New Nest (new + nest)

Distribution by Scientific Domains

Selected Abstracts

Effect of soil hardness on aggression in the solitary wasp Mellinus arvensis

Jaboury Ghazoul
Summary 1. Two alternative nesting strategies are exhibited by soil-nesting Mellinus arvensis females, digging a new nest (diggers) and searching for an old unoccupied burrow (searchers). Wasps appear unable to distinguish between occupied and unoccupied nests, and aggressive interactions between searchers and nest owners at nest entrances are frequent. 2. In aggressive encounters, there is an advantage in size and residency status. 3. The costs associated with the two nesting strategies vary across geographically separated populations: nest digging incurs costs in terms of time, and these vary according to the hardness of the soil substrate; nest searching is variably costly in terms of risk of injury in aggressive encounters with nest-owning females. 4. Individual female wasps can switch between nesting strategies, and thus soil hardness, by affecting the cost of nest construction, affects the relative frequencies of the two nesting strategies within a population, favouring an increase in the searching strategy. This, in turn, affects the frequency and intensity of aggression between females at a nesting aggregation. 5. Female body size is correlated with soil hardness. As aggressive encounters are more frequent in sites with hard soil substrates, there is increased selective advantage in having large body size at these sites. 6. Body size is determined primarily by the availability of food resources during larval development, which is, to a degree, a function of the size of the adult female. There is a trade-off between provisioning a few cells with many provisions in each, leading to the development of few but large adults, as opposed to many cells with few provisions, leading to many small offspring. The relative advantage of these two provisioning strategies is, at least in part, a function of the hardness of the soil substrate. [source]

Home-Range Dynamics in a Solitary Subterranean Rodent

ETHOLOGY, Issue 3 2009
Despite an important role of subterranean rodents as ecosystem engineers, their belowground mobility is poorly documented. It is supposed that their underground burrow systems, once established, are relatively stable because of high-energy costs of digging. We chose the silvery mole-rat, Heliophobius argenteocinereus (Bathyergidae, Rodentia) from mesic Afrotropics as a representative of solitary subterranean rodents to investigate how, and how fast these rodents process their established burrow systems. We combined radio-tracking of individual animals with subsequent mapping of their burrow systems, and we developed a new method for assessing the rate of burrowing. Mole-rats continuously rebuilt their burrow systems; they excavated approx. 0.7 m of new tunnels per day and backfilled on average 64% of all tunnels. On average, every 32 d they established a new nest. They often completely backfilled newly excavated peripheral burrows, while other parts of their burrow systems were more permanent. Their home-ranges were dynamic and continuously shifted in space. Burrow system processing continued even in the advanced dry season, when soil is difficult to work. [source]

Seasonally Variable Eusocially Selected Traits in the Paper Wasp, Mischocyttarus mexicanus

ETHOLOGY, Issue 7 2007
Charles W. Gunnels IV
The expression of alternative traits that benefit eusocial individuals but are not directly involved in reproductive differences among those individuals, which I call ,eusocially selected traits', may vary in response to environmental changes if this increases an individual's inclusive fitness. In this study, I describe traits that separate individuals within the reproductive division of labor of Mischocyttarus mexicanus, a eusocial paper wasp, and determine whether observed eusocially selected traits vary across seasons. I examined M. mexicanus because females initiate new nests throughout most of the year where they experience different conditions depending on the season. Findings from this study suggest two main conclusions: (1) phenotypic differences among M. mexicanus females are mixed, showing specialized, generalized, and context-dependent eusocially selected traits and (2) a female's position within the reproductive division of labor may be influenced by its state. The presence of context-dependent traits, e.g. large females initiated solitary nests in the spring and grouped nests during the summer, suggests that the payoff for pursuing different positions within the reproductive division of labor changes across seasons. The expression of context-dependent eusocially selected traits also suggests that, roles, instead of castes, may better reflect the reproductive division of labor among individuals of eusocial species like M. mexicanus. [source]

Ant nest location, soil nutrients and nutrient uptake by ant-associated plants: does extrafloral nectar attract ant nests and thereby enhance plant nutrition?

Diane Wagner
Summary 1. As central place foragers, ants accumulate organic debris near their nests. Consequently, soil nutrient stocks are often enriched near the nest site. We investigated the hypothesis that plant-derived food sources, such as extrafloral nectar (EFN), can encourage soil-dwelling ant colonies to nest near the plant, thereby inadvertently providing the plant with an additional source of mineral nutrients. The study focused on a population of Acacia constricta, a North American shrub bearing EFNs. 2. Several lines of evidence supported the notion that food rewards drew ant nests close to A. constricta plants. Firstly, ant species that visit EFNs nested significantly closer to A. constricta plants than would be expected by chance, whereas this was not the case for two ant species that do not visit EFNs. Secondly, A. constricta plants with an ant nest occurring naturally underneath the canopy had greater foliar volume, more EFNs per leaf and more EFNs per cm of leaf rachis than plants lacking an ant nest under the canopy. Thirdly, experimental supplementation of the nectar resources on acacias led to the establishment of significantly more new nests near the plant, relative to controls. However, nectar supplementation did not affect acacia seed production within the year of the study. 3. Soil from the nests of three, EFN-visiting ant species contained higher average stocks of most mineral nutrients than nearby soils outside the influence of the nest. 4. To test whether A. constricta can assimilate the nutrients in ant nests, we fed 15N-labelled food to Dorymyrmex sp. (smithi complex) workers nesting near acacias. Twenty-four days later, the leaves of acacias with an experimentally fed ant colony under the canopy contained significantly higher 15N and %N than acacias without a nest under the canopy, indicating that acacias assimilated and benefited from nutrients derived from ants. 5.Synthesis. The results indicate that nectar resources can attract the nests of some ant species, and that plants may benefit from access to soil nutrients derived from ant nests. Our data support the hypothesis that EFNs may confer nutritive, as well as protective, benefits. [source]