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Save Our Bats, Save Our Tequila: Industry and Science Join Forces to Help Bats
and Agaves
Author(s): Roberto-Emiliano Trejo-Salazar, Luis E. Eguiarte, David Suro-Piñera and Rodrigo A.
Medellin
Source: Natural Areas Journal, 36(4):523-530.
Published By: Natural Areas Association
DOI: http://dx.doi.org/10.3375/043.036.0418
URL: http://www.bioone.org/doi/full/10.3375/043.036.0418
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Volume 36 (4), 2016 Natural Areas Journal 523
ABSTRACT: The genus Agave is one of the most diverse and rich groups of plants of Mexico. Mexican
people have developed several technologies to extract products from Agave, and for many years they
have consumed five different alcoholic beverages derived from Agave: Tequila, Mezcal, Bacanora,
Raicilla, and Pulque. Additionally, Agave has coevolved with nectar-feeding bats, and in several cases,
bats play the main role as functional pollinators in this ecological relationship. But with growth in the
demand of agave derived products, management practices have reduced dependence on bat pollination,
using instead clonal shoots to replant fields and harvesting plants before flowering, thereby negatively
affecting both bats (by decreasing food availability) and agaves (by lowering their genetic diversity). We
explore the possibility that bat-friendly practices may be incorporated into the production system. We
compiled data about the pollination biology of Agave to infer how many bats could use the available
resources, if Mezcal and Tequila producers allowed 5–10% of agave crop inflorescences to flower based
on a linear projection using Agave angustifolia (a sister group of A. tequilana). If only 5% of the plants
in one hectare were allowed to flower (approximately 222 individuals), then, depending on nectar con-
centration and total volume, a minimum of 89 individual bats could feed every night during flowering
period. This means that allowing 5% of the current total population of A. tequilana reproductive agaves
to flower could feed a total of 2,336,250 nectar feeding bats per month.
Index terms: Agave, bat-friendly, conservation, tequila production
INTRODUCTION
Agave
in Mexico
Mexico is a megadiverse country due to its
great diversity of many groups of organ-
isms (Ceballos et al. 1998; Frías-Alvarez
et al. 2010; Martínez-Meyer et al. 2014).
Between 4−8% of the world’s flora lives
in Mexico, and 51% of the Mexican flora
is endemic (Villaseñor 2004; Villaseñor et
al. 2005; Sosa and De Nova 2012).
The genus Agave is endemic to the
American continent; Mexico contains
the largest number of agave species and
it is the largest genus in the subfamily
Agavoidea (Eguiarte et al. 2013). Agave
is the third largest genus of the Mexican
flora, including approximately150 species
(García-Mendoza 2002). About 75% of
all species of Agave are found in Mexico,
69% are endemic (García-Mendoza 2002;
Villaseñor et al. 2005). Agaves grow
mainly in extreme climates that are dry
and hot (García-Mendoza 2002) and are
often dominant elements in tropical dry
forest, scrub, and xerophytic environments,
which occupy more than 50% of Mexico’s
territory (Rzedowski 1993).
Partly influenced by the complexity of
ecosystems in Mexico, agaves (commonly
called maguey) have diversified into many
species and colonized most of the country
(Figure 1). They are adapted to arid envi-
ronments due to their physiological and
ecological traits, such as CAM metabolism
(Eguiarte et al. 2013). Agaves are perennial
and with exception of one small group of
species they are semelparous, accumulating
huge reserves of carbohydrates that the
plant invests in a single flowering event
resulting in the development of a vertical
flowering stalk with up to thousands of
flowers, after which the plant dies (Gentry
1982). They can be distinguished from
other plants by their rosette-like growth
form, and by their elongated, tapered
leaves that have a terminal thorn. The most
visible characteristic is the large flowering
stalk (also called scape) that they produce
at 5−20 years of age, depending on the
species. This is the signal that indicates
the beginning of the reproductive event and
the final life stage of the plant. Flowering
stalks can be spicate (without branches)
or paniculate (a branched inflorescence,
each branch including several flowers)
(Gentry 1982).
Mexico is the center of origin of Agave
(Good-Avila et al. 2006) and it is not
surprising that since pre-Columbian times,
people in Mexico have developed different
technologies to obtain and use several
agave products, such as food, fibers, and
alcoholic beverages including Mezcal,
Tequila, Bacanora, Raicilla, and Pulque
(Callen 1965; Kasiak 2012; Radding
2012), which led to the development of a
culture around agaves and their products.
Interest in Agave as an alternative source
for biofuel has increased in some regions
(Valenzuela 2011; Escamilla-Treviño 2012;
Natural Areas Journal 36:523–530
3 Corresponding author: medellin@miranda.
ecologia.unam.mx; +52 (5) 56 22 90 42
•
Save Our Bats,
Save Our Tequila:
Industry and
Science Join Forces
to Help Bats and
Agaves
Roberto-Emiliano Trejo-Salazar1
1Instituto de Ecología
Departamento de Ecología Evolutiva
Universidad Nacional Autónoma
de México
Ap. 70-275, CP 04510, México, DF
Luis E. Eguiarte1
David Suro-Piñera2
Rodrigo A. Medellin1,3
2Tequila Interchange Project
1604 Locust St.
Philadelphia, PA 19103
•
524 Natural Areas Journal Volume 36 (4), 2016
Stewart 2015). Today agaves are used for
many purposes (Radding 2012; Stewart
2015). However, production of spirits is,
by far, the most economically important.
Cultural Landscape of
Agave
Landraces
Agaves have been part of the culture,
identity, and tradition of the Mexican peo-
ple for a very long time (Radding 2012)
because of their wide distribution, natural
characteristics, and the ancestral human
relationship. The use of agave products was
documented 9000 years ago in northern
Mexico (Callen 1965).
The Mexican states most closely linked
with the agave cultural landscape and bi-
ological diversity are Oaxaca, with more
than 50 agave species; Durango, Puebla,
Sonora, and Jalisco with more than 40
species; and Coahuila, San Luis Potosí,
Nuevo León, Zacatecas, State of Mexico,
and Tamaulipas are inhabited by 25 species
of agaves (García-Mendoza 2002). There
are more species that have not been de-
scribed or are still very poorly known and
there are several areas of high endemism
(Tambutti 2002).
In 1977 and 1995 respectively, Tequila and
Mezcal obtained the Appellation of Origin
signed before the World Intellectual Prop-
erty Organization in Geneva, Switzerland.
Currently, the two industries are monitored
by Mexican technical legislations called
NOM (Norma Oficial Mexicana): NOM-
006-SCFI-2012 and NOM-079-SCFI-1994
for Tequila and Mezcal, respectively. But
these rules also protect the heritage promot-
ing traditional and sustainable use (Diario
Oficial de la Federación 2012).
In July 2006, the regions of Magdalena,
Amatitán, El Arenal, Tequila, and Teuchit-
lan within Jalisco, Mexico, were included
in the list of World Heritage Sites by
UNESCO based on different criteria, but
mainly because of the aesthetics of the cul-
ture landscape and the traditional distillery
practices developed by ancient people. The
management plan, prepared by Instituto
Nacional de Antropología e Historia (IN-
AH-Mexico), the Government of Jalisco,
and World Heritage Mexico, contains the
proposal that the Tequila landscape should
be part of the list of World Heritage, rec-
ognizing that sustainable use should be
also a part of that heritage (WIPO 2006).
The production of both agave-distilled
beverages, Tequila and Mezcal, has in-
creased in recent years (National Chamber
of Tequila Industry 2015); Distilled Spirits
Council of the United States (2015) and
the production of spirits corresponds to
the region where species are distributed.
Additionally, different Mexican state gov-
ernments have requested inclusion in the
appellation given that some agave species
occur within their boundaries and they
use them to produce spirits. These states
conform the Tequila and the Mezcal route,
however each locality must demonstrate
ancestral tradition for these beverages in
order to be included in it (Diario Oficial
de la Federación 2012).
Tequila Production
From January to December 2014 alone, the
National Chamber of the Tequila Industry
reported a production of 242 million liters
at 40% (alcohol volume) in order to cover
the demand of 1615 brands, of which a total
of 172.5 million of liters were exported.
This production required 788,200 tons of
Agave tequilana Weber var. azul. On the
domestic market, profits reached 13,900
million pesos (National Chamber of the
Tequila Industry 2015). In August 2015,
this industry represented 70,000 jobs and
exports with a profit of 1.2 billion US
dollars (National Chamber of the Tequila
Industry <https://www.crt.org.mx/Estadis-
ticasCRTweb/> 2015). The export to the
United States of America was the most
substantial in the period from January
to December 2014, and an equivalent to
742 million dollars was exported, where
Tequila represented 6.3% of sales spirits
in that country (according to the National
Chamber of the Tequila Industry 2015).
This represents about 117,347,772 liters,
considering the total production estimated
by the Distill Spirits Council of the United
States (2015). Due to high demand, tequila
production is a very important economic
activity in Mexico. Given their depen-
dency on bats for pollination, developing
bat-friendly and ecologically sustainable
production techniques is key to keep and
expand opportunities for this and other
industries, such as Mezcal.
For several decades, there has been a grow-
ing tendency for people to acquire prod-
ucts whose production is environmentally
friendly, socially responsible, sustainable,
and/or organic (Kilbourne and Beckmann
1998; Diamantopoulos et al. 2003). This
tendency is paralleled by marketing strat-
egies (Zimmer et al. 1994), primarily in
industrialized countries, where consumers
Figure 1. Potential distribution of different species of Agave in Mexico according to CONABIO (Comisión
Nacional para el Conocimiento y Uso de la Biodiversidad) and GBIF (Global Biodiversity Information
Facility) databases. Darker color represents higher species richness.
Volume 36 (4), 2016 Natural Areas Journal 525
seek government-endorsed labels related
with environmentally friendly practices
(D’Souza et al. 2007).
Natural Agave Landscapes and Bats
Several researchers have recorded and de-
scribed the relationship between agaves and
the nectarivorous bats Leptonycteris yerb-
abuenae (Martínez & Villa-R), L. nivalis
(Saussure), and Choeronycteris mexicana
(Tschudi) (Álvarez and González-Quin-
tero 1970; Easterla 1972; Howell 1979;
Howell and Hart 1980; Howell and Roth
1981; Arizaga et al. 2000; Molina-Freaner
and Eguiarte 2003; Silva-Montellano and
Eguiarte 2003; Scott 2004; Rocha et al.
2005; Sánchez and Medellin 2007; Trejo
et al. 2015). These three bat species are
migratory and their distribution covers most
of the Mexican territory (Figure 2), some
localities in United States, and small areas
in Central America (Arita and Santos Del
Prado 1999; Figure 2). All three species are
under protection in two categories (Threat-
ened and Endangered) by Mexican, US, or
international regulations (Diario Oficial de
la Federación 2012; US Fish and Wildlife
Service 1995, 2006; IUCN 2016). Although
it is unknown whether food is a limiting re-
source, the tequila landscape was virtually
sterile to the bats, with no available nectar
for many decades (Zizumbo et al. 2013).
Recently, L. yerbabuenae populations had
recovered from an important decline and
for this reason will be delisted in Mexico
(Paz 2013) and the official revised list, in
press, will reflect this change (C. Alvarez,
SEMARNAT, pers. comm.).
Although bat pollination of agaves has
been recorded in wild species, and nec-
tar-feeding bats have been noted as the
main pollinator, the pollination ecology in
both wild and cultivated species of agaves
is still scarcely studied. Particularly, the
presence of nectar-feeding bats in the
flowers of Mezcal agave has been reported
for some species, including A. americana
(Linneo) (Knudsen and Tollsten 1995),
A. angustifolia (Linneo) (Molina-Freaner
and Eguiarte 2003), A. inaequidens (Koch)
(Sánchez and Medellin 2007), and A. po-
tatorum (Zuccarini) (Estrella-Ruiz 2008).
Only in a few cases has the role of visitor
been described in detail (Table 1). Several
publications include reports of bats visiting
flowers of additional agave species and the
presence of agave pollen on the body or in
the feces of bats (Rocha et al. 2006; Egui-
arte et al. 2013). The agave anthers dehisce
at night and shed pollen before the stigma
is receptive (Schaffer and Schaffer 1977;
Gentry 1982; Slauson 2000; Rocha et al.
2005). Pollen is able to germinate for only
a few hours after dehiscence (Shivanna et
al. 1991), meaning that effective pollination
primarily occurs at night.
Dry and semiarid zones cover about 50%
of the Mexican territory, where 20% of the
total Mexican flora is found (approximately
6000 species), and there is a high incidence
of endemism, about 60% (García-Mendoza
2002). This information emphasizes the
importance of the conservation of bats
and the plants they pollinate in Mexico,
which provide benefits not only to natural
ecosystems, but also to crops where the
bats can help promote genetic diversity.
Leptonycteris yerbabuenae, L. nivalis, and
C. mexicana are good examples because
they feed mainly on plants that dominate
the Mexican arid landscapes and these
nectar-feeding bats are the principal pol-
linators of many agave species (Álvarez
and González-Quintero 1970; Easterla
1972; Howell 1979; Howell and Hart
1980; Howell and Roth 1981; Arizaga et al.
2000; Molina-Freaner and Eguiarte 2003;
Silva-Montellano and Eguiarte 2003; Scott
2004; Rocha et al. 2005; Sánchez and Me-
dellin 2007; Trejo et al. 2015). Ecological
relationships between these bats and agaves
has been described based on the presence
of bats in areas with high abundance
and diversity of Agave (i.e., Barranca de
Metztitlán and Tehuacán Valley) during
their flowering period (Rojas-Martínez and
Valiente-Banuet 1996; Rojas-Martínez et
al. 1999; Moreno-Valdez et al. 2000; More-
no-Valdez et al. 2004; Rocha et al. 2005).
Additionally, the migration of the two Mex-
ican Leptonycteris species coincides with
the flowering period of some agaves in the
north of their distribution (Molina-Freaner
and Eguiarte 2003; Moreno-Valdez et al.
2004; Peñalba et al. 2006).
Pollination ecology of plants of the ge-
nus Agave is scarcely studied; there are
only a few records of nectar production
for some species (Table 1). In addition,
consumption of nectar by bats is poorly
studied; a few authors have calculated
total food intake in nectar-feeding bats
(Ayala-Berdon et al. 2008; Ayala-Berdon
et al. 2009; Ayala-Berdon and Schondube
2011; Ayala-Berdon et al. 2011a; Aya-
la-Berdon et al. 2013). Early estimates
suggested that an average bat weighing
11.5 g can consume around 15 ml of nectar
per night (Helversen and Reyer 1984). A
more recent study reports that a Mexican
long-nosed bat (L. nivalis) consumes a
Figure 2. Overlapping distribution of known occurrence of agave-visiting nectar-feeding bats (Leptonyc-
teris nivalis, L. yerbabuenae and Choeronycteris mexicana) and Agave potential distributions in Mexico.
Gray scale represents richness of Agave.
526 Natural Areas Journal Volume 36 (4), 2016
wide range from 18,500−119,000 mg of
nectar in one night, depending on sugar
concentration (Ayala-Berdon et al. 2013).
Additionally, the lesser long-nosed bat (L.
yerbabuenae) and Pallas´s long tongued bat
(Glossophaga soricina Pallas) can change
their total consumption in response to sugar
concentration and energy requirements in
different seasons (Ayala-Berdon et al. 2008;
Ayala-Berdon et al. 2009; Ayala-Berdon
et al. 2011; Ayala-Berdon and Schondube
2011; Ayala-Berdon et al. 2013).
Agave inflorescences are capable of pro-
ducing thousands of flowers (Sutherland
1987), but flowering is progressive so that
flowers display pollen by spatiotemporal
clusters within the inflorescence. Nectar
production and concentration is variable in
every species (Table 1). For instance, each
flower of A. marmorata (Roezl) produces
about 570 µl of nectar in one night (Ornelas
et al. 2002), while A. angustifolia, a species
closely related to A. tequilana, produces
about 180µl in one night (Molina-Freaner
and Eguiarte 2003). Agave species also
differ in flowering timing. For instance,
A. angustifolia begins flowering in January
and ends in May, and highest abundance
of inflorescences is documented to occur
in March (Molina-Freaner and Eguiarte
2003). Sugar concentration in nectar in
Agave spp. ranges from 18−26% (Rocha
et al. 2006). In general, nectar-feeding bats
consume nectar from 5−29% sugar con-
centration (Tschapka and Dressler 2002).
Nectar feeding bats in nature exhibit a
particular way to feed; they first visit
several flowers and consume nectar until
they satiate, then they rest in order to digest
that meal, then they visit flowers again. In
this way they can visit up to 1000 flowers
per night (Tschapka and Dressler 2002).
In this paper the mutualistic relationship
between bats and agaves is explored, along
with the ensuing interaction with the tequila
industry, and how the three elements (bats,
agaves, and industry) can benefit from
fostering the interaction.
METHODS
Maps of the richness distribution of Agave
and nectar-feeding bats were built using
Rstudio v0.98.501 based on GBIF and
CONABIO database information. We used
data from five agave species (Table 1) to
explore how much resource they contribute
to the bat diets. There is no information
about flowering production of A. tequilana,
so we proposed A. angustifolia as a model
to project data in an A. tequilana crop, due
to their close phylogenetic relationship
(Eguiarte et al. 2013). Nectar consumption
by bats was compiled from the literature
(see above; Table 1).
Currently, commercial producers of A.
tequilana var. blue cultivate contiguous
individual plants every 1.5 m (Zizum-
bo-Villareal et al. 2013); therefore, one
hectare can contain approximately 4444
individuals. Unfortunately, as mentioned
above, there is no data about pollination
biology of A. tequilana, so we used data
from closely related species to represent
possible scenarios. It is also true that these
fields are empty of food resources for
bats, since the industry maximizes taking
the accumulated sugars in agave heads to
produce tequila by harvesting them before
they produce any flowering stalks. Each
new planting season, farmers replant their
fields with the clonal shoots produced by a
small selection of the plants, thus resulting
in further genetic diversity loss.
We developed a linear model with Rstudio
v0.98.501 to predict how many bats can
feed from different agave species. We
considered the value of nectar volume
and concentration from A. angustifolia
to represent the potential contribution
of food available for nectar-feeding bats
(Table 2). Nevertheless, these measures are
only a crude approximation, as volumes
and concentration of sugar in nectar vary
widely among different Agave species
(Tables 1 and 2). The only available data
on the number of active agave flowers per
night is an average of 100 flowers (Rocha
et al. 2005).
In order to perform these analyses, vol-
ume units expressed in microliters were
transformed to equivalent weight using
the formula presented by Dafni (1992):
Milligrams of sugar in volume of nectar
= (% sugar reading of the refratometer)/100
× volume in µ1 × Density of sucrose at
the obs. concentration
Density of sucrose = 1.59 mg/µl (Dafni
1992).
RESULTS
Available data (Table 2) indicate that
one L. nivalis bat, which is the largest
of the nectar-feeding bats in Mexico, can
consume the nectar produced by 2.48 in-
Table 1. Sugar concentration and total volume of nectar production in different paniculate Agave species. Modified from Rocha et al. 2006.
Species Concentration (%) Total volume (µl) Bat visits recorded
A. angustifolia 18−26 180 Yes
A. chrysantha 14−18 470 No
A. macroacantha -- 110 Yes
A. marmorata 9−37 576.61 No
A. palmerii 14−19 713 No
A. salmiana 12 102 Yes
A. subsimplex
22−25
40 Yes
Volume 36 (4), 2016 Natural Areas Journal 527
florescences of A. angustifolia (Table 2).
Approximately 89 Leptonycteris (or other
nectar-feeding bats species) could feed
each night during the six month flowering
period (Molina-Freaner and Eguiarte 2003)
in 1 hectare of agaves for tequila production
(with approximately 4444 plants) if only
5% of inflorescences (222 inflorescences)
are allowed to flower with a sugar concen-
tration of 26% and 180µl of total nectar
production (as in A. angustifolia) in 100
active flowers per night per inflorescence.
If the percentage of inflorescences from
cultivated plants increased up to 10%
(444 inflorescences), then the number of
individual bats fed would be a minimum
of 178. A case that illustrates the amount
of resources offered to flower visitors is
the Mezcal agave species A. marmorata,
which is capable of producing 576 µl of
nectar per flower at a sugar concentration of
37% (Ornelas et al. 2002). Thus, the offer
of floral rewards to bats by this Mezcal
species is much larger than that of other
species. Following the linear projection,
there is a two to one relationship among
them (Table 2).
Bat-Friendly Tequila Concept
As estimated above, if 5% of the agaves
in one hectare intended for the tequila
industry are allowed to flower, they can
provide food for 89 bats. According to
the National Chamber of Tequila Industry
(August 2015), there are about 105,000 ha
of A. tequilana Weber var blue cultivated
in appellation of origin territory (Cámara
Nacional de la Indistria del Tequila 2015).
Thus, the amount of potential nectar-feed-
ing bats feeding on these fields could be
as high as 9,345,000 during the four-
month flowering period (Gentry 1982), or
2,336,250 bats each month. The greater the
number of agaves that are allowed to flower,
the greater the number of pollinators that
can be sustained.
In addition, given that cultivated blue
agaves have extremely low genetic diver-
sity (Eguiarte et al. 2013), fertilization
of flowers of cultivated agaves and some
wild individuals of Agave tequilana, often
found in the barrancas and other landscapes
close to many of these fields, will likely
help recover genetic variation.
DISCUSSION
There are about 750 species of plants polli-
nated by bats in the world (Kunz et al. 2011)
and around 360 species inhabit tropical
America. Most records of bat-pollinated
families are Cactaceae, Bignoniaceae,
Bombacoidea (a clade of the Malvaceae)
and in the genus Agave (Arizmendi et al.
2002). It has been suggested that the loss
or decrease in nectar-feeding bat popula-
tions can cause a negative impact on some
cultivated plants as well as wild plant
communities (Allen-Wardell et al. 1998).
Farmers do not allow flowering of several
species of cultivated agaves so pollination
dynamics in many species is disrupted,
but this has not been studied in detail.
The relationship between these cultivated
agaves and bats is unknown. In order to
ensure the future of agaves, nectar-feeding
bats, Mezcal, Tequila, and other related
products, data on the floral biology of
all cultivated and sustainably used Agave
species, and their relationship with bats,
are urgently needed. Direct measurements
of nectar production by flowers, number of
flowers, pollen production and fertilization,
and cross-breeding experiments of A. te-
quilana flowers should also be part of this
research agenda.
Some authors have reported that A. te-
quilana and A. americana produced just
a few viable seeds when they were tested
in self-pollination experiments (Esco-
bar-Guzmán et al. 2008). A. angustifolia
is self-incompatible or has very strong
inbreeding depression, thus, floral visi-
tors are essential for fecundity since they
move pollen between individuals (Rocha
et al. 2006). In the same sense, the role
of pollinators in outcrossing is crucial to
increase genetic diversity of commercial
varieties of A. tequilana Weber var. blue.
An increasing percentage of plantations
of A. tequilana Weber var. blue are being
severely affected by the bacterium Erwinia
caratovora (Jones) and the fungus Fusar-
ium oxysporum (Schlechtendal) (Small
and Catling 2002). The documented low
genetic diversity in blue agave may cause
greater vulnerability to attack by these
and other diseases and bacterial infections
(Eguiarte et al. 2013). And again, the role
of bats as pollinators may help solve this
serious issue.
Because the nectar-feeding bat species that
Table 2. Number of inflorescences required to feed one Leptonycteris nivalis bat (18,500 mg of food), considering 100 active flowers per night per inflorescence.
Species
Total production of
sucrose per flower per
night (mg)
N
umber of necessary
inflorescences to feed one
L. nivalis bat References
A. angustifolia 74.41 2.48
Molina-Freaner and
Eguiarte 2003
A. chrysantha 134.51 1.37 Rocha et al. 2006
A. marmorata 339.22 0.54 Ornelas et al. 2002
A. palmerii 215.39 0.85 Rocha et al. 2006
A. salmiana 19.46 9.5 Rocha et al. 2006
A. subsimplex 15.9 11.63 Rcoha et al. 2006
528 Natural Areas Journal Volume 36 (4), 2016
pollinate agaves move across the Mexi-
co-United States international border (in-
cluding L. nivalis, L. yerbabuenae, and C.
mexicana), conservation of these species is
particularly important and there should be a
bi-national strategy and effort to protect the
three species. Their movements are critical
for the survival and reproductive success
of the plants they feed on. The protection
of roosts and migratory routes that they
follow are also of utmost importance and
their foraging resources should be a prior-
ity conservation objective. Nectarivorous
bats forage in the areas of both continuous
habitats and fragments, thus migratory
bats help to maintain genetic connectivity
between the different fragments and plant
populations visited. It is, therefore, timely
that only in April of 2015, the need to
protect bats was recognized as a priority
by the federal governments of Canada,
Mexico, and the United States (US Fish
and Wildlife Service 2015).
The concept of environmentally friendly
products is gaining traction in the general
population. It opens a brand new door for
collaboration among producers, bottlers,
importers, conservationists, and consum-
ers. Given that Tequila is a two billion USD
a year industry, and that the economy of
40,000 families is linked to blue agaves
(and thus, indirectly to bats), it is in the
best interest of all stakeholders (from
small producers to industrial giants such
as Sauza, Cuervo, and Patron) and from
government to the individual consumer, to
protect the future of Tequila and Mezcal
agave crops under sustainable practices,
which incorporate protection to pollinators
and genetic sources as key safeguards.
This collaboration is already promoting
bat friendly products using species such
as A. cupreata (Trel. & A. Berger), a
species endemic to the states of Guerrero
and Michoacán that reproduces only sex-
ually through bat-mediated pollination.
Producers of A. cupreata-based mezcal
long ago adopted the practice of allowing
about 10% of the plants (they leave the
largest plants for this process) to flower
so that they obtain the seeds to plant the
next generation of agaves (E. Vieyra, pers.
comm.). Because of these conditions, A.
cupreata-based mezcal is, by definition,
bat friendly.
In addition, A. cupreata-based mezcal pro-
duced in central Michoacán is one of the
very few alcoholic beverages in the world
that does not come from monocultures, but
from thinned-out forests in which agaves
are interspersed (R. Medellin, pers. obs.).
The Mezcal Regulatory Council, and
other organizations including the Tequi-
la Interchange Project and the National
Autonomous University of Mexico, are
cooperating to ensure that these practices
do not only remain in place, but become
mainstream in the agave spirits industry.
Only consistent cooperation among all
the sectors involved, from conservation
professionals and land owners to the final
consumer, will secure the future of these
practices and, thus, of the very old (about
6−9 million years; Trejo 2013) and tightly
linked mutualistic interaction between
bats and agaves, as well as high quality
agave-derived spirits.
ACKNOWLEDGMENTS
The Tequila and Mezcal producers contact-
ed for this initial pilot phase of the project
have been not only essential, but absolutely
committed, to applying these practices
in their fields and we acknowledge their
dedication to it. Dr. V. Wojcik, guest editor,
and two anonymous reviewers provided
feedback that greatly improved our paper.
We also thank Dr. Enrique Scheinvar and
Dra. Niza Gamez for support in preparing
the distribution maps.
Roberto-Emiliano Trejo-Salazar studied
biology and conducted field work on the
pollination ecology of agaves as an un-
dergraduate. More recently he obtained a
Master Degree from Universidad Nacional
Autónoma de México with a titled thesis,
“Divergence Times in Phyllostomidae: Or-
igin of nectarivory.” Currently, he is a PhD
student working in the phylogeography of
Leptonycteris in Laboratorio de Ecología
y Conservación de Vertebrados Terrestres,
Instituto de Ecología, UNAM.
Luis Eguiarte Fruns is Senior Professor
at the Institute of Ecology UNAM. He
has conducted research about ecology
pollination and genetic population of many
agaves’ species. He also has developed
projects with other important crop plants
from Mexico, including maize (Zea mays)
and pumpkins (the genus Cucurbita). Now-
adays he is conducting a genome project
of Leptonycteris yerbabuenae.
David Suro-Piñera is the President and
Co-Founder of the Tequila Interchange
Project (TIP), a 501(c)3 nonprofit orga-
nization that advocates the preservation
of sustainable, traditional, and quality
practices in the industries of agave distilled
spirits. The work of the organization that
he presides facilitates the translation of
academic work, and sponsors research
projects such as the Bat Friendly Program.
TIP considers the Bat Friendly Project to
be fundamental in establishing sustainable
practices for the fragile ecosystem of bats
and agave.
Rodrigo Medellín is Senior Professor at
the Institute of Ecology UNAM, and has
conducted research for the conservation of
bats and other mammals for over 30 years.
His research seeks to inform and orient
policy and decision-making processes
in conservation. Partly, his work led to
delisting of Leptonycteris yerbabuenae in
Mexico. Rodrigo is Co-Chair of the Bat
Specialist Group of IUCN.
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