The Bee Tree of Sahyadri
S Basavarajappa, Department of Zoology, University of Mysore
The giant Asian honey bee Apis dorsata builds remarkable, large, vertically hanging combs. During our research in the semi-arid region of Bhadra Reservoir amazing Apis dorsata colony aggregates were observed.
Bhadra Reservoir Project, at an altitude of 680-720 m, is considered a favourable habitat for honey bees. The region is locally called Sahyadri and lies at the foot hills of the southern tracts of the Western Ghats in Karnataka State, India. There are deciduous forests and a few crops including acara nut, coconut, and mango gardens in the vicinity of Nilgiri plantation owned by Mysore Paper Mills Ltd. Besides the natural vegetation, the plantation provides large quantities of floral resources for honey bees.
Apis dorsata nest in trees and on cliffs and in this area select the white silk cotton tree Ceiba pentandra, a dense, deciduous tree with many branches, growing up to 18 m. A large number of colony aggregates were on the defoliated Ceiba pentandra and we recorded 79 combs. The combs were fixed to the rough sub-surface of the tree branches, orientated east-west, north-east and south-west at different elevations. It was the first record made in this part of Karnataka, and the tree is now called Bee Tree of Sahyadri.
The 70 inhabited and nine abandoned combs were unevenly distributed within 15 colony aggregates. Each aggregate consisted of five to eight combs. These aggregates would remain undisturbed for a 12-14 month period during the study years 1999-2001. Later all these nests were abandoned within one week.
In the Nilgiris, Eucalyptus is grown on a large-scale, and felled by Paper Mills Ltd, to use as raw material for the manufacture of pulp and paper. Eucalyptus trees are one of the forage plants of the giant honey bee, and the rapid loss of these trees might have caused havoc for Apis dorsata.
Such dearth periods were extended for several years and were exacerbated by drought in 2001-2002. As a result, many Apis dorsata colonies became victims and disappeared from the Bee Tree. This unscrupulous loss of the gian honey bee population was unfortunate. Sadly not a single colony has reappeared on Ceiba pentandra since 2001 to date. Despite the abundance of other tree flora, colonies have not been seen on any tree species within 5 km2 of this area.
Whether successful reappearance of Apis dorsata nests on Ceiba pentandra will occur only with reforestation of Eucalyptus species from the same area is still being debated. If this trend continues unchecked, it may also affect the reproductive success of innumerable numbers of both cultivated and wild plant species. In addition the people who live in the forests and nearby villages who have the best opportunity to make use of honey and beeswax will be deprived of these resources.
Many cases of this type go without notice by the scientific community, and before we fully understand these species and their role within the ecosystem.