Orientation of mounds in the antSolenopsis invicta (Hymenoptera, Formicidae, Myrmicinae)

Hubbard, Michael; Cunningham, William G.

doi:10.1007/bf02223276

Cited by 16 publications

(7 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The south sides of mounds were often sloped more than the north and free of grass that would shade the mound (presumably the ants are weeding), which is common in other mound-building species (Seeley and Heinrich, 1981;Vogt et al, 2004) excepting mounds of Lasius flavus, which are located in grasslands and usually covered with various grasses (Waloff and Blackith, 1962). During the winter, mounds are extended on the south side and cause nests open to direct sunlight to have a north-south axis of elongation, which contributes to the nest shape and may be linked to temperature tracking (Hubbard and Cunningham, 1977). In Solenopsis richteri, Vogt et al (2004) showed that mound size was smallest just before winter and reached a maximum in May, which means that energy involved in mound construction peaks at the same time temperature tracking is most important (during Spring sexual production).…”

Section: Discussionmentioning

confidence: 99%

Thermoregulatory brood transport in the fire ant, Solenopsis invicta

Penick

Tschinkel

2008

Insect. Soc.

View full text Add to dashboard Cite

Nest structure in ants is often designed to optimize the colonys ability to thermoregulate, and this specialization is most highly developed in mound-building ant species. Solenopsis invicta invest a large amount of energy in building mounds and transporting their brood up and down in their nests as a means of thermoregulation. Because few ant species build true mounds, we wanted to determine the effectiveness of these mounds in harvesting solar heat as well as to distinguish what factors (temperature vs. circadian rhythm) govern where fire ants place their brood in the mound and when they place it. We measured temperature patterns in the mound over several days at different depths and under different conditions (under direct sunlight or shade), and then conducted a series of field experiments to manipulate the orientation and time of heating.On cool mornings in spring or fall, surface temperatures of the mound rise at the fastest rate on the side receiving the most direct sunlight (usually the south side). This heating causes a temperature gradient through different depths in the mound, and shows little difference from outside ground temperature at a depth greater thañ 40 cm inside the nest. In the morning, fire ants move their brood up into the mound on the side most directly heated, and when temperatures exceed optimal (~328C) they move their brood down the temperature gradient to lower depths in the nest. In addition to this, mound temperature does not only increase due to direct sunlight, but temperature also increases higher than ground temperatures when the mound is in the shade due to its low specific heat.Experiments in which sunlight was mirrored to the normally shaded side of the mound, or when mounds were heated at night, revealed that S. invicta primarily track temperature patterns and do not rely on behavioral habits or circadian rhythms for the thermoregulatory transport of their brood. When mounds were shaded, S. invicta brood was evenly distributed directly under the surface of the mound rather than aggregating towards a specific side. The fire ant mound is important for thermoregulation because, compared to moundless subterranean nests, it absorbs heat more rapidly both in direct sunlight and shady conditions. Temperature tracking within the nest is key to understanding thermoregulatory placement of fire ant brood, as well as insight into the production of sexual brood and reproduction.

show abstract

Section: Discussionmentioning

confidence: 99%

Thermoregulatory brood transport in the fire ant, Solenopsis invicta

Penick

Tschinkel

2008

Insect. Soc.

View full text Add to dashboard Cite

show abstract

“…Most mounds have faces sloping to the south and southeast, thus increasing the amount of sunlight intercepted (Foret 1874;Andrews, 1927;Linder, 1908;Scherba, 1958;Hubbard and Cunningham, 1977). Most mounds have faces sloping to the south and southeast, thus increasing the amount of sunlight intercepted (Foret 1874;Andrews, 1927;Linder, 1908;Scherba, 1958;Hubbard and Cunningham, 1977).…”

Section: Sixteenmentioning

confidence: 99%

The Hot-Blooded Insects

Heinrich¹

1993

321

144

View full text Add to dashboard Cite

“…Imported Þre ants move within the column of the nest soil depending on daily temperature changes (Pinson 1980), going deeper in the mounds to avoid cold (Morrill et al 1978). Other factors, such as colony size (Green 1959, Callcott et al 2000, clustering behavior (Kaspari and Vargo 1995), and nest construction/location (Hubbard andCunningham 1977, Morrill et al 1978), may also play an important role in imported Þre ant winter survival.…”

mentioning

confidence: 97%