By: Jessica Browne and Alanna MacDonald Lizards!!!! By: Jessica Browne and Alanna MacDonald

Godfreya, Sihc, and Bulla The response of a sleepy lizard social network to altered ecological conditions Godfreya, Sihc, and Bulla

Introduction Social Network: direct and indirect associations between all members of a population Stability of these associations can vary - short term or long term partnerships (i.e. monogamy) Gain a better understanding of how social networks respond to environmental changes

Introduction Previous studies have typically involved comparisons of populations over ecological gradients There have been conflicting results Stanley & Dunbar (2013): in species of goat, social networks were stable among populations that varied in ecological conditions

Introduction Chaverri (2010): bat clustering behaviour differed across populations with different conditions Edenbrow et al. (2011): guppies showed differences in social behaviour in populations with higher predation risks Trend disappeared when predation was experimentally manipulated

Introduction Require long term study that tracks changes over time as there are ecological fluctuations More specifically, do social interactions within a population remain stable over changing ecological conditions?

Introduction Flexible populations are able to quickly adapt to ecological changes But populations that retain their social structure are protected from rapid changes that may not be beneficial in the long term

Introduction This study will examine the overall network stability, and the stability of different associations within a social network over 3 years that varied in ecological conditions Will examine the Sleepy Lizard

Introduction Sleepy Lizard large, long lived Australian lizard Occupies stable home ranges In the spring, they form a monogamous pair for 20 weeks before they mate Often re-establish those partnerships in subsequent years

Introduction Predictions: Rainfall influences abundance of flower that lizards feed on Reduced food makes the lizards less active Therefore, expected that intersexual pairing would be reduced in drier conditions

Introduction But may be forced to aggregate around food resources So predict that non-pairing interactions would increase in response to drier conditions and pairing interactions would decrease

Methods Conducted in a shrubland in Southern Australia from 2008 - 2010 Sample Size: 2008 N=47 (27 ♂, 20 ♀) 2009 N=58 (31 ♂, 27 ♀) 2010 N=60 (30 ♂, 30 ♀) Conducted from August to December Annual rainfall and temperatures were recorded © Google Earth

Methods A GPS logger and a step counter were placed on each lizard and used to measure activity and location The GPS recorded the location of the lizard every 10 minutes for 4 months of the year Lizards were found every 12 days to replace batteries

Methods The weight and snout-to-vent length was measured A regression was found to measure Lizard body condition © Laboratorie Informatique & Systema

Home Range and Activity Pattern Home Range was calculated by looking at the 95% minimum convex polygons, while accounting for overlap with other lizards A lizard was considered active if it took more than 10 steps in 2 minutes Two sample randomization test was used and mean difference in home range overlap was found

Social Networks GPS locations were monitored and any time the lizards were within 2 meters, this was considered social contact Since the GPS had a precision to 6 meters, anytime the lizards were within 14 meters was considered social contact

Network metrics used Many parameters were measured Mainly, encounter rate and the number of social connections of each lizard were analyzed

Social Network Structure Analysis Analyses were compared between years to investigate stability (lack of change) Mantel test was used Compared network metrics between years Examined intrasexual and intersexual relationships Picked 40 lizards to construct the networks

Results rainfall temperature

Results: Body Condition •Body Condition was significantly lower in 2008 (ANOVA p<0.001)

Results: Activity • Spent significantly more time active each year (ANOVA p<0.001) number of steps

Results: Home Range Home range area remained stable (p=0.1) More home range overlap in 2008 Follows predictions

Results: Associations Observed number of associations of each individual was compared to a model of random associations Observed number of associations was significantly lower than the random model Came into contact with fewer than half of the individuals they would be expected to by chance Avoidance of conspecifics

Results: Association Stability •Plotted associations of one year against associations from another year to test for correlations to determine how similar each year was •Male-female associations were correlated across all years – reflects the stability of pairing

Results: Association Stability •Male-Male interactions were correlated between 2009 and 2010 (the wetter years) •Different in 2008 •Female-Female interactions correlated between adjacent years

Results: Associations Strength Primary pair interactions: strongest interaction type in wet years lower in the dry year than the wet years Extra-pair interactions: significantly stronger in the dry year than wet years Intrasexual interactions: no different across years

Discussion Climatic changes made a significant difference in interactions, although the basic structure was maintained In drier years, lizards conserved energy by reducing foraging time Home range overlap increased during this time - likely so that lizards could remain in an area with plants

Discussion Lizards usually stayed within the same network positions Fewer strong linkages in the dry year (2008) There was less frequent intersexual contact Male-male interactions were common each year

Conclusions They had intended to look at climate change but not enough years were studied Dry years may be limiting food supplies and therefore animal behaviour Further study is needed

Questions?