If I went to a doctor and said “Tell me how to diagnose a patient,” or I went to a judge and said “Tell me how to interpret the law,” or I went to an artist and said “Tell me how to be creative,” do you think they would be able give me a few sentences that completely answer my question and prepare me for professional work as a doctor, judge, or artist? If they had spent years as students learning their subject matter, and additional years teaching or writing a textbook on their specialty, they might be very good in their professions but I’d bet they’d all find it tough to answer such a question in any meaningful way.
1 Historical review: Some topics are better understood if a brief historical review of the topic is presented to lead into the discussion of the moment. Such topics might include "a biographical sketch of a war hero," "an upcoming execution of a convicted criminal," or "drugs and the younger generation." Obviously there are many, many more topics that could be introduced by reviewing the history of the topic before the writer gets down to the nitty gritty of his paper. It is important that the historical review be brief so that it does not take over the paper.
The factors underlying brown-tail moth population dynamics are little understood and have been only thoroughly investigated by few researchers.        They found that parasitoids , microsporidial disease and intraspecific competition were the most important mortality agents. In North America, the incidence of parasitism is the most important factor dictating the persistence of the exotic populations exclusively in coastal habitats.  Knowledge concerning the role of plant factors is limited to larval performance and development on different host plants. With regard to weather factors, it is known that diapausing larvae are cold tolerant but susceptible to freezing by extreme cold.   In North America, besides parasitism, cold temperatures may prevent the browntail moth from extending its invasive range from coastal to inland habitats. Intraspecific competition may also be implicated in brown-tail moth mortality, since in several populations survival was higher at low densities. During outbreaks browntail moth females show an increased fecundity .