Phyllostomus hastatus
Greater Spear-nosed Bat
Physical Description
Phyllostomus hastatus has a body length of about 100-130 mm and adult weight
of about 50-100 grams. Forearm length ranges from 83 to 95 mm and the wingspread
averages 457 mm. P. hastatus is generally dark brown or blackish brown overall, and
grayish, reddish, or chestnut brown above and paler below (Nowak 1997). Male body
mass is 15% greater than the female. Young bats are the size of adults by the eighth
week and start to fly at 6-7 weeks (Stern 1998).
Distribution
P. hastatus is widely distributed in the Neotropics (Kunz 1998) and can be found
from Honduras to Paraguay and southeastern Brazil to Trinidad (Nowak 1997).
P. hastatus can often be found near streams and in other moist places, but may be found
in drier areas as well. This species seems to inhabit both forested and open areas.
Roosting sites include caves, culverts, hollow trees, holes in trees, and buildings. P.
hastatus is also frequently found near gardens where bananas are grown (Nowak 1997).
Ontogeny and Reproduction
P. hastatus forms harems made up of several adult females. There is one adult
male and sometimes a few sub-adult males associated with each harem. Males defend
females or their roosts from other males. The mating period runs from November
through January. Females have one pup in April-May (Kunz 1998). Females of the
harem give birth synchronously. The mating system is resource-defense polygyny.
Males may father more than 50 offspring (Stern 1998).
Porter and Wilkinson (2001) state that social cues substantially modify
reproductive timing, and that these cues result in birth synchrony. This synchrony cannot
be explained by environmental factors alone, as in other bat species. It has been
suggested that chemical or tactile cues from the male in each harem might co-ordinate
reproduction among females. There is also a strong effect of rainfall on timing of
reproduction. P. hastatus has a 5-month gestation (Porter and Wilkinson 2001). Young
weigh about 13 grams at birth. They are carried with the mother for several days, and are
then left at the roost while the mothers forage. Young begin to fly in the cave at about six
weeks and are able to go out on their own at 2 months. After several months, juveniles
disperse and young females from different clusters form new stable harems (Nowak
1997).
Ecology and Behavior
P. hastatus forms “highly-structured” groups of 10-100 individuals (Kunz 1998).
Females forage in groups depending on the season. They use a special screech call to
form foraging groups, which is group specific, meaning only certain individuals respond.
Feeding in groups of the same roost mates may improve the ability to defend a
predictable feeding site (Wilkinson 1998).
Most researchers of P. hastatus agree that it is an omnivorous species, but there is
disagreement on what makes up the major portion of their diet. According to Wilkinson,
they have a seasonal diet, consisting of insects, Rollinia multiflora, Cecropia peltata,
wild cucumber fruit, and balsa pollen (1998). According to Koay, they prefer meat and
may prey on small vertebrates, including other bats (2002). Kalko found that they eat
fruit regularly (1998). Fleming found that P. hastatus is insectivorous with 96% of
stomach contents insects and only 4% fruit (Fleming 1972).
P. hastatus uses echolocation to find fruit. This species forages over 80 ha and
may fly many kilometers from roosting to feeding sites. They use short, downward,
frequency-modulated, multiharmonic calls with a low intensity and short duration to find
fruit. This type of call is good for exact localization of target while in flight (Kalko 1998).
Remarks
P. hastatus has no documented predators, but several large owls and hawks take
prey of similar size (Wilkinson 1998).
Literature Cited
Fleming, T.H., E.T. Hooper, and D.E. Wilson. 1972. Three Central American Bat
Communities: Structure, Reproductive Cycles, and Movement Patterns. Ecology,
53: 555-569.
Kalko, V.K.E., and M.A. Condon. 1998. Ecolocation, olfaction and fruit display: how
bats find fruits of flagellichorous cucurbits. Functional Ecology, 12: 364-372.
Koay, G., et.al. 2002. Hearing in American leaf-nosed bats. Hearing Research, 171: 96102.
Kunz, T.H., S.K. Robson, and K.A. Nagy. 1998. Economy of harem maintenance in the
greater spear-nosed bat, Phyllostomus hastatus. Journal of Mammalogy, 70: 631642.
Nowak, R.M. Walker’s Mammals of the World. Johns Hopkins University Press. 1997.
online:http://www.press.jhu.edu/books/walkers_mammals_of_the_world/chiropte
ra/chiroptera.phyllostomidae.phyllostomus.html.
Porter, T.A., and G.S. Wilkinson. 2001. Birth synchrony in greater spear-nosed bats
(Phyllostomus hastatus). Journal of Zoology, 253: 383-390.
Stern, A.A., and T.H. Kunz. 1998. Intraspecific variation in postnatal growth in the
greater spear-nosed bat. Journal of Mammalogy, 79: 744-763.
Wilkinson, G.S. and J.W. Boughman. 1998. Social calls and foraging in greater spearnosed bats. Animal Behavior, 55: 337-350.
Reference written by Stephanie Stewart, Biology 378 (Mammalogy), University of
Wisconsin – Stevens Point. Edited by Christopher Yahnke. Page last updated August 15,
2005.
http://www.press.jhu.edu/books/walkers_mammals_of_the_world/chiroptera/images/ima
ge.mid.chiroptera.phyllostomidae.phyllostomus.hastatus.1.html
Bolivia, E.Peru, Ecuador, Colombia - Surinam, E.Brazil.
Phyllostomus hastatus (Pallas, 1767)
http://www.funet.fi/pub/sci/bio/life/mammalia/chiroptera/phyllostomidae/phyllostomus/i
ndex.html