Insect Diversity is Abundant in Genetically Modified Maize Fields.


Genetically modified (GM) crops are a hotly debated topic, given their potential impact on existing ecosystems as well as the long term food supply used by both humans and animals. Certain factions are calling for increasing their use, campaigning for crops that can reduce farmers' reliance on pesticides, while increasing production yields as well as vitamin and nutrition levels. Those, in this camp, believe that 30 years of tried and true testing has generated sufficient scientific evidence to support the benefits of growing GM crops (1).


On the other hand, those against GM crops argue that increased use will not solve the world's hunger problem and will, in fact, exacerbate them by undermining traditional farming techniques (2). Those against GM crops believe that these farming protocols also have a negative impact on wildlife (2). There is also an increasing call in the United States for more accurate labelling of food where GM products are used, to allow consumers the ability to make a better informed choice.


Genetically Modified Corn vs. “the Real Thing.” How are Dependent Insect Species Populations Impacted?

GM Crops are found throughout the US*

While the debate rages, studies conducted in China, Spain and the United States on GM rice, cotton and maize (corn) have all shown that the biodiversity of insects and related arthropods in GM crop fields was essentially the same as that among conventional crops.


Those arguing against GM crops, due to their assumed potentially negative impact on surrounding wildlife, will not be pleased to hear that a new South African study confirms that there is little if any issue . The study is described in an article called “Comparative Diversity of Arthropods on Bt Maize and Non-Bt Maize in two Different Cropping Systems in South Africa,” which appeared in the February 2014 issue of Environmental Entomology.


“The aims of the study were to compile a checklist of arthropods that occur on maize in South Africa and to compare the diversity and abundance of arthropods and functional groups on Bt maize (Genetically Modified maize) and non-Bt maize,” the authors wrote. “Results from this short-term study indicated that abundance and diversity of arthropods in maize and the different functional guilds were not significantly affected by Bt maize, either in terms of diversity or abundance.”


Collections of arthropods were carried out during two growing seasons on Bt maize and non-Bt maize plants at two locations. Three maize fields were sampled per location during each season. Twenty plants, each of Bt maize and non-Bt maize, were randomly selected from the fields at each site. Over a two-year period, a total of 8,771 individual arthropods were collected from 480 plants sampled from Bt maize and non-Bt maize fields. The researchers found no significant differences in abundance or diversity in the wildlife (detritivores, herbivores, predators, or parasitoids).


“The results of our study indicate that arthropod diversity, even in high-input farming systems, is as high as in subsistence farming systems,” said Dr. Johnnie van den Berg, a professor at North-West University and one of the co-authors of the article. “More recently, surveys of arthropod and plant beta-diversity inside and adjacent to maize fields have been completed, during which 30,000 arthropods and 15,000 plant individuals were surveyed along a 1,000 kilometer swath of land. It seems that maize field diversity is homogenized and field margins had a high beta diversity,” he added.


Studies like these are important in assessing the impact that GM crop production can have on ecosystem functions. Biodiversity of wildlife is important because it influences ecological functions that are vital for crop production in sustainable agricultural systems as well as the surrounding environment. Assessing the potential environmental risk of a GM crop and whether its use has any impact on the species within the ecosystem helps us decide which crops have continued viability and which do not.



Research like this is vital for demonstrating the impact that GM crops may have on wildlife and surrounding environments. Using the data collected and the conclusions drawn, it can help us to make decisions about whether the continued use of a particular GM crop is beneficial or not.

With this latest study indicating that wildlife is not impacted by GM crops and that the numbers of arthropods are not significantly lower in either abundance or diversity, those on the side of using GM crops more will have another weapon in the fight for increased production. In the meantime, those campaigning against GM crop use will need to take their argument in a new direction.





*Image courtesy of  Free Digital Images