Monogamy in large bee societies: a stingless paradox

Area of Science:

• Insect genetics
• Social behavior
• Evolutionary biology

Background:

• High genetic diversity is crucial for large insect societies, often achieved through polygyny or polyandry.
• Species with the largest colonies typically exhibit high colony-level genetic diversity.

Purpose of the Study:

• To investigate the genetic structure of Trigona spinipes, a stingless bee species with exceptionally large colonies.
• To determine the mating system and genetic diversity within T. spinipes colonies.
• To explore the implications for the evolution of sociality and mating strategies in insects.

Main Methods:

• Genotyping of adult workers and pupae from 43 Trigona spinipes nests across three Brazilian biomes.
• Analysis of genetic structure to infer mating patterns and colony composition.

Main Results:

• Trigona spinipes colonies are predominantly headed by a single, singly mated queen.
• This finding contrasts with the expected high genetic diversity in large insect societies.
• Results support the absence of polyandry in stingless bees and challenge the sperm limitation hypothesis.

Conclusions:

• Trigona spinipes presents a unique model for studying large insect societies with low genetic diversity.
• Further research is needed to understand alternative mechanisms for increasing genetic diversity or the adaptive value of low diversity in such colonies.
• Findings contribute to understanding the evolution of mating systems and social organization in Hymenoptera.