Fig 1.
Timeline of data collection by month.
We recorded nocturnal activity from 5 nights before to 5 nights after the full moon of every month except October and November, where we recorded nocturnal activity from the full moon to 5 nights after the full moon due to delays in obtaining A. dorsata colonies. The colony observed each month is shown, as is the season to which each month belongs. We obtained minimum temperatures for every observation day through an online resource (https://www.wunderground.com/history/daily/in/bangalore/VOBL). In addition to the observations focused on the full moon, we also observed Colony 4 for two complete lunar cycles, indicated by the text above; illumination readings were collected every observation night during the January to February lunar cycle (lunar cycle 1).
Fig 2.
Daily foraging activity patterns of A. dorsata.
Daily foraging activity on the days of the (A) December full moon, (B) January full moon, (C) March full moon, and (D) May full moon are shown as representative examples of A. dorsata daily activity patterns. Purple shaded regions indicate twilight, gray shaded regions indicate night, and white indicates daytime. The red dotted line indicates moonrise, while the solid red line indicates moonset. Arrows on the January full moon panel (B) indicate times corresponding to the sample videos provided in the supplementary materials (S1 and S2 Videos). Figures depicting the daily foraging activity for every day of the January–February and March–April lunar cycles can be found in S1 Fig. Data were collected from Colony 3 in December, Colony 4 in January and March, and Colony 5 in May.
Fig 3.
Relationship between bee arrival rates and dance rates.
Regressions of number of bee arrivals against number of bee dances per census period are shown for (a) day time periods, (b) twilight time periods (both morning and evening), and (c) night time periods. Strong correlations were found between arrival and dance rates for all diel times (rs > 0.82 for all). Data from all five A. dorsata colonies are included in this analysis.
Fig 4.
Relationship between nighttime illumination and bee arrival rates.
A regression between environmental illumination at night and number of bee arrivals to the nest per census period is shown. Illumination had a significant positive effect on arrivals, such that as illumination increased arrivals also increased (rs = 0.56, P = 0.0084). Arrivals were seen even when illumination was recorded as 0 cd/m2 at the limit of the photometer’s sensitivity. Data shown here were collected exclusively from A. dorsata Colony 4.
Fig 5.
Estimated marginal mean arrival rates across moon phases.
Estimated marginal mean arrivals rates during different diel times are shown across moon phases. Activity was consistently the highest and equal during the day and twilight (all P > 0.05) except during the waning gibbous and waning crescent moons (P < 0.05) where more activity was seen during twilight time periods. Nocturnal activity was generally low compared to activity the rest of the day (P < 0.05), except the moon phases including and between the waxing gibbous and third quarter moons, where it was equal to activity seen during the day (P > 0.05). Error bars represent 95% confidence intervals. Data shown here stem exclusively from observations of A. dorsata Colony 4, and include only data collected during the lunar cycle observation periods from January 21, 2019 –February 19, 2019 and March 21, 2019 –April 19, 2019.
Fig 6.
Estimated marginal mean arrival rates in each lunar cycle.
Estimated marginal mean arrival rates during each diel time over both lunar cycles are shown. In both lunar cycles the highest number of arrivals were seen during twilight (P < 0.001), and the least number of arrivals were seen during the night (P < 0.001). An interaction was seen where nocturnal activity decreased but diurnal activity increased from the January lunar cycle to the March lunar cycle (P < 0.001). Error bars represent 95% confidence intervals. Data shown here stem exclusively from observations of A. dorsata Colony 4, and include only data collected during the lunar cycle observation periods from January 21, 2019 –February 19, 2019 and March 21, 2019 –April 19, 2019.
Fig 7.
Boxplots showing arrival rates during each diel time across seasons are shown. Nocturnal arrival rates were higher and diurnal arrival rates were lower in winter compared to spring/summer (P < 0.05), but did not differ between autumn and spring/summer or autumn and winter (P > 0.05). In both winter and spring/summer arrival rates were significantly different between every diel time, with twilight having the highest rates. Arrival rates were higher at night than during the day in winter (P < 0.05), which was not seen in any other season. Arrival rates during twilight was also higher than the nocturnal arrival rate in autumn (P < 0.05), but the arrival rates during twilight did not significantly differ between seasons (P > 0.6). The significance of all pairwise differences can be found in Table E in S1 File. Data shown here includes all observations from all five focal colonies studied over the course of the investigation.
Fig 8.
Relationship between minimum temperature and arrival rate.
A regression between minimum daily temperature and bee arrival rates throughout the day are shown. There was no relationship between minimum temperature and bee arrivals, with high activity seen even during the coldest nights in winter (P > 0.05). Data shown here includes all observations from all five focal colonies studied over the course of the investigation.