Just as humans have a circadian rhythm that can be changed when entering a new time zone or season, other animals also exhibit time behavior - especially for food collection. As an animal’s environment changes over time, the they have to evolve to constantly change their time intervals for when they collect their food. This is very common in nectarivorous animals such as honeybees or bats. For example, honeybees know when to go out of their hive and obtain nectar from flowers because they have adapted to learn at what times a flower will “re-fill” its nectar.
To study these timing behaviors in animals, Fixed Interval (FI) procedures are used. In a FI procedure, first animals train until they become familiar with a FI interval that is set specifically for the experiment. After the animal has established a stable reaction to the set FI interval, the actual experiment begins. During the experiment, animals are rewarded if they perform a specific task at the set FI interval. If the animal takes the reward, the trial is labeled as a rewarded trial. However, if the animal fails to perform the task in the fixed time interval, the trial is labeled as an empty trial. When the whole experiment is graphed, the rewarded trials are interspersed with the empty trials to show an oscillation from the peak FI time that was set before the experiment began. Based on earlier studies that were done, a law on animal timing behavior was set called Weber’s Law. This law states that with increasing Fixed Interval time, the distribution of the response trials when graphed around the peak time widened proportionally to the increase in FI duration. The spread of the distribution around the FI time is hypothetically caused by a break-run-break pattern. Researchers believe animals exhibit this pattern because they increase their responses from a low rate (break) suddenly to a high rate (run).
This experiment was done on bats of the Glossophaga soricina species. These bats are known to have a long-tongue and their diet is mainly nectar. In the experiment, these bats had to hover in front of a feeder to obtain their reward (nectar) at specific FI times (3s, 11s, and 20s). Hovering could only be maintained for a few seconds, so the bats had to learn when to rest and hover to obtain their reward at the specific time interval.
This experiment most is related to Big Idea 1: The process of evolution drives the diversity and unity of life. In an ecosystem, to maintain efficiency, animals need to learn timing behavior, so the food cycle can run without delay. Learning when to collect food in an ecosystem is a fixed action pattern in species. Also, if the animal migrates to a different ecosystem ,then it must adapt to it’s surroundings in order to survive and reproduce because the timing of food collection would be different in a different environment.
If 6 Glossophaga soricina bats are tested in a 3 second Fixed interval for a 12 hour period, then 80% percent of...