Resource Exploitation Strategies Research Articles

Role of Archaeomalacological Research in Sri Lanka: A Synthesis

This article focuses on the role of malacological research in Sri Lanka and the significance it holds within the field of archaeology. We aim to explore and synthesize the diverse applications of malacology to understand past societies and environments that once thrived on the island. Malacology, the study of Mollusca, is an interdisciplinary field that combines elements of biology, ecology, and archaeology. In the last fifty years, malacological research has gained traction within archaeological investigations, contributing valuable insights into human-environment interactions, subsistence patterns, and cultural dynamics. By integrating data from archaeological excavations with molluscan remains found at sites, researchers can reconstruct past environments, identify resource exploitation strategies, and shed light on human dietary choices. We explore the implications of malacological studies for understanding trade networks, migration patterns, and the socio-economic complexities of ancient Sri Lankan societies. We summarize existing literature on archaeomalacological research worldwide, as well as specific case studies conducted within Sri Lanka. By placing these findings within the broader context of Sri Lanka’s archaeology, this research aims to bridge existing knowledge gaps and contribute to a more comprehensive understanding of the island’s rich cultural heritage, highlighting the pivotal role of archaeomalacology and its potential to enhance interpretations of past societies and environments. This synthesis seeks to examine the potential contributions of archaeomalacology in the understanding of Sri Lanka’s past.

The stone connection: Functional and microbotanical analysis of prehistoric macrolithic tools on the island of Formentera (Balearic Archipelago)

Formentera was one of the last Mediterranean islands to be colonized by humans at the end of the third millennium BC. This island is rather small (83 km2) with marked biogeographical constraints. Typical of a semi-arid environment, the island is poor in resources and biodiversity. Macrolithic tools from the prehistoric sites of Ca na Costa (ca. 2130–1790 cal BC), Cap de Barbaria II (ca. 1740–900 cal BC), and Sa Cala (ca. 800–570 cal BC) showed similar technological, typological, and functional patterns documented in other prehistoric tool assemblages from the Balearic Islands. This common technology is reflected in the way the raw materials were procured, as well as the manufacture, the maintenance strategies, and the use of macrolithic tools (e.g., grinding stone tools, abraders, and percussion tools). Integrated phytolith and starch analyses from grinding toolkits show evidence of people’s exploitating millet-tribe species (Paniceae) during the Bronze Age, cereals that are well-adapted to nutrient-poor soils, including exotic taxa such as possible foxtail millet (Setaria cf. italica). The production and use of this stone technology suggests how the first human communities on the island achieved and shared social knowledge about the insular landscape and its environmental constraints. This integrative archaeological research in Formentera has shown development of a set of innovative, diversified, and intensive resource exploitation strategies, underlining the high adaptability and resilience of prehistoric societies as well as the sharing of technology within the Balearic archipelago and its independent evolution from mainland technologies.

Habitat fragmentation and the sporadic spread of pastoralism in the mid-Holocene Sahara

The transition from hunting and gathering to food production in the Central Sahara is complex and variable. The paucity of direct radiocarbon dates and poor preservation of organic remains makes it difficult to track the origins, spread and intensity of food production in this part of the world. Nevertheless, the prevailing narrative in North African prehistory is that cattle pastoralism was the defining characteristic of mid-Holocene African economies, against a backdrop of widespread aridification. Here we present the first ever trans-Saharan analysis of mid Holocene subsistence behaviour using a novel comparative analysis of zooarchaeological remains, organic residue analysis from pottery and palaeohydrological mapping. In some areas, domestic animal resources appear to have played only a marginal role in economic practices, which were typically diverse and potentially even specialised as a response to local environmental conditions. We utilise organic residue analysis (ORA) from 478 potsherds in conjunction with zooarchaeological data to examine animal resource exploitation strategies and environmental change. We demonstrate a significant increase in the δ13C value of the C16:0 fatty acid through time, reflecting a substantial increase in C4 vegetation associated with increased aridity. However, despite the changing environmental conditions, North Africa offered a unique context for Neolithic developments. Lakes that persisted during the onset of Saharan aridification provided highly productive and sustainable ecological niches that supported the resilience of hunter-gatherer fisherfolk. Analysis of site distance to water and faunal exploitation strategies reveals a significant correlation between aquatic resource strategies and proximity to water. As such, we propose that rather than being a wave of expansion, as has often been suggested, cattle pastoralism in the Sahara happened as a sporadic expansion, with mid-Holocene populations adapting and specialising in the context of habitat fragmentation and increasing environmental diversity.

Early Bronze Age obsidian networks: A view from Project ArAGATS

As a testimonial to Ruben Badalyan’s indelible contributions to the archaeology of the South Caucasus, this paper presents the results of a portable X-ray fluorescence study of a large sample of securely provenienced Early Bronze Age obsidian artifacts and debris from the excavations of Project ArAGATS, the collaborative program of archaeological research that we co-founded a quarter of a century ago. Statistical analyses were performed on a corpus of 467 pXRF assays of materials from the sites of Gegharot and Aragatsi Berd, located on the northeast flank of the Tsaghkahovit Plain of central Armenia. The results shed important new light on changing resource exploitation strategies over time that may be indices of variable homelands for Gegharot’s settlers. Moreover, variation in exchange networks across Gegharot’s topographically defined sectors indicate differential participation in regional exchange networks by contemporaneous households. Taken together, the results of this study indicate that the material homogeneity of Kura-Araxes villages like Gegharot need not suggest a lack of variability in daily experiences, social networks, and exchange relationships.

SAGAscape: Simulating Resource Exploitation Strategies in Iron Age to Hellenistic Communities in Southwest Anatolia

In this paper, we present SAGAscape, an agent-based model of resource exploitation and subsistence strategies to explore the human impact of hilltop settlements on the natural environment in the study area of Sagalassos (southwest Turkey) during the Iron Age to Hellenistic period. Using realistic GIS data and empirical settlement patterns as input, we simulate communities with resource exploitation strategies for three main resources: food, wood and clay. The model produces results consistent with empirical observations by simulating anthropogenic zones of human impact embedded in a forest matrix. General patterns of sustainability for most communities under most model settings can be observed. Under certain high demand settings, however, trade-offs between resource exploitation strategies start to emerge, resulting in disruption of resource stocks in certain communities. The SAGAscape model provides a suitable baseline for the assessment of socio-ecological sustainability in subsistence and resource exploitation of local communities. Through this work, we aim to advance the usage of computational modelling and simulations in Classical and Anatolian archaeology.

Investigating the Plant Microremains on Ceramic Li Tripods to Ascertain Their Function and the Plant Resource Exploitation Strategies During the Lower Xiajiadian Culture Period in Chifeng, Northeast China

In undertaking a functional study of ceramic Li tripods, a common archaeological artifact in Northeast China during the Bronze Age, this study provides a crucial insight into both the function of these ceramics, plant resource strategies and human diets during this period. The precise function of the Li tripod has to date been controversial due to a lack of direct contextual evidence. Hence, this paper presents analyses of 10 Li tripods from six sites in the Chifeng area of Northeast China, all of which can be dated from their excavation contexts to the Lower Xiajiadian cultural period (3,900–3,400 cal a B.P.). The interior and exterior surfaces of the tripods were analyzed using starch grain analysis, phytolith analysis and microfossil charcoal analysis. A total of 133 starch grains were recovered, of which 111 (83.46%) were found on 80% of the interior surfaces examined. Further analysis found that these starch grains had damage features specifically gelatinised characteristics, which were consistent with the starch grains that had been boiled in our cooking simulations. In addition, there were obvious soot traces on the surfaces of the tripods, 2,835 microfossil charcoal grains not completely burned were identified, and 70% of the exterior surface samples had a higher frequency of contact with fire. These findings serve to confirm that Li tripods were used in the cooking of food. Of the 133 starch grains found, only 62 could be identified to species level. These were foxtail millet (Setaria italica) and broomcorn millet (Panicum milliaceum) and plants from Triticeae taxa, as well as roots and tubers. The 3,424 phytoliths recovered from the 10 tripods were found to belong to the Panicoideae and Pooideae genera, of which the husks from foxtail and broomcorn millets from the Panicoideae genus accounted for 6.19% of the total. These results indicate that millets, the Triticeae, roots, and tubers, in addition to plants from Panicoideae and Pooideae genera, were utilized in the Chifeng area of Northeast China during the Bronze Age. This study deepens our understanding of the local subsistence patterns and the social context of early Bronze age civilization in the region.

‘We hunt to share’: social dynamics and very large mammal butchery during the Oldowan–Acheulean transition

ABSTRACT The Early Pleistocene (2.58–0.78 Ma) was a period of major evolutionary changes in the hominin lineage. The progressive consolidation of bipedal locomotion, alongside increases in cranial capacity and behavioural flexibility, allowed early Homo to exploit an increasing diversity of resources and environmental settings within the changing landscapes of East Africa and beyond. These complex processes were not necessarily linear or spatially uniform, given the technological diversity documented, particularly during the Oldowan–Acheulean transition. In this paper, we argue that human populations experienced a considerable demographic expansion from c.1.7–1.5 Ma onwards, expressed in the number, size, density, and distribution of archaeological sites. These patterns resulted from the interplay of high-yielding animal resource exploitation strategies, technological investment, prosocial behaviours as well as increasingly structured land use patterns. A more consolidated hominin demographic structure led to the extinction of large sympatric carnivore species, while larger group sizes would have led to more successful Out-of-Africa dispersals.

Offshore Hydrocarbon Exploitation Observations from VIIRS NTL Images: Analyzing the Intensity Changes and Development Trends in the South China Sea from 2012 to 2019

The South China Sea is rich in hydrocarbon resources and has been exploited for decades by countries around it. However, little is known about the hydrocarbon exploitation (HE) activities in the South China Sea in recent years, especially its intensity changes and development trends. Here, a long-time series of monthly Visible Infrared Imaging Radiometer Suite (VIIRS) nighttime light (NTL)images were applied to observe and analyze the HE dynamics in the South China Sea from 2012 to 2019. A target recognition method combining feature increment strategy and random forest model was proposed to obtain the spatial distribution of offshore HE targets, with an average comprehensive precision of 94.44%. Then, a spatio-temporal statistical analysis was carried out on the intensity changes and development trends of HE activities. The results showed that: (1) From 2012 to 2019, the quantity of HE targets in the South China Sea has increased from 215 to 310, from rapid to stable increasing taking 2014 as a turning point. (2) The distribution density of HE targets increases year by year, with the maximum density reaching 59/ 10,000 Km2, and with the most significant increase in the new hydrocarbon-bearing fields close to the deep-sea. (3) The quantity of HE targets shallower than -300m has been increasing with years, but showing a decreasing proportion trend, falling from 96.7% in 2012 to 94.2% of the total in 2019. (4) After 2015, the exploitation core of most hydrocarbon-bearing basins began to shift from shallow-sea to deep-sea, with gradually increasing exploitation depth, among which the maximum depth reaching −1580 m. Against the background of the changes in international crude oil prices and the vigorous development of deep-sea HE, this research provides important information and methodological references for the formulation and analysis of offshore hydrocarbon resource exploitation strategies.

Intra-specific multi-trait approach reveals scarce ability in the variation of resource exploitation strategies for a dominant tall-grass under intense disturbance

Mowing is a suitable practice to restore the grassland coenological composition after invasion of tall-grasses. However, how it affects the tall-grass intraspecific variation is still unknown. We investigated if mowing decreases the competitive ability of the tall-grass Brachypodium rupestre, and if this reduction is due to its poor ability to adapt to the new conditions by reducing resource investment in leaf and flower production, resource storage in belowground organs, increasing seed output and reducing seed mass.In 2017, we measured vegetative and reproductive traits of B. rupestre in two fenced areas in central Apennines (Italy). Half of each area had been mown twice a year since 2010 and half remained unmown. To investigate the effect of mowing on B. rupestre’s functional strategies, we used linear mixed-effects modelling and correlation analysis.Mowing significantly reduced the trait values related to competitive ability/resource acquisition (vegetative height and leaf traits), resource storage (mature hypogeogenous rhizome), and sexual reproduction (mean seed mass, number of flowers, reproductive height), but increased seed output. We did not find significant variation of dry matter content in epigeogenous rhizomes and in the shoot number.B. rupestre is not prone to endure a prolonged disturbance, not being able to reallocate resources from acquisitive and retentive to reproductive structures. However, it is able to guarantee the presence of individuals to a certain degree by changing the reproductive strategies, such as decreasing the seed mass and increasing the seed output.

Dietary adaptations and palaeoecology of Lophialetidae (Mammalia, Tapiroidea) from the Eocene of the Erlian Basin, China: combined evidence from mesowear and stable isotope analyses

AbstractLophialetidae is an extinct group of endemic Asiatic tapiroids that are widely distributed in the Eocene sediments of Asia. Schlosseria magister and Lophialetes expeditus are the most abundant species in this family. However, their dietary and ecological characteristics are largely unknown. For the first time, we reconstruct the palaeodiet and habitat of these two lophialetids using a combination of mesowear and stable carbon isotope analysis of fossil teeth excavated from the Erlian Basin, China. Mesowear analysis (n = 141) suggests that the dietary structure of S. magister and L. expeditus shifted from less to more abrasive diets from ~52 to ~42 Ma. Stable carbon isotope analysis (n = 137) suggests that the habitats of S. magister and L. expeditus became drier and/or more open through time. The dietary shifts of the two lophialetids are consistent with evident changes in habitat. The changes in the diet and habitat were probably related to global climate change during that time period. The gradual drop in global temperatures during the early–middle Eocene led to a drier and more open terrestrial ecosystem in the Erlian Basin, probably resulting in changes in floral composition of the environment inhabited by S. magister and L. expeditus. Hence, herbivores highly susceptible to vegetation modification had to develop new resource exploitation strategies to adapt to these changes. Schlosseria magister, considered to be the sister‐group of L. expeditus and with a low level of ecological flexibility, was unable to adapt to the habitat changes finally becoming extinct at ~45 Ma.

Variaciones y continuidades: el uso de los recursos faunísticos en asentamientos indígenas del siglo XX en el centro-oeste de Santa Cruz

En este trabajo se propone un abordaje a las estrategias de uso de los recursos por parte de grupos familiares de origen indígena que habitaron la meseta del Strobel (Santa Cruz) durante el siglo XX. Dichos grupos se instalaron en la región evitando su incorporación a las reservas indígenas dispuestas por el Estado nacional. Como parte de la ocupación de este espacio, dichas unidades familiares implementaron diversas estrategias económicas, marcadas por el acomodamiento y reajuste ante el avance de la economía pastoril y la pérdida de tierras. Se concluye que las estrategias adoptadas se caracterizaron por su diversidad y exibilidad, combinando prácticas tradicionales con aquellas vinculadas al nuevo lugar que estos grupos adquirieron en la economía. A pesar de ello, la aparición de nuevas legislaciones y el progresivo arrinconamiento de los grupos locales llevaron al abandono de la meseta por parte de éstos.

Spatial distribution of Donax trunculus (Linnaeus, 1758) populations along the intertidal area of the Gulf of Cádiz (SW, Spain)

Spatial distribution of Donax trunculus (Linnaeus, 1758) populations along the intertidal area of the Gulf of Cádiz (SW, Spain)

Impacts of dietary amino acid composition and microbial presence on preference and performance of immatureLucilia sericata(Diptera: Calliphoridae)

1. As primary colonisers of ephemeral resources, the common green bottle fly,Lucilia sericata, must exercise efficient resource exploitation strategies to maximise fitness. Foraging incurs costs, so the efficient evaluation of resources is essential for individuals relying on fragmented patches whose dissimilarity may result in fitness consequences for offspring. Thus, selective pressures between carrion‐using insects and carrion‐associated microbes are expected to occur.2. Microbes play a pivotal role in adult fly assessment of resources via production of volatile organic compounds (VOCs) resulting from the breakdown of essential amino acids. If one assumes that chemoreception of these VOCs provides public information regarding the corresponding essential amino acids, the resulting effects on maternal decision‐making could impact larval resource exploitation.3. The essential amino acids phenylalanine, methionine, valine, and tryptophan, the corresponding VOCs of which are known fly attractants, were used to construct imbalanced diets with and without antimicrobial treatment to investigate the impact of suboptimal food sources on larvalL. sericata.4. The results of this study demonstrate that both amino acid composition and microbial presence influence behaviour, with larvae displaying a preference for untreated diets lacking methionine and a complete reversal in preference for antimicrobial‐treated diets. This interaction between diet and antimicrobial treatment indicates that the presence of microbes that produce essential amino acids may impact larval resource utilisation strategies. This investigation into larval performance on diets deficient in amino acids that provide important VOC cues to maternal flies provides a stepping stone for dissecting larval behavioural strategies on ephemeral resources when faced with limited choices.

Pre-Hispanic settlements in hydrometeorologically susceptible areas during the late Holocene: The Upper Delta of the Paraná River Case

In this paper, we present the results of the geoarchaeological studies carried out in two archaeological localities of the Upper Delta of the Paraná River (Argentina). The main objective of these studies is to depict the pre-Hispanic strategies involved in the colonization and settlement of southern South America wetlands. Paraná Delta is one of the most conspicuous areas of these lowlands and comprises a large wetland macrosystem. Its current geomorphological configuration was established after the last transgressive mid-Holocene event c. 600014C yr BP. In this environment, a high ecological heterogeneity, with diverse and abundant tropical and temperate biota, was developed. These features were important factors to the human colonization and utilization of these wetlands. However, this environment has the highest hydrometeorological susceptibility of La Plata basin. This susceptibility had an impact on settlement systems and resource exploitation strategies established in the area since at least 200014C yr BP. These strategies involved at least two settlement types: semi-permanent residential camps and transitory camps oriented to exploit particular resources. The semi-permanent settlements were located in anthropogenic elevated mounds, locally known as ‘cerritos’, and were not subjected to seasonal inundations. Conversely, the transitory camps are found in levees exposed to recurrent flooding.

Neandertal versus Modern Human Dietary Responses to Climatic Fluctuations.

The Neandertal lineage developed successfully throughout western Eurasia and effectively survived the harsh and severely changing environments of the alternating glacial/interglacial cycles from the middle of the Pleistocene until Marine Isotope Stage 3. Yet, towards the end of this stage, at the time of deteriorating climatic conditions that eventually led to the Last Glacial Maximum, and soon after modern humans entered western Eurasia, the Neandertals disappeared. Western Eurasia was by then exclusively occupied by modern humans. We use occlusal molar microwear texture analysis to examine aspects of diet in western Eurasian Paleolithic hominins in relation to fluctuations in food supplies that resulted from the oscillating climatic conditions of the Pleistocene. There is demonstrable evidence for differences in behavior that distinguish Upper Paleolithic humans from members of the Neandertal lineage. Specifically, whereas the Neandertals altered their diets in response to changing paleoecological conditions, the diets of Upper Paleolithic humans seem to have been less affected by slight changes in vegetation/climatic conditions but were linked to changes in their technological complexes. The results of this study also indicate differences in resource exploitation strategies between these two hominin groups. We argue that these differences in subsistence strategies, if they had already been established at the time of the first contact between these two hominin taxa, may have given modern humans an advantage over the Neandertals, and may have contributed to the persistence of our species despite habitat-related changes in food availabilities associated with climate fluctuations.

Diet and trophic niche breadth of the rare acrobatic cavy Kerodon acrobata (Rodentia: Caviidae) in a seasonal environment

We investigated diet and feeding behavior of the acrobatic cavy Kerodon acrobata, a rare caviomorph rodent endemic from the Cerrado (Brazilian savannah). We tested whether its trophic niche breadth varies between seasons and whether this species shows seasonal differences in food resource use. Feeding behavior was observed through observations of foraging activities in dry forest associated with limestone outcroppings in central Brazil. K. acrobata showed a generalist diet, feeding on leaves from at least 16 native plant families, also consuming flowers and fruits collected directly from plants or litterfall as well as branches, sprouts, and bark. The diversity of feeding behavior categories did not differ significantly between rainy and dry seasons. The trophic niche breadth considering the plant species consumed, however, decreased during the dry season, when this rodent relied mainly on fallen flowers of Handroanthus serratifolius (Caricaceae; about 44 % of the identified feeding records). The diet of the acrobatic cavy was influenced by the availability of falling leaves and flowers during the dry season, when the animals focused their foraging activities on litterfall. The animals seemed not to extend their behavioral repertoire of foraging in the dry season; instead, they seasonally changed their resource exploitation strategy by altering the proportions of items used and the plant species consumed. The trophic niche breadth and plastic feeding behavior of the acrobatic cavies may explain their persistence in disturbed habitats. Their close relationship with the forests studied indicates the vulnerability of K. acrobata to activities that may threaten the integrity of dry forest areas.

Orchestration of multicellular heterogeneous networks, resources management, and electromagnetic interference mitigation techniques

Abstract The primary goal of this study is to develop a simulation platform that ensures a synergy between WiMAX and WiFi at the PHY and MAC layers, manages the available resources efficiently, mitigates electromagnetic interference (EMI), and enhances the overall performance of heterogeneous networks. To achieve this synergy, the OFDMA physical layer protocol is implemented and combined with radio resource exploitation strategies and judicious power allocation to users. The COOPERATIVE subcarrier allocation strategy outperforms the RANDOM strategy in terms of mean capacity and EMI mitigation, because it efficiently manages radio resources and inherently combats CCI (hence, EMI is mitigated). Results also show that in real scenarios (low SINR WiFi ), the synergy between WiMAX and WiFi leads to a high mean capacity (and in some cases, a 15-fold increase). In terms of power levels, the dissipation by a user corresponds to less than 23% of the total available power (1 W).

A multidimensional functional trait analysis of resource exploitation in European ants.

The major factors explaining ecological variation in plants have been widely discussed over the last decade thanks to numerous studies that have examined the covariation that exists between pairs of traits. However, multivariate relationships among traits remain poorly characterized in animals. In this study, we aimed to identify the main multivariate trait dimensions that explain variance in important functional traits related to resource exploitation in ants. To this end, we created a large ant trait database. This database includes information on 11 traits that are important in ant resource exploitation; data were obtained for 150 European species found in different biomes. First, we examined the pairwise correlations between the traits included in the database. Second, we used multivariate analyses to identify potential trait dimensions. Our study shows that, to a great extent, resource exploitation strategies align along two main trait dimensions. The first dimension emerged in both the overall and group-specific analyses, where it accounted for the same pairwise trait correlations. The second dimension was more variable, as species were grouped by levels of taxonomy, habitat, and climate. These two dimensions included most of the significant pairwise trait correlations, thus highlighting that complementarity, but also redundancy, exists among different pairs of traits. The first dimension was associated with behavioral dominance: dominance was associated with large colony size, presence of multiple nests per colony, worker polymorphism, and a collective foraging 'strategy. The second dimension was associated with resource partitioning along dietary and microhabitat lines: it ranged from species that consume liquid foods, engage in group foraging, and mainly nest in the vegetation to species that consume insects and seeds, engage in individual foraging, and demonstrate strictly diurnal activity. Our findings establish a proficient ecological trait-based animal research that minimizes the number of traits to be measured while maximizing the number of relevant trait dimensions. Overall, resource exploitation in animals might be framed by behavioral dominance, foraging strategy, diet, and nesting habitat; the position of animal species within this trait space could provide relevant information about their distribution and abundance, for today as well as under future global change scenarios.

What is on the craftsmen’s menu? Plant consumption at Datrana, a 5000-year-old lithic blade workshop in North Gujarat, India

The exploitation of lithic resources was an important aspect of prehistoric resource exploitation strategies and adaptation. Research has mostly focused on technological and spatial aspects of lithic factory sites, often overlooking how these sites were integrated within local socioecological dynamics in terms of food acquisition and consumption. The aim of this paper is to study plant consumption at Datrana, a 5000-year-old lithic blade workshop in North Gujarat, India, in order to understand its occupants’ subsistence strategies. The results of archaeobotanical, mineralogical and soil pH analyses show that the occupants of this factory site were consuming local crops but not processing them, suggesting that either (a) food was being processed in other areas of the site or (b) it was acquired in a ‘ready-to-consume’ state from local food-producing communities. This study highlights the integration of a lithic factory site within its surrounding cultural and natural landscape, offering an example of how the inhabitants of a workshop interacted with local communities to acquire food resources.

Living on the Edges: Spatial Niche Occupation of Asian Citrus Psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), in Citrus Groves.

The spatial niche occupation of the Asian citrus psyllid, Diaphorina citri Kuwayama, 1908, was evaluated to determine its field colonization and food resource exploitation strategies in citrus groves. Mature grapefruit and sweet orange groves were surveyed as part of an area-wide program in 2009–2010 to determine D. citri population densities and between-tree distribution. In both cultivars, significantly more psyllids were found on perimeter trees throughout the study period suggesting a strong edge effect in D. citri distribution in the groves. D. citri densities and infestation levels gradually declined from the edge to the center of grove. Higher numbers of D. citri were recorded on trees located on the east and south sides of the groves than those on the west and north sides. Citrus groves located at the outer edge of the study with at least one side non-surrounded to other citrus groves harbored significantly more D. citri than groves located within the block cluster and entirely surrounded by other groves. In detailed field studies during 2012, infestation of D. citri started from border trees in the grove where possibly one generation is completed before inner trees become infested. In addition, psyllid densities decreased significantly with increasing distance from the grove edge. Using the selection index, D citri exhibited a strong niche occupation preference for border trees.