Recent work by Aneta Joanna Strachecka, Jerzy Paleolog, Grzegorz Borsuk and Krzysztof Olszewski (Department of Biological Basis of Animal Production, Faculty of Animal Biology and Breeding, University of Life Sciences in
Lublin, Akademicka 13, 20-950 Lublin, Poland) demonstrates the harmful effect of miticides on honey bee colony defenses. Naturally, the effects of mites would be worse but harm due to miticides is non-trivial and may require some sort of compensatory or remedial action.

> Generally, formic acid destabilizes the body surface proteolytic system activity, lowering protein concentration, decreasing protease activity in workers and considerably reducing natural protease inhibitor activity in larvae and pupae. ... our results demonstrate that the treatment increased inhibitor activity in foragers and protease activity in all of the developmental stages, but only after five weeks of treatment.  
> 
> In a polluted environment, worker cuticular protein concentration, protease activity and natural protease inhibitor activity decrease in comparison to an unpolluted one (Strachecka et al., 2010). The present study confirmed that formic acid treatment may also be regarded as another harmful, anthropogenic, external factor. Grzywnowicz et al. (2009) suspected that bees, as with ants (Currie, 2001), might have protective microbial biofilms on their body surfaces. If so, formic acid could suppress the biofilm activity conditioned by the proteolytic system.  
> 
> Despite the negative effects of formic acid use in apiculture, it is still used against V. destructor. Our results show that formic acid is harmful to the proteolytic barrier. A "vicious circle" may be created, in which the acid use reduces resistance, leading to weaker colonies, and thence to more losses in the apiary which necessitate more intensive drug application. This corresponds with our in vivo tests which confirmed beekeepers’ concerns about the greater incidence of mycosis in bees treated with formic acid.

The influence of formic acid on the body surface proteolytic system at different developmental stages in Apis mellifera L. workers
Aneta Joanna Strachecka, et al.   Journal of Apicultural Research 51(3): 252-262 (2012)


> This work verifies that amitraz and oxalic acid treatment affect honeybee cuticle proteolytic enzymes (CPE). Three bee groups were monitored: oxalic acid treatment, amitraz treatment, control. Electrophoresis of hydrophilic and hydrophobic CPE was performed.  ... The activities of natural cuticle inhibitors of acidic, neutral, and alkaline proteases were suppressed as a result of the treatments, corresponding with reduced antifungal and antibacterial activity. 
> 
> Amitraz and oxalic acid may upset the cuticle proteolytic defense system in A. mellifera. Therefore, a Varroa treatment including these drugs may make honeybee workers more susceptible to pathogenic (especially fungal) invasions. The bees were not age-controlled, thus the drugs’ effects might be direct and indirect (via pupae and within-colony environment).  
> 
> Our previous experiments proved that some external factors could supress the proteolytic barrier on the apian cuticle. In a polluted environment, lower values of protein concentrations, protease activities, and natural protease inhibitor activities were observed in the worker cuticles as compared with the cuticles of bees from an unpolluted environment [11]. Bee diet may also affect the barrier efficiency [28]. The present study revealed that amitraz and oxalic acid theraphy may also reduce cuticular proteolytic system activity and therefore may be regarded as harmful external factors.


Influence of Amitraz and Oxalic Acid on the Cuticle Proteolytic System of Apis mellifera L. Workers
Aneta Strachecka, et al. Insects 2012, 3(3), 821-832
             ***********************************************
The BEE-L mailing list is powered by L-Soft's renowned
LISTSERV(R) list management software.  For more information, go to:
http://www.lsoft.com/LISTSERV-powered.html

Guidelines for posting to BEE-L can be found at:
http://honeybeeworld.com/bee-l/guidelines.htm