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Nest use and its implications for social organisation and conservation of the northern giant mouse lemur Mirza zaza, in Sahamalaza, northwestern Madagascar
Eva Johanna Rode1,2, K. Anne-Isola Nekaris2, Matthias Markolf3, Susanne Schliehe-Diecks3, Melanie Seiler1,4, Ute Radespiel5, Christoph Schwitzer1*
Author affiliations: 1 Bristol Conservation and Science Foundation, c/o Bristol Zoo Gardens, Clifton, Bristol, UK 2 Nocturnal Primate Research Group, Oxford Brookes University, Oxford, UK 3 German Primate Center, Göttingen, Germany 4 School of Biological Sciences, University of Bristol, Bristol, UK 5 University of Veterinary Medicine Hannover, Hannover, Germany
*Contact: • Christoph Schwitzer [email protected] • Johanna Rode [email protected]:
Table 1 Medians for five nest tree variables and comparison to used and random trees. Asterisks
indicate significant differences according to Mann-Whitney U tests between the respective column
and the nest trees.
Median
Nest
Used trees
Forest A
Used trees
Forest B
Random trees
forest A
Random trees
forest B
Height (m) 16.00 12.00** 12.00** 12.00(*) 13.00**
DBH (cm) 29.92 17.63 18.78 16.62(*) 15.28**
Canopy diameter (m) 8.50 6.00 6.00 6.00 5.00*
Lianas (no.) 15 2*** 2*** 2***
Connectivity (no.) 3 3 4 2
N 7 45 55 DBH: n = 164
Height and canopy
diameter: n = 65
228
Empty cells indicate where no data were available. Significance level was set to P < 0.0125 and
indicated by p < 0.05 (*), p < 0.01 **, p < 0.001 ***
Discussion
M3
M1
M2 M4
M5
M6
MS7
F2
FJ3
FS4
F5
FS1
Group 1:
R = 0.03
Group 4:
R = 0.20
Group 2:
R = 0.35
Group 3:
R = -0.11
Forest A Forest B
Fig. 1: Genetic composition of sleeping groups in two forest fragments. Circles:
females; boxes: males. Thick lines indicate likely first degree relatives. Arrows
pointing from parents towards their potential offspring. Mean relatedness for
each nest group is provided. Colours represent three different haplotypes that
differ in 1, 2 and 3 base pairs.
Introduction
• Nests are an important resource for nocturnal strepsirrhines
• Social organisation of nocturnal primates can be inferred from
nest group composition
• Mirza zaza (Kappeler et al. 2005) is a nocturnal lemur, body
mass 300 g, IUCN Red List Vulnerable (Rode et al. 2011)
• Aims of the study:
To investigate nest characteristics and preferences of M.
zaza towards nest trees and nest microhabitat in order to
provide information for effective conservation planning
To explore the social organisation of M. zaza as inferred
by nest group composition
Methods
• Study site: Ankarafa Forest, Sahamalaza National Park, northwest
Madagascar, during dry season from May to July 2011
• Capturing Mirza zaza, taking DNA samples, fitting radio-collars
• Identifying nest trees by following animals and direct observation
• Describing nests
• Comparing nest trees, trees animals used during nightly activity (as
identified during radio-tracking), random trees, nest microhabitat (using
centred-quarter method) and used and random microhabitat (variables see
Table 1), in two forest fragments
• Pairwise relatedness for all possible dyads were investigated based on
five nuclear microsatellite loci and mitochondrial haplotypes using the
software Kingroup 2.10.12.02
Results – NESTS • Seven nests used by three nest groups
• Maximum 3 nests used per group in a 50 day period
• Nests were well covered by canopy and located near the
tree trunk a few meters below the tree top
• Animals preferred large and tall nest trees with many
lianas if compared to trees during nightly activity and
random trees (Table 1)
• No differences were found between
nest microhabitat, used and
random microhabitat
Results – Nest groups • Two to four animals including several adult males shared
group-exclusive nests
• Relatedness of co-sleeping dyads (N=14, mean r=0.06) was higher
than relatedness within non-co-sleeping dyads (N=77, mean r = -0.12,
Wilcoxon rank sum test: W = 471, p-value = 0.04)
• Mean relatedness within nest groups varied (Fig. 1)
• According to the comparison of individual genotypes, r-values and mt-
haplotypes, we found eight dyads that reach a level of relatedness compatible
with first degree relatives (Fig. 1)
• Co-sleeping adult males were unrelated except for one dyad (M1/M3) with an r-
value of 0.72 and a high P-value (P = 0.0015), which indicates full-siblings
• Predation pressure might explain hidden and high position of nests
• Additionally, strong and large nest trees might provide protection from
environmental forces (e.g. cyclones)
• Low number of nests used might suggest strong preferences and/or scarcity of
suitable nest sites
• Due to low sample size and only five loci, kinship results are preliminary
• The presence of closely related and unrelated males sharing a nest suggests
social nests groups instead of rearing, family or mating groups (Radespiel et al.
2009)
• Gregarious nesting behaviour may be explained by behavioural thermoregulation
• Sleeping associations of unrelated males are rarely observed (but see Weidt et
al. 2004) and may indicate a mating strategy (Radespiel et al. 2000) but may
also be caused by limitation of crucial resources
Conclusion
• Mirza zaza shows a preference
towards certain nest sites and uses
only few nest trees
• Animals including adult unrelated
males sleep in gregarious exclusive
social nest groups
• We recommend the protection of
forest fragments with large and tall
trees and discourage selective
logging
• Kappeler PM, Rasoloarison RM, Razafimanantsoa L, Walter L, Roos C (2005), Primate Report 71:3-26 • Queller DC, Goodnight KF (1989), Evolution: 258-275 • Radespiel U (2000), Am J Primatol 51 (1):21-40 • Radespiel U, Juric M, Zimmermann E (2009), Behaviour 146:607-628 • Rode EJ, Nekaris KAI, Schwitzer C, Hoffmann M (2011), www.iucnredlist.org. Accessed 25 October 2011 • Weidt A, Hagenah N, Randrianambinina B, Radespiel U, Zimmermann E (2004), Am J Phys Anthropol 123 (1):40-51
References:
Thanks to: