Detectability of Halyomorpha halys (Hemiptera: Pentatomidae) by portable harmonic radar in agricultural landscapes

摘要

Harmonic radar technology enhances capability to track the movement of individual small insects under field conditions. To maximize the capacity of this technology, it is necessary that radar tags must be securely attached to insects and that the tags remain functional when subjected to mechanical stress. In this study, a series of experiments was carried out to test an improved harmonic radar tag designed to be more resistant to mechanical stresses and to establish that a portable harmonic radar system can effectively detect adult Halyomorpha halys St?l (Hemiptera: Pentatomidae) on various structures in different landscapes. The functional resistance of radar tags to ~1-m free falls on a hard surface was improved significantly by reinforcing the adhesive bond between the radar transponder and the radar wire by application of cyanoacrylate glue. This measure did not affect the detectability of radar tags, and it significantly increased the resistance of radar tags against random mechanical impacts inflicted on the insects and tags. The success rates of locating radar-tagged H. halys were compared among different landscapes, including a mowed grasscovered plot (250 m2), a mature peach tree plot (50 m2), and an unmanaged hedgerow (50 m2). The success rates were > 90% in all landscapes tested. There was no significant difference in the search time needed to locate tagged adults. In general, it took less than 2 min to detect and recover H. halys. The success rates of locating radar-tagged H. halys were also compared among different locations within mature fruit trees. There was no significant difference in the success rates between the inner third (87%) and the outer third of the host tree canopy (100%). However, a significantly longer period of time was required to locate H. halys in the inner canopy (372 s ± 95 SE) compared with the outer canopy (148 s ± 39 SE). When H. halys were concealed in the lower, middle and upper thirds of the outer tree canopy, the success rates of locating tagged adults were consistently 95% or greater at all canopy heights with no significant difference in search times needed to locate tagged adults. The results of this study provide context for researchers to reliably use this radar system in the field to study the dispersal biology of H. halys.?La tecnología de radar armónico mejora la capacidad para seguir el movimiento de peque?os insectos individuales bajo condiciones de campo. Para maximizar la capacidad de esta tecnología, es necesario que las etiquetas de radar estén firmemente pegadas a los insectos y que las etiquetas sigan funcionando cuando se someten a estrés mecánico. En este estudio, se realizó una serie de experimentos para probar una etiqueta mejorada de radar armónico dise?ada para ser más resistente al estrés mecánico y para establecer un sistema de radar armónico portátil que puede detectar con eficacia los adultos de Halyomorpha halys St?l (Hemiptera: Pentatomidae) sobre varias estructuras en diferentes áreas de campo. La resistencia funcional de las etiquetas de radar a una caida libre de ~ 1 m sobre una superficie dura se ha mejorado de manera significativa al reforzar la unión adhesiva entre el transponedor de radar y el cable de radar con una aplicación de pegamento cianoacrilato. Esta medida no afectó a la detectabilidad de las etiquetas de radar y aumentó significativamente la resistencia de etiquetas de radar contra los impactos mecánicos infligidos al azar a los insectos y las etiquetas. Las tasas de éxito de localizar las H. halys con etiquetas de radar fueron comparadas entre las áreas distintas incluyendo una parcela cubierta de hierba cortada (250 m2), una parcela de árboles de durazno maduro (50 m2), y una fila de arbustos no manejada (50 m2). Las tasas de éxito fueron > 90% en todos las áreas probadas. No hubo diferencia significativa en el tiempo de búsqueda necesario para localizar adultos etiquetados. En general, se tardó menos de 2 minutos para detectar y recuper