Mixed Fruit Orchards Research Articles

Mediterranean fruit fly population phenological patterns are strongly affected by elevation and host presence

The Mediterranean fruit fly (medfly) (Ceratitis capitata, Diptera: Tephritidae), is an extremely polyphagous pest that threatens the fruit production and trading industry worldwide. Monitoring C. capitata populations and analysing its dynamics and phenology is considered of outmost importance for designing and implementing sound management approaches. The aim of this study was to investigate the factors regulating the population dynamics of the C. capitata in a coastal and semi-mountainous area. We focused on effects of topography (e.g. elevation), host presence and seasonal patterns of ripening on the phenological patterns considering data collected in 2008. The experimental area is characterized by mixed fruit orchards, and Mediterranean climate with mild winters. Two trap types were used for population monitoring. The female targeted McPhail type and the male targeted Jackson type. Traps were placed in farms located at different elevations and landscape morphology (coastal and semi-mountainous areas). The main crops included citrus, apples, peaches, plums, pears, figs, quinces and apricots. Adult captures were first recorded in May, peaked in mid-summer and mid-autumn and almost ceased at the end of the season (January 2008). Captures in the coastal areas preceded that of highlands by 15 days. Most of the adults detected during the fruit ripening of late stone fruit cultivars (first peak) and citrus (second peak). The probability of capturing the first adults preceded almost three weeks the peak of adult captures either considering the elevation or host focus analyses. The results provide valuable information on the seasonal population trend of C. capitata in mixed fruit Mediterranean orchards and can support the set-up of IPM systems in areas with various landscapes and different hosts throughout the fruit growing season.

Local and landscape context affects bee communities in mixed fruit orchards in Southern Thailand

Abstract Bees play an important role by contributing to the pollination of a diverse range of crops and wild plants. However, bees are threatened by deforestation and habitat degradation caused by urbanization and agricultural intensification, which reduce floral and nesting resources. In this study, the effects of local (orchard size, flowering plant abundance and richness and floral abundance) and landscape factors (surrounding agricultural, forest and urban cover) on bee richness and abundance in mixed fruit orchards were determined from 28 mature orchards interspersed along a gradient of landscape complexity. Bees were observed for 15 min in 2 × 2 m plots. We categorized all bees into one of the three groups: (a) honey bees, (b) solitary bees and (c) stingless bees. Several local and landscape factors were found to influence bee richness and abundance. Honey bee abundance was positively affected by orchard size, whereas honey bee richness was not. Stingless bee richness and abundance were positively correlated with floral abundance. Forest cover within a 3‐km radius positively affected solitary bee richness. Solitary bee abundance was positively affected by forest cover within a 3‐km radius and negatively impacted by urban cover within a 1.5‐km radius. In our study area, small forest patches are found in abundance; thus, the high proportion of forest edge, relative to the forest interior, greatly supports solitary bee abundance and richness in this landscape. Moreover, most solitary bees are soil‐nesting species that may be excluded from environments that are converted from natural to anthropogenically developed areas. Recommendations to protect pollinators included conserving existing forest patches, especially forest margins; restoring forest patches within farmland landscapes; maintaining a diversity of herbs and grasses within mixed fruit orchards; establishing live fences composed of diverse plant species and retaining dead trees within farmland. For urban areas, augmenting floral resources in green spaces is suggested.

Bangkok’s existing mixed fruit orchards are tree diversity hotspots for city greening

Bangkok’s Inner Orchard (BIO), located in the west peri-urban area of the city, provides both fresh products and ecological benefits to its inhabitants. Although this unique forest-like cultivation of mixed fruit trees growing on dikes has the potential to become an urban forest, it has never been thoroughly investigated. Urban expansion is a threat to this orchard. Sustainable cities must maintain a balance between development and the environment. In this study, six orchards were surveyed by collecting data on tree species, plant height, crown width, and location and analyzed to identify the orchard areas covered by forest canopy and clarify the forest structure and tree species diversity in the orchards. Overall, 98.64% of the forest canopy within the orchard area was evaluated using cover analysis. Analysis of the forest structure of the BIO revealed that the average tree height was greater than that of common orchard trees. Tree diversity analysis showed an average Shannon index value of 2.53, indicating mid-range diversity. Older orchards showed a greater diversity of fruit tree species, whereas newer orchards, replanted after major flood and drought events, showed a lesser diversity of fruit tree species. In order to protect BIO on the long-term, it is essential to identify and apply appropriate conservation strategies. Including BIO areas in the Bangkok greening scheme would cause rapid increases in the green area per capita ratio. Both urban food forest and urban agriculture concepts could be applied to existing BIO orchards, which represent new urban green area types. BIO thus has the potential to act as an urban forest and tree diversity hotspot for Bangkok.

Adoption and Cost-benefit Analysis of Drip Irrigation for Production of High-Value Crops in Pakistan

Drip irrigation is regarded as one of the highly efficient methods that allow limited water resources to be properly utilized. The study has been conducted to perform the economic analysis of low and high head drip irrigation systems throughout the country based on data from 100 adopters of drip irrigation through a research & development project funded by the International Center for Agricultural Research in the Dry Areas (ICARDA-Pakistan)/United States Department of Agriculture (USDA). A field survey for the study was conducted in the year 2018 in all the provinces of Pakistan. The study revealed that technology is generally adopted by the farmers having diversified income sources and medium-sized land holdings i.e. ranging from 12.5 to 25 acres. System installation cost-shared 11 percent in low-head drip system of the annual production cost of fruits. While, it shared 29, 32, and 27 percent in case of a high-head system for grapes orchards, vegetables in tunnels, and open fields, respectively. Low-head drip irrigation is profitable for dates/ lemon orchards in Khyber Pakhtunkhwa with a benefit-cost ratio (BCR) of 1.27:1.00. It results in considerable profitability for grapes orchards with BCR of 1.73:1.00 and 1.32:100 in Punjab and Balochistan provinces, respectively. The low-head system is also beneficial for mixed fruit orchards in rain-fed Punjab with a BCR of 1.24:1.00. Similarly, for high-head systems, the benefit-cost ratio was the highest for grapes produced in rain-fed Punjab (2.62:1.00), followed by squash-gourd in irrigated Sindh (2.17:1.00) bitter-gourd in rain-fed Punjab (1.50:1.00) and okra in Sindh (1.22:1.00). However, low and high-head systems could not result in considerable returns for farmers in the case of mixed fruits in Balochistan and cucumber production in tunnels in Punjab province during the study year.

Diversity and Cross-Infection Potential of Colletotrichum Causing Fruit Rots in Mixed-Fruit Orchards in Kentucky.

Fungi in the genus Colletotrichum cause apple, blueberry, and strawberry fruit rots, which can result in significant losses. Accurate identification is important because species differ in aggressiveness, fungicide sensitivity, and other factors affecting management. Multiple Colletotrichum species can cause similar symptoms on the same host, and more than one fruit type can be infected by a single Colletotrichum species. Mixed-fruit orchards may facilitate cross-infection, with significant management implications. Colletotrichum isolates from small fruits in Kentucky orchards were characterized and compared with apple isolates via a combination of morphotyping, sequencing of voucher loci and whole genomes, and cross-inoculation assays. Seven morphotypes representing two species complexes (C. acutatum and C. gloeosporioides) were identified. Morphotypes corresponded with phylogenetic species C. fioriniae, C. fructicola, C. nymphaeae, and C. siamense, identified by TUB2 or GAPDH barcodes. Phylogenetic trees built from nine single-gene sequences matched barcoding results with one exception, later determined to belong to an undescribed species. Comparison of single-gene trees with representative whole genome sequences revealed that CHS and ApMat were the most informative for diagnosis of fruit rot species and individual morphotypes within the C. acutatum or C. gloeosporioides complexes, respectively. All blueberry isolates belonged to C. fioriniae, and most strawberry isolates were C. nymphaeae, with a few C. siamense and C. fioriniae also recovered. All three species cause fruit rot on apples in Kentucky. Cross-inoculation assays on detached apple, blueberry, and strawberry fruits showed that all species were pathogenic on all three hosts but with species-specific differences in aggressiveness.

Use of Telomere Fingerprinting to Identify Clonal Lineages of Colletotrichum fioriniae in Kentucky Mixed-Fruit Orchards.

Multiple species in the fungal genus Colletotrichum cause anthracnose fruit rot diseases that are responsible for major yield losses of as much as 100%. Individual species of Colletotrichum typically have broad host ranges and can infect multiple fruit species. Colletotrichum fioriniae causes anthracnose fruit rots of apples, blueberries, and strawberries in Kentucky orchards where these fruits grow in close proximity. This raises the possibility of cross-infection, which may have significant management implications. The potential occurrence of cross-infection was investigated by using telomere fingerprinting to identify C. fioriniae clones in several mixed-fruit orchards. Telomere fingerprints were highly polymorphic among a test group of C. fioriniae strains and effectively defined clonal lineages. Fingerprints were compared among apple, blueberry, and strawberry isolates of C. fioriniae from three different orchards and similarity matrices were calculated to build phylograms for each orchard group. Multiple clonal lineages of C. fioriniae were identified within each orchard on the same fruit host. Related lineages were found among isolates from different hosts, but the results did not provide direct evidence for cross-infection of different fruit species by the same clones. Recovery of the same clonal lineages within orchards across multiple years suggested that local dispersal was important in pathogen population structure and that C. fioriniae strains persisted within orchards over time. Isolates from blueberry were less diverse than isolates from apple, perhaps related to more intensive anthracnose management protocols on apple versus blueberry. Telomere fingerprinting is a valuable tool for understanding population dynamics of Colletotrichum fruit rot fungi.

Foraging Behaviour of Three Sympatric Babblers (Family: Timaliidae)

We investigated the foraging ecology of three species of babblers in Kampung Gumbang, Kampung Padang Pan and Dered Krian National Park, Bau. Vegetation in Kampung Gumbang include tall trees, shrubs and patches of kerangas. Dered Kerian National Park consists of mixed dipterocarp forest and limestone forest, which is surrounded by orchards and few villages. In Kampung Padang Pan, the vegetation is a mixed fruit orchard and secondary forest. Foraging data were obtained to compare foraging behaviour in three species. From 133 observations, suspended dead leaves was the most frequently used substrate by the three species. Stachyris maculate showed the most general foraging behavior, and it adopted probing strategy. Cyanoderma erythropterum and Mixnornis gularis obtained food items by gleaning. These three babblers utilize different foraging strategies and substrates, irrespective of their resemblances in other characteristics. C. erythropterum and S. maculate forage mainly among dead and curled, twisted leaves in understory vegetation at significantly different heights. M. gularis forages on dead and living leaves and this species can be found abundantly in disturbed forest and plantation or farm habitats. All the three areas were observed never lacked falling leaves and structural complexity required as foraging substrates by those three babbler species. All three babblers occupy different foraging niches, and therefore interspecific competitions among themselves are minimized.

Local and Landscape Compositions Influence Stingless Bee Communities and Pollination Networks in Tropical Mixed Fruit Orchards, Thailand

Stingless bees are vital pollinators for both wild and crop plants, yet their communities have been affected and altered by anthropogenic land-use change. Additionally, few studies have directly addressed the consequences of land-use change for meliponines, and knowledge on how their communities change across gradients in surrounding landscape cover remains scarce. Here, we examine both how local and landscape-level compositions as well as forest proximity affect both meliponine species richness and abundance together with pollination networks across 30 mixed fruit orchards in Southern Thailand. The results reveal that most landscape-level factors significantly influenced both stingless bee richness and abundance. Surrounding forest cover has a strong positive direct effect on both factors, while agricultural and urbanized cover generally reduced both bee abundance and diversity. In the local habitat, there is a significant interaction between orchard size and floral richness with stingless bee richness. We also found that pollinator specialization in pollination networks decreased when the distance to the forest patch increased. Both local and landscape factors thus influenced meliponine assemblages, particularly the forest patches surrounding an orchard, which potentially act as a key reservoir for stingless bees and other pollinator taxa. Preservation of forest patches can protect the permanent nesting and foraging habitat of various pollinator taxa, resulting in high visitation for crop and wild plants.

The diversity of small mammals in a mixed fruit orchard at Bukit Bekong limestone massif, Merapoh, Pahang, Malaysia

The increasing forest fragmentation due to human encroachment has isolated and scattered forest patches and limestone karsts. Agroforestry has been touted as a sustainable solution for the agriculture sector to yield crops and also provide alternative habitats for wildlife outside protected areas and linking forest patches and isolated limestone karsts. This initial survey was conducted to evaluate small mammals (bats and non-volant) assemblages present in a mixed fruit orchard bordering Bukit Bekong limestone massif in Merapoh, Pahang. We captured 193 individuals from 28 species (13 for bats & 15 for non-volant) using mist nets, harp traps and cage traps. This orchard contains Nycteris tragata and Kerivoula pellucida, listed as Near Threatened plus Maxomys rajah as Vulnerable in the IUCN Red List, revealing the fact that this small area in comparison to protected areas possesses unprecedented conservation value. Furthermore, 15 out of 28 small mammal species captured are habitat generalist may provide a cause of concern for the loss of forest specialists. Nonetheless, our results show that less intensively managed agroforest like mixed fruit orchard can also support forest specialists that are sensitive to disturbance. Moreover, the presence of limestone karst nearby contributes to bat diversity, especially cave-roosting bats. In summary, the diversity of small mammals in agroforest is worth to be studied as the species accumulation curve in this one mixed fruit orchard has yet to reach an asymptote. We hope future biodiversity data in agroforest will be incorporated in agriculture management strategies to stimulate sustainable agriculture and promoting mammal diversity.

Potential host fruits for Drosophila suzukii: olfactory and oviposition preferences and suitability for development

AbstractDrosophila suzukii (Matsumura) (Diptera: Drosophilidae), the spotted wing drosophila, is a pest endemic to Southeast Asia that invaded the Americas and Europe in 2008. In contrast to most of its congeners, D. suzukii possesses a serrated ovipositor that allows it to lay eggs in unwounded commercial fruits, resulting in severe revenue losses for the industry. The purpose of this study was to determine the susceptibility of known host fruits, including cherry, strawberry, blueberry, and grape, and potential host fruits, such as banana and apple, to attack by D. suzukii. Based on the responses to volatile cues offered in a six‐choice olfactometer, the preference of female D. suzukii was ranked in the following order: strawberry = cherry > banana = apple = blueberry = grape, but in no‐choice and choice oviposition tests, the preferences were ranked as follows: cherry > strawberry = blueberry > grape = banana > apple. Furthermore, we reconfirmed that D. suzukii mainly targets rotten fruit for feeding and ripe fruit for oviposition, and females preferred fruits with intensive mechanical damage. Based on developmental parameters, apple was the least suitable host. This study has implications for the control of D. suzukii, especially in mixed fruit orchards, by providing a promising avenue for exploiting behaviour‐based control tools and emphasizing the importance of phenology in host fruit susceptibility.

Forest proximity and lowland mosaic increase robustness of tropical pollination networks in mixed fruit orchards

More than 30% of global crop plants rely on pollinators to set fruit or seed. While several studies have documented the negative effects of habitat degradation and distance from natural habitats on pollinator diversity in tropical areas, such studies have focused on single crops in particular areas without examining entire plant-pollinator communities. Here, we compared the plant-pollinator network structure between mixed fruit orchards that were near to (<1 km) and far from (>7 km) tropical forests and further investigated the effect of landscape composition in surrounding areas on plant-pollinator network structure. Our ten pairs of orchards were in Thailand and grew a range of tropical fruits pollinated by insects, birds and bats. The average number of visitor-flower interactions was higher at sites near the forest. Similarly, network robustness (the resistance of the network to losing species as a result of primary species removal) and interaction evenness (evenness of interactions among species) were higher at the sites closer to the forest. Robustness was strongly positively influenced by the proportion of lowland mosaic within a 1 km radius, while interaction evenness was positively affected by the proportion of urban area and montane mosaic within a 4 km radius of each site. Conservation of (semi-) natural habitats is therefore important for maintaining the diversity of wild pollinators and agricultural production.

The role of bats in pollination networks is influenced by landscape structure

Nectarivorous bats are essential to the functioning to both agricultural and natural ecosystems in the tropics, yet these pollinator communities are declining as a result of habitat loss and hunting. Temporal variation and habitat changes lead to both roost and floral resource loss, which is the major driver of bat pollination decline. This study aims to determine how the bat pollination networks in mixed-fruit orchards are affected by flowering seasons and different land-use types. We estimated the abundance of nectarivorous and frugivorous bats using video observations to determine floral visitation rates from 18 mixed-fruit orchards in Southern Thailand. Pollination networks were then created based on network level indices (number of interactions and specialisation) and species level indices (strength−dependence of plant on each bat, and generalised degree−the number of interactions per species divided by the number of possible interacting partners) for each bat group at each orchard. We found that specialisation in low season networks was higher than those from peak season. Nectarivorous bats showed higher levels of normalised degree, and strength than frugivorous bats. The normalised degree of frugivorous bats, but not nectarivorous bats increased with the proportion of urban area within 30 km radius. The strength of bats was positively correlated with the proportion of plantations within a 2 km radius. Our results show that both bat guilds are strongly integrated into pollination networks where they occur and provide evidence that increasing the area of plantation and urban alters the degree of generalization of pollinators which can significantly impact pollination success of plants.

Effects of forest and cave proximity on fruit set of tree crops in tropical orchards in Southern Thailand

Abstract:Deforestation and forest fragmentation are contributing to declines in crop pollinator populations worldwide. Several studies have examined the impact of forest proximity on plant pollination ecology, but concentrated on single crop species. However, it can be more informative to investigate multiple crop and pollinator species in a community, because different pollinator groups may respond differently to forest distance. We evaluated flower visitor diversity, visitation frequency, and fruit set for three crop species (rambutan, durian and mango) in 10 pairs of mixed fruit orchards. Each pair consisted of one orchard near to (&lt; 1 km) and one orchard far from (&gt; 7 km) the forest edge. Rambutan fruit set was significantly influenced by distance to forest. The main visitors of rambutan flowers were stingless bees. In contrast, the dominant visitors to durian and mango flowers were nectarivorous bats and flies, respectively, and the fruit set of these crops were not significantly influenced by distance to forest. However, durian fruit set was negatively affected by distance to the nearest cave inhabited by nectarivorous bats. This study demonstrates that both caves and forests can be important pollinator sources for agricultural crops, and that the dispersal success of pollinators is related to isolation from source habitats. Maintaining forest patches and limestone karsts may provide stepping stones across fragmented landscapes, and attract greater numbers of pollinators to agricultural areas.

Specialized and facultative nectar-feeding bats have different effects on pollination networks in mixed fruit orchards, in Southern Thailand

Recent advances in the study of pollination networks have improved our ability to describe species interactions at the community level. In this study, we compared the abundance and network strength of facultative and obligate nectar-feeding bats to determine their roles in pollinating mixed fruit orchards. We were particularly interested in the effect of distance from forests and caves on the foraging activity of these two bat groups. For this study, we examined 10 pairs of orchards; each pair consisted of one orchard near to (&lt; 1 km) and one orchard far from (&gt; 7 km) the forest edge. We estimated the abundance of each bat group (nectarivorous vs. frugi-nectarivorous) using video observations to determine floral visitation rates. A pollination network was then created for each of the 20 study orchards and network strength was calculated for each bat group at each orchard. We found that nectarivorous bats showed higher abundance and network strength than frugi-nectarivorous bats. Both bat abundance and network strength were negatively correlated with distance to the nearest cave, however, only network strength was affected by distance to the forest. These results corroborate the importance of nectarivorous bats in pollinating crops within southern Thailand’s mixed fruit orchards. Higher network strength of bats near forests and caves emphasizes the role of natural habitats as pollinator sources.

DATE PALM FRUITS AS A POTENTIAL HOST OF THE PEACH AND MEDITERRANEAN FRUIT FLIES IN FAYOUM GOVERNORATE

The peach fruit fly, Bactrocera zonata (Saunders) and the Mediterranean fruit fly Ceratitis capitata (Wiedmann) are two of the most destructive fruit flies that attack commercial fruits causing significant damages. This study was contributed for monitoring the relative abundance and infestation percentage of B. zonata and C. capitata during two successive seasons, 2010 and 2011 in Fayoum governorate. The experimental locations included various types of date palm cultivation including, firstly, the mixed fruit orchards that containing mango and citrus beside date palm trees, secondly, the orchards containing field crop and vegetables bedside fruit and date palm trees, thirdly, an aggregated date palm orchards only. During The 1st season, the means of CTD (captured flies per trap per day) of B. zonata were 7.68 , 4.55,and 1.65 flies, for the forementioned types, respectively, while during the 2nd season, the means of CTD were 15.31, 6.55 and 0.47 flies for the same cultivations, respectively. The highest CTD values of B. zonata were 11.95 and 26.71 flies / trap/ day observing on 3rd week of October and 3rd week of September during the two seasons, 2010 and 2011, respectively, recorded on the mixed orchard cultivations. Population of C. capitata was low in mixed-cultivation orchards, whereas the means of CTD were 0.16 and 0.48 fly during the 1st and 2nd seasons, respectively, while, there weren't captured flies of C. capitata on the other two types of mentioned date palm cultivations.The samples of fallen date fruit were free of infestation by either of B. zonata or C. capitata in the mature stage for the four tested varieties (Siwi, Amhat, Zaghloul and Balady) of date palm. Percentages of infestation of B. zonata in the fallen palm fruits for the half-ripe and ripe stages during the 1st season in Siwi, Amhat, Zaghloul and Balady varieties were 18.29, 6.31, 6.36, 4.37, 16.29, 5.50 and 20.51, 5.66%, respectively, and during the 2nd season, the percentages of infestation were 34.40, 17.00, 9.42, 3.10, 25.00, 11.76 and 28.96, 6.15%. The obtained data suggests that the earlier control of the fly on the former crop, removal of the infested date fruits that are shelter of immature stages of B. zonata and C. capitata, also, the early harvesting of some date varieties that could be marketing on mature stage results in reducing the population and percentages of infestation of the two flies. Also, avoidance of mixed fruit host cultivation and removing the secondary hosts support such procedures.

Population Dynamics of the Mediterranean Fruit Fly in Montenegro.

Population dynamics of the Mediterranean fruit fly was studied along Montenegro seacoast. Tephri traps baited with 3 component female-biased attractants were used in 11 different localities to monitor the fruit fly population in commercial citrus orchards, mixed-fruit orchards, and in backyards. From 2008–2010, the earliest captures were recorded no earlier than July. In 2011, the first adult fly was detected in mid-June. Low captures rates were recorded in July and August (below 0.5 flies per trap per day; FTD) and peaked from mid-September to the end of October of each year. Our results indicate fluctuation of fly per trap per day depending on dates of inspection and locality, with significant differences in the adult population density. A maximum population was always reached in the area of Budva-Herceg Novi with an FTD of 66.5, 89.5, 71.63, and 24.64 (from 2008–2011 respectively). Fly activity lasts from mid-June/early-July to end December, with distinct seasonal variation in the population.

Spatio-temporal distribution of Ceratitis capitata population in a heterogeneous landscape in Central Italy

The spatio-temporal dynamics of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), was investigated to evaluate the effect of the landscape elements and host plants on pest distribution, in an agricultural landscape of 500 ha located in Central Italy. Two farms (farm 1 and farm 2) are located in the experimental area, composing mixed fruit orchards and surrounded by hedgerows, small woodlots, private gardens and cereal fields. Ceratitis capitata population fluctuation was monitored, from 2006 to 2008, using traps baited with trimedlure. Geostatistical methods such as Inverse distance squared weighted were used to obtain distributional maps of adults, mainly males. Results showed that the adult Mediterranean fruit flies were primarily distributed inside farm 1, with the maximum density found in the months of September and October. Away from the principal host plants, particularly in cereal fields, the number of trapped individuals was always low or zero. In both farms, flies were caught sequentially in traps located on host plants (i.e. peach, apple, pear, oriental persimmon and prickly pear) at varying times of maturation, especially when fruits remained on the trees. Distributional maps provided evidence that allowed to identify habitats in which the fly developed early in the season (mixed peach orchards) and afterwards during the periodic flights.

The utility of microsatellite DNA markers for the evaluation of area-wide integrated pest management using SIT for the fruit fly, Bactrocera dorsalis (Hendel), control programs in Thailand

The oriental fruit fly, Bactrocera dorsalis (Hendel), is a key pest that causes reduction of the crop yield within the international fruit market. Fruit flies have been suppressed by two Area-Wide Integrated Pest Management programs in Thailand using Sterile Insect Technique (AW-IPM-SIT) since the late 1980s and the early 2000s. The projects' planning and evaluation usually rely on information from pest status, distribution, and fruit infestation. However, the collected data sometimes does not provide enough detail to answer management queries and public concerns, such as the long term sterilization efficacy of the released fruit fly, skepticism about insect migration or gene flow across the buffer zone, and the re-colonisation possibility of the fruit fly population within the core area. Established microsatellite DNA markers were used to generate population genetic data for the analysis of the fruit fly sampling from several control areas, and non-target areas, as well as the mass-rearing facility. The results suggested limited gene flow (m < 0.100) across the buffer zones between the flies in the control areas and flies captured outside. In addition, no genetic admixture was revealed from the mass-reared colony flies from the flies within the control area, which supports the effectiveness of SIT. The control pests were suppressed to low density and showed weak bottleneck footprints although they still acquired a high degree of genetic variation. Potential pest resurgence from fragmented micro-habitats in mixed fruit orchards rather than pest incursion across the buffer zone has been proposed. Therefore, a suitable pest control effort, such as the SIT program, should concentrate on the hidden refuges within the target area.

The pollination ecology of durian (Durio zibethinus, Bombacaceae) in southern Thailand

Abstract:The floral biology and pollination ecology of durian, Durio zibethinus, were determined in eight semi-wild trees in mixed-fruit orchards in southern Thailand during April-May 2003 and 2005. Flowers open fully at 16h00–16h30 and most androecia drop around 01h00. Anthers dehisce at 19h30–20h00 when the stigmata are already receptive. In a series of pollination experiments, fruit was set in all treatments within 10 d. The greatest pollination success occurred after hand-crossed (76.6%), open (54.4%) and emasculation pollination (53.3%). Consistently, hand-crossed (12.2%), emasculation (8.7%) and open pollination (5.1%) yielded a substantial fruit set 2 mo after the pollination experiments. Very low pollination success in facilitated autogamy suggests that most durian trees are highly self incompatible. No mature fruit was found after insect pollination and automatic autogamy. Fruit bats, especially Eonycteris spelaea, are the major pollinators of this durian although the giant honey bee (Apis dorsata) was the most frequent visitor to the flowers. Bats visited durian flowers at the rate of 26.1 (SD = 20.7) visits per inflorescence per night. Since this semi-wild durian depends on fruit bats as its pollinator, protecting fruit bat populations and their roosts is vital for the production of the durian fruit crop.

A comparison of bird communities in mixed fruit orchards and natural forest at Khao Luang, southern Thailand

The avifauna of a mixed fruit orchard and nearby isolated forest patch on the mountain of Khao Luang, southern Thailand, was compared with that in natural forest. The orchard was about 75% as rich in bird species as the forest and was dominated by smaller frugivores, nectarivores and widespread generalists. Sundaic birds contributed 26% of sightings in the orchard, and understorey insectivores were poorly represented. The avifauna of the 4.5-ha forest patch was similarly depauperate and bore greater resemblance to that in the orchard than to that in forest. These results have implications for management since increasing emphasis is being placed upon the rights of local communities to manage and exploit resources in protected areas. While agricultural diversification may assist in restoring modest levels of diversity in areas already degraded or committed to human use, it should not be seen as a substitute for conventional protection of forest and wildlife through exclusion of such use.