Cricket Behavior in Principles of Biology
Combat versus Courtship
Introduction
When adult, male domestic crickets encounter other crickets they may view the other as a competitor or as a potential mate. This perception will be reflected in how communication is initiated; is it tentative and exploratory or does it escalate quickly? Before the lab, list as many ways as you can imagine that one cricket could communicate with another. Divide your list into "modes" i.e., tactile, olfactory, visual, auditory or gustatory. A mode of communication is defined by the sense used to perceive it, i.e., olfactory is smelled, gustatory is tasted, visual is seen, etc. On a cricket many of the senses are located on the antennae.
ways crickets communicatemode
1. pheromones produced by one gender and sensed olfactory and gustatory
by either (or both) gender (s).
2. chirping produced by males when they rub wingsauditory
together
3.
4.
5.
6.
7.
Now review your list and decide what level of escalation (that means how much effort measures as time and/or energy) each of your communication methods represents. You could rank these by number, just define your numbers here (i.e., is a "1" the highest ranking (most effort) or the lowest ranking (least effort)?).
Procedures
Decide whether you feel that crickets living with many other crickets become habituated to encounters (numb). If you think they do, put some experimental crickets in isolation before you go on.
Simple encounter observations:
As baseline data you will want to see how males encounter females and compare this to simple encounters between males. Obtain a male and female and introduce them simultaneously to your arena. Pile books etc., around the arena so that there is as little distraction as possible. For five minutes, observe
a)orientation (do they face each other or does one consistently turn away?),
b)antennal movements
c)physical contact or overt avoidance,
d) noises or other behaviors you listed above. Now repeat with two males (or two females).
Pheromonal communication:
You are asking "Do male crickets perceive and respond to chemicals given off by females?". The tools available for you to answer this question are: an arena (freshly cleaned?), vaseline, cardboard, wax pencils, and tape. Lay out your experimental design in your lab notebook and have me check it (or run it by your partners). Clearly state how this set-up will be used to answer your question.
Results: List these in your lab notebook and do not stop until you have sufficient sample size to address your question (above, in quotes).
Combat:
Between which pairs of crickets ( ) would you expect combat (circle one)? To what resource(s) would contests be settling access? Phrase your answers to these questions as an experimental question (as was done for you in the pheromonal communication experiment above). Could you design an experiment to answer your question? Try just varying one factor at a time so your answer is not blurred.
Results: Again, list these in your laboratory notebook and do not quit until you have sufficient data.
How many repetitions for each is enough to make the results reliable? Explain this.