THERYA NOTES 2021, Vol. 2 : 140-142 DOI: 10.12933/therya_notes-21-50

Early observations on the use of termite nests by bats

Primeras observaciones sobre el uso de nidos de termitas por murciélagos

Robert M. Timm1*

1Natural History Museum & Biodiversity Institute and Department of Ecology & Evolutionary Biology, University of Kansas, Lawrence, KS 66045, U.S.A. E-mail: btimm@ku.edu.

*Corresponding author

The remarkable discovery of Neotropical round-eared bats (Phyllostomidae, Lophostoma) actively hollowing out cavities in termite nests for roosting sites has enabled researchers to explore several aspects of their previously unknown behavior.  We now know that round-eared bats excavate cavities in Nasutitermes nests that are actively used by the termites and the bats roost only in these cavities, as well as a number of other aspects of the bats’ behavior.  In the early 1800s, a British naturalist, Charles Waterton, observed and published that bats “clear out” and roost in termite nests, and how he was able to ascertain if a termite nest was being used by bats.  Waterton’s descriptions of this behavior have long been overlooked and now provide us with additional insights on the distribution and ecology of these poorly known bats.

Key words: Lophostoma; Nasutitermes; Neotropics; Phyllostomidae; roosting behavior; round-eared bats.

El notable descubrimiento de murciélagos de orejas redondeadas neotropicales (Phyllostomidae, Lophostoma) que habitan las cavidades en los nidos de termitas como sitios de anidamiento, ha permitido a los investigadores explorar varios aspectos desconocidos de su comportamiento. Ahora sabemos que los murciélagos de orejas redondeadas excavan cavidades en los nidos de Nasutitermes que son utilizados activamente por las termitas y que los murciélagos anidan exclusivamente en esas cavidades, entre otros aspectos de su comportamiento de los quirópteros. A principios de la década de 1800, un naturalista británico, Charles Waterton, publicó la observación de que los murciélagos hacen agujeros y se posan en nidos de termitas y cómo fue capaz de comprobar si un nido de termitas estaba siendo utilizado por murciélagos. La descripción por parte de Waterton de este comportamiento se ha obviado durante mucho tiempo y ahora nos proporciona información adicional sobre la distribución y la ecología de estos quirópteros poco conocidos.

Palabras clave: Anidamiento; Lophostoma; Nasutitermes; Neotrópicos; Phyllostomidae; murciélagos de orejas redondeadas.

© 2021 Asociación Mexicana de Mastozoología, www.mastozoologiamexicana.org

One of the remarkable discoveries on roosting behavior in bats is that the Neotropical round-eared bats of the genus Lophostoma (Chiroptera: Phyllostomidae) hollow out the nests of the termite genus Nasutitermes (Isoptera: Termitidae) for roosting sites. Nasutitermes termitaria are large, often 0.5 m or more in length and width, and often 2 or more meters off the ground on the trunks of trees. These nests provide both the termites and bats with a waterproof and warm refuge with a stable temperature regime, as well as providing the bats with a well-camouflaged daytime roost and maternity site. It is currently believed that at least three species of round-eared bats (Lophostoma brasiliense, L. carrikeri, and L. silvicola) roost exclusively in these arboreal termite nest cavities they have excavated. Recent authors have documented that round-eared bats roost only in active Nasutitermes termitaria that they regularly modify. Males excavate the cavities, cavity use is tied to social organization, associations stay together year-round, and perhaps the chemical defenses used by the termites contribute to reduced parasite load in the bats (Dechmann et al. 2004, 2005; Kalko et al. 2006; Dechmann et al. 2007; Timm and McClearn 2007; Dechmann and Kerth 2008; York et al. 2008).

Round-eared bats historically had been considered uncommon or rare and little was known about their behavior or ecology. Although it was reported that round-eared bats were occasionally found in termite nests, it was believed that they were roosting in cavities excavated by birds. In the first modern study of these bats, Kalko et al. (1999:349) wrote, “Possibly, the bats use termite nests opened by nesting birds such as trogons (Trogon sp.) or orange-chinned parakeets (Brotogeris sp.)”. The discovery in the early 2000s that round-eared bats hollow out arboreal termite nests for roosting sites was a breakthrough in unraveling the behavioral ecology of these species because they could be observed at the roost site and captured unharmed (Dechmann et al. 2004, 2005).

This roosting behavior and that round-eared bats actually modify the termite nests however, was first observed in the early 1800s and recent researchers seemingly were unaware of these observations. Charles Waterton (born 1785, died 1865), British aristocrat, explorer, and naturalist, described his observations of bats roosting in termitaria: “Independent of the hollow trees, the Vampires have another hiding-place. They clear out the inside of the large ants’ nests, and then take possession of the shell . . . we stopped under an ants’ nest; and, by the dirt below, conjectured that it had got new tenants . . . an Indian boy ascended the tree; but, before he reached the nest, out flew above a dozen Vampires” (Waterton 1879:319–320).

To Waterton, all bats were called vampires. He did know what true vampires (= Desmodus rotundus) were because he tried in vain to get them to feed on him (they frequently feed upon other members of his traveling party, especially younger people, but were disinclined to choose him). In the explanatory notes later in the book, “the large ant’s nest” he discusses were correctly attributed to termite termitaria; today we know this is the genus Nasutitermes.

Wateron traveled extensively throughout Guiana in 1812, 1816, 1820, and 1824 as well as in Brazil. His description of bats roosting in termite nests was presented as part of a chapter on his travels in 1824 although he seems to be summarizing observations from his earlier travels also. Now, two centuries later, we can more fully appreciate the observations of this early naturalist and note that he should be attributed with the discovery that Nasutitermes termitaria are actively modified and are an effective roost site for Neotropical round-eared bats.

The nearly two centuries between Waterton’s observations and the recent “rediscovery” of round-eared bats actively modified Nasutitermes nests highlights how cryptic the roost sites can be. When investigators develop a search image and with diligent searching of Nasutitermes nests, the cavities created by round-eared bats are visible. There is only a single opening of the cavity and it is always ventrally directed (Figure 1; Figure 2A, B). Not all cavities observed are occupied by a colony or singleton bat but bats are only found in active termite nests. Much remains to be learned about the roosting ecology, social behavior, and relationships among individuals that are found within a cavity; but Charles Waterton and more recent investigators provide us a route to explore this fascinating behavior.

Acknowledgements

I thank H. A. York for providing the images used as Figures 1 and 2 here that contribute significantly to our understanding of the roosting behavior in these bats. P. F. Foster’s efforts in providing outstanding logistic support for researchers and educational classes at Reserva Ecológica Bijagual de Sarapiquí, Heredia, Costa Rica is greatly appreciated. A. Romero provided the Spanish translation for the Resumen. Comments from D. McClearn and two anonymous reviewers improved earlier versions of this manuscript.

Literature cited

Dechmann, D. K. N., E. K. V. Kalko, and G. Kerth. 2004. Ecology of an exceptional roost: energetic benefits could explain why the bat Lophostoma silvicolum roosts in active termite nests. Evolutionary Ecology Research 6:1037–1050.

Dechmann, D. K. N., E. K. V. Kalko, B. König, and G. Kerth. 2005. Mating system of a Neotropical roost making bat: the white-throated, round-eared bat, Lophostoma silvicolum (Chiroptera: Phyllostomidae). Behavioral Ecology and Sociobiology 58:316–325.

Dechmann, D. K. N., E. K. V. Kalko, and G. Kerth. 2007. All-offspring dispersal in a tropical mammal with resource defense polygyny. Behavioral Ecology and Sociobiology 61:1219–1228.

Dechmann, D. K. N., and G. Kerth. 2008. My home is your castle: roost making is sexually selected in the bat Lophostoma silvicolum. Journal of Mammalogy 89:1379–1390.

Kalko, E. K. V., D. Friemel, C. O. Handley, Jr., and H.-U. Schnitzler. 1999. Roosting and foraging behavior of two Neotropical gleaning bats, Tonatia silvicola and Trachops cirrhosus (Phyllostomidae). Biotropica 31:344–353.

Kalko, E. K. V., K. Ueberschaer, and D. Dechmann. 2006. Roost structure, modification, and availability in the white-throated round-eared bat, Lophostoma silvicolum (Phyllostomidae) living in active termite nests. Biotropica 38:1–7.

Timm, R. M., and D. K. McClearn. 2007. The bat fauna of Costa Rica’s Reserva Natural Absoluta Cabo Blanco and its implications for bat conservation. Pp. 303–352 in The quintessential naturalist: Honoring the life and legacy of Oliver P. Pearson (Kelt, D. A., E. P. Lessa, J. A. Salazar-Bravo, and J. L. Patton, eds.). University of California Publications in Zoology 134:1–981.

Waterton, C. 1879. Wanderings in South America. The north-west of the United States, and the Antilles, in the years 1812, 1816, 1820, & 1824. Macmillan and Co., London, England.

York, H. A., P. F. Foster, M. F. Jones, W. H. Schwarz, and A. L. Vezeau. 2008. Observations of cavity-roosting behavior in Costa Rican Lophostoma brasiliense (Chiroptera: Phyllostomidae). Mammalian Biology 73:230–232.

Associated editor: Consuelo Lorenzo

Submitted: August 6, 2021; Reviewed: September 7, 2021.

Accepted: October 5, 2021; Published on line: October 18, 2021.

Figure 1. An adult female pygmy round-eared bat, Lophostoma brasiliense, that was observed as part of the roosting colony in the Nasutitermes nest illustrated in Figure 2.

Figure 2. A) Nest of Nasutitermes in the melastome Loreya mespiloides, at the Bijagual Ecological Reserve in the Caribbean lowlands of northeastern Costa Rica, containing a roosting colony of pygmy round-eared bats (Lophostoma brasiliense). Note the roost cavity opening on the underside of the nest. Foliage from a living epiphyte is incorporated into the termite nest. B) Four round-eared bats hanging in the roost cavity are visible from below. Fresh chewing on the termite nest is visible as the dark rough areas. See York et al. (2008) for additional details. All photographs courtesy of H. A. York.