Jagd auf den Adlermörder — Entdeckung eines neuen Cyanotoxins

Hunting down the eagle killer: Vacuolar myelinopathy is a neurological disease affecting wildlife — including the iconic bald eagle — in the United States. Its cause has been elusive for decades, but its occurrence has been linked to the cyanobacterium Aetokthonos hydrillicola colonizing the invasive aquatic plant Hydrilla verticillata. In a recent study, we found that A. hydrillicola produces a novel highly toxic biindole alkaloid (aetokthonotoxin), and proved that it is causing the disease.

Chevroned Water Hyacinth weevil Neochetina bruchi Hustache (Insecta: Coleoptera: Curculionidae)

Neochetina bruchi Hustache is commonly referred to as the chevroned water hyacinth weevil and is a weed biological control agent used to manage water hyacinth, Pontederia crassipes Mart. [formely Eichhornia crassipes (Mart.) Solms (Pellegrini et al. 2018)], in more than 30 countries (Winston et al. 2014). Imported from Argentina, the insect was first introduced into the United States in Florida in 1974 and released in Louisiana later in 1974 (Manning 1979), Texas 1980, and California 1982 to 1983 (Winston et al. 2014). Now Neochetina bruchi occurs throughout the Gulf Coast States (Winston et al. 2014). The target weed of Neochetina bruchi, water hyacinth, is an invasive aquatic plant in the United States and is included on Florida’s list of prohibited aquatic plants. Neochetina bruchi is among four species of insect biological control agents that have been introduced into the United States to manage water hyacinth. The other three species include a weevil, Neochetina eichhorniae; a moth, Niphograptaalbiguttalis; and a planthopper, Megamelus scutellaris, which were introduced into the United States in 1972, 1977, and 2010, respectively (Tipping et al. 2014). Although the larvae and pupae of Neochetina bruchi and Neochetina eichhorniae have similar appearance and behavior and can be difficult to differentiate by casual observation (Deloach and Cordo 1976), the adult stages of the two species of water hyacinth weevils can be distinguished relatively easily based on the color patterns on their elytra (hardened fore wings).

Mottled Water Hyacinth Weevil Neochetina eichhorniae Warner (Insecta: Coleoptera: Curculionidae)

Sometimes referred to as the ‘mottled water hyacinth weevil’, Neochetina eichhorniae Warner is a weevil that attacks the invasive, aquatic plant, water hyacinth, Eichhornia crassipes (Mart.) Solms. Water hyacinth is considered one of the most destructive plants in aquatic ecosystems in the United States and, as a result, is listed in both the federal noxious weed list and Florida’s list of prohibited aquatic plants. Neochetina eichhorniae is host specific and causes substantial damage to water hyacinth, making it a valuable biological control agent for this invasive weed in many parts of the world. The insect was first introduced into the United States from Argentina in 1972, when scientists released the insect in Broward County, Florida, to manage water hyacinth (Perkins 1973). Since then, the insect has been introduced in more than three dozen countries worldwide (Winston et al. 2014). Post-introduction studies indicate the insect substantially suppresses the growth of water hyacinth, significantly reducing biomass, flowers production, and water surface coverage (Grodowitz et al. 1991, Center et al. 1999, Tipping et al. 2014, Nesslage et al. 2016) and the need for herbicide applications (Haag 1986).

Monitoring Re-Growth of Invasive Plants Using an Autonomous Surface Vessel

Invasive aquatic plant species, and in particular Eurasian Water-Milfoil (EWM), pose a major threat to domestic flora and fauna and can in turn negatively impact local economies. Numerous strategies have been developed to harvest and remove these plant species from the environment. However it is still an open question as to which method is best suited to removing a particular invasive species and the impact of different lake conditions on the choice. One problem common to all harvesting methods is the need to assess the location and degree of infestation on an ongoing manner. This is a difficult and error prone problem given that the plants grow underwater and significant infestation at depth may not be visible at the surface. Here we detail efforts to monitor EWM infestation and evaluate harvesting methods using an autonomous surface vessel (ASV). This novel ASV is based around a mono-hull design with two outriggers. Powered by a differential pair of underwater thrusters, the ASV is outfitted with RTK GPS for position estimation and a set of submerged environmental sensors that are used to capture imagery and depth information including the presence of material suspended in the water column. The ASV is capable of both autonomous and tele-operation.