Host preference and survivorship of Euschistus heros (Hemiptera: Pentatomidae) strains on cotton and soybean
The Neotropical brown stink bug Euschistus heros (Fabricius) (Hemiptera: Pentatomidae) is a key pest of soybeans, Glycine max, and recently became an economically important pest of cotton, Gossypium hirsutum. This stink bug has two allopatric strains, one prevalent in southern Brazil (SS), and another in the north (NS). The two strains hybridize in central Brazil. Knowledge of host preferences and host suitability of these strains can clarify the contribution of the different gene pools to contemporary adaptive features such as the ability to harm cotton crops. We tested the attraction of the E. heros strains and reciprocal hybrids [[female]N x [male]S (HNS) and [female]S x [male]N (HSN)] to soybean and cotton plants and evaluated the nymph development and survivorship of the two strains and reciprocal hybrids fed on soybean or cotton. We conducted host-choice experiments with 4th instars and adult females and evaluated the survival of immatures on soybean and cotton plants in laboratory conditions. The SS strain preferred soybean over cotton. NS and hybrid strains chose randomly between soybean and cotton plants. All strains developed on soybean, with similar survival rates. On cotton, the pure strains did not reach adulthood; however, the hybrids developed on cotton but with a survival rate less than 1%. Our results showed that E. heros SS was more attracted to soybeans, and NS and hybrid strains had a polyphagous choice behavior, suggesting that current host selection has been mediated by historical and, mainly, contemporary relationships of E. heros strains with these hosts.