Nest Structure, Seasonality and Female Behavior of Epicharis (Anepicharis) dejeanii Lepeletier (Hymenoptera, Apidae, Centridini) in a Restinga Ecosystem, in Southern Brazil

We investigated the nesting behavior of females of Epicharis dejeanii and the architecture of their nests, in a large aggregation in a Restinga area, on Ilha do Superagui, southern Brazil. Surveys were carried out intermittently through the warm-wet seasons from different years between 2013 and 2017. The nest aggregation occupied an area of approximately 2,000 m2 and was situated on a sand bank and on flat sandy soil. Each nest consisted of a long unbranched tunnel, averaging 1.45 ± 0.35 m (N = 8), connected to a single brood cell with a mean length of 3.13 ± 0.2 cm (N = 13) and mean diameter of 1.2 ± 0.1 cm (N = 11). On average, females carried out 4.0 ± 2.4 foraging trips per day (N = 109) to collect floral resources for provisioning brood cells. Similar times were spent by females in their foraging trips for: only pollen (15.8 ± 14.3 min, N = 72), oil (22.5 ± 15.7 min, N = 45), or both resources (17.0 ± 15.1, N = 63). Our findings reveal that some variation in both nesting architecture and female behavior of E. dejeanii during nesting activities can occur in different locations from the same region.

A study of the biology of Epicharis (Epicharoides) picta using emergence-traps

This study investigates the nesting habits of Epicharis picta in a nest aggregation located in a fragment of the Atlantic forest in Southeastern Brazil. Ten emergence-traps were set up in this nest aggregation to standardize data collection of phenology, natural enemies, and sex ratio. Epicharis picta nests were in an area of 160 m² with a density of 41 nests/m². Nest and cell architecture are described. Epicharis picta is a protandrous, univoltine species with its emergence in this study occurring between 28 January and 15 April. We provide direct evidence of parasitism on E. picta by Rhathymus friesei, Tetraonyx sexguttata and T. aff. lycoides. The predator Apiomerus lanipes was found to prey Epicharis for the first time. We suggest the use of emergence-traps as tools to support studies of ground-nesting bees. In addition, we compile, update, and discuss data on the nesting biology of all Epicharis subgenera.

Thermoregulation strategies in ants in comparison to other social insects, with a focus on red wood ants (Formica rufa group)

Temperature influences every aspect of ant biology, especially metabolic rate, growth and development. Maintenance of high inner nest temperature increases the rate of sexual brood development and thereby increases the colony fitness. Insect societies can achieve better thermoregulation than solitary insects due to the former’s ability to build large and elaborated nests and display complex behaviour. In ants and termites the upper part of the nest, the mound, often works as a solar collector and can also have an efficient ventilation system. Two thermoregulatory strategies could be applied. Firstly the ants use an increased thermal gradient available in the mound for brood relocation. Nurse workers move the brood according to the thermal gradients to ensure the ideal conditions for development. A precise perception of temperature and evolution of temperature preferences are needed to make the correct choices. A second thermoregulatory strategy used by mound nesting ants is keeping a high temperature inside large nests. The unique thermal and insulation properties of the nest material help to maintain stable conditions, which is the case of the Wood ant genus Formica. Ants can regulate thermal loss by moving nest aggregation and alternating nest ventilation. Metabolic heat produced by ant workers or associated micro organisms is an important additional source of heat which helps to maintain thermal homeostasis in the nest.

Thermoregulation strategies in ants in comparison to other social insects, with a focus on Formica rufa

Temperature influences every aspect of ant biology, especially metabolic rate, growth and development. Maintenance of high inner nest temperature increases the rate of sexual brood development and thereby increases the colony fitness. Insect societies can achieve better thermoregulation than solitary insects due to the former’s ability to build large and elaborated nests and display complex behaviour. In ants and termites the upper part of the nest, the mound, often works as a solar collector and can also have an efficient ventilation system. Two thermoregulatory strategies could be applied. Firstly the ants use an increased thermal gradient available in the mound for brood relocation. Nurse workers move the brood according to the thermal gradients to ensure the ideal conditions for development. A precise perception of temperature and evolution of temperature preferences are needed to make the correct choices. A second thermoregulatory strategy used by mound nesting ants is keeping a high temperature inside large nests. The unique thermal and insulation properties of the nest material help to maintain stable conditions, which is the case of the Wood ant genus Formica. Ants can regulate thermal loss by moving nest aggregation and alternating nest ventilation. Metabolic heat produced by ant workers or associated micro organisms is an important additional source of heat which helps to maintain thermal homeostasis in the nest.