Tramp Ants Research Articles

Anti-predator Fan-blowing in Guard Bees, Apis mellifera capensis Esch

Honeybees employ different defensive strategies depending on the nature of potential predators. The Cape honeybee, Apis mellifera capensis, exhibits a unique fan-blowing behaviour to repel ants and similar sized insects at the nest entrance. Guard bees turn in alternating clockwise and anticlockwise circles on a fixed vertical axis and fan their wings when encountering tramp ants (Pheidole megacephala), aphids (Myzus persicae) and termites (Trinervitermes trinovoides) on the landing board of a hive. The blowing force was constant and was driven by fanning with a wing-beat frequency of 274.8 ± 16.3 Hz, which exceeds that of flight. On the contrary, small hive beetles (Aethina tumida) were removed by mauling and expulsion whereas larvae of the greater waxmoth (Galleria mellonella) and the mealworm (Tenebrio molitor) were seized with mandibles and thrown from the nest area.

Difference in seasonal activity pattern between non‐native and native ants in subtropical forest of Okinawa Island, Japan

AbstractBiological invasions by non‐native tramp ants are reported throughout the world, particularly in island ecosystems. In Okinawa Island, a subtropical island in south‐western Japan, many tramp ants including the invasive ant, Anoplolepis gracilipes, already occur. In this study activity patterns of the ground‐foraging tramp and native ants were investigated for one year by using food bait traps at the forest edges where both categories of ants coexist. On a seasonal time scale, activity patterns were different between exotic and native ants. Native ants are active and seemingly more dominant from spring to summer whereas tramp ants become more dominant from autumn to winter. These results suggest there might be temporal niche partitioning between tramp and native ants, and native ants might be able to dominate tramp ants in their suitable seasons.

Ant communities (Hymenoptera: Formicidae) in an urban ecosystem near the Atlantic Rainforest

The relationships between an urban ecosystem located near the Atlantic Rainforest in southeastern Brazil and ant communities were studied with the objective of quantifying the ant richness and abundance in the household environment and its surroundings. Eighty residences were sampled, where 58 species and 28 genera pertaining to 7 sub-families were found to be present. Inside the residences, the species richness was found to be lower (26), although the abundance was greater (10,670), with the wash area and kitchen being the locales that contributed with the greatest number of hits. The opposite was true in the areas outside the residences, where 54 species and 3,747 ants were observed. Inside houses, the species known as Tramp ants were found, in the following order of importance: Solenopsis saevissima, Tapinoma melanocephalum, Linepithema humile, Paratrechina fulva, Wasmannia auropunctata, P. longicornis, Pheidole megacephala, Monomorium pharaonis and M. floricola. Externally, mainly in the yards and gardens, species such as Octostruma rugifera, Heteroponera dolo, Hypoponera sp.1 and sp.6, Gnamptogenys sp. 4, G. striatula, Odontomachus meinerti, Pachycondyla constricta and P. striata were found. In general, a greater number of species and lower abundance of individuals were observed in the neighborhoods nearer the mountains than in those closer to the urban center.

Relative risk of invasive ants (Hymenoptera: Formicidae) establishing in New Zealand

Human‐assisted spread of species poses a major challenge to border security agencies. Ideally, limited resources need to be targeted at species posing the most risk. Climate matching is an important component of assessing risk but often little or no biological information is available to enable detailed modelling. To assess if distribution records alone provide useful establishment predictions we compare the climate in New Zealand and its outlying islands to that found in the current native and introduced ranges of 12 tramp ant species, three of which are already established in New Zealand, using the climate module of BIOSECURE, a risk assessment tool. Eleven species showed a similar general pattern, with mean annual temperature being the climatic variable with the least overlap between the estimated realised niche and the predicted New Zealand niche. The twelfth species, of temperate origin, is less restricted by temperature, but much of New Zealand may have too high a rainfall. The present and future threats posed by tramp ants are discussed in relation to climate limitations.

Ability of Resident Ants to Destruct Small Colonies ofSolenopsis invicta(Hymenoptera: Formicidae)

The ant Solenopsis invicta Buren has spread across the United States and is reported to have significantly reduced the diversity of the native ants. Much of this spread is occurring on land that has been repeatedly disturbed by continually changing land use practices. S. invicta seems to outcompete and eliminate other resident ant species. However, this inference may not be true because several resident native ant species are known to persist in S. invicta-infested areas. Thus, in this study, we analyze the aggressive interaction between selected resident ants and S. invicta by evaluating whether some of these ants are capable of attacking small worker-defended S. invicta colonies or are instead attacked by the S. invicta colonies. Our results suggest that the native ant species Monomorium minimum (Buckley), Pheidole dentata Mayr, and Solenopsis molesta (Say) and exotic tramp ants Tetramorium bicarinatum (Nylander) and Monomorium pharonis (L.) do interact with the S. invicta and will attack and eliminate worker-defended S. invicta colonies of varying sizes ranging from 30 to 480 workers. M. minimum, P. dentata, S. molesta, T. bicarinatum, and M. pharonis also were observed to prey upon S. invicta brood once most of the defending workers were eliminated. The native species Forelius sp. was not observed to invade the S. invicta colonies; instead, it prevented S. invicta workers from leaving their nest to forage, which may have contributed to the decline of S. invicta colonies of up to 60 workers over time.

Immediate impacts of invasion by Wasmannia auropunctata (Hymenoptera: Formicidae) on native litter ant fauna in a New Caledonian rainforest

Abstract For the last 30 years, Wasmannia auropunctata (the little fire ant) has spread throughout the Pacific and represents a severe threat to fragile island habitats. This invader has often been described as a disturbance specialist. Here we present data on its spread in a dense native rainforest in New Caledonia. We monitored by pitfall trapping the litter ant fauna along an invasive gradient from the edge to the inner forest in July 1999 and March 2000. When W. auropunctata was present, the abundance and richness of native ants drops dramatically. In invaded plots, W. auropunctata represented more than 92% of all trapped ant fauna. Among the 23 native species described, only four cryptic species survived. Wasmannia auropunctata appears to be a highly competitive ant that dominates the litter by eliminating native ants. Mechanisms involved in this invasive success may include predation as well as competitive interactions (exploitation and interference). The invasive success of W. auropunctata is similar to that of other tramp ants and reinforces the idea of common evolutionary traits leading to higher competitiveness in a new environment.

Influence of Argentine and coastal brown ant (Hymenoptera: Formicidae) invasions on ant communities in Perth gardens, Western Australia

A survey examined the influence of Argentine (Linepithema humile (Mayr)) and coastal brown ant (Pheidole megacephala (Fabricius)) populations on other ants in the Perth metropolitan area, Western Australia. Twelve gardens (yards) were sampled; four infested by Argentine ants, three infested by coastal brown ants, and five controls where these two tramp ants were absent or collected only as isolated strays. Collection methods used were pitfall trapping and hand collection. A total of 27 species was recorded. Eight of these species, including the above two tramp ants, are non-native to the region. Pheidole megacephala was the most abundant species, comprising 95.4% of ants in P. megacephala–infested gardens. Linepithema humile comprised 92.1% of ants in L. humile–infested gardens. Other common ants were the native Iridomyrmex chasei and the introduced species Tetramorium simillimum and Tetramorium bicarinatum. The cryptic introduced species Cardiocondyla nuda and Tetramorium simillimum appear able to persist in small numbers in L. humile–infested gardens, but virtually no other ant species occurred where the coastal brown ant was well established. Mean richness, diversity, and evenness were significantly different between P. megacephala–infested and control gardens, and significantly different between L. humile–infested and control gardens. Diversity and evenness, but not richness, were significantly different between P. megacephala–infested and L. humile–infested gardens. Ordination analysis revealed that the three types of gardens had very different ant community profiles.

Ecological Dominance by Paratrechina longicornis (Hymenoptera: Formicidae), an Invasive Tramp Ant, in Biosphere 2

Tramp ants are invading disturbed ecosystems worldwide, exterminating untold numbers of native species. They have even invaded Biosphere 2, a 1.28-hectare closed greenhouse structure built in the Arizona desert as a microcosm for studying ecological interactions and global change. Invertebrate surveys within Biosphere 2 from 1990 to 1997 have revealed dramatic changes in faunal composition, including an almost complete replacement of the ant fauna by a single tramp ant species. In 1990-91, surveys in Biosphere 2 found no one ant species dominant. By 1993, populations of the crazy ant, Paratrechina longicornis (Latreille), a tramp species not found in 1990-91, had increased to extremely high levels. In 1996, virtually all ants (>99.9%) coming to bait were P. longicornis. We observed P. longicornis foragers feeding almost exclusively on the sugary excretions (honeydew) produced by vast numbers of Homoptera, primarily scale insects and mealybugs, found on many of the plants. High densities of ants were associated with high densities of homopterans. In 1997, soil and litter surveys found that the only invertebrates thriving in Biosphere 2, besides P. longicornis and homopterans, were either species with effective defenses against ants (well-armored isopods and millipedes) or tiny subterranean species that can escape ant predation (mites, thief ants, and springtails). A convergent pattern of biodiversity occurs in disturbed tropical and subtropical ecosystems dominated by tramp ants.