OUTLINE

Invasion of the Black Rat – Rattus rattus

1. Rattus rattus overview
2. Introduction of Research Studies
1. Potential spread of introduced black rat parasites to endemic deer mice on the California Channel Islands
2. Space invaders? A search for patterns underlying the coexistence of alien black rats and Galapagos rice rats
3. Black Rat Vs. Deer Mice
1. Deer Mice Overview
2. Methods

                                                              i.      Specimen Collection

                                                            ii.      Parasite Process

3. Collection Sites

                                                              i.      Figure 1 – California Channel Islands

4. Parasite Analysis

                                                              i.      Inter-specific parasite transfer criteria

                                                            ii.      Trichus muris

                                                          iii.      Syphacia

                                                          iv.      Hymenolepis

5. Results

                                                              i.      Trichus muris - transfer

6. Composition and Prevalence of Parasites
7. Conclusion
3. Black rat and Galapagos Rice rat
1. Overview
2. Similarities and Differences
3. Methods
4. Results

                                                              i.      Abundance of Galapagos Rice Rats and Black Rat from live trapping

                                                            ii.      Correlation of mature cacti and rice rats

5. Conclusion
4. Further Recommendations
5. References

 

 

 

 

 

 

 

 

 

ABSTRACT

 

            Rattus rattus, commonly known as the black rat, is an invasive species found in many tropical coastal regions around the world. This rodent has displaced numerous endemic species including deer mice native to the California Channel Islands and rice rats native to the Galapagos Islands. The black rat has been found to be a disease vector transferring parasites to the California deer mice even after being removed from the population (Smith & Carpenter, 2006). These scientists determined the parasite transfer was due to overlapping habitats and similar foraging behaviors. The black rat has also been found to drive other species to extinction when introduced. The Galapagos rice rats were rediscovered 90+ years after their presumed extinction because they were able to use cactus as a resource refuge from the black rat (Harris et al., 2006).

 

            To further understanding of the interactions between the black rat and endemic species, we propose a study in the Galapagos with black rats and rice rats as the subjects. We will track the interactions and population numbers of the two species in a scrub habitat with cactus (which the rice rats prefer) and an arid environment (which the black rat prefers). We will then introduce black rats infected with the parasite Trichus muris to both environments and compare the rates of parasite transfer. We expect the parasite transfer rates to be lower in the scrub habitat as we predict less interactions between the 2 species in this habitat.

 

 

REFERENCES

 

Harris, Donna B., Gregory, S.H., Macdonald, D.W.  2006. Space invaders? A search for patterns underlying the coexistence of alien black rats and Galápagos rice rats. Oecologia 149:276-288.

 

Smith, Katherine F., Carpenter, S.M. 2006. Potential spread of introduced black rat (Rattus rattus) parasites to endemic deer mice (Peromyscus maniculatus) on the California Channel Islands. Diversity Distributions 12:742-48.