Final answer:
Little brown bats are classified as tertiary consumers because they primarily feed on insects, which are themselves consumers of plant-based matter.
Step-by-step explanation:
Little brown bats are tertiary consumers. They are carnivores that feed on other carnivores or, in some cases, secondary consumers such as insects.
In a food web, trophic levels indicate the feeding position of different organisms, ranging from producers at the first level to higher levels that include primary consumers, secondary consumers, and tertiary consumers. Being insectivorous, little brown bats primarily consume insects, which are themselves consumers of plant-based matter, making the bats at least third-level consumers. Therefore, in delineating the ecological position of little brown bats, they fit best at the fourth trophic level.
It's important to note that some organisms can operate at multiple trophic levels depending on their dietary habits. Omnivores like humans, for instance, can be primary, secondary, or tertiary consumers based on what they eat. However, the little brown bat primarily eats insects, making them squarely tertiary consumers according to the definitions of trophic levels.
According to the given information, little brown bats belong to the secondary consumers trophic level in the food web.