Understanding the morphology, neurophysiology and behavior of the invasive Halyomorpha halys for its management in agricultural ecosystems

The rate of introduction of invasive alien species has been increasing dramatically over the past few decades, as a result of growing global trade and climate change. One successful invader in both agricultural and domestic settings is the brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae). Originating from East Asia, this polyphagous pest has been expanding its range since the early 2000’s in North America and Europe, where it is known to feed on over 170 host plants, many of which are of economic importance. Currently, the control of H. halys relies on broad-spectrum insecticides that provide short term protection of crops and negatively impact the environment and non-target organisms. Despite the numerous studies conducted so far on this species, some gaps of knowledge related to its chemical ecology and vibrational communication still exist. In this light, the aim of this doctoral dissertation was to investigate the morphology, neurophysiology and behavior of H. halys, to enhance its sustainable management strategies. We identified five types of sensilla on the antennae of H. halys adults and fifth instar nymphs, using scanning and transmission electron microscopy techniques. The examined sensilla were assigned putative functions based on their morphological characteristics. We found that the majority of these sensory structures are located on the flagellomeres and are thought to have an olfactory role. On another front, the morphological and physiological properties of some of the neurons involved in the vibrational communication of this pest were explored using intracellular recording and electrophoretic staining techniques. Four types of neurons were identified in the thoracic ganglion of H. halys adults, all of which are intersegmental with axons projecting anteriorly towards the prothoracic ganglion. The presumed roles of these neurons in processing the vibrational signals are discussed according to their sensitivity and location. Concerning the third and last objective of this dissertation, long-lasting insecticide nets were used under laboratory conditions to assess their effect on the behavior and survivorship of H. halys nymphs and adults. The nets showed promising potential for reducing the mobility and inflicting high mortality rates even after short exposure durations. Findings from these various studies are herein presented in the context of the chemical ecology, vibrational signaling and behavior of H. halys. Moreover, the future implications of this novel contribution and its relevance for integrated pest management strategies are highlighted.