Caterpillars are cold-blooded, and need warmth to induce feeding activity. Thus in a cool spring they take longer to develop, so more get eaten by birds, and more get attacked by parasitoids. In the case of 
nocturnal larvae the reverse is the case - cloudy weather stops night time temperatures from dropping, and increases the caterpillar's growth rate. So in poor weather they develop quicker and less get attacked by parasitoids.
Vertebrate predators possess varying degrees of intelligence and quickly learn how to overcome the huge variety of defense mechanisms employed by their prey. In many cases it is known that birds can pass on their learnt behavior to their offspring, so their ability to locate and consume butterflies and their larvae increases with
each passing generation.
Luckily butterflies have a couple of advantages over birds. Firstly, a high percentage of species are polyvoltine ( producing several generations per year ). This rapid rate of reproduction enables them to recover their numbers quickly even after major losses of population. Secondly, butterflies and moths intrinsically produce high genetic diversity. These 2 factors result in an ability to evolve rapidly, the consequence being that the battle between birds and butterflies has become a closely run race - the birds catch enough caterpillars and butterflies to feed themselves and their offspring, but at the same time enough butterflies survive to ensure that both predator and prey can continue to co-exist. This is the so-called "balance of nature" - a long term evolutionary battle for survival between predator ( or parasitoid ) and prey.
But with great effect of climate change, butterfly and other flying animal survival get even smaller.
In the wild, butterflies may expect to enjoy a 2 percent survival rate between ova and adult.
The 98% that perish along the way may be devoured by prey, succumb to virus or diseases or not be able subsist if the climatic conditions (drought, wind, temperatures changes, fires) are not right.
A successful butterfly culture/farming can increase the survival rate of these delicate, spectacular creatures from 2% to as high as 90 percent.
nocturnal larvae the reverse is the case - cloudy weather stops night time temperatures from dropping, and increases the caterpillar's growth rate. So in poor weather they develop quicker and less get attacked by parasitoids.Vertebrate predators possess varying degrees of intelligence and quickly learn how to overcome the huge variety of defense mechanisms employed by their prey. In many cases it is known that birds can pass on their learnt behavior to their offspring, so their ability to locate and consume butterflies and their larvae increases with
each passing generation.Luckily butterflies have a couple of advantages over birds. Firstly, a high percentage of species are polyvoltine ( producing several generations per year ). This rapid rate of reproduction enables them to recover their numbers quickly even after major losses of population. Secondly, butterflies and moths intrinsically produce high genetic diversity. These 2 factors result in an ability to evolve rapidly, the consequence being that the battle between birds and butterflies has become a closely run race - the birds catch enough caterpillars and butterflies to feed themselves and their offspring, but at the same time enough butterflies survive to ensure that both predator and prey can continue to co-exist. This is the so-called "balance of nature" - a long term evolutionary battle for survival between predator ( or parasitoid ) and prey.
But with great effect of climate change, butterfly and other flying animal survival get even smaller.
In the wild, butterflies may expect to enjoy a 2 percent survival rate between ova and adult.
The 98% that perish along the way may be devoured by prey, succumb to virus or diseases or not be able subsist if the climatic conditions (drought, wind, temperatures changes, fires) are not right.A successful butterfly culture/farming can increase the survival rate of these delicate, spectacular creatures from 2% to as high as 90 percent.
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