User:LibbyWard/sandbox

The morphology of L. acervorum is extrememly similar to that of other ants. The difference arises in the two-toned appearance of L. acervorum, with the head and metasoma being darker than the mesosoma segment of the body. Following Bergmann's rule, body size increases with latitude.

Similar to other ants, L. acercorum displays elbowed-antennae, metapleural glands, and a constriction of the second abdominal segment. The exoskeleton provides a protecting casing of the body, which can be divided into 3 segments: the head, mesosoma, and metasoma. The head contains eyes that detect acute movement, three small ocelli to detect light and polarization, and two mandibles. Attached to the head are two antennae. All six legs are attached to the mesosoma. The metasoma houses vital internal organs. “The pedicel of the metasoma is two-segmented,” which is unique for the Subfamily Myrmicinae (740).

Colony Dynamics
Colonies of R. marginata consist of a queen and many non-egg laying workers. The number of workers can range from 0, solitary foundress nest, to over 100. The average period of development from egg to adult is 62 days. However, a female only has a .12 probability of surviving the full 62 days. Therefore, if she is solitary nesting, her expected reproductive success is low. Gadagkar estimated that a female increases her expected reproductive success by 3.6-fold as a result of group nesting.

There are three possible paths available to a female. She can leave the nest to form a new nest by herself or with others, she can remain in the natal nest as an altruistic worker for the remainder of her life, or she can work for her natal nest for a while and then drive away the queen to become the new replacement queen.

Gadagkar devised a unified model that makes predictions about what proportion of the population of R. marginata “should opt for a selfish solitary nesting strategy and what proportion should opt for an altruistic worker strategy” (853). From this, he was able to predict that 5% should opt for the selfish solitary nesting strategy while 95% should opt for the altruistic worker strategy.

Gadagkar et al. genotyped R. marginata mothers and daughters at a “few non-specific esterase loci” to infer the genotypes of the haploid fathers or estimate the number of fathers needed to produce the daughters observed (850). The researchers ultimately found, “R. marginata queens mate with 1–3 different males and the average relatedness among their daughters thus drops from the theoretically expected 0.75 to about 0.50, thus entirely negating the advantage of haplodiploidy for social evolution, as predicted by Hamilton” (851). Gadagkar “found no evidence for intra-colony kin recognition” (851).

Queen
While the queen is docile, she maintains a complete reproductive monopoly, using a non-volatile pheromone to regulate the reproduction of the workers.

Worker
The workers aid the queen in foraging, nest-building, and brood care. Gadagkar calculated that the genetic relatedness between the worker and the brood ranged from .0165 to .75.

When the queen is lost or removed, one of the non-egg laying workers becomes extremely aggressive, then gradually becomes docile, develops ovaries, and begins egg laying. Gadagkar et al. observed that workers will continue working for the replacement queen. Bang and Gadagkar demonstrated that there is not just one designated worker to take over reproduction, but a long queue of potential queens that are not only daughters, but also sisters, nieces, and cousins. They found that age is a substantial predictor, though not a perfect one.

Male
Males do not assist in any of the colony maintenance activities while they reside in the nest. However, they do consume the food and liquid brought to the nest by females. The behaviors they do perform include, “soliciting food, antennating nest, antennating another wasp, feeding self, snatching things, fanning wings, body jerks, wing jerks and dominance–subordinate behaviors” (963-4). Due to this behavior, females show physical aggression towards males in the nest.