Ecotoxicological experiments with caddisfly larvae were conducted aiming to study emergence success as one endpoint. Timing of emergence was registered and the adults were preserved in 70% EtOH in order to measure final DW.
The responses in timing of emergence and emergence success to the treatments were however so unexpected and exciting that I would be really curious to measure the fitness of the adult caddisflies - especially with respect to expected survival and reproductive success in the terrestrial environment. Hence my thoughts concerning Triglyceride measurements.
The question of course now arises how reliable this measure would be since the animals were stored in EtOH.
Such lipids are only weakly soluble in ethanol, especially at low temperatures (e.g. if stored in a fridge). And most of the insect's lipids are within cells and protected by the integument. Therefore when the insect body is still in good condition and not disintegrated, and the samples are not too (the older the more will be gone) old and/or stored at higher temperatures I'd think most of the fat is still in the body. To be sure you can look for lipid droplets on the EtOH and also measure lipid content of the EtOH (together with the insect if they were stored individually or separately, if they were stored in bulk, and then as overall correction factor for all insects).
Another problem might be oxidation, not sure how this will influence measurements.
Dear Peter,
Thanks for your response. Luckily, I have preserved each animal individually, so I will have the oppotunity to measure lipids lost to the EtOH sollution. All the animals were preserved without harming them (other than killing them in EtOH).
Intuitively my thoughts are along the line with yours - that it should not significantly influence the triglyceride concentrations, since they are not strongly polar..
I wonder if you would happen to know of primary literature that could support these thoughts and claims?
I have not been able to dig them up from Google searches or WoS.
I guess it's quite difficult to get such papers online since most research is quite old. For the direct effect of ethanol storage on lipid content, I have no idea if literature exists. Anyway for solubility you can find data e.g. here:
http://pubs.acs.org/doi/abs/10.1021/ja01224a010
and Arnold. L.K.. Choudhury, B.B.R. & Guzman. A. (1963) J. Am. Oil Chem. Soc. 4: 33 (don't have a link)
- Badges
- Science topic
- Similar topics
- Biological Science
- Zoology
- Invertebrate Zoology
- Entomology