I've been trying to find published studies about the physiological effects of saline injections in insects. So far, I have only found one paper (Jarosz, J (1988) Cytobios 53:19-29) that suggests saline injections increase levels of lysozyme activity and resistance to parasites in insects. I would like to know if anyone knows of more recent papers about this topic. I would also like to know why these saline injections are use as 'control treatments' for immunological assays if they seem to have an effect in immune response. Thanks in advance for your input!
I'm not sure what you mean by "saline"? Do you mean a physiologically reasonable salt solution approximating insect hemolymph (asking this because "saline" to many people means mammal-level salts)? The technique is sometimes used as a control in Drosophila research for injections of various compoiunds. The oldest reference to injection of saline in Drosophila is Myrtle J. Bird 1952, but this doesn't characterize the effects. Injection of saline into embryos is a control in http://www.sciencemag.org/content/293/5529/514/suppl/DC1 and slows development. Saline injections in crickets were used as controls in a variety of associative learning experiments (http://journal.frontiersin.org/Journal/10.3389/fnbeh.2010.00172/full).
Typically, breaking the cuticle induces an immune response in Drosophila, and other insects. Since the first symptom of attack by a parasitoid is breaking of the cuticle, an enhanced immune response to this signal makes sense. Thus some fruit fly papers use either pinpricks or saline injections as controls for the cuticle effect, when the topic of interest is the response to something like injected bacterial LPS. Only by comparing the LPS injection to a saline injection does one fully control for the stimulatory effects of injection. An example of this in a PNAS article using both fruit flies and beetle larvae is http://www.pnas.org/content/104/16/6602.full. NOTE that in the article main text the authors state they injected "water" but in the supplementary they refer to "insect saline".
I didn't find a direct source for the effects of cuticle puncture or saline injection, but suggest that somewhere in the earlier literature by Lemaitre and others this may be documented.
Clement,
Thanks for your input! These papers are really useful for the literature search I am doing!
The citation below is also useful one for other people interested in this post:
Jarosz, J (1988) The use of saline W, a physiological salt solution for experimentation on insect immunity Cytobios 53:19-29
Joao B. T. Rocha
Margarita,
Have you any idea about the survival of injected animals? We are trying to do experiments with cockroaches by the mortality is quite variable (within 2 weeks) after injection.
Hi João,
Our experiments only lasted 72 hours. The mortality rate with saline injection was low (less than 75%) in bees.
Hope this helps!
dear Margarita, thank you. You meant 25% mortality and 75%...is this?
- Badges
- Science topic
- Similar topics
- Biological Science
- Zoology
- Invertebrate Zoology
- Arthropods
- Insects