Growth of the damselfly Ischnura heterosticta is better in saline water than freshwater.
Increasing salinity has the potential to affect freshwater organisms. Yet sub-lethal effects of salinity on macroinvertebrates are poorly understood. Growth and development of Ischnura heterosticta (Odonata: Coenagrionidae) was experimentally shown to be faster in 5-20 mS/cm than 0.1-1 mS/cm, while in 35 mS/cm all individuals died. In 30 mS/cm about half died and growth was similar to the 0.1 mS/cm treatment. The salinity-growth relationship cannot be explained indirectly, that is salinity affecting the survival of their prey. Tissue content and concentration of Ca, Mg, Na and K in emerged adults showed no evidence of deficiencies at low salinity. Heart beat rate was similar across treatments, except at 35 mS/cm, where it was slower. Respiration and feeding were similar at 0.1, 10 and 30 mS/cm. While there are similarities in I. heterosticta and other species' salinity response, there are differences and studies on more species are urgently needed.
Kefford
Ben J
BJ
Biotechnology and Environmental Biology, School of Applied Sciences, RMIT University, PO Box 71, Bundoora 3083, Victoria, Australia. ben.kefford@rmit.edu.au
Zalizniak
Liliana
L
Nugegoda
Dayanthi
D
D000222:Adaptation, Physiological; D000818:Animals; D017753:Ecosystem; D004784:Environmental Monitoring / Q000379:methods*; D005618:Fresh Water; D007313:Insecta / Q000187:drug effects / Q000254:growth & development*; D007814:Larva; D012965:Sodium Chloride / Q000494:pharmacology*; D014874:Water Pollutants, Chemical / Q000494:pharmacology*
D014874:Water Pollutants, Chemical; D012965:Sodium Chloride