Survival instinct guides a species either to avoid if possible or adapt to a situation. Euphydryas editha, a species of checkered butterflies learned the hard way that in evolution there are no shortcuts. Here is how the story unfolds .
The setting is Sneider Meadows, Nevada, USA. In the opening scene evolution has enabled E. editha butterflies to forge a symbiotic relationship with Collinsia parviflora, a local annual plant species. There is a mismatch between the life cycles of the host and the guest but they have learned to live with it. Often the plant withers before the adult butterflies emerge from the larvae with the result that baby butterflies are forced to starve. Mama butterflies, as Singer et al point out thus "face a trade off between maternal fecundity and offspring survival" .
And then humans intervened in the eighties. But let us be fair to ourselves; E.editha and C. parviflora were far from our minds. We were interested in converting the barren wilderness into a lush green grazing ground for cattle by planting the nutritious herbal species Plantago lanceolata. The newcomer grew and spread quickly. It looked greener, healthier and perhaps more attractive than the Collinsia. Seduction and betrayal followed, E.editha shifted its allegiance completely from Collinsia to Plantago. And why not? Plantago is a perennial plant and E.editha need no longer worry about infant mortality from starvation.
This went on for sometime. Then disaster, human intervention of course , struck. The meadow changed hands and new owners didn't want it to be a cattle ranch. Wild grass grew tall and dwarfed the Plantago making its leaves 6 degrees cooler than the ambience. E.editha larvae couldn't withstand the cold and the species was pushed to the brink of extinction. Indeed Sanger and Parmesan who were closely monitoring the butterfly population for decades couldn't spot any during 2008-2012. It seems to have taken another year for Nature to effectively reset the whole program. In 2013-14 the butterflies reappeared, but this time solely feeding on old buddy Collinsia.
References
1. Plantain (Plantago lanceolata) – a potential pasture species
2. Rapid human induced evolution of host-insect associations Singer et al Nature 366, 681-683 (1993)
3. Lethal trap created by adaptive evolutionary response to an exotic resource. Singer et al Nature 357, 2018, pp 238-241
4. Human influences on evolution and the ecological and societal consequences.
 |
| Euphydras editha (Walter Siegmund: wikipedia) |
 |
| Collinsia parviflora (Walter Siegmund: wikipedia) |
 |
| Plantago lenceolata (Sannse: wikipedia) |
This went on for sometime. Then disaster, human intervention of course , struck. The meadow changed hands and new owners didn't want it to be a cattle ranch. Wild grass grew tall and dwarfed the Plantago making its leaves 6 degrees cooler than the ambience. E.editha larvae couldn't withstand the cold and the species was pushed to the brink of extinction. Indeed Sanger and Parmesan who were closely monitoring the butterfly population for decades couldn't spot any during 2008-2012. It seems to have taken another year for Nature to effectively reset the whole program. In 2013-14 the butterflies reappeared, but this time solely feeding on old buddy Collinsia.
References
1. Plantain (Plantago lanceolata) – a potential pasture species
2. Rapid human induced evolution of host-insect associations Singer et al Nature 366, 681-683 (1993)
3. Lethal trap created by adaptive evolutionary response to an exotic resource. Singer et al Nature 357, 2018, pp 238-241
4. Human influences on evolution and the ecological and societal consequences.
No comments:
Post a Comment