Bumblebees Fight Agrochemicals

Brazil’s bumble bees are learning how to become Roundup-Ready, so anticipating the day when agrochemicals penetrate every corner of their natural world.

Herbicides like Monsanto’s Roundup do not, of course, specifically target insects. But even quite low doses of the chemical – which in Brazil is widely used in conjunction with genetically modified crops such as soybeans or maize – end up affecting members of the genus Bombus such as Bombus morio.

Scientists tracking the effects of trace-metals such as cadmium, and agrochemicals on bumblebee health and populations, found that those insect organs which correspond to the heart, liver and central nervous system in mammals, were all affected.

What’s more, they found insects were learning to adapt to these new pollutants by developing some resistance and the capacity to break down these toxins. In effect, bumblebees are learning how to become “Roundup-Ready.” The findings could contribute significantly to those studying the ecology of stress as applied in environmental management.

Bombus:  skilled at fighting against chemical intoxication

Bombus: skilled at fighting against chemical intoxication

The discovery is contained in a paper published in PLOS One by Caio Eduardo da Costa Domingues and Fábio Camargo Abdalla, a professor at the biology department of the Federal University of São Carlos (UFSCar). It is entitled “Hepato-nephrocitic system: a novel model of biomarkers for analysis of the ecology of stress in environmental biomonitoring” e by Abdalla & Domingues, and can be seen here. www.plosone.org/article/related/info:doi/10.1371/journal.pone.0132349.

Bombus presents a serious global decline of populations and even loss of species. This phenomenon is complex and multifactorial: environmental degradation due to increasing cultivation and grazing areas, indiscriminate use of agrochemicals, and a plethora of synthetic chemicals or xenobiotics daily discharged in the environment.

The researchers found that the fat body and hemocytes in these bees serve as a filter to start removing the toxin. This also triggers coordinated action by the pericardial cells to serve as a second line of defence. While the fat body plays a role analogous to the liver and kidneys, the pericardial cells play the role of the immune system. In fact the bees have an integrated cell system, which ensures protection against chemical stressors up to a certain limit.

Overall, this integrated cell system is capable of compensating for the toxic effects of glyphosphates and even masking the chemical impact up to certain levels of concentration, the researchers found. They also proposed naming the integrated response of fat body and pericardial cells as the hepato-nephrocitic system (HNS).

Researchers found that the internal organs of bumblebees are capable of a coordinated combat against agrochemicals, by monitoring insect blood cells counts during the intoxication process. Synthetic chemical substances that are successfully broken down and neutralised by twin action of the fat body and the pericardial cells, end up being excreted via the Malpighi tube, equivalent to a mammal’s large intestine.

Just as the liver and kidneys work together expel toxins from the human body after say, a night of partying, so these “Roundup-ready” insects can expel synthetic chemicals from their organisms.

Whilst the research covers bumblebees only and does not focus on honeybees (apis mellia), any research that creates links between the increased use of herbicides and the decline in bee stocks worldwide and the accompanying threat to food security, will surely set alarm bells ringing. After all, the whole tenor of the science sponsored by Monsanto is that glyphosphate becomes inert upon touching the ground and that it  has no reaction with organisms besides the broad-leafed weeds it targets. The sensitive reactions of bumblebees may justify revisiting that science.

Monsanto, known globally for its highly pugnacious stance on any research concerning its patents or any conclusions by scientists it might consider unfavourable for its commercial activities, has not yet issued any rebuttal of the research being done in Brazil. But it cannot be long before denials and challenges are issued – especially on so sensitive a topic as the world’s bee population.

Brazil's  bumblebees could be markers for  what's happening to honeybees. Photo: wikipedia creative commons.

Brazil’s bumblebees could be markers for what’s happening to honeybees. Photo: wikipedia creative commons.

But if the research has uncovered a hitherto-unknown process of chemical self-regulation in insects, it could make an important contribution to understanding the pressing problem of the world’s disappearing bees. The research conducted at UFSCar by Domingues was financed by the São Paulo research Foundation (FAPESP). You can find more details here: Bolsa.

You can read a full Portuguese language article on this topic by Brazilian journalist Elton Alisson by clicking here.

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