Patterns of intranidal temperature fluctuation for Melipona beecheii colonies in natural nesting cavities

Intranidal temperature fluctuation was studied in colonies of Melipona beec heii, an economically important stingless bee from Yucatan, Mexico. Two fer al colonies nesting in tree cavities were used in the experiments. The broo d and storage pots inside the nests were monitored for temperature changes using a telethermometer. Ambient temperatures immediately outside the logs were recorded simultaneously with thermohygrometers. Temperatures were reco rded every hour for 24 h on four non-consecutive days. Differences between ambient temperatures and temperatures within nests were noted during the da y and night. In all cases temperatures in brood and storage pots area were different from the ambient temperature (P < 0.01). There was no significant relationship between intranidal and ambient temperatures during the day (0 9.00 h to 20.00 h) on all days of measurement (P > 0.01). However, during l ower ambient temperatures at night (21.00 h to 08.00 h) intranidal and ambi ent temperatures were significantly correlated (P < 0.01). These findings i ndicate that temperatures inside natural nesting colonies of M. beecheii re main relatively stable during the day, but tend to vary at night. Colony te mperatures at night may lag from 5-6 h behind ambient temperatures. Active temperature control in nests of M. beecheii thus seems unlikely, and theref ore the ability to ensure stable temperatures within the nest might be an i mportant factor limiting the successful adaptation of this species to hive culture.