Host preference and survivorship ofEuschistus herosstrains on cotton and soybean

Abstract

The Neotropical brown stink bug, Euschistus heros (Fabricius) (Hemiptera: Pentatomidae), is a key pest of soybean, Glycine max (L.) Merrill (Fabaceae), and recently became an economically important pest of cotton, Gossypium hirsutum L. (Malvaceae), in Brazil. 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 may clarify the contribution of the various 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 – ♀N × ♂S (HNS) and ♀S × ♂N (HSN) – to soybean and cotton leaves and reproductive structures, 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 fourth instars and adult females and evaluated the survival of immatures on soybean and cotton plants under laboratory conditions. The SS strain preferred soybean over cotton. Hybrid and NS strains chose randomly between soybean and cotton plants. All strains developed on soybean, with similar survival rates. On cotton, pure strains did not reach adulthood; however, hybrids developed on cotton but with a survival rate of <1%. Our results showed that the SS strain of E. heros 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.

Molecular insights on the historical dispersion of Piezodorus guildinii (Hemiptera: Pentatomidae) in Brazil

“…In conclusion, our findings an older establishment of P. guildinii current strain in the Caribbean basin with subsequent geographical dispersion to the Brazilian territory, without secondary dispersion events from the Caribbean to Brazil. This long period of geographic isolation between these P. guildinii strains from the North and South American hemispheres raises questions about the genetic, physiologic, and behavioral traits of these isolated populations and their impact on the management strategies since these strains could answer differently to insecticide and climatic stress tolerance, pheromone attraction, and their fitness in different hosts (Nagoshi and Meagher 2022, Tietjen et al 2022, Hickmann et al 2023). Furthermore, the Brazilian populations of P. guildinii are genetically structured among soybean MRs and show strong signals of demographic and spatial expansion, probably accelerated by the presence of soybean fields, a highly preferred host for P. guildinii .…”

“…Damage to soybeans by P. guildinii and other stink bug species has become more frequent in recent years throughout Brazil. This phenomenon is associated with the ongoing expansion of soybean fields to the country's central and northern regions, as well as the adoption of no-tillage production systems, climate changes and the adaptation of native stink bugs to soybean cultivation systems (Sosa-Gómez et al 2020, Panizzi et al 2022, Hickmann et al 2023). Nonetheless, most of these associations are speculative, and studies to understand historical processes affecting P. guildinii population dynamics in Brazil are still lacking.…”

Assessing matting patterns, chromosome composition, host suitability, and diapause expression of >i<Euschistus>/i< (Hemiptera: Pentatomidae) strains and species

“…Furthermore, in the last decade, there have been frequent reports of E. heros individuals moving to cotton crops after the soybean harvest, causing damage to cotton plants, especially in areas cultivated near soybean crops . However, despite cotton being a native species, it is not a suitable host for E. heros, which can barely complete their life cycle on this crop Hickmann et al, 2023a).…”