- Insects have an open circulatory system, which means their blood flows freely through their bodies instead of being contained in vessels.

- This allows nutrients to be delivered directly to cells without having to pass through multiple layers of tissue, reducing energy expenditure.

Low Energy Requirements

- Insects are ectothermic, meaning they rely on external sources of heat to regulate their body temperature. This means they do not need to expend energy to generate body heat, unlike warm-blooded animals.

High Surface-Area-to-Volume Ratio

- Insects have a high surface area relative to their volume, which means they can release heat more efficiently. This helps them to maintain a lower body temperature, reducing the need for energy to cool down.

Limited Nutrient Storage

- Insects have a limited capacity to store nutrients, which means they must consume food frequently.

- This prevents them from overeating and accumulating excess fat.

Rapid Reproduction

- Insects have a rapid reproductive rate, which means they can quickly replace individuals that die or are lost. This reduces the need to store large amounts of energy for reproduction.

- Overall, the combination of these factors helps insects maintain a lean body composition despite consuming a relatively high-energy diet.