title: Ammonia concentration at emergence and its effects on the recovery of different species of entomopathogenic nematodes.
abstract: The life cycle of entomopathogenic nematodes (EPN) occurs inside an insect cadaver and an accumulation of ammonia initiates as a consequence of the nematodes defecation. This accumulation reduces the food resources quality and creates a detrimental environment for nematodes. When a given ammonia concentration is reached, the nematodes start their emergence process, searching for a new host. In the present work, this parameter, ammonia triggering point (ATP) was measured in 7 Steinernema species/strains. The effect of different ammonia concentrations on the recovery process and their consequences in the nematodes survival were also investigated. The results indicate that ATP varies among nematode species; Steinernema glaseri showed the highest ATP of the evaluated species (1.98±2.6 mg of NH4-N*g of Galleria mellonella(-1)); whereas Steinernema riobrave presented the lowest ATP (1.16±0.1 mg of NH4-N*g of G. mellonella(-1)). On the other hand, the nematode emergence could be a repulsive response when ATP is reached. As the ammonia concentration increased the recovery percentage of Steinernema feltiae (Chile strain) dropped gradually from 79.4±11.9% in the control treatment to 0% when 1mg of NH4-N*ml of bacterial broth(-1) was added. It is possible, that emergence process could be a repulsive response of the nematodes due to ammonia concentration when is reaching the ATP. The role of ammonia inside the insect cadavers, might suggests connections with some stages of the EPN life cycle.
authors.affiliation: Instituto Venezolano de Investigaciones Científicas, Centro de Estudios Botánicos y Agroforestales, Laboratorio de Protección Vegetal, Calle 79 con Av. 8, Maracaibo, edo. Zulia CP 4001, Venezuela. Electronic address: esanblas@yahoo.com.
authors.forename: Ernesto
authors.initials: E
authors.lastname: San-Blas
authors.affiliation: Instituto Venezolano de Investigaciones Científicas, Centro de Estudios Botánicos y Agroforestales, Laboratorio de Protección Vegetal, Calle 79 con Av. 8, Maracaibo, edo. Zulia CP 4001, Venezuela.
authors.forename: Deynireth
authors.initials: D
authors.lastname: Pirela
authors.affiliation: Instituto Venezolano de Investigaciones Científicas, Centro de Estudios Botánicos y Agroforestales, Laboratorio de Protección Vegetal, Calle 79 con Av. 8, Maracaibo, edo. Zulia CP 4001, Venezuela.
authors.forename: Dana
authors.initials: D
authors.lastname: García
authors.affiliation: Instituto Venezolano de Investigaciones Científicas, Centro de Estudios Botánicos y Agroforestales, Laboratorio de Protección Vegetal, Calle 79 con Av. 8, Maracaibo, edo. Zulia CP 4001, Venezuela.
authors.forename: Edgar
authors.initials: E
authors.lastname: Portillo
mesh_terms: D000641:Ammonia / Q000378:metabolism* / Q000494:pharmacology; D000704:Analysis of Variance; D000818:Animals; D008018:Life Cycle Stages / Q000502:physiology*; D009036:Moths / Q000378:metabolism / Q000469:parasitology*; D017168:Rhabditida / Q000187:drug effects / Q000382:microbiology / Q000502:physiology*; D013559:Symbiosis; D020593:Xenorhabdus / Q000502:physiology
chemical_list: D000641:Ammonia
keywords: Ammonia; Behaviour; Defecation; Emergence; Food depletion; Galleria mellonella; Life cycle; Recovery; Steinernema