The bagworms Metisa plana is a recurrent indigenous invasive defoliator in oil palm plantations. A moderate foliar injury can cost up to 40% and above of yield loss for years. As an effective biological control agent (BCA) or by integrated pest management (IPM) on insect pests of economic significance affecting major crops of the countries in Asia-Pacific region, the adoption of the Asian weaver ant Oecophylla smaragdina might support farmers facing outbreaks. Information about the foraging activity and population dynamic (PD) of Oecophylla are important in implementing such program. Oecophylla being an obligate arboreal by nature was observed spending extended periods on the ground by occupying a vast territory under constant surveillance mode, which is significant and valuable feature for pest control. The foraging activity of major workers, their exploratory venture is closely related to systematic predation-hunting activity. The scarcity of population dynamic studies on the Oecophylla species contrast with the reports frequency of subterranean species. Estimation of population density of Oecophylla by direct nest counting method is feasible, practical and sustainable. This is contrasting with calculation done on excavated underground colonies consequential of their extinction. Simulation inaccuracy due to insufficient experimental evidence from using exclusively mathematical models is giving to real time long term field population dynamic more importance. Oecophylla colonies' stability, forager abundance and permanent patrol hunting oriented activity, are key factors for pest reduction. If the evaluation on O. smaragdina is higher, for this last decade, a significant upsurge of study on O. longinoda provided substantial novel highlights. The introduction of Oecophylla may alleviate pests management cost and offers a healthier environment by stopping the harmful usage of broad spectrum contact pesticides.

The Asian weaver ant (Oecophylla smaragdina) is a natural enemy, generalist predator of diverse major pest species (i.e. the highly destructive oriental fruit fly Bactrocera dorsalis) in economically strategic agricultural landscapes in Australia and Southeast Asia countries. For effective implementation of the weaver ant for biological control of the invasive bagworms Metisa plana, the dominant pest in the oil palm plantation, its distribution was investigated in Malaysia. From 2018-2022, censuses were first carried out to record Oecophylla colonies presence. Oecophylla colonies’ occupation patterns were monitored on 8 selected plantations. To distinguish between brood and barracks nests, 26 captured nests were evaluated to define the main predictor variable for its practical visual identification. More than 11000 palms with 10821 nests for over 500 colonies were sampled in this study. Results showed that O. smaragdina colonies distribution pattern exhibited three-dimensional ubiquitous occupation dominance. We also found that by observing the colony’s dense population spatial arrangements, it demonstrates them as spreading by waves featuring interconnected irregular geometrical patches shaped for each colony. The height to the ground nest location in palm canopies was the significant visual discriminant factor between Brood and barrack nests. Moreover, polydomous arboreal nesting behavior occupation occurred irrespective of palms or associated host plants sizes (≥ 3 m), throughout the year. However, colony nesting behaviors were polydomous and monodomous on shorter plants (≥ 2 m), while being strictly monodomous on small plants (≤ 1.5 m). Colonies occupied an average 3 to 4 palms yearly beginning from the newly founding phase up to the stable mature phase (3 to 4 years). Furthermore, we found that matured stable colonies (3 ≥ age ≥13) occupied 10-12 palms on average, on 800 m² to 2500 m² area delimited by a minimum average 20 m² of “no ants land” zone between each colony. Our results suggest that a sustained agriculture system in this area would be possible with the presence of matured colonies nests exploitation which could provide an efficient biological control ecosystem service.

The Asian weaver ant Oecophylla smaragdina is a natural enemy (predator) used as a biological control agent in Australia and several Southeast Asian nations against the most destructive and economically important oriental fruit fly Bactrocera dorsalis. For biological control of the invasive bagworm species Metisa plana in oil palm plantations, the composition of the colony's social structure was investigated to ensure its efficacy. On two colonies, all castes were examined stereo microscopically after nest collection and dissection. The head's width, head, thorax, abdomen, and body lengths of workers were evaluated during the morphology analysis. All colonies with more than a thousand eggs comprise of a founding egg-laying queen, reproductive winged green and newly emerged yellow queens, as well as adult drone males and workers. Future queens, males, and workers' pupae and larvae comprised immature individuals. It is the first study to characterise one caste of minor workers, two previously unidentified castes of intermediate workers, and two castes of major workers. The lengths of the body and abdomen are proposed as differentiating factors for workers. The discovery of a polymorphic size frequency distribution model contrasts with the consistently reported existence of archetypical bimodal systems in ants. Intermediate workers foraging outside the nest revealed reconnaissance and aggressive behaviours that aided major workers in their daily tasks. Due to their short lifespan and segregated nests, it is difficult to successfully sample adult males in wide plantations. An entire year's worth of reproductive individuals are produced by stable, three-year-old colonies, with a decrease in population size correlated with a significant decline in rainfall interception.