The other day i discovered that my garden was invaded by a black and yellow stripes caterpillars, after researching it online, i found out that these were the caterpillar stage of the burnet moths or more scientifically know as “Cinnabar Moth”.
Cinnabar moths a day-flying insects … the larvae use members of the genus Senecio as foodplants… for long-term population success, the presence of the larger species such as ragwort is needed… Females lay up to 300 eggs, usually in clusters of 30 to 60 … Newly hatched larvae feed from the underneath of ragwort leaves within the area of their old eggs. The larvae absorb toxic and bitter tasting alkaloid substances from the foodplants, and assimilate them, becoming unpalatable themselves. The bright colours of both the larvae and the moths act as warning signs, so they are seldom eaten by predators… They are voracious eaters; large populations can strip entire patches of ragwort clean, a result of their low predation… Often, very few survive to the pupal stage, mainly due to them completely consuming the food source before reaching maturity;
So you have this moth that have very few predators in pupal stage, and lays a high number of eggs, and yet most die before reaching maturity due to starvation! I mean is this a failure in evolution? why they didn’t evolve to be able to consume other plants as well? But let’s imagine for a minute that these creature did evolve to be able to consume alternative plants once main food is consumed, in this case with such a high reproduction rate & with few predators, this moth will entirely consume the “Senecio” genus, that’s around 1200 plant species!
But why the starvation road? why the moth didn’t evolve to lay less eggs?
less eggs, seams to be a good evolutionary road, less eggs, more caterpillar survive, eventually the variation with less eggs will become dominant … or will it?