Water relations and drought sensitivity of Folsomia candida eggs (Collembola: Isotomidae)

Drought tolerance of juvenile and adult life stages is relatively well understood, but very little is known about the tolerance of eggs to drought in this group of animals. The aim of the present study was therefore to investigate the water relations and drought sensitivity of eggs of the hygrophili...

Full description

Bibliographic Details
Main Author: Martin HOLMSTRUP
Format: Article
Language:English
Published: Institute of Entomology, Biology Centre, Czech Academy of Science 2019-06-01
Series:European Journal of Entomology
Subjects:
Online Access:https://www.eje.cz/artkey/eje-201901-0025_water_relations_and_drought_sensitivity_of_folsomia_candida_eggs_collembola_isotomidae.php
Description
Summary:Drought tolerance of juvenile and adult life stages is relatively well understood, but very little is known about the tolerance of eggs to drought in this group of animals. The aim of the present study was therefore to investigate the water relations and drought sensitivity of eggs of the hygrophilic springtail, Folsomia candida Willem, 1902 (Isotomidae), exposed to a range of soil water potentials above and below the permanent wilting point of plants (-1.5 MPa). Under saturated conditions, eggs absorbed water during development and increased water content from 1.1 to 2.9 mg mg-1 dry weight. By increasing drought conditions, water absorption was gradually reduced and was nullified approximately at the soil water potential equivalent to the osmolality of egg fluids (630 mOsm corresponding to -1.53 MPa). Eggs had a lower permeability for water (68 ± 13 µg water cm-2 h-1 mm Hg-1) than adults (about 400 µg water cm-2 h-1 mm Hg-1), but eggs were much more sensitive to drought than adults. Eggs did not survive exposure to -1.5 MPa, whereas adults readily survive this level of drought by absorbing water vapour. In conclusion, eggs of F. candida are sensitive to drought and would perish if soil water potential in the field approaches the wilting point of plants, which is often reached during summer droughts. The persistence of this species depends on the survival of post-embryonic life stages.
ISSN:1210-5759
1802-8829