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andscapes in spite of insufficient research into the long- — and behavioural development of bees. That is, given that erm effects of pollen from GM crops on the behaviour of | the development of physiological structures involved in bee colonies. On the one hand are beekeepers struggling —_ olfaction and learning performances in larvae and young © cope with the increasing incidence of the honey bee __ bees takes place while they are fed pollen, are larvae and colony collapse disorder (CCD) or honey bee young adult bees fed pollen from GM crops at risk of depopulation syndrome (HBDS). On the other hand is exposure to toxins? Are there any subsequent he increasingly widespread adoption of GM crops. deleterious effects on the development and learning The concern expressed by beekeepers stems from the performance of these young bees as they mature? act that in GM crops such as Bt cotton, one of the most Learning is of primary importance in honey bee foraging, widely grown GM crops worldwide, the DNA representing —_ since impaired learning let alone failure to learn could he insecticidal traits of the common bacterium Bacillus indirectly lead to colony death due to failure to collect thuringiensis is incorporated into the genome of the plant. enough food to sustain the hive. Consequently, as the plant grows, its Bt gene or primary In this context, it is noteworthy to cite a study by R. oxin, a protein scientifically called CrylAb, is replicated | Ramirez-Romero et al.'* The goal of the study was to in every cell of the plant, including its pollen. Whereas assess the potential sub-lethal effects of two previously the bacterium pesticide concentrations of the CrylAb protein sprayed on crops to control crop (3.0 parts per billion [ppb] and 5,000 damage from insects like stem- and ppb) on three major life traits of young root-borers and butterfly larvae was adult honey bees: their survival during only ingested by the target insects, . sub-chronic exposure to CrylAb, the now a natural outcome of growing GM ww iMN GM crops such bees' feeding behaviour and their tt is that the Bt ti | i f t the ti that the pollen is ingested by non-target | @S Bt cotton...the | cr seccme forages insects like honey bees. As for the DNA representing The results of the study are an eye- presence of CrylAb in beehives, . * os opener, to say the least. The tested Canadian beekeepers spraying Bt the insecticidal concentrations of CrylAb protein did under hive lids to control the wax moth traits of the not induce a lethal effect on the honey (their larvae cause messy webs on the common bees, which means that there was no drastic impact at the scale of entire colonies. However, the feeding behaviour of young adult honey oney) have noted the disappearance of this moth even in untreated bacterium Bacillus ives, apparently the result of bees ingesting CrylAb while thuringiensis IS bees that were exposed to the oraging in GM canola plants."° incorporated into ighest concentration of CrylAb It is not as though no research protein was affected, with the as been conducted to evaluate the genome of bees taking longer to ingest the he potential effects of the primary the plant. contaminated syrup. This could mean that smaller amounts o pollen would be collected. Moreover, honey bees exposed to 5,000 ppb of Cry1Ab had disturbed earning performances which oxin CrylAb on non-target species in agricultural ecosystems. Specifically for honey bees, the problem is that most studies only assess the lethal toxicity of pollen. Scientists from could adversely affect their ability Bayer have reported that neither o gather pollen to sustain a hive. imidacloprid in sunflower seeds dressed with the Honey bees are usually able to recognise the absence o insecticide" nor maize seeds dressed with the insecticide food, even when an odour is present, and thus move to or released from the seeds during planting’ is seek other sources of food. In terms of foraging detrimental to honey bees. What is noteworthy, however, optimality, this extinction process, as it is called, is is that the Bayer studies did not deal with sub-letha crucial for the exploitation of food resources because i behaviour of toxin-exposed bees. enables foraging honey bees to leave depleted food Overall, few studies have investigated the sub-letha sources.’ However, the young adult honey bees studied effects of Bt proteins on bees—effects which become continued to respond to a conditioned odour even in the apparent only when examining the lethal effect is not the | absence of a food reward. As a result, foragers could aim of a study—and fewer of these studies have been _— spend more time foraging in sub-optimal or depleted highlighted in the mainstream media. This implies tha food sources instead of exploring new ones, leading them beekeepers, let alone the masses, have limited _ to collect inadequate food supplies to sustain a hive and understanding of the potential effects of the CrylAb eventually to possible colony collapse. protein on the immune system and on the physiologica In a small study conducted at the University of Jena in DNA representing the insecticidal traits of the common the genome of the plant. NEXUS ¢ 23 ...in GM crops such as Bt cotton...the bacterium Bacillus thuringiensis is incorporated into DECEMBER 2009 - JANUARY 2010 www.nexusmagazine.com