Biological control of the fruit‐spotting bug Amblypelta lutescens using weaver ants Oecophylla smaragdina on African mahoganies in Australia

• 1 African mahogany Khaya senegalensis is a high‐value timber tree. Pilot plantings showed that the fruit‐spotting bug Amblypelta lutescens causes severe damage of the tree in the wet–dry tropics of northern Australia. The weaver ant Oecophylla smaragdina is an efficient biocontrol agent in some horticulture crops. To investigate whether the ants control this pest, field experiments were conducted from April 2006 to January 2009 at two study sites in the Darwin area, Australia. A laboratory experiment was carried out in March 2007 at Berrimah Farm.
• 2 During the experimental period, in the weaver ant treatments, the overall percentage of trees damaged by the pest was 0–8% at both sites, and the damaged trees were attacked once only. In the treatments without weaver ants, however, the damage level was > 80% at Berrimah Farm and 31–100% at Howard Springs, and the damaged trees were attacked more than once.
• 3 The mean percentage of trees damaged per monitoring occasion was 0–2.6% in the weaver ant treatments at both sites, whereas, in the treatments without the ants, the damage percentages were 14.2–27.0% at Howard Springs and 28.2–48.6% at Berrimah Farm.
• 4 Extrafloral nectar of African mahoganies is attractive to weaver ants. Fruit‐spotting bugs only damage the tender parts of flushing shoots and growing tips. Weaver ants live on sugar solution and meat, and they frequently harvest extrafloral nectar on growing shoots, on which they catch nymphs of the pest for their meat supply. The aggressive behaviour of the ants also repels the pest away from flushing shoots.
• 5 The data suggest that weaver ants were effective biocontrol agents of fruit‐spotting bugs, and the ants can be used to manage the pest on African mahoganies.
• 6 The present study demonstrates that the introduced African mahogany comprises another major host of the fruit‐spotting bug.

     

The widespread collapse of an invasive species: Argentine ants (Linepithema humile) in New Zealand

Synergies between invasive species and climate change are widely considered to be a major biodiversity threat. However, invasive species are also hypothesized to be susceptible to population collapse, as we demonstrate for a globally important invasive species in New Zealand. We observed Argentine ant populations to have collapsed in 40 per cent of surveyed sites. Populations had a mean survival time of 14.1 years (95% CI = 12.9-15.3 years). Resident ant communities had recovered or partly recovered after their collapse. Our models suggest that climate change will delay colony collapse, as increasing temperature and decreasing rainfall significantly increased their longevity, but only by a few years. Economic and environmental costs of invasive species may be small if populations collapse on their own accord.     

Blackboard Mechanism Based Ant Colony Theory for Dynamic Deployment of Mobile Sensor Networks

A novel bionic swarm intelligence algorithm, called ant colony algorithm based on a blackboard mechanism, is proposed to solve the autonomy and dynamic deployment of mobiles sensor networks effectively. A blackboard mechanism is introduced into the system for making pheromone and completing the algorithm. Every node, which can be looked as an ant, makes one information zone in its memory for communicating with other nodes and leaves pheromone, which is created by ant itself in naalre. Then ant colony theory is used to find the optimization scheme for path planning and deployment of mobile Wireless Sensor Network （WSN）. We test the algorithm in a dynamic and unconfigurable environment. The results indicate that the algorithm can reduce the power consumption by 13% averagely, enhance the efficiency of path planning and deployment of mobile WSN by 15% averagely.     

Limiting Spread of a Unicolonial Invasive Insect and Characterization of Seasonal Patterns of Range Expansion

Limiting dispersal is a fundamental strategy in the control of invasive species, and in certain situations containment of incipient populations may be an important management technique. To test the feasibility of slowing the rapid spread of two Argentine ant (Linepithema humile) supercolonies in Haleakala National Park, Hawaii, we applied ant bait and toxicant within an experimental plot situated along a supercolony boundary. The 120×260 m plot simulated a small section of what could potentially be a 120 m wide treatment encompassing the entire expanding boundaries of both supercolonies. Foraging ant numbers at baited monitoring stations decreased sharply within two weeks after treatment, and ant spread was completely halted within the plot for at least one year. In contrast, an adjacent untreated colony boundary advanced an average of 65.2 m over the course of 1 year. Most of this spread took place in the summer and fall, at the time of highest ant abundance at bait monitoring stations, while no outward dispersal occurred during the spring and early summer. These patterns are consistent with the hypothesis that local budding dispersal in this unicolonial species stems from density dependent pressure rather than inherent founding behavior associated with mating. Based on results from this experiment, we are investigating the effectiveness of annual boundary treatments in slowing the Argentine ant invasion at Haleakala National Park. The goals of this program are to protect populations of native arthropods and to keep options open for eventual attempts at eradication. This revised version was published online in July 2006 with corrections to the Cover Date.     

Analysis and Design of an Agent Searching Algorithm for e-Marketplaces

Recently, agent techniques in electronic marketplaces (e-marketplaces) bring B-to-B trading into a new era. However, not much analysis on the behavior of agents has been reported. In this paper, based on the ant algorithm in network routing, we introduce a jumping (searching) model for agents in an e-marketplace network. However, we should be aware that if there are too many agents in the e-marketplace network, they will use up all communication bandwidth and computing resource. It is inevitable to investigate the behavior of agents, such as agent population. Based on the existing results in the ant algorithm in network routing, we present the behavior of agents in an e-marketplace network. Hence, we can control the agent population by setting the appropriate agent generation rate.     

Polymorphic microsatellite markers from the formicine ant Lasius (Dendrolasius) fuliginosus

Six polymorphic microsatellite loci were isolated and characterized from the temporary social parasitic ant Lasius fuliginosus by a highly efficient enrichment procedure. Observed allele numbers ranged from three to 20 per locus, whereby four out of the six tested loci had more than 10 alleles and showed both observed and expected heterozygosities greater than 70%. For each locus we present suitable primer sequences. With these microsatellite markers we will be able to reveal colony and population structure of L. fuliginosus.     

Eight highly polymorphic microsatellite markers for the army ant Eciton burchellii

The army ant Eciton burchellii is a nomadic predator in the rain forests of Central and South America. Detailed work has documented many aspects of this species’ ecology, behaviour and life history. However, a detailed investigation into within colony relatedness structure requires the development of genetic tools. Here we present eight microsatellite markers with between nine and 25 alleles. For each loci there is close agreement between observed and expected heterozygosity.     

Host plant derived feeding deterrence towards ants in the turnip sawfly Athalia rosae

Larvae of the sawfly Athalia rosae ruficornis Jakovlev (Hymenoptera: Tenthredinidae) feed on several glucosinolate-containing plants and have been shown to sequester the main glucosinolates of different hosts, namely sinalbin (p-hydroxybenzylglucosinolate) from Sinapis alba L., sinigrin (allylglucosinolate) from Brassica nigra (L.) Koch, and glucobarbarin ((S)-2-hydroxy-2-phenylethylglucosinolate) from Barbarea stricta Andrz. (Brassicaceae). These plant metabolites are stored in the haemolymph, which is readily released when larvae are attacked by predators. In a dual-choice bioassay the bio-activity of sawfly haemolymph collected from larvae reared on different host plants (S. alba, B. nigra, and B. stricta) was tested against the ant Myrmica rubra L. (Hymenoptera: Formicidae). The haemolymph had a stronger deterrence effect when the corresponding sawfly larvae were reared on S. alba than when reared on B. nigra and B. stricta. Haemolymph of caterpillars of Pieris rapae L. (Lepidoptera: Pieridae) that had fed on S. alba was not deterrent to the ants. No sinalbin could be detected in their haemolymph. The glucosinolates sinalbin and sinigrin, offered in a concentration comparable to that in the sawfly haemolymph, were deterrent to the ants, but not as strongly as the corresponding haemolymph samples. This suggests, that glucosinolates are not the only compounds involved in the chemical defence of A. rosae. However, the presence of sequestered glucosinolates is already a sufficient defence towards predators such as ants, and their effectiveness is modulated by the host plant chemistry.     

Pit-Building Decisions of Larval Ant Lions: Effects of Larval Age, Temperature, Food, and Population Source

Foraging decisions are an integral component of growth and maintenance and may reflect both environmental and genetic effects. We used a common garden experiment to evaluate the effects of food, temperature, and population source on pit-building decisions of the larval ant lion Myrmeleon immaculatus. In a laboratory common garden experiment, first-instar larvae from two southern (Georgia, South Carolina) and two northern (Connecticut, Rhode Island) populations were reared for 14 months in incubators under high- and low-food and high- and low-temperature regimes. For all populations, there was no effect of larval age on pit-building behavior. All larvae built and maintained pits more frequently at high temperatures than at low temperatures, and larvae in the low-food treatments built and maintained pits more frequently than larvae in the high-food treatments. Larvae from the southern populations built and maintained pits more frequently than larvae from northern populations. These results suggest that regional differences in foraging behavior may contribute to latitudinal gradients in life history strategies seen in this insect.     

Characterization of polymorphic microsatellites in the castration parasite plant‐ant Allomerus octoarticulatus cf. demerarae (Formicidae: Myrmicinae)

Fifteen microsatellite loci were isolated from the Peruvian tropical plant‐ant Allomerus octoarticulatus cf. demerarae (Hymenoptera: Myrmicinae) and their polymorphism was characterized. High levels of within‐population variation were observed at most loci, with number of alleles ranging from one to 21, and heterozygosity from 0 to 1 per population sample. Cross‐species amplification of these loci was also tested in one other species of the ant genus Allomerus (Allomerus decemarticulatus), displaying similar life history.