Is the aestivation of the earthworm Hormogaster elisae a paradiapause?

• Published in: Invertebrate biology Vol. 125; no. 3; pp. 250 - 255
• Main Authors: Díaz Cosín, Darío J., Ruiz, María Pilar, Ramajo, Marta, Gutiérrez, Mónica
• Format: Journal Article
• Language: English
• Published: Malden, USA Blackwell Publishing Inc 01.08.2006; American Microscopical Society, Inc
• Subjects: Aestivation; aestivation chambers; Agricultural soils; Body weight; Diapause; Earthworms; Microcosms; Moisture content; quiescence; Soil temperature regimes; Soil water; Soil water content
• ISSN: 1077-8306; 1744-7410
• DOI: 10.1111/j.1744-7410.2006.00057.x

We report the results of a laboratory study of the aestivation of Hormogaster elisae to determine the nature of the inactive period (diapause or quiescence) and to evaluate the influence of soil moisture, temperature, season, and earthworm body weight on the process. The results showed that specimens of H. elisae underwent facultative diapause-paradia-pause-characterized by the construction of aestivation chambers in which the animal coils up and its activity decreases. Soil moisture appeared to be the most important environmental factor involved in the onset of aestivation. Temperature and time of year also had some influence, but earthworm body weight appeared to have none. Aestivating earthworms showed a decrease of 41.6% in mean body weight. Once replaced in soil with 20% moisture content, they took 6.4 ± 3.1 d to exit their chambers and another 6.5 ± 3.6 d to recover their initial body weight.