The effects of drought upon epigeal Collembola from arable soils

1 Springtails (Hexapoda, Collembola) are usually associated with moist microhabitats. However, some species show adaptations to ecosystems subjected to periodic desiccation. This study examined the effects of short-term drought conditions upon epigeal Collembola collected from arable fields. 2 An emergence trap was used in the laboratory to investigate collembolan activity, particularly the emergence of newly hatched juveniles from soils subjected to a simulated drought and to varied levels of simulated rainfall. 3 Addition of water to soils subjected to a 4-month simulated drought resulted in synchronized emergence of juveniles of Sminthurinus elegans, Sminthurus viridis and Bourletiella hortensis. As anhydrobiotic nymphs were not found in the soil, these juveniles are likely to have recently hatched from eggs in the soil. 4 The same species were shown to emerge when desiccated soil samples were treated with simulated heavy rainfall. No emergence occurred in soils which received no water, whilst only a few juveniles were present under a regime of the lowest monthly rainfall recorded for the area in the spring. 5 This study provides the first evidence that in northern European arable systems some epigeal Collembola can survive considerable periods of drought as eggs, emergence of which is triggered by rainfall. These findings have implications for the effects of predicted climatic changes upon collembolan populations, the recovery of collembolan communities following pesticide applications in agroecosystems, and also provide a plausible mechanism for dispersal of Collembola as wind-blown eggs.