Distribution and Ecology of Invasive Ants

This project examines exactly how invasive specific types of ants are, and what effect that has on the ecosystem. To do so, most of the research must be compiled for the first time, as there is a lack of knowledge and research on this subject. Through former research, Tillberg finds that there are invasive pavement ants in Oregon state parks, but due to a lack of research on the species, their impact is unknown. The research will follow a paired design, comparing similar areas with and without pavement ants, to discover what differences this invasive species has on habitats

Distribution and Ecology of Invasive Ants

This project examines exactly how invasive specific types of ants are, and what effect that has on the ecosystem. To do so, most of the research must be compiled for the first time, as there is a lack of knowledge and research on this subject. Through former research, Tillberg finds that there are invasive pavement ants in Oregon state parks, but due to a lack of research on the species, their impact is unknown. The research will follow a paired design, comparing similar areas with and without pavement ants, to discover what differences this invasive species has on habitats

Nutritional Asymmetries Are Related to Division of Labor in a Queenless Ant

Eusocial species exhibit pronounced division of labor, most notably between reproductive and non-reproductive castes, but also within non-reproductive castes via morphological specialization and temporal polyethism. For species with distinct worker and queen castes, age-related differences in behavior among workers (e.g. within-nest tasks versus foraging) appear to result from physiological changes such as decreased lipid content. However, we know little about how labor is divided among individuals in species that lack a distinct queen caste. In this study, we investigated how fat storage varied among individuals in a species of ant (Dinoponera australis) that lacks a distinct queen caste and in which all individuals are morphologically similar and capable of reproduction (totipotent at birth). We distinguish between two hypotheses, 1) all individuals are physiologically similar, consistent with the possibility that any non-reproductive may eventually become reproductive, and 2) non-reproductive individuals vary in stored fat, similar to highly eusocial species, where depletion is associated with foraging and non-reproductives have lower lipid stores than reproducing individuals. Our data support the latter hypothesis. Location in the nest, the probability of foraging, and foraging effort, were all associated with decreased fat storage

Nutritional asymmetries are related to division of labor in a queenless ant.

Eusocial species exhibit pronounced division of labor, most notably between reproductive and non-reproductive castes, but also within non-reproductive castes via morphological specialization and temporal polyethism. For species with distinct worker and queen castes, age-related differences in behavior among workers (e.g. within-nest tasks versus foraging) appear to result from physiological changes such as decreased lipid content. However, we know little about how labor is divided among individuals in species that lack a distinct queen caste. In this study, we investigated how fat storage varied among individuals in a species of ant (Dinoponera australis) that lacks a distinct queen caste and in which all individuals are morphologically similar and capable of reproduction (totipotent at birth). We distinguish between two hypotheses, 1) all individuals are physiologically similar, consistent with the possibility that any non-reproductive may eventually become reproductive, and 2) non-reproductive individuals vary in stored fat, similar to highly eusocial species, where depletion is associated with foraging and non-reproductives have lower lipid stores than reproducing individuals. Our data support the latter hypothesis. Location in the nest, the probability of foraging, and foraging effort, were all associated with decreased fat storage

Descriptive statistics for each colony.

<p>Fat content is as a proportion of total dry body mass. Fat content and head width are reported as means +/- standard error with sample size in parentheses. Brood was present but not counted for colony 5. Colony 5 was collected in 2004 while the remainder in 2009.</p

The relationship between individual fat content (as a proportion of total dry body mass) and the relative depth at which the individual was collected (1 being deepest and 0 being the surface) for five colonies of <i>Dinoponera australis</i> (each colony is coded by a different color).

<p>Colonies differed in the slope of the relationship between fat content and relative depth (F_4,267 = 3.41, P = 0.01), but the relationship is highly significant (F_1,267 = 137.93, P<0.0001) and colonies did not differ in average individual fat content (F_4,267 = 1.27, P = 0.28). The inset shows brood (larvae and pupae) as a function of depth; only the deepest chambers contained brood.</p