Sympatric woodland Myotis bats form tight-knit social groups with exclusive roost home ranges (dataset)

The article relating to this dataset is available in ORE: http://hdl.handle.net/10871/15799Dataset associated with the PLOS journal article with the same title. The two sets of data in the Excel file were used to create the networks in the Tiff file.Natural Environment Research Council (NERC

Sympatric woodland Myotis bats form tight-knit social groups with exclusive roost home ranges

Background: The structuring of wild animal populations can influence population dynamics, disease spread, and information transfer. Social network analysis potentially offers insights into these processes but is rarely, if ever, used to investigate more than one species in a community. We therefore compared the social, temporal and spatial networks of sympatric Myotis bats (M. nattereri (Natterer's bats) and M. daubentonii (Daubenton's bats)), and asked: (1) are there long-lasting social associations within species? (2) do the ranges occupied by roosting social groups overlap within or between species? (3) are M. daubentonii bachelor colonies excluded from roosting in areas used by maternity groups? Results: Using data on 490 ringed M. nattereri and 978 M. daubentonii from 379 colonies, we found that both species formed stable social groups encompassing multiple colonies. M. nattereri formed 11 mixed-sex social groups with few (4.3%) inter-group associations. Approximately half of all M. nattereri were associated with the same individuals when recaptured, with many associations being long-term (>100 days). In contrast, M. daubentonii were sexually segregated; only a quarter of pairs were associated at recapture after a few days, and inter-sex associations were not long-lasting. Social groups of M. nattereri and female M. daubentonii had small roost home ranges (mean 0.2 km2 in each case). Intra-specific overlap was low, but inter-specific overlap was high, suggesting territoriality within but not between species. M. daubentonii bachelor colonies did not appear to be excluded from roosting areas used by females. Conclusions: Our data suggest marked species- and sex-specific patterns of disease and information transmission are likely between bats of the same genus despite sharing a common habitat. The clear partitioning of the woodland amongst social groups, and their apparent reliance on small patches of habitat for roosting, means that localised woodland management may be more important to bat conservation than previously recognised

Distribution of a) <i>M. nattereri</i> both sexes and b) female <i>M. daubentonii</i> social groups in Wytham Woods.

<p>Roosts used by bats, and home range estimates are coloured according to social group - colours are comparable to Figure 2, panels a) and c) – symbols indicate colony size and roosts identified by radio-tracking. Roost home ranges are estimated using 100% minimum convex polygons (MCPs). MCPs exclude roosts occupied by a single individual (<i>M. nattereri</i>, n = 42; <i>M. daubentonii</i>, n = 44) or separated by over 1 km from a roost of the same social group (n = 1 for each species). Four adult female <i>M. daubentonii</i> were radio-tracked; two from each of two social groups. The daytime roosts (including trees) used by these individuals are indicated by asterisks and are coloured according to the social group to which they belonged.</p

Social network visualisation a) male and female <i>M. nattereri</i>, b) male and female <i>M. daubentonii</i>, c) female <i>M. daubentonii</i>, and d) male <i>M. daubentonii.</i>

<p>a) <i>M. nattereri</i> male (n = 85) and female (n = 214), modularity  = 0.74, b) <i>M. daubentonii</i> (n = 344), modularity  = 0.66, c) female <i>M. daubentonii</i> (n = 145), modularity  = 0.67, d) male <i>M. daubentonii</i> (n = 199), modularity  = 0.64. Nodes represent individual bats (males, circles; females, triangles) and associations are represented by the lines that join them. Colours indicate the assignment of individuals to social groups using the Girvan-Newman algorithm. Colours do not correspond between panels. Colours in a) and c) are comparable to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0112225#pone-0112225-g003" target="_blank">Figure 3</a>. The position of individuals within these networks indicates their position in social space and is not an indication of an individual's geographical location.</p

Lagged association rates within and between sexes of <i>M. daubentonii</i> (left) and <i>M. nattereri</i> (right).

<p>Standard error is calculated by jackknifing over a 30-day period.</p