Electropenetrography Monitoring of the Neotropical Brown-Stink Bug (Hemiptera: Pentatomidae) on Soybean Pods: An Electrical Penetration Graph-Histology Analysis

Abstract

The Neotropical brown-stink bug Euschistus heros (F.) (Hemiptera: Pentatomidae) is the most important pest damaging soybean in the Neotropics, the world largest production area. The alternating current–direct current (AC–DC) electropenetrography (EPG) technology was used to develop an EPG waveform library of adult females feeding on soybean (Glycine max (L.) Merr.) pods at different input resistor (Ri) levels. Thirteen waveform types/subtypes were identified and described. They were divided into non-probing (Z, Np, Dw1, and Dw2), and probing waveforms (Eh1, Eh2, Eh3, Eh4, and Eh5). Probing waveforms were grouped into three phases: 1) pathway (Eh1a, Eh1b, Eh1c, and Eh1w), 2) ingestion (Eh2, Eh3a, Eh3b, and Eh4), and 3) interruption (Eh5). Correlations between waveforms Eh1b, Eh1c, Eh2, Eh3, and Eh4 and stylets tip position and/or salivary sheath in the pod tissue were determined via histological studies. Non-probing waveforms, Z and Np were visually associated with the bug resting and walking on pod surface, respectively. Waveform Dw1 was correlated with egestion, and the ingestion of fluids (droplets) was proposed for Dw2. Eh1a and Eh1b corresponded to initial and deep stylet penetration through pod tissue, and secretion of a salivary sheath. In Eh1c, stylets penetrated the rigid cell layer of sclerenchyma, and during Eh1w they were withdrawn. Eh2 represents sustained xylem sap ingestion. Eh3a corresponded to lacerate and macerate cell rupture feeding behavior in seed endosperm, whereas Eh3b corresponded to ingestion of cellular contents. Eh4 represented short ingestion from an unknown site, and Eh5 represented short interruptions during xylem sap ingestion.

Unveiling the Feeding Behavior of Tibraca limbativentris (Hemiptera: Pentatomidae) on Rice Using an Electropenetrography Waveform Library

“…During T12, all histological analyses showed that the stylet tips were in xylem vessels while visual analyses showed that the stylets remained immobile within the plant tissue. The appearance and electrical origins of this waveform were similar to those of other xylem ingestion waveforms in heteropterans ( Lucini and Panizzi 2017a , 2018a ). According to Mitchell et al (2018) , Lucini and Panizzi (2018a) and Rivera and Mitchell (2020) , insects ingest from xylem for hydration, which may explain the long ingestion periods in xylem vessels.…”

“…Tl3b frequently alternated with Tl3a and was visually correlated with periods when the stylet remained immobile within the plant tissue. Other studies have shown similar stink bug behavior while feeding on vegetative ( Lucini and Panizzi 2017a ) and reproductive structures ( Lucini et al 2016 ; Lucini and Panizzi 2017b , 2018a ). Thus, Tl3a represented the laceration/maceration preparation behaviors, while Tl3b (regular waveform and frequency) were short and represented the ingestion of cell content that was degraded during Tl3a.…”

“…Similarly, Eu. herus ( Lucini and Panizzi 2018a ) and N. viridula ( Mitchell et al 2018 ) feeding on soybean pods use both strategies (salivary sheath and cell rupture). We found that T. limbativentris also used both strategies (salivary sheath and cell rupture) while feeding on rice stalks (vegetative structure).…”

“…EPG was first used to study the feeding behavior of aphids ( McLean and Kinsey 1964 ); however, in recent years, this technique has also been used to evaluate the feeding behavior of other piercing-sucking insects, such as leafhoppers ( Joost et al 2006 ), psyllids ( Bonani et al 2010 ), and pentatomids ( Lucini and Panizzi 2016 ). The feeding behavior of several pentatomid species has been described using EPG: Edessa meditabunda (F.) in soybeans ( Lucini and Panizzi 2016 ), Piezodorus guildinii (Westwood) in soybeans ( Lucini et al 2016 ), Dichelops melacanthus (Dallas) in maize ( Lucini and Panizzi 2017a ), Dichelops furcatus (F.) in wheat ( Lucini and Panizzi 2017b ), Euschistus heros (F.) in soybeans ( Lucini and Panizzi 2018a ), Nezara viridula (L.) in soybeans ( Mitchell et al 2018 ), and Halyomorpha halys Stål in broad beans (Vicia faba L.) ( Serteyn et al 2020 ). According to Lucini and Panizzi (2018b) , EPG has great potential for increasing our understanding of the feeding process of stink bugs, which may in turn lead to new ways of mitigating impacts on crops, and potential management strategies such as selecting plants with greater insect resistance.…”

The Principal Salivary Gland Is the Primary Source of Digestive Enzymes in the Saliva of the Brown Marmorated Stink Bug, Halyomorpha halys

“…Stink bugs feed by inserting their piercing-sucking mouthparts (stylets) into plant tissues (phloem or xylem) either by salivary sheath feeding or by physically rupturing cells (Backus et al, 2005; Lucini and Panizzi, 2018a, b). For salivary sheath feeding on phloem or xylem vessels, stink bugs secrete gelling or SS to form a flange at the site of penetration into the plant and a stabilizing sheath around the stylets (Lucini and Panizzi, 2018b). For both feeding strategies, WS is released to digest cell contents, and the predigested plant material is subsequently ingested.…”