How Chemical Compounds Affect Fruit Bats’ Plant Interactions

Fruit bats are known to be able to discriminate, select, and track the essential oils of their preferred fruits. A few years ago, our research group hypothesized, experimented, and confirmed that these bats can be attracted with essential oils only – concentrated volatile aromas – of their preferred fruits both in forested and open areas. These findings led to the proposal of a restoration tool that uses essential oils of chiropterochoric fruits (fruits eaten by bats) to attract seed-dispersing bats to degraded areas with the objective to increase seed arrival and germination.

Nevertheless, the role played by different chemical compounds in attracting the bats was largely unknown. Now, our recent study, “Chemical compounds in Neotropical fruit bat-plant interactions,” unveils how fruit bats can find fruiting trees and ripe fruits in the dark within dense canopies. To do so, we have combined gas chromatographic (GC) analysis and attraction trials with captive bats to investigate the molecular basis of fruit foraging in two common neotropical species: Artibeus lituratus and Carollia perspicillata (Figure 1).

Figure 1. Bat species used in captivity tests (L. C. Parolin).

We began by impregnating a series of rubber septa (Figure 2) with the raw essential oil of Piper gaudichaudianum, a chiropterochoric fruit highly appreciated by these animals. The septa were kept on a laminar flow cabinet until GC analysis or attraction trials, both conducted on the same day, and then we tested and analyzed the septa every 5 days for up to 60 days. The tests indicated whether the septa (with the remaining components of the essential oil) were still attractive to the bats after the oil had aged. The CG analysis allowed us to identify which volatile oil compounds were lost and which ones remained on the rubber septum throughout the trial and, consequently, could be responsible for bat attraction.

Figure 2. Rubber septum that was impregnated with essential oils of fruit eaten by bats (L. C. Parolin).

The tests with captive bats revealed that the bats’ response toward the septum with essential oils decreased significantly beginning on the 25th day (Figure 3). The chemical analysis then suggested that eight oil compounds had a prominent role in bat-oil interaction – five monoterpenes: α-pinene, β-pinene, cymene, limonene, and dihydro carveol, and three sesquiterpenes: α-copaene, 9-epi-caryophyliene, and cis-eudesma-6, 11-diene (Figure 3B).

Figure 3. (A) PCA analysis of GC-MS profiles of the essential oil of Piper gaudichaudianum remaining in rubber septa – the first two principal components clearly separated attractive septa for Carollia perspicillata, (B) correlation loadings of the peak areas in terms of contribution to component 1 and 2 of Figure A, in which (1) α-pinene, (2) β-pinene, (3) cymene, (4) limonene, (5) dihydro carveol, (6) α-copaene, (7) 9-epi-caryophyliene and (8) cis-eudesma-6, 11-diene (Parolin et al., 2019). Republished with permission from Elsevier from https://doi.org/10.1016/j.mambio.2018.06.009

Out of these, α-copaene appears to have a key role in fruit-bat interactions, since its concentration decreased strongly until the turning point in bat response (Figure 4). Based on these results, additional trials (two for each compound and bat species) were conducted with two essential oil compounds: α-pinene and α-copaene against a blank septum (control).

Figure 4. The behavior of α-copaene, 9-epi-caryophyllene, and cis-eudesma-6-11-diene along the duration of the experiment (60 days) (Parolin et al., 2019). Republished with permission from Elsevier from https://doi.org/10.1016/j.mambio.2018.06.009

In the end, we were able to demonstrate that fruit bats can discriminate between two classes of essential oil compounds: monoterpenes and sesquiterpenes. Monoterpenes seem to provide an initial short-living signal, allowing bats to locate fruiting trees while moving through the dark forest. Sesquiterpenes, on the other hand, seem to provide longer-lived information on fruit ripeness, thus allowing bats to make optimal foraging choices.

Such findings give a unique perspective on the molecular mechanism of bat-plant communication and have important implications in forest restoration. Specifically, simple mixtures of commercially-available mono and sesquiterpenes (e.g. α-pinene and α-copaene) could be used as attractants to seed-dispersing bats into degraded landscapes improving the density and diversity of plants.

These findings are described in the article entitled Chemical compounds in Neotropical fruit bat-plant interactions, recently published in the journal Mammalian Biology.

About The Author

Lays Cherobim Parolin

Lays Cherobim Parolin is a professor at PUCPR - Pontifícia Universidade Católica do Parana

Sandra Bos Mikich

Sandra Bos Mikich is a research scientist at the Brazilian Agricultural Research Corporation (EMBRAPA).

FAH
Fabricio Augusto Hansel
Fabrício Augusto Hansel currently works at the Brazilian Agricultural Research Corporation (EMBRAPA). Fabrício does research in Analytical Chemistry.
GVB
Gledson Vigiano Bianconi

Gledson Vigiano Bianconi is a researcher at the Instituto Federal do Paraná, Campus Pinhais in Paraná, Brazil.

Speak Your Mind!

READ THIS NEXT

Ex-Employees Of Facebook And Google Create Coalition To Fight Social Media Addiction

A group of former, early employees at large Silicon Valley companies like Facebook and Google have recently created a coalition to build awareness about the addictive qualities of social media and smartphone technology. The group will be overseeing the creation of a new nonprofit dubbed the Center for Humane Technology. CHT will be working alongside […]

How Does Soap Work?

How soap works is due to its unique chemistry, the hydrophilic (loves water) and hydrophobic (hates water) parts of soap act to combine soapy water with grease, dirt, or oil. This combination creates clusters of soap, water, and grime called micelles. Soap is a product that most of us use every day, yet most of […]

Research Suggests That Religious Suppression Of Sexual Thoughts Only Creates More Preoccupation With Those Thoughts

A new study published in the Journal of Sex Research suggests that the willful suppression of sexual ideas, thoughts, and fantasies only creates a stronger preoccupation with these fantasies and thoughts. The effect is pronounced in religious communities with strong sexual norms or taboos. Yaniv Efrati, from Beit Berl College, is the author of the […]

Investigating How Occupational Styrene Exposure In The Plastics Industry Could Lead To Dyschromatopsia

Styrene is an organic compound commonly utilized as a solvent and cross-linking agent in the manufacture of plastic products. As such, the chemical can be found in disposable containers, insulation materials, automobile parts, and even some artificial flavoring products. In the US, industrial production of styrene has increased steadily in recent decades, more than doubling […]

Mimicking Nature In Cryopreservation

Freezing is regarded as the best technique for long-term preservation of food, organs, and even living organisms. As temperature drops, reactions slow down and microbial activity is reduced to a minimum. Although it is the technique of choice when it comes to preservation, cryopreservation poses several challenges. Water is the most common component of cells […]

An Analysis Of Occupant Responses To Transitions Across Indoor Thermal Zones

Across a building or even a floor of the building, one encounters spaces with different thermal conditions. Through our everyday life, we move across these spaces with different degrees of warmth or cool multiple times. Inherently, a sudden change in thermal conditions is likely to affect occupant thermal comfort. At the same time, there must […]

$180bn Invested In Plastic Production Risks Irreversibly Damaging The Environment

The world uses a massive amount of plastic, which threatens the integrity of the world’s oceans and food chains. The problem is so widespread that a massive pile of plastic garbage million square miles wide (or roughly the size of Mexico) exists in the middle of the Pacific ocean. Furthermore, plastic fibers have recently been […]