Bats – forget everything you ever thought

Throughout history, bats have ‘enjoyed’ very unfavorable public relations. Different myths and superstitions have created the image of a scary, harmful animal. The “insectivorous bat” word combination does not improve its image, but rather arouses additional fear. But it turns out that not only is this small, flying animal harmless, it can contribute to reducing pesticide damage in agriculture.

A new study is examining the potential of insectivorous bats as biological control agents in vineyards in and around Hanadiv Valley, and we are invited to change our approach and open up to this fascinating animal.  

Bats are unique animals – they are the only mammals in Israel that are able to fly. Most of us are familiar with the fruit bat, but this is only one of 33 species of bats living in Israel. The rest of them actually prefer to munch on insects. Most of the bat species in Israel are insectivorous bats that feed on enormous quantities of insects at night. A bat eats about 4 g of insects per night, which is about 50% of its bodyweight, and up to 100% of the bodyweight of a lactating female bat.

Insectivorous bats forage for food in natural areas and some species forage for food in agricultural areas as well. Recent studies emphasize the importance of bats in providing an important “ecosystem service” for humans – pest control in agricultural systems. In other words, insectivorous bats have great potential as biological control agents for the population of insect pests in agriculture.

In Israel, research on insectivorous bats in agricultural systems is in its infancy and is being conducted in apple orchards in the Upper Galilee by Regev et al. in 2013 and by Prof. Carmi Korine from Ben-Gurion University of the Negev, mainly in cotton fields. Nevertheless, most of the insectivorous bat species living Israel also have potential as foragers in vineyards for both wine- and table-grapes.

In order to determine the potential of bats as biological control agents in this branch of agriculture, a study on the importance of vineyards in Hanadiv Valley as foraging areas for insectivorous bats has begun under the leadership of Prof. Korine, within the framework of The Partnership for Regional Sustainability.

The aim of the study is to characterize the spatial distribution of insectivorous bats in vineyards with different pest control protocols and to estimate their activity and food composition in agricultural areas in Hanadiv Valley. The hypothesis is that the bats’ activity in agricultural areas is linked to the type of pest control implemented, as well as to the landscape elements in their surroundings, such as open water sources. The researchers expect that bat activity and the species richness of this group will increase in areas managed by “Integrated Pest Management” which promotes environmentally-friendly pest control methods, and therefore reduces the use of traditional chemical control agents.

                                                          Photo By: Ezra Hadad                                                                                                                                                                                     

Another aim of the study is to estimate the contribution of this environmentally-friendly regime to the diversity of insectivorous bats.

In the next stage, the possibility of implementing this knowledge will be assessed, by installing a long-term infrastructure in the plantations, in the form of “bat nesting boxes”. This infrastructure will be installed by the growers and perhaps in the future by the Ministry of Agriculture. The expectation is, as mentioned, to reduce the pest population and strengthen the contribution of bats as biological control agents.

Within the framework of this study, the vineyards are sampled using a bat detector that records the bats’ ultrasonic sounds. They use these sounds for different purposes such as orientation, capturing insects and interspecific communication. Since most bat species have a unique sound pattern, the recording can be analyzed by a sound program and the bats species sampled in the vineyards can be identified. Besides monitoring bat sounds, insect pests in the region are also being sampled.

The study began in the spring of 2017 and will continue throughout the summer and autumn. To date, 6 species of insectivorous bats have been recorded, all of which are protected by law.