Lesser Long-nosed Bats: Do They
Follow the Nectar Trail?
Contributed by Dr. Ginny Dalton, Bat Biologist
U.S. & Mexico
Leptos (lesser long-nosed bats) are nectivorous and frugivorous,
meaning they eat nectar and fruit. While they sometimes eat insects,
like most of the bats you probably know, in the spring time they feed
primarily on the nectar found in flowers. This means they must always
find flowers that are in bloom. Since flowers bloom at different times
of the year in different locations, the bats' food sources can change
with the seasons. The blooming calendar below shows some of the most
important nectar sources available to bats at different locations.
- Look at the blooming calendar along with your
range map to see how you'll answer this question: Does there
seem to be a nectar pathway across the bats' range that they
could follow to Arizona and New Mexico each spring?"
- After you compare the blooming calendar with the range map you made,
state your conclusion. THEN see the Traveling Bats facts at the bottom
of this page to see if they support your conculsion.
November through January:
There is a frost-free zone south of Sinaloa and Durango, Mexico. Tree morning
glories and wild tequila century plants bloom in the foothills of the Sierra
Madres as well as from nearby fields where the plants are cultivated as a
cash crop. Localities for these plants in bloom include Chapala, Jalisco
and Infiernillo, Michoacan. Peak blooming of these plants at these locations
is over by the end of April.
February through March:
In Sinaloa and in the "barrancas" of central and southern Sonoran,
nectar is available from flowers of the northern-most tree morning glories
and bacanora century plants. (The "barrancas" are similar to the
Grand Canyon. The local people make bootleg mescal, a local form of tequila,
from these century plants.) Localities for these plants in bloom include Pericos
and Concordia, Sinaloa.
Giant columnar cacti that Leptos are known to feed upon are in bloom in western
Mexico from the northern part of Sinaloa (Pericos) southward through the southern
part of Nayarit (Nayar). By early May, peak blooming in those areas for those
cacti is over. Agaves do not begin to flower in those areas until late May/early
The majority of the saguaro cacti are in bloom from southern Sonora, Mexico
northward into southern Arizona. Early May to late June is during the peak
of cactus flowering. Localities for these plants include Guaymas and Carbo
in Sonora and Ajo in Arizona. These cacti are not located in Portal, Arizona.
The fruit of the giant columnar cacti begin to ripen in the same
locations as are mentioned in May. In addition, Palmer and Parry's
agaves begin to bloom
in southeastern Arizona (Portal and Sierra vista) and southern New Mexico (Animas).
Each flowering stalk, or "panicle", of these agaves produces as much
as a cup of nectar! (These wild century plants were
historically a major food source for Mescalero Apaches.)
July and August:
In mid to late July, in the U.S., century plants are in bloom in the mountainous
regions of southwest Arizona (e.g. Portal and Sierra Vista); namely the Chiricahua
Mountains, Huachuca Mountains and the Santa Rita mountains. Near Ajo, Arizona,
the peak flowering and fruiting is past, although some are still produced.
Agaves are more scarce in this region. In Mexico, agaves that bats feed upon
bloom from July through late September/early October in the state of Sonora.
September and October:
Agaves in Arizona, New Mexico and northern Sonora have passed the peak flowering.
More agaves are now blooming in
southern Sonora, western Chihuahua, Durango and Jalisco (e.g. Chapala).
Traveling Bats: Facts About Arrivals
Does the following information support the idea that the lesser long-nosed bats
do indeed migrate northward as their food resources begin to bloom? Explain.
- Bats have been found in the roosts (or captured nearby) in Chapala, Jalisco
and Infiernillo, Michoacan in November and December. They are usually gone
from those roosts by March.
- Roosts located at Pericos and Concordia, Sinaloa do not have bats arrive
until late February through early March.
- By April, bats have arrived at in Alamos and Guaymas, Sonora.
- By late April and early May, bats have arrived at the Bania Kino and
Carbo, Sonora roosts, plus the roosts near Ajo, Arizona.
- In August, bats are found in the western part of Arizona (Portal) and
eastern New Mexico (Animas).
- In September, bats are gone from the U.S. and have been seen in the vicinity
of Pericos, Sinaloa.