Textbook Problem

Summoning Moaquitoes Parasites sometimes alter their host’s behavior in a way that increase their chances of transmission to another host.

Dr. Jacob Koella and his associates hypothesized that Plasmodium might benefit by making its human host more attractive to hungry mosquitoes when gametocytes are available in the host’s blood. Gametocytes taken up by the mosquito will mature into gametes and mate inside its gut.

To test their hypothesis, the researchers recorded the response or mosquitoes to the odor or Plasmodium-infected children and uninfected children over the course of 12 trials on 12 separate days. FIRGURE 21.18 shows their results.

FIGURE 21.18 Attracting mosquitoes. The graph shows that the number of mosquitoes (out 100) attracted to uninfected children, children harboring the aseoual stage of Plasmodium, and children with gametocytes in their blood. The bars show the average number of mosquitoes attracted to that category of child over the course of 12 separate trials.

On average, which group of children was most attractive to mosquitoes?

Summary Introduction

To determine: The group of children who were the most attractive to mosquitoes.

Introduction: Plasmodium is one among the genus of unicellular eukaryotes that are obligate parasites of vertebrates and insects. It infects humans and is responsible for most malarial infections. It is transmitted through the bite of the female Anopheles mosquito. The life cycle involves the mosquito and the human as a host. During the blood meal, the malaria-infected mosquito inoculates sporozoites into the human host. The sporozoite infects the liver cells and matures into schizonts that rupture and releases the merozoites.

Explanation of Solution

In this study, the groups of children who have gametocytes in their blood were more attractive to the mosquitoes. Gametocytes that arise from the erythrocytic asexual stage are responsible for the transmission of the parasite from the mammalian host to the mosquito. The graph shows the number of mosquitoes in the y-axis, and the children with gametocytes, children with asexual stage, and uninfected children in the x-axis. The graph shows that children with gametocytes of Plasmodium are more attracted to mosquitoes.

Conclusion

The children with gametocytes present in their blood are most attractive to mosquitoes.