Sample Data

A location choice experiment consisting of 26 independent trials (different females) was performed by Morehouse College Ecology students. In each trial, the location of a female was recorded every two minutes during a 60 minute observation period, so a total of 30 observations were made on each female. Within each trial, the location of the natal beans was switched after the first 30 minutes. All trials were conducted in 100mm dishes divided in three equal area sectors, one sector was empty, one contained mung beans and the third contained adzuki beans. Preferences for the natal bean species were observed for females from both mung and adzuki beans (Figure 1). The raw data are available in the Downloads section.

Figure 1. Number of observations in which a female was on mung beans, adzuki beans, or in an empty sector during 60 minute observation periods. A total of 30 observations were made on each of 26 different females, 13 females whose natal bean was mung and 13 females whose natal bean was adzuki. The preference for the natal beans by females from mung beans was not significant (chi-squared = 5.4, df=2 p<0.067) but the preference for the natal beans by females from adzuki beans was highly significant (chi-squared = 44, df=2 p<0.0001).

When an individual female from mung beans was provided with equal numbers of beans from the natal and non-natal species (mung and adzuki), and allowed to lay eggs for 24-hours, a very clear preference was observed in the bean species on which eggs are laid (Figure 2). The raw data are available in the Downloads section.

Figure 2.  Mean number of eggs laid by a single bean beetle on mung and adzuki beans during a 24-hour period.  The means are significantly different (paired t-test, t=2.72 df=37 p=0.0099).  Each dish contained 10 beans of each bean species and one female beetle.  These data were provided by Calvin Greene II, a Morehouse College student.