1. The pest is polyphagous, has obvious selectivity for hosts and good adaptability to tobacco.

2. More than a half polyphagous, nearly a half Oligophagous or knowing only one host.

3. The feeding and oviposition preferences of polyphagous flies in urban garbage were more plastic than those of saprophagous flies.

4. Multitudinous host plants and the inherent polyphagous characteristics enhance the wide invasion of B and Q biotypes in different counties.

5. The beet armyworm, Spodoptera exigua (Hubner), is a polyphagous noctuid of worldwide importance that feeds on various agricultural crops, including vegetable, cotton and ornamental.

6. A majority of plant families rely on secondary plant metabolites for protection from polyphagous insects.