Question

Eastern tent caterpillars (Malacosoma americanum) live in large groups in silk nests resembling tents, which they build in trees. They are among the first insects to be active in early spring when the daily temperature fluctuates from freezing to very hot. Over the course of a day, they display striking differences in behavior: Early in the morning, they rest in a tightly packed group on the tent's east-facing surface. In midafternoon, they are on its undersurface, each caterpillar hanging by a few of its legs. Propose a hypothesis to explain this behavior. How could you test it?

Short answer

The behavior of the caterpillar is related to temperature adjustment. During the early morning, caterpillars rest in a tightly packed group to conserve their body heat. The silk nest of the caterpillar is typically oriented towards the east to obtain the sunshine from the morning sun.

In the afternoon, they become active, and each caterpillar is hanging by its legs. The hypothesis to test the caterpillar's behavior would be subjecting them to different temperatures in a laboratory condition for a whole day. The behavioral changes to specific temperatures will be recorded.

Step-by-step solution

Abiotic factors of ecosystem

An ecosystem is formed by its abiotic factors such as soil, light, temperature, water, and many other non-living parts of the environment.

These factors influence the physiological and behavioral actions of the organism. The organisms adapt themselves in accordance with the ecosystem's abiotic and biotic (competition and reproduction) factors.

Endotherms and ectotherms

The organisms that have the ability to adjust their body temperature are endotherms. Ectotherms cannot alter their body temperature, but they modify their behavior following the surrounding sources.

For example, endotherms regulate body temperature by changing their metabolic rate. Ectotherms subject themselves to sunlight to withstand cold temperatures.

Behavioral changes of eastern tent caterpillars (Malacosoma Americanum)

Eastern tent caterpillars are ectotherms. They cannot increase or decrease their metabolic rate to maintain the temperature. Therefore, they modify their behavior as per the availability of sunlight. They prefer to build their silk nest in the crook of the host tree.

The nest is always created in the southeast direction so that the caterpillar can take advantage of the morning sun. As the temperature rises, they settle in the bottom of the nest and hang freely to escape from the hot temperature.

The behavior of the caterpillar is studied in a laboratory setup. A setup with an adjustable temperature is preferable. A group of caterpillars is placed in the design. When the temperature is less, they tightly pack in a group.

As the temperature rises, they separate. Recording the temperature as per their behavior assist in developing result.