Natalus stramineus stramineus Gray 1834

P, S C., L, P A., G, H H., M, M N., L, K C. & C, J, 2007, B B, N L A, Occasional Papers of the Museum 271, pp. 1-20 : 12-13

Natalus stramineus stramineus Gray 1834

Specimens examined (12).— Dark Cave, 17°37'26.1"N, 61°45'12.1"W, 24 m, 12 ( TTU) .

Specimens captured/released (20).— Bryant’s Cave , 17°37'25.00"N, 61°45'18.86"W, 1; Dark Cave, 17°37'26.1"N, 61°45'12.1"W, 24 m, 2; New Cave, 17 .

Additional record.— Deer Cave , 17°38'14"N, 61°47'05"W (2007 photograph - Cindric).

These specimens represent the first record of the Lesser Antillean funnel-eared bat from Barbuda. There are conflicting views on the specific relationship among populations of the large funnel-eared bats occurring in the Lesser Antilles, Greater Antilles, Mexico, and Central America ( Varona 1974; Hall 1981; Koopman 1993; Arroyo-Cabrales et al. 1997; Dávalos 2005). Dávalos (2005) and Tejedor et al. (2005) presented evidence that unrecognized taxa of Natalus exist within currently named populations in the West Indies. Goodwin (1959), in his revision of members of the subgenus Natalus , restricted the type locality of Natalus stramineus to Antigua rather than Lagoa Santa, Minas Gerais, Brazil, as was done by earlier authors. This decision was reconfirmed by Handley and Gardner (1990) and Tejedor (2006). Tejedor (2006) restricted N. stramineus to the northern Lesser Antilles, ranging from Dominica to Anguilla, and in a canonical analysis of external and cranial characters, demonstrated that “the sample from Dominica is morphometrically distinct from that of the remaining islands.” Although Tejedor (2006) did not use it, the name N. s. dominicensis Shamel (1928) is available for the population on Dominica, leaving the nominate subspecies, N. s. stramineus , as the appropriate name to apply to the other populations in the northern Lesser Antilles, including those on Barbuda Table 1 presents length of forearm and seven cranial measurements for five males and five females collected on Barbuda in 2003. The sexes differed significantly only in length of the maxillary toothrow (P ≤ 0.01) in which males were larger. In three measurements (condylobasal length, postorbital constriction, and mastoid breadth), the sexes averaged the same size. In the remaining four measurements, males averaged slightly larger than females. Of the 17 animals netted in Dark Cave in 1994, six were non-reproductive males and 11 were non-reproductive females. An adult male and female hand-collected at Dark Cave in 1994 weighed 6.2 and 5.2, respectively, and had forearms lengths of 40.7 and 39.2, respectively. On 3 June 2003, eight males and six females were netted in Dark Cave, four of these females carried embryos with crown-rump lengths of 16, 20, 20, and 20. Four of the males captured on the same date had measurable testis lengths of 1, 1, 2, and 2. The two reproductively inactive females weighed 4.3 and 4.6, whereas the pregnant females weighed 4.5, 5.8, 6.1, and 6.5. The six males weighed an average of 4.8 (4.5-5.1).

Natalus stramineus is an obligate cave dweller ( Goodwin 1970), and was found in many of the large caves visited in 1994 and in large numbers at Dark Cave in 2003. It seems likely that N. stramineus needs dark, moist caves in which to roost ( Blankenship 1990; also see McFarlane 1986); certainly, it has been proposed that the high humidity of caves used as roosts is necessary to prevent dehydration of the delicate wing membranes of these bats ( Goodwin 1970). All of the N. stramineus collected in 2003 in Dark Cave were snared in an old mist net draped over the entrance into a side tunnel located approximately 10 m from a well-lit antechamber where humidity was 100% and the temperature exceeded above-ground surface temperature (33°C). We did not explore this 1-m diameter sidetunnel, but the cavity extended a considerable distance beyond the reach of our headlamps.

In the sinkhole, Deer Cave, three passages lead away from the five-meter high central chamber. Two of the passages were hot, low, dusty cavities that required some excavation to permit travel. The third passage was different from the other two in being rocky and it had discernible air movement. After a hands-andknees crawl of 15 m there was a small domed chamber wherein there were several hundred funnel-eared bats. In one photograph (Cindric) of a portion of this colony, at least 120 individuals can be counted, most of which are hanging separately. The passage became too small to pass beyond this chamber, although the air movement would indicate an additional opening to the surface.

Roost conservation is an obvious priority for this species, yet with Barbuda’s wealth of large moist caves and its small human population, populations of N. stramineus do not seem to be threatened and it is not surprising that the Barbuda population is among the largest that we have observed in the northern Lesser Antilles ( Pedersen et al. 1996, 2003, 2005, 2006; Genoways et al. 2007 a, 2007b; Larsen et al. 2007 a, 2007b).