Zoological Studies

Vol. 47 No. 4, 2008

Thermal Characteristics of Nests of the Taiwanese Stingless Bee Trigona ventralis hoozana (Hymenoptera: Apidae)

I-Hsin Sung1,2,*, Sichi Yamane2, and Satoshi Hozumi3

1Division of Crop Environment, Tainan District Agricultural Research and Extension Station, Council of Agriculture, Executive Yuan, Tainan 712, Taiwan
2Biological Laboratory, Faculty of Education, Ibaraki University, Mito 310-8512, Japan.  E-mail:yamaneso@mx.ibaraki.ac.jp
3Satellite Venture Business Laboratory, Graduate School of Science and Engineering, Ibaraki University, Hitachi, Ibaraki 316-8511, Japan.  E-mail:shoz@mx.ibaraki.ac.jp

I-Hsin Sung, Sichi Yamane, and Satoshi Hozumi (2008) Temperatures in 3 natural nests of the Taiwanese stingless bee Trigona (Lepidotrigona) ventralis hoozana were measured in Dapu and Tsaoshan, Chiayi County, Taiwan from Dec. 2002 to Mar. 2004.  The temperature in the brood rearing zone of 2 nests was kept relatively constant in a range of 29-32C.  Even in the morning in Jan., the temperature in the brood area was maintained at 29.5C, about 21C higher than the ambient temperature.  Healthy nests could tolerate ambient temperatures even lower than 8C, judging from the elevational distribution limit of this species and corresponding meteorological records.  The maintenance of constant temperatures in the brood area is chiefly due to ameliorated thermal conditions in the nesting cavity.  This is realized by the thermostatic effect of the thick wood of the living tree enclosing the cavity.  The involucrum, which completely encloses the brood combs, may retain thermal energy generated by the adults and partially by the mass of brood in the brood area.

Key words: Stingless bee, Trigona ventralis hoozana, Nest architecture, Nest temperature.

*Correspondence: Tel and Fax: 886-6-5912908.  E-mail:issung@mail.tndais.gov.tw