Antlions build pits to capture prey and alter their pit construction in response to prey density. The aim of the project is to determine if there are any differences in pit construction of antlions, Myrmeleon immaculatus (n=24), in response to pulsed availability of high (4 fruit flies/week) and low (1 fruit fly/week) densities of prey. Three antlions from each of four collection sites were randomly assigned into treatment groups (n=12/treatment). Individuals were weighed at the beginning and end of the five-week experimental period. Measurements of pit ratio (diameter/depth) were taken daily. Data on antlion percent weight change were analyzed using a two-way ANOVA. Data on pit ratios were analyzed using a three-factor (treatment, location, and time) mixed model with repeated measures design with ‘antlion’ nested within treatment as a random effect.
Results/Conclusions
There were differences in percent weight loss (F= 5.04, p= 0.004). All antlions lost weight with antlions in the low-density treatment losing more weight than those in the high-density treatment (F=6.26, p=0.024). Location also had an effect on percent weight change (F=6.02, p=0.006) and there was an interaction between these two factors (F=3.65, p=0.035). With respect to pit ratios, there were no differences between or within treatment groups. All individuals lost weight suggesting not enough food was provided over the course of the experiment. Thus, pit ratios are similar among all individuals. Differences due to location suggest there may be genetic/physiological differences between individuals from each site. These hypotheses require further investigation.