Phyllostomus hastatus - Greater Spear-nosed Bat​

Image from Walker’s Mammals of the World

http://www.press.jhu.edu/books/walkers_mammals_of_the_world/chiroptera/images/image.mid.chiroptera.phyllostomidae.phyllostomus.hastatus.1.html

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).

Distribution of Phyllostomus hastatus.

http://www.funet.fi/pub/sci/bio/life/mammalia/chiroptera/phyllostomidae/phyllostomus/index.html

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: 96-102.

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: 631-     642.

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/chiroptera/chiroptera.phyllostomidae.phyllostomus.html. (Accessed: December 2, 2004).

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 spear-  nosed 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.