ARBEITSGEMEINSCHAFT DER INSTITUTE FÜR ... - HAL - INRIA

gezogen werden, daß nicht alle artspezifisch variierenden Komponenten des Larvenfuttersaftes
nach diesem Prinzip evolutiv verändert wurden.
SUMMARY
Caste differentiation in meliponine bees. Comparative analyses of larval
food under the aspect of balanced nutrit’ion
Studies on the trophogenic basis of caste differentiation in honey bees have
led to the almost general acceptance of a concept which regards « balanced
nutrition » as an important presupposition for the differentiation of queen specific
characters. In order to evaluate this concept for caste differentiation in
stingless bees comparative analyses were carried out on the composition of larval
food from 7 meliponine species (Scaptotrigona depilis, Scaptotrigona bipunctata,
Nannotrigona testaceicornis, Partamona cupira, Tetragonisca angustula, Plebeia
droryana and Melipona quadrifasciata). The larval food from freshly provisioned
worker cells was analysed for the following parameters : water content, content
of reducing sugars and total protein including the free amino acid and protein
fractions. The water content in the different types of larval food amounted to
40-60 % and the sugar content made up 5-14 % of the fresh weight. The protein
content revealed a strong divergence of the group Scaptotrigona/Nannotrigona
from the other species. Free amino acids amounted to 0.14-1.3 % of the fresh
weight. With respect to the free amino acid composition in the larval food, the
7 species differed greatly from each other. The polypeptide pattern (SDS-PAGE)
of the larval food types revealed 5 bands which the 7 species had in common
from a total of 28 bands. The protein patterns from the larval food of the two
closely related species S. depili.s and S. bipunctata could hardly be distinguished,
while Melipona larval food differed from the trigonine pattern by the almost
general lacking of polypeptides of higher molecular weights (40-80 Kd). For a
comparative discussion of the larval food composition, under the aspect of
« balanced nutrition », distance matrices were calculated for the two parameters
free amino acid composition and polypeptide pattern. From these matrices
minimal distance trees were constructed and could be compared to phylogenetic
trees from classical taxonomic work on stingless bees (M OURE , 1951, 1961 ;
WILLE , 1979). The degree of conformity between the minimal distance trees
and the phylogenetic tree can be discussed as a measure for a species-specific,
selected larval food composition. The minimal distance tree for the amino acid
composition in the larval food of the 7 species was completely incongruent with
the phylogenetic tree, while the minimal distance tree for the protein pattern
coincided with the latter. Thus, it appears to be problematic to speak generally
of a « balanced composition of the larval food of stingless bees. It certainly