title: Effect of temperature, photoperiod, flooding, and drying on the hatching pattern of the eggs of Strelkovimermis spiculatus (Nematoda: Mermithidae).
abstract: We assessed the number of Strelkovimermis spiculatus preparasites obtained from a known initial number of nematode eggs and the effect of abiotic conditions (temperature, photoperiod, flooding-drying) on the number of emerged preparasites. Two egg groups were maintained: one continuously flooded, another with flooding-drying cycles (every 15, 30, 60 days). Each egg group was studied at 25°C and 14:10 (L:D) and 16°C and 12:12 (L:D). The flooded eggs contained a higher overall percentage of S. spiculatus preparasites compared to the wet-dry-cycle eggs. The conditions of continuous flooding at 16°C and 12:12 (L:D) produced the maximum percent of emerged J2s (30±15%). Preparasites were recorded by 7 (25°C) and 14 (16°C) days, suggesting this period as the minimum time for embryonic development. The preparasite-emergence time observed from the same flooded-egg batch (98 and 112 days at 25°C and 16°C, respectively) suggested a nonsynchronous hatching, possibly through nonuniform egg embryonation. The time of exposure to drought in the assays did not significantly affect the total average percentage of J2s obtained at 25°C and 14:10 (L:D), whereas at 16°C the number of emerged J2s diminished with a prolongation of the drying period. The oviposition period was also recorded only at 16°C and 12:12 (L:D): S. spiculatus eggs were detected at 12.6 days after postparasite emergence, and oviposition was complete at 51days under those conditions. We propose a flooding schedule to optimize the mass-rearing of S. spiculatus.
authors.affiliation: Centro de Estudios Parasitológicos y de Vectores, CEPAVE (CONICET-CCT La Plata-UNLP), calle 2 No. 584, 1900 La Plata, Buenos Aires, Argentina. vmicieli@fcnnym.unlp.edu.ar
authors.forename: María V
authors.initials: MV
authors.lastname: Micieli
authors.forename: Paula
authors.initials: P
authors.lastname: Risso
authors.forename: María F
authors.initials: MF
authors.lastname: Achinelly
authors.forename: M
authors.initials: M
authors.lastname: de Los M Villar
authors.forename: Juliana
authors.initials: J
authors.lastname: Tarquini
mesh_terms: D000818:Animals; D009033:Culicidae / Q000382:microbiology; D055864:Droughts; D055868:Floods; D008632:Mermithoidea / Q000033:anatomy & histology / Q000502:physiology*; D010058:Oviposition; D010063:Ovum / Q000254:growth & development; D010572:Pest Control, Biological / Q000379:methods; D017440:Photoperiod; D013696:Temperature