Ovary development, dominance, and chemical signaling in a eusocial tropical paper wasp (Mischocyttarus pallidipectus)
In primitively eusocial Mischocyttarus pallidipectus paper wasp colonies, separation of members into reproductive castes is characteristic. Mischocyttarus pallidipectus castes are monomorphic: females on the nest are similar in morphology at emergence but differentiate into castes by social dominance. We tested the hypothesis that ovary size is correlated positively with dominance, and whether caste status is associated with individual chemical cues. In the field, I worked alongside a small team of researchers to locate wasp nests and observe individual wasp behavior for four hours each day over two days to identify dominance interactions and determine the social hierarchy of females. Following observations, the wasps were collected, and the females were dissected. Female ovaries were photographed and measured in order to examine the behavioral data against the size and development of their ovaries. The gasters of each wasp were swabbed for their cuticular hydrocarbons which were then run on chromatography columns, allowing us to evaluate whether there is a difference in the chemical identity of females with and without developed ovaries. Initial cuticular hydrocarbon analyses show a chemical distinction between females with developed and filamentous ovaries. However, further analysis will be performed to examine the hydrocarbon profiles of the various members of the same colony (males vs females, dominant vs subordinate behavior) as well as between different colonies.
In primitively eusocial Mischocyttarus pallidipectus paper wasp colonies, separation of members into reproductive castes is characteristic. Mischocyttarus pallidipectus castes are monomorphic: females on the nest are similar in morphology at emergence but differentiate into castes by social dominance. We tested the hypothesis that ovary size is correlated positively with dominance, and whether caste status is associated with individual chemical cues. In the field, I worked alongside a small team of researchers to locate wasp nests and observe individual wasp behavior for four hours each day over two days to identify dominance interactions and determine the social hierarchy of females. Following observations, the wasps were collected, and the females were dissected. Female ovaries were photographed and measured in order to examine the behavioral data against the size and development of their ovaries. The gasters of each wasp were swabbed for their cuticular hydrocarbons which were then run on chromatography columns, allowing us to evaluate whether there is a difference in the chemical identity of females with and without developed ovaries. Initial cuticular hydrocarbon analyses show a chemical distinction between females with developed and filamentous ovaries. However, further analysis will be performed to examine the hydrocarbon profiles of the various members of the same colony (males vs females, dominant vs subordinate behavior) as well as between different colonies.