Behavioral Data Analysis

Data Analysis Module 1: Mean Comparisons

Case Description:

A local zoo is having trouble with the rearing of an exotic lizard species they wish to breed for a new exhibit. They believe part of the problem lies in recreating the complex natural diet of the species that is naturally rich in proteins. While importing the specific bugs that these lizards feed on has proved impossible, the zoo believes they may be able to shortcut this issue by increasing the protein content in the diet of the prey they use to feed their lizard: the domestic cricket Acheta domesticus. However, the zoo is also worried that better fed crickets may be harder to capture for lizards offspring, which can be particularly problematic as proper nutrition is essential during the early stages of this species development. While the zoo is working on an artificial diet, one of the staffer has also begun to take behavioral measurements on the crickets in order to test the effect of the protein-supplemented diet on their behavior. This person has limited knowledge of how to conduct research on animal behavior and is contacting you in order to get guidance on his preliminary data. She sends you the following details on her experiment:

· Exposed 20 juvenile crickets to either a high (45%) and low protein (18%) content diet for 30 days.

· Measured the activity of each cricket in an open-field arena (OF) and a predator cue response test (PC). See descriptions in following page.

· Measured the mass of each cricket at the end of the experiment.

Learning objectives:

• Use knowledge of animal behavior and experimental designs to generate recommendation for stakeholder

• Learn to analyze and think critically about behavioral data

Instructions:

Prepare a report for the zoo where you will analyze the data provided and send additional recommendations. Be mindful of the following aspects:

· Is the data sufficient to conclude on any particular recommendation regarding the use of protein-supplemented diets for crickets in order to facilitate lizard rearing?

· What would be additional experiments that would have to be conducted in order to get a more robust answer?


Open-Field Test

The crickets are introduced to a 60 x 60 cm arena and left to rest for 60s under a plastic shelter. At the end of the 60s period, the cover is lifted and the cricket is left to freely explore the arena for 180s. The company then used a video tracking software allowing to extract the distance travelled by the cricket (in cm).

Predator Cue Response Test

The crickets are introduced to a 15 cm cylindrical arena and left to rest for 60s under a plastic shelter. A filter paper coated with diluted lizard urine is set at the bottom of the arena to serve as a cue for predator exposure. Previous trials have shown that crickets tend to increase their movement in presence of the cue compared to a water control test and your contact interprets that as an escape response when in contact with the predator cue. At the end of the 60s rest period, the cover is lifted and the cricket is left to freely explore the arena for 180s. As above, a video tracking software allows to extract the distance travelled by the cricket (in cm).


Data Analysis Module 2: Behavioral Correlations

Case Description:

The same zoo staffer gets back in touch with you after having made a curious observation. After feeding crickets to her young lizards, the enclosures are often full of females with only just a few males remaining. The zoo does not control for how many prey of each sexes are fed to the lizards, but your contact presumes the sex ratio is relatively close to 1. Having noticed that males are often heard calling even after having been introduced to the enclosure, she hypothesizes that the lizard must be cueing on the males’ songs to locate their prey. She also noticed that the remaining males are often very jumpy and active when conducting enclosure maintenance and cleaning. After a few emails back and forth, you settle on a simple protocol allowing to test whether calling behavior, general activity and response to predator cues are correlated. You decide to conduct the following experiment:

· Randomly select 30 adult male crickets

· Run each individuals through an open-field trial and a predator cue response trial as was done in Module 1

· Record the males’ calls for 45 minutes. Your recording equipment allows you to extract the following call components:

o The total time spent calling (in seconds)

o The call’s frequency

o The call’s intensity

· Weigh each cricket after the call recordings

Your contact runs the experiment and within two week, sends you the data (see attached Excel spreadsheet).

Instructions:

Prepare a report for your contact where you will analyze the data provided and send additional recommendations. Be mindful of the following aspects:

· Generate a conceptual diagram explaining how the different traits ought to be correlated in order to explain why only jumpier male crickets remain in the lizard enclosures. This will serve as your predictions.

· Based on the data available, do the observed patterns of correlations among behavior confirm or reject your predictions?

· Offer alternative explanations and follow-up experiments in order to conclude on the validity of your contact’s observations.