Posted: March 31, 2017

This is the 4th of thirteen short news articles written by students, during the professional development class, about each other's research.

Hawk Moths are Hot Moths
By Hillary Morin

A large hawk moth (Manduca sexta) flies through a cool summer night, searching for flowers to feed on. She finds the one she is looking for, and begins to hover and feed. As her long tongue dips into the flower, anyone witnessing this moment could mistake the moth for a hummingbird. Intriguingly, this ability to feed like a hummingbird is not the only similarity between the moth and the bird. Brandon Gominho, a master's student at Penn State University in the Entomology Department is investigating how this moth also maintains its body temperature like a bird.

"Because it is a nocturnal moth, it cannot rely on the sun for body heat, like most other moths. Instead of using the sun for heat, Manduca sexta can vibrate its flight muscles really fast to create heat," explains Brandon. Hawk moths are capable of heating their own muscles from 72 degrees Fahrenheit all the way up to 104 degrees Fahrenheit. That is some serious heat!

Animals generate and maintain heat in different ways. Mammals (such as humans and elephants) and birds are called "warm blooded;" reptiles, amphibians, fish, and insects are called "cold-blooded." "Warm-blooded" animals (homeotherms) regulate heat inside their bodies, much like a thermostat changes heat within a house to keep it warm. Contrastingly, "cold-blooded" animals (ectotherms) rely on things outside their body, like the sun, to change their bodies temperature.

While most insects are "cold-blooded", hawk moths are an exception to this rule. Not only can these insects generate their own body heat, they are capable of withstanding enormous changes in heat without any injury to their bodies. "As humans, our internal body temperature is held at an optimal 98.6 degrees Fahrenheit. If our internal temperature changes even 5 degrees Fahrenheit, we would be in serious danger of death due to overheating, yet the hawk moth is able to increase its internal temperature up by 35 degrees Fahrenheit every time it flies," Brandon notes. That is seven times the amount of change that the human body is able to handle. Understanding how the moth's flight muscles function at high temperatures can help us understand how our own muscles react during fever, exercise, and inflammation.

Brandon couples thermal videography with a variety of molecular techniques to study the relationship between body temperature and muscular structure. Brandon hopes to discover exactly how the moths are capable of heating up their muscles quickly, and how they are able to do this without being injured by the rapid change in temperature. Hovering over flowers in the dark of the night, this magnificent moth may help us understand our own bodies!