Use of Mauritia flexuosa (Arecaceae) leaves as day roost by the Dwarf Little Fruit Bat Rhinophylla pumilio (Phyllostomidae) in Mato Grosso, Brazil

Abstract

We describe a group of Dwarf Little Fruit bats (Rhinophylla pumilio) using the Buriti palm (Mauritia flexuosa) as day roost in a Cerrado area in Cuiabá, Mato Grosso, Brazil. With ten individuals roosting under a dry Buriti palm leaf, we estimate that the group was composed of five females and their young. This is the first record of R. pumilio using leaves of M. flexuosa, and the third publication reporting the use of leaves of this palm as shelter by Phyllostomidae fruit bats. RESUMO Neste estudo, descrevemos um grupo de morcegos da espécie Rhinophylla pumilio utilizando a palmeira buriti (Mauritia flexuosa) como abrigo diurno em uma área de Cerrado em Cuiabá, Mato Grosso, Brasil. Com dez indivíduos empoleirados em uma folha seca de buriti, nós estimamos que este grupo era composto de cinco fêmeas e seus filhotes. Este é o primeiro registro do uso de folhas de M. flexuosa por R. pumilio e é a terceira publicação a reportar o uso de folhas de buriti como abrigo para morcegos Phyllostomidae. The Dwarf Little Fruit bat, Rhinophylla pumilio Peters, 1865, is a small phyllostomid that lives in the humid forests of cis-Andean South America, from Colombia and Venezuela to southeastern Brazil. This frugivorous bat uses leaf tents and unmodified foliage as day roosts, but it may occasionally roost in culverts and inside buildings. In this note, we report the first case of R. pumilio using leaves of the Buriti palm (Mauritia flexuosa) as day roost in a Cerrado vegetation area. Based on the observed roosting group, we also comment on group behavior and reproduction of this bat species. On December 11, 2019, while setting mist nets for birds, we found a group of R. pumilio roosting under a dry leaf of a Mauritia flexuosa (Arecaceae) palm. The leaf did not appear to have any modification, nor did it show signs of biting (Figure 1). The observation site is a riverine forest within a Cerrado vegetation type at Ecoville da Chapada, Cuiabá, Mato Grosso (Brazil), bordering Parque Nacional da Chapada dos Guimarães (15° 11’ 21.0” S; 55° 56’ 19.4” W; ca. 290 m above sea level). Recibido el 22 de febrero de 2020. Aceptado el 4 de junio de 2020. Editor asociado: Mariano Sánchez. Versión on-line ISSN 2618-4788 http://doi.org/10.31687/saremNMS.20.0.15 Guilherme S. T. Garbino, Vitor Q. Piacentini, Rogerio Vieira Rossi, Thiago B. F. Semedo N OTAS S O B R E M A M í F E RO S S U DA M E R I C A N O S 3 A total of 10 bats were observed, but an individual flew away before the photograph was taken (Fig. 1). We identified the species as R. pumilio based on the central chin protuberance bordered by elongated fleshy pads, uniformly-colored noseleaf, brownish ears with whitish inner base, and olive-brown pelage. Our assumption that the photographed bats were R. pumilio is reinforced by the capture of an adult male on December 10, 2019, in the same area that the roosting group was recorded, which showed the same external characteristics described above. The collected specimen was captured using ground-level mist-nets, and handled following the guidelines of the American Society of Mammalogists (Sikes et al. 2016). It was deposited as a fluid-preserved specimen in the mammal collection of the Coleção Zoológica da Universidade Federal de Mato Grosso, Cuiabá, under the number UFMT 4890. The forearm length of the captured specimen is 34.2 mm, there is no diastema between I2 and C, the I1 has a cingular style, and the uropatagium is not conspicuously hairy, allowing us to determine it as R. pumilio. Additionally, R. pumilio is the only non-Stenodermatinae phyllostomid known to regularly use foliage as roosts. Because parental care in Rhinophylla pumilio is carried out exclusively by the mother, we assumed that the larger animals with olive-brown pelage were females, and the smaller individuals with grayish pelage were their young. If the individual that flew away is accounted for, the roosting group consisted of ten bats, of which five were adult females and five were juveniles (we discard the possibility of the animal that escaped being a male because the group was left with five juveniles and four adults). The bats were huddled in a central position relative to the leaf lamina, and close to the leaf’s petiole (Fig. 1). Day roosts of R. pumilio in unmodified foliage are documented in at least 16 plant species, of which four are palm trees (Arecaceae): Astrocaryum sciophilum, Attalea attaleoides, Jessenia bataua, and Mauritia flexuosa (Table 1). We only found two other mentions of Mauritia leaves used as roosts by frugivorous leaf-nosed bats in the literature: an observation of Artibeus lituratus roosting under Mauritia sp. leaves in an urban area in southeastern Brazil, and records of unoccupied umbrella tents in M. flexuosa leaves on the island of Trinidad. Considering adult individuals only, the size of the group recorded here is within the expected for R. pumilio. In French Guiana, group sizes ranged from 2 to 7 individuals, and in southeastern Brazil limited observations have recorded only roosting pairs. Reproductive data for the Dwarf Little Fruit bat is scarce, and no clear pattern can be defined for the species. We assume that the females reported in this study were lactating due to the presence of younger animals attached to them. The lactating females of this study were recorded in the rainy season (early December), therefore births must have occurred by November/December. In the Amazon of south-western Colombia, pregnant individuals have been recorded in May and July, and lactating individuals were captured in April, June, and December. In the Amazon of southern Venezuela, pregnant or lactating R. pumilio were found in December. Both in the Colombian and Venezuelan localities, there is a fairly constant rainfall volume throughout the year, so reproduction would not be correlated with the climatic season. In the Amazon of Brazil, pregnancies have been recorded in March and June, and lactating females in the dry season in August. In Espírito Santo, southeastern Use of Mauritia flexuosa leaves as day roost by the Dwarf Little Fruit bat Rhinophylla pumilio in Mato Grosso, Brazil N OTAS S O B R E M A M í F E RO S S U DA M E R I C A N O S 4 Figure 1. Groupof Dwarf Little Fruit bats (Rhinophylla pumilio) roosting under a Buriti palm (Mauritia flexuosa) dry leaf. A) lateral view of the leaf; B) ventral view of the leaf showing the group of R. pumilio with four adults (ad) and five juveniles (ju), and a detail of the face of one of the adult bats. Guilherme S. T. Garbino, Vitor Q. Piacentini, Rogerio Vieira Rossi, Thiago B. F. Semedo N OTAS S O B R E M A M í F E RO S S U DA M E R I C A N O S 5 Brazil, pregnant females were captured during the rainy season between December and January. Our reproductive data suggests a pattern in central Brazil similar to what has been observed in southeastern Brazil, with births occurring in the rainy season when fruits are most abundant. Most of what is known about the ecology of the Dwarf Little Fruit bat is from rainforest areas. As fruit seasonality is an important factor in determining the reproductive patterns of tropical bats, more studies on the ecology of frugivorous bats from Table 1. Foliage roosts used by Rhinophylla pumilio throughout its distribution, with the case reported herein marked in bold. Plant species Family Roost type Locality Reference Philodendron fragrantissimum Araceae leaf tent French Guiana, Nouragues Henry and Kalko (2007) P. melionii Araceae leaf tent French Guiana, Nouragues and St. Elie Charles-Dominique (1993) P. ornatum Araceae leaf tent French Guiana, Nouragues Henry and Kalko (2007) P. ornatum Araceae leaf tent French Guiana, St. Elie and Nouragues Charles-Dominique (1993) Rhodospatha latifolia Araceae leaf tent French Guiana, Nouragues Charles-Dominique (1993) Attalea attaleoides Arecaceae unmodified leaf French Guiana, St. Elie Charles-Dominique (1993) A. attaleoides Arecaceae leaf tent French Guiana, St. Elie Charles-Dominique (1993) Atrocaryum sciophilum Arecaceae leaf tent French Guiana, Paracou, Nouragues, and St. Elie Charles-Dominique (1993); Simmons and Voss (1998) A. sciophilum Arecaceae unmodified leaf French Guiana, Nouragues Henry and Kalko (2007) Jessenia bataua Arecaceae unmodified young leaf French Guiana, Nouragues Henry and Kalko (2007) Mauritia flexuosa Arecaceae unmodified dry leaf Brazil, Mato Grosso, Cuiabá This study Bromeliaceae sp. indet.* Bromeliaceae unmodified leaf French Guiana, Nouragues Charles-Dominique (1993) Cyclanthaceae sp. indet.* Cyclanthaceae unmodified leaf French Guiana, Nouragues Charles-Dominique (1993) Heliconia sp. Heliconiaceae leaf tent Brazil, Espírito Santo Zortéa (1995) Sterculia sp. Malvaceae leaf tent French Guiana, Nouragues Charles-Dominique (1993) Musa sp. Musaceae leaf tent Brazil, Espírito Santo Zortéa (1995) Phenakospermum guyannense Strelitziaceae leaf tent French Guiana, Paracou Simmons and Voss (1998) P. guyannense Strelitziaceae unmodified leaf French Guiana, Paracou Simmons and Voss (1998) Cecropia obtusa* Urticaceae unmodified dry leaf French Guiana, Nouragues Charles-Dominique (1993) C. sciadophylla Urticaceae unmodified dry leaf French Guiana, Nouragues Henry and Kalko (2007) * used as roost after experimental removal of leaf tents (Charles-Dominique 1993). Use of Mauritia flexuosa leaves as day roost by the Dwarf Little Fruit bat Rhinophylla pumilio in Mato Grosso, Brazil N OTAS S O B R E M A M í F E RO S S U DA M E R I C A N O S 6 the drier and more seasonal Cerrado habitats are necessary, to verify the existence of intraspecific differences between populations living in areas with different climates.