The impact factors of the mid-emergence time of V.
sinensis
We recorded 91 mid-emergence events of V. sinensis , only two
events occurred before sunset. The difference between mid-emergence time
and sunset ranged from −4 to 62 min. Here, the positive values meant
mid-emergence events happened after
sunset. The light intensity of mid-emergence events was approximately
0.6–400 lux (40.46±68.72). In addition, 90.11% (82/91) mid-emergence
events occurred when the light intensity was below 100 lux, and 45.05%
(41/91) of mid-emergence events occurred when the light intensity was
below 10 lux.
Our analyses indicated that the best model of variation in mid-emergence
time of V. sinensis used LIFE, LISS, LS, and PHNHM as the
predictor variables (Table 3). Further, model averaging revealed that
the four predictor variables were also significantly associated with the
mid-emergence time of V. sinensis (Table 4). First, differences
between the mid-emergence time and sunset time were significantly and
negatively associated with light intensity of first emergence (linear
regression: t = −6.73, P < 0.001, Fig. 2b;
curvilinear regression: t = −9.974, P < 0.001,
Fig. 5b). That is, the higher the light intensity of first emergence,
the earlier the mid-emergence time of V. sinensis. Second, a
significant and positive correlation between the mid-emergence time and
light intensity at sunset was observed (t = 5.882, P< 0.001; Fig. 2a). Third, a significant difference in the
mid-emergence time was detected between lactation and post-lactation
(t = −2.903, P = 0.004; Fig. 2d). During the lactation
period, V. sinensis departed earlier from the roost than during
the post-lactation period (Fig. 2d). Specifically, the mid-emergence
events started approximately −4–40 (15.435±10.051) min after sunset
during the lactation period. In contrast, the mid-emergence events
started about 12–62 (29.511±9.201) minutes after sunset during the
post-lactation period. Finally, bats also departed from the roost
earlier when predators were hunting (t = −3.713, P< 0.001; Fig. 2c). We found that predators were hunting bats
during 36 mid-emergence events. Consistent with the results of the
hierarchical partitioning analysis, the independent contributions of
LIFE, LISS, LS, and PHNHM were 46.41%, 13.60%, 22.74% and 17.25%,
respectively (Fig. 4b).