Research Paper Example about Guppies

In this study, we will be researching what physical characteristics of fish make them more likely to be selected as mates. It has been found that color, size, pattern, and other physical characteristics of fish may influence the likelihood that they are chosen to reproduce with other fish of their same species. Our hypothesis was that the brighter colored neon orange (120001) female guppies would attract more males than the warm grey (101001) would. In the original experiments that we collected our data from, both colors of model fish were inserted into a 38L fish tank and spaced to give equal zones for both groups. The male test subject guppy was then placed in the middle of the tank for a 5 minute interval. The male guppy’s courtship behavior was recorded as well as his time spent in the proximity of the female models. Our results did not support our hypothesis as it was shown he actually spent more time in closer proximity to the warm grey (101001) control group female guppy. This leads to the conclusion that male guppies do not choose mates based on the brightness of their color.

Introduction:

Guppies are live-bearing, sexually dimorphic fish and have a promiscuous, non-resource-based mating system in which males court one female after another, and male mating success is largely determined by female acceptance (Baerends et al., 1955). Although female guppies receive no obvious direct benefits from mating, they are choosy most likely because indirect (genetic) benefits may be conferred, leading to increased offspring fitness (Reynolds and Gross, 1992).  And the way male fish find mates, is they look for certain characteristics or behaviors in the female guppies that look good, or are beneficial for survival. This is known as sexual selection which is a subgroup of natural selection. Male guppies will try and attract the female guppies by using visual behaviors that the female will assess and determine if they like, mainly: sigmoid movements, gonopodial swing, fin spread, and biting genitals (French 2016). We know from prior research, that larger female guppies have shown to be more fertile, and this may be the reason for the preferred choice of larger females by males (Hagen 1967). Moreover, they also look for which colors the male fish like more. Our group decided to use the color Neon Orange as our bright color and warm gray as our dull color. And they did this to compare it to other prior researchers' results. They hypothesized that the male guppy will be more attracted to the neon orange-colored 3D fish than the warm gray 3D fish because guppies look for flamboyant colors in mates. Therefore, we hypothesize that the male will spend more time and effort trying to attract the brightly colored female because male guppies perceive bright colors better than dull colors.

Methods: 

To carry out this experiment the experimenters utilized a 38L fish tank equipped with a filter and heater to hold our male guppy subject. Afterwards they then used a wooden meter stick cut to fit across the length of the tank as a presentation device. Then drilled 2 separate holes into the wooden meter stick at precise points where they will insert our 3D female guppy models. They did this in order to allow equal space for each of their two decision zones. These two decision zones housed both the experimental and control groups, the experimental group being the neon orange (120001) colored female guppy models, and the control group being the warm grey (101001) colored models. The tank was set up in a way that allowed equal space between the two choice areas of the tank as well as a middle no choice zone where time would be stopped. They measured the amount of time each male guppie spends in proximity to these female models in trial intervals of 5 minutes. They also observed different examples of courtship behavior in guppies as well to support us in determining which female model the male guppy prefers. They observed behaviors such as Gonopodal swings, sigmoid curves, fin fanning, as well as biting. They then sequentially inserted the male test subject into the center “no choice zone” of the tank with their experimental group on one side and the control on the other. Through separate 5 minute trials they then measured the amount of time the male subject spent in proximity to the female model. In addition, they also measured the amount of sigmoid behaviors the male subjects exhibited as additional information to support their studies. Using the figures from these trials we were able to analyze the statistical properties of these results in order to determine both the mean and percentage of error for both time spent and number of sigmoid behaviors. 

Results: 

After observing the resulting information given from the past experimental trials, we have discovered the mean (N = 36)  and percentage of error for both time spent (p = 0.0577) and Number of sigmoid behaviors (p = 0.3211). While observing these statistics provided we have been able to divulge from the individual trial summaries for both time spent and the number of sigmoid behaviors the males displayed. We are able to see an indicated trend with our control group averages spending significantly more time in comparison to the amount of time spent in reference to our experimental groups (Figure 1). In addition to this, we see the same supporting trend when observing the total number of mating behaviors exhibited by the male test subject (Figure 2). Due to the nature of these results, it is fair to infer that the control group received more attention from the male subject in comparison to our experimental group.

Figure 1: Time spent next to each model (N = 36; p = 0.0577). Bars represent means and error bars represent standard error.

Figure 2: Total number of behaviors shown towards each model (N = 36; p = 0.3211). Bars represent means and error bars represent standard error.

Discussion:

According to Figures 1 and 2, our hypothesis was dead wrong. On average the male guppies spent more time on the side of the warm gray 3D female model (the control), than the neon orange female model (the experimental). Figure 1 shows that the guppies spent more time on the side of the control model, and Figure 2 shows that they practiced more mating behaviors towards the control model as well.  After reviewing the results, we noticed that on three of the thirty-six experiments there were excessive amounts of mating behaviors. The average number of behaviors is in between one time to two times per experiment, these three experiments had an average of thirteen behaviors per trial. We conclude that our hypothesis is unsupported in the fact that the male spent more time with the warm gray female guppy than with the neon orange female, and did more mating behaviors to the warm gray as well. As stated earlier we wish to know whether those three trials were outliers that happened by chance.

French, D.P. 2016. Investigating Biology. 2015 Edition Fountainhead Press. Texas, United States

Hagen, D.W. 1967. Isolating mechanisms in threespine sticklebacks. Journal of fisheries board of Canada. 24:1637-1692

Baerends GP, Brouwer R, Waterbolk HT, 1955. Ethological studies on Lebistes reticulatus (Peters): I. An analysis of the male courtship pattern. Behavior 8: 249-334. 

Reynolds JD, Gross MR, 1992. Female mate preference enhances offspring growth and reproduction in a fish, Poecilia reticulata. Proc R Soc Lond B 250: 57-62.