Factors affecting hatching pattern of the eggs of Strelkovimermis spiculatus (Nematoda: Mermithidae)

MICIELI MARÍA VICTORIA; RISSO, PAULA; ACHINELLY, MARÍA FERNANDA; VILLAR, MARÍA DE LOS MILAGROS; TARQUINI, JULIANA

Halifax, Nova Scotia

Congreso; 2011 International Congress on Invertebrate Pathology and Microbial Control & 44th Annual Meeting of Society for Invertebrate Pathology; 2011

Saint Mary`s University

We assessed the number of Strelkovimermis spiculatus Poinar and Camino, 1986 preparasites obtained from an initial known number of nematode eggs and how some abiotic factors (temperature-photoperiod, flooding-diseccation) could affect the number of emerged preparasites. Two groups of eggs, one maintained flooded and other under different number of flooding-diseccation events (each 15, 30 and 60 days), were performed. Each group of eggs was also studied under two conditions: 25° C and 14:12 (L:D) photoperiod, and at 16° C and 12:12 (L:D) photoperiod. When eggs were maintained flooded a higher total percentage of S. spiculatus preparasites was reported compared to treatments subject to drying-flooding cycles. The maximum percent of J2s emerged was found in the treatments maintained flooded at 16° C and 2:12 (L:D) photoperiod (30 ± 15.04 %). Preparasites were observed from 7 (25° C) and 14 (16° C) days suggesting this period as the minimum time for embryonic development. The period of time over which preparasites coming from the same batch of eggs were observed in flooded assays (98 and 112 days at 25° C and 16° C, respectively) suggested a nonsychronous hatching of nematode eggs possibly due to non uniform embryonation of eggs. The different periods of exposure of the assays to drought conditions no affected significantly the total average percentage of J2s obtained at 25° C and 14:12 (L:D) photoperiod, although at 16° C floods every 15 days showed the highest percent of emerged J2s. A schedule of flooding to optimize the mass rearing method for S. spiculatus is proposed.