BIOLOGY OF XYLOCOPA-VIOLACEA (HYMENOPTERA) - IN-NEST ETHOLOGY

Nest-building behaviour was studied in Xylocopa violacea, with particu lar attention to that exhibited In the construction of each cell, from the formation of the pollen paste to the construction of the diaphrag m. Seven inside characteristics of 28 nests excavated in dried Arundo donax canes were determined. The cell length ranged from 14 to 20 mm. The diaphragms separating the cells were 2 mm thick in the middle, and 4-5 mm at the edge. In 37 additional nests, only data on some charact eristics were taken: (a) colour of the pollen paste; (b) cane internod e used for nesting. X. violacea is univoltine and solitary, and as in all the other Xylocopa species, female average fecundity is very low ( 7.43 eggs per nest), despite considerable maternal investment. Univolt ine Xylocopa species are less fertile than multivoltine Xylocopa speci es because of the one to three supplementary generations per year.