Bats Prefer Organic Farms, Serve as Insect Predators

Foraging bats–bats who live in green spaces– prefer organic farms over conventional farms, according to a recent Italian study. Farm management was the greatest indicator of bat activity, and organic farms hosted 3 times the amount of bat visits of non-organic farms.

Bats provide valuable ecosystem services to agricultural production when they eat insects that consume crops or infect the crops  with diseases. Bats also help control mosquitos, which can provide an important service for public health. 

Organic farmers rely on natural services to boost plant health, and when they employ crop diversity and preserve large areas of natural habitats, a breadth of ecosystem services are boosted by beneficial biodiversity. Although non-organic farmers often use pesticides to control insect populations, pesticide resistance is becoming more common, which means that these chemical tools are becoming less effective over time.

Bats and other natural predators are essential in controlling insect populations without the use of chemicals, and it will be critical to the success of agriculture to accommodate these natural enemies moving forward.  This study explores the link between habitat structure–including method of farming– and bat activity. 

Researchers sampled farms in 4 different areas of Italy, surveying adjacent farms in organic/conventional pairs to control for regional differences. Comparable plots in each farm were matched up and surveyed simultaneously, using audio recording to measure the amount of bat passes over the course of several nights. The surrounding area of each plot was geospatially examined, classifying the land within a 500 meter radius to quantify habitat structure.

Over the course of surveying, there were 1321 bat passes, 75% of which occurred in organic plots. The greatest determinant for bat activity was the type of farm, with organic farms hosting far more bat activity. There was little correlation between other aspects of habitat structure and bat activity. 

In this study, 11 species of bat were detected. Researchers examined species diversity, but found no correlation between farm management and bat diversity. Likely, changes would have to be created on a larger scale in order for these areas to host more bat species and differences would not be apparent on adjacent farms.

This study supports the findings of many other studies that show organic farming does not just rely on existing ecosystem services, but enhances those services when compared to non-organic farms. Organic farmers create a suitable environment for natural predators of insects, allowing for a reliable, safe, and easy way of controlling insect populations.


Photo Credit: James Wainscoat;