It turns out that fat may actually stunt growth. Scientists discovered that caterpillars that eat a high-fat diet are actually smaller than their counterparts eating a medium- or low-fat diet.
Fat metabolism pathways are similar among vertebrates. This includes humans and also invertebrates such as the tobacco hornworm caterpillar. Understanding the role of fats in insects, however, could help understand human metabolic processes.
Fat is crucial for reproduction and development in insects. With that said, very little is known about what happens when insects eat fat since they normally have a high-carbohydrate diet.
In order to find out a bit more about what happens when this occurs, researchers fed tobacco hornworm caterpillars low-, medium-, or high-fat diets. This revealed quite a difference between the three groups.
In the group that was fed the high-fat diet, about 80 percent of the young larvae died. Not only that, but the larvae's body mass was 43 percent lower than the body mass of the larvae that were fed low- and medium-fat diets. Development was also slower for the caterpillars that were fed the high-fat diet.
With that said, the scientists did find that older insects that were fed the high-fat diet did a little bit better than younger caterpillars. They had similar mortality rates as the other groups, though they did grow more slowly.
So why did the high-fat caterpillar group experience such negative surges of growth? Scientists found that the caterpillars that were fed the high-fat diet had a smaller body size because they ate less overall. In fact, the insects also produced fewer fecal pellets. This indicates that a high-fat diet causes the caterpillars to simply stop feeding, which can cause a host of issues when it comes to the health of these insects.
The findings reveal a bit more about how fat interacts with these insects. This, in turn, is important for not only understanding these insects, but also human diseases. It's possible to extrapolate from these findings and apply a few of the discoveries to the research of human metabolic diseases.
The findings were presented at the Experimental Biology 2016 meeting in San Diego.
