Social versus individual behaviour: a comparative approach to thermal behaviour of the honeybee ( Apis mellifera L.) and the American cockroach ( Periplaneta americana L.)

• Published in: Journal of insect physiology 2005-03, Vol.51 (3), p.315-322
• Main Authors: Grodzicki, Przemysław, Caputa, Michał
• Format: Article
• Language: English
• Subjects: ambient temperature; Analysis of Variance; Animals; Apidae; Apis mellifera; Bees - physiology; biological rhythms; Blattaria; Blattidae; Body Temperature Regulation - physiology; Circadian Rhythm - physiology; Cockroaches; diurnal variation; group effect; heterothermy; homeothermy; Honeybee workers; individual behavior; insect behavior; Nychthemeral rhythms; nycthemeral rhythms; Periplaneta - physiology; Periplaneta americana; poikilothermy; Social Behavior; social insects; Social thermoregulation; species differences; Temperature; thermal behavior; Thermal behaviour; thermal preference; thermoregulation; Time Factors; worker honey bees
• ISSN: 0022-1910; 1879-1611
• DOI: 10.1016/j.jinsphys.2005.01.001

To study the relationship between the individual and social thermoregulatory behaviour, we used honeybee workers and American cockroaches. Single insects or groups of 10–20 individuals were placed in a temperature gradient chamber, and their thermal preference was recorded for 48 h under natural summer photoperiod. Single bees showed diurnal changes in selected ambient temperature, which culminated at 14:00 reaching 34±2 °C, and then slowly decreased, reaching a nocturnal minimum of 28±2 °C at 04:00. In contrast, the zenith of temperature selected by groups of bees (31±1 °C) was reached at 04:00 and the nadir (29±2 °C) was recorded at 14:00. Groups of bees clustered together during the night time, and dispersed during intense day time activity. Such changes were absent in groups of cockroaches. Cockroaches selected an ambient temperature of 30±1 °C both during day and night. In conclusion, there is a striking analogy in the diurnal thermal behaviour between a colony of bees and mammals. During their nychthemeral rest phase, both of them select higher temperatures than during the activity phase and, simultaneously, they reduce their overall surface area of heat loss to conserve metabolic heat. Therefore, the colony behaves as a homeothermic superorganism. In contrast, a single bee, isolated from the colony, utilizes a heterothermic strategy to save energy for a morning warm up.