Biology 312: Animal Behavior
Lab 2: Behavioral observations in guppies
Lab due Wednesday, Feb. 5, 2003
Introduction
In today's lab, you will observe mating behavior in guppies. The purpose of this lab is to develop skills in carefully observing and recording behavior. You will practice describing behavioral sequences, and think about different ways of recording behavior. I am not looking for "correct" answers here, only that you describe what you see as clearly and accurately as possible.
Comments about the format of the lab
Your lab should include an Introduction, Methods, Results and Discussion section. For today’s lab, these sections will be fairly straightforward.
Introduction: A brief description of the organisms you are studying and the purpose of what you are doing. It would be appropriate to have an introduction, methods and results section for each of the lab stations.
Methods: A clear description of what you did. This shouldn’t be a repetition of my methods section, but rather a step-by-step explanation of what you actually did.
Results: This is the heart of today’s lab. This section will include the behavioral observations you make. Be clear and organized. Outline form works well for a play-by-play description. Include data tables where required and/or helpful.
Discussion: Comment on the observations you have made, and also answer any discussion questions indicated in each section (complete sentences here...).
The study organism
The guppy, Poecilia reticulata, is a fresh-water teleost fish in the family Poeciliidae. It
is native to mountain streams of Trinidad and northeastern South America but has been introduced to many parts of the world in mosquito control programs. They are also a favorite of the aquarium trade with individuals from many individual strains judged in championships. Guppies are live-bearing, with brood sizes of 1-25, according to the size of the female. Maturation occurs after 6-8 weeks at which point the male anal fin develops into an elongated organ, the gonopodium, which is used for internal fertilization. Several successive broods may arise from a single insemination. With pronounced sexual dimorphism, female guppies are large with silvery-tan coloration, while males are small and brightly colored. Variation in coloration are common among natural strains and relate to predation pressure from piscivorous fish. Differences in pigment variants have been enhanced through extensive breeding leading to some individuals with spectacular coloration.
Basic methods
1)Familiarize yourself with the differences in outward appearance of male vs. female guppies within the holding tanks. When you are ready, remove one male and one female from the holding tank and place them in your own tank. Observe theanimals for at least 15 minutes. Try to remain stationary so that your own movements will affect the behavior of the fish as little as possible.Watch carefully.
Soon you will begin to recognize patterns of movement, like a folding of the dorsal fin or bending the caudal peduncle, or nipping the water surface in feeding, because you will see the same actions repeatedly. Once you have discovered the behavior patterns of your animals you will have units of behavior with which to work further.
2)Describe the individual behaviors you see, and give them a code. Be as precise and detailed as possible.
NOTE: A list of described behaviors has been provided to give you a sense of a “unit” of behavior. Consider this as a guideline; the behaviors you see may be somewhat different, and you should develop your own terminology for the behaviors you see. Also, I don’t think the behaviors on this list are particularly well-described in the handout. You can do better!
3)Quantify the behaviors you see.
- Duration. (NOTE: Create a data sheet for this exercise in your lab notebook before you begin.) The duration of a behavior pattern can serve as a measure of the behavior’s intensity. Use a stopwatch to time the duration of one of the behaviors in an individual fish to determine the level of variation. You will need to time this behavior several times to adequately determine the variation. Repeat this part of the exercise for each of the more common behaviors you observed.
- Frequency. Another measure of intensity is the frequency with which a behavior pattern occurs, that is, the number of occurrences per unittime. (NOTE: Create a data sheet for this exercise before you begin.) Observing only one fish at a time and record the letter code of each behavior pattern in order of occurrence. Using a clock ortimer, draw a line through the protocol at one minute intervals
- Calculations. Perform as appropriate (see discussion below for ideas, and think of your own!)
4)Create a more complex social situation (i.e. add additional fish, one at a time). Watch for awhile to ascertain whether any new behaviors are occurring, and describe them. Then, repeat Part 3 above. Note that 2 groups can work together here so more females can be included within a group.
Discussion:
Which behaviors were of the longest duration? Which behaviors occurred at the highest frequencies? Speculate about the function of the behaviors you observed. Compare the data you obtained for two fish with those for more complex interactions. Comment on any patterns you found in your observations that might be of interest in future studies.
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