Puddling
Mud-puddling, or simply puddling, is a behaviour most conspicuous in butterflies, but occurs in other animals as well, mainly insects; they seek out nutrients in certain moist substances such as rotting plant matter, mud and carrion and they suck up the fluid. Where the conditions are suitable, conspicuous insects such as butterflies commonly form aggregations on wet soil, dung or carrion. From the fluids they obtain salts and amino acids that play various roles in their physiology, ethology and ecology.
Wikipedia
The Puddling of Butterflies
On a recent trip to the Great Smoky Mountains National Park I took a side trip to the less frequented Cataloochee Valley region on the east side of the park in North Carolina. While elk, reintroduced in 2001, are the area's main attraction, they were staying cool in the woods beside the open meadows in the middle of this hot summer day. However, much to my delight, the edges of the gravel road were teeming with butterflies, intent on the damp mud.
In my research, I discovered that some Lepidoptera (butterflies and moths) do what's referred to as puddling or mud-puddling.
Mud-puddling ... the
butterfly's dirty little secret
In fact, it is believed that butterflies congregate on mud and other such substances primarily for salts. The salts and amino acids absorbed during mud-puddling play various roles in butterfly ecology, ethology and physiology. Males seem to benefit more from the sodium uptake as it aids in reproductive success, with the precious nutrients often transferred to the female during mating. This extra nutrition helps ensure that the eggs survive.
Resource Specialization
in Puddling Lepidoptera
Lepidoptera feed at mud puddles, dung, and carrion in a behavior known as puddling. Sodium and sometimes protein are feeding cues, are actively collected, and play a potentially important role in lepidopteran nutritional and mating ecology.
"Puddling" is a behavior in which adult Lepidoptera feed from mud, dung, carrion, or sweat. Such feeding is stimulated by sodium, or in some species, by proteins. Additionally, puddling intensity differs within species among sex and age classes