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 cschwitzer@bristolzoo.org.uk • Johanna Rode eva.rode-2011@brookes.ac.uk:

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: