:

"'Galls are like tumors in many ways," Egan said. "The wasps induce them to grow at the site where they lay their eggs, but the galls are part of the tree. The cells there have the same DNA as any other cell in the tree. They've just been reprogrammed to grow and behave in a way that is ultimately harmful to the tree.


"Gall-forming wasps are among 13,000 insect species worldwide that use biochemistry to trick trees and other plants into growing their nurseries for them. One species that's native to Texas and Florida is Belonocnema treatae,—also called B. treatae—which lays its eggs only on the underside of newly growing oak leaves. A mix of venom and proteins laid down with the egg coax the tree into growing a smooth sphere of hard brown material around the egg. Encased inside this crypt, the larval wasp feeds on a steady flow of nutrients drawn directly from the tree's vascular network, and emerges when it is mature.


"The group gathered all the material it had just sorted and went through all of it again. The biologists found several more samples, and in the months since, Egan, Hood, Zhang and co-author Mattheau Comerford, another Ph.D. student, have found dozens more, including examples of the vines attacking other species of gall-forming wasps. Out of 51 dissected samples of B. treatae galls attacked by love vines, 23 contained a desiccated, mummified adult. In contrast, only two of the 101 galls not attacked by vines contained dead wasps.

"'The attacks are also associated with different gall sizes," Egan said. "We found the vines attached to galls that were slightly larger than average. That means the vine is either only attacking larger galls, or the vine is inducing the galls that it attacks to grow bigger, perhaps to draw more energy from them."

"Egan said the discovery of the new trophic interaction is exciting because it shows an aspect of nature that hadn't previously been noticed and because it's possible that similar interactions happen between many other species.

"'This is the first time anyone has ever discovered a parasitic plant and parasitic gall wasp interacting on a shared host plant," Egan said. "This could be unique, but biologists have catalogued more than 1,300 species of gall-forming wasps and more than 4,000 species of parasitic plants, so this could just be the tip of the iceberg.'"

Comment: More opportunistic behavior. Did the wasp find a way to invent this attack or was it designed? And the same point fits the vine.

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