The impact factors of first emergence time of V.
sinensis
A total of 140 first emergence events of V. sinensis were
recorded. There were no significant differences in first emergence time
among the three consecutive years (Kruskal-Wallis test: H =
2.804, P = 0.246). In 49 records, V. sinensis started to
emerge before sunset at dusk. Differences between sunset and first
emergence ranged from −36 to 33 min (4.49 ± 13.23). Here, the negative
values meant that first emergence events started before sunset.
Our analyses indicated that the best model describing the variation in
first emergence time of V. sinensis used LIFE, LISS, and LS as
the predictor variables (Table 1). Further, model averaging revealed
that the three predictive variables were also significantly associated
with the first emergence time ofV. sinensis (Table 2). Differences between first emergence time
and sunset time were significantly and negatively associated with light
intensity of first emergence (linear regression: t = −11.447,P < 0.001, Fig. 1b; curvilinear regression: t =
13.728, P < 0.001, Fig. 5a). In other words, the higher
the light intensity at first emergence, the earlier the first emergence
of V. sinensis. Moreover, differences between first emergence
time and sunset time were significantly and positively associated with
light intensity at sunset (t = 7.801, P < 0.001;
Fig. 1a). Finally, significant differences in the first emergence time
were detected between lactation and post-lactation (t = −4.779,P < 0.001; Fig. 1c). During the lactation
period, V. sinensis departed
earlier from the roost than during the post-lactation period (Fig. 1c).
Specifically, 65.67% of first emergence events (44/67) started before
sunset during the lactation period. In contrast, only 6.85% of first
emergence events (5/73) were observed before sunset during the
post-lactation period. A Chi-square test of independence showed that the
first emergence events had a higher probability of occuring before
sunset during the lactation period (χ 2 = 26.34,P = 2.86×10-7). Consistent with the results of
the hierarchical partitioning analysis, the independent contributions of
LIFE, LISS, and LS were 53.86%, 25.54%, and 14.17%, respectively
(Fig. 4a).