have been found, surprisingly, to be a deterrent to the more dominant stingless bee species Trigona hyalinata. The reason for this is not clear, but it is hypothesized that the dominant specie wants to avoid costs and injuries associated with seizing a food source from Trigona spinipes rather than finding its own source. Trigona hyalinata are attracted to food sources with fewer Trigona spinipes foragers, because they can easily overpower a small number of their competitors. Aggression Trigona spinipes is locally known for its aggressiveness. Despite lacking the ability to sting, workers will pursue intruders and bite them. Each of their two mandibles have 5 sharp teeth. A study found that among 12 stingless bees investigated, Trigona spinipes was one of the 6 species that engaged in suicidal biting. The phenomenon of suicidal biting involved workers biting a target intruder so tenaciously that a significant number of the workers suffered fatal injuries. Of the 6 bees which engaged in suicidal biting, Trigona spinipes displayed the most aggressive behavior overall. Kin selection Sex and caste determination Sex in Trigona spinipes is determined by whether or not the eggs are fertilized. Fertilized eggs are diploid and become females while unfertilized eggs are haploid and become males. Caste determination is trophic, meaning that it is not hereditary, but rather depends on the quantity and quality of food consumed by larvae. Female larvae which consume better and higher quality food develop 12 rather than the usual 4 ovarioles at the pupal stage which later develop into queens. This trophic caste determination is the reason that Trigona spinipes queens are larger than workers. There is no size difference between queens and workers in other Meliponini species which utilize trophogenic caste determination mechanisms. Virgin queens pose a threat to established queens. They are usually not needed by the colony so they are usually either killed by workers or imprisoned. Workers laying eggs Although they are smaller and have fewer ovarioles than queens, workers retain the ability to lay viable eggs. This ability is somewhat limited. Workers which are in close proximity to the queen often lay trophic or sterile eggs presumably due to hormone signals from the queen. In addition, the queen caste routinely consumes eggs laid by workers. Lack of polyandry Unlike what might be expected for such large colonies, there is no polyandry or polygyny in Trigona spinipes, such as can be found in