Question

An introduced insect is devastating several related plant species within a diverse natural area. An environmental manager is tasked with developing and preserving the area. He decides to use a biological control method, a parasitic fly that feeds on the pest insect's larvae. Would this be considered a density-dependent or a density-independent approach to population control?

Density-dependent, because both pest and biological control agent are introduced Density-independent, because both pest and biological control agent are introduced Density-independent, because the parasite could become a pest, causing a natural disaster Density-dependent, because it reduces the population density of the pest Density-independent, because it is not likely to completely control the pest's density

Answer 1

This is a density-dependent approach. As the population of the pest increases, the number of larvae also increase. The parasite populations which feed on the larvae would also increase. This would result in a decrease in the population of the pests which in turn lead to the decrease in the population of parasites as they do not get enough food to eat. Once the population of parasites decreases, again the population of pests would increase and this cycle would continue as a predator-prey cycle.
This form of population regulation is always considered as density-dependent approach.

So, the correct answer is option 4.