A new species of Aprostocetus Westwood (Hymenoptera: Eulophidae), parasitizing mango leaf gall midge (Diptera: Cecidomyiidae), from India

A new species of Aprostocetus doonensis Singh sp. nov. is described from northern India. The new species is a parasitoid of mango leaf gall midge, Procontarinia mangiferae (Felt) (Diptera: Cecidomyiidae). Some observations on biology and parasitization rate are also given.     

Morphological,genetic and symptomatic identification of an invasive jujube pest in Korea,Dasineura jujubifolia Jiao & Bu (Diptera: Cecidomyiidae)

Correct identification of invasive species is an important step for further management of this species. New type of leafcurling gall midge feeding on jujube, Ziziphus jujube Miller (Rhamnaceae), was discovered in Korea in 2011. At that time, this species was not identified as specific level, so it was recorded as Dasineura sp. Since then, the jujube gall midge has become a serious alien insect pest in Korea. In this study, this jujube gall midge was surveyed by collecting damaged leaf samples from different major jujube-producing regions in Korea. Morphological, genetic and symptomatic identification of this invasive jujube pest identified as Dasineura jujubifolia Jiao & Bu. Here we provided its taxonomic status, geographical distribution, morphological characteristics of all stages and infestation symptoms. In addition to classical morphological characters, mitochondrial COI barcoding sequences were generated for several specimens. The possible pathway of invasion and subsequent socioeconomic consequences were discussed.     

The mango seed weevil Sternochetus mangiferae (Fabricius) (Coleoptera: Curculionidae) is characterized by low genetic diversity and lack of genetic structure

1. The mango seed weevil Sternochetus mangiferae (Fabricius) is distributed across the major mango-producing areas of the world and causes significant economic losses of mango fruit. Despite its importance as a crop pest, we have only limited information on the population genetics of the mango seed weevil.
2. Here, we examined the genetic diversity of this important pest using specimens intercepted by Beijing Customs District P. R. in China from 41 countries and regions. We used segments of the mitochondrial gene cytochrome c oxidase subunit I and the nuclear gene elongation factor 1-alpha to examine population genetic structure in this species.
3. Our results showed that genetic diversity is low in S. mangiferae, with a mean genetic distance of 0.095–0.14%. Other population genetic parameters also indicated a low level of genetic diversity among samples from a large geographic range. Analysis of molecular variance revealed little population genetic structure, and mismatch distribution analyses provided evidence of a population expansion, although other demographic metrics of population expansion were nonsignificant.
4. We suggest that the observed low level of genetic diversity and population genetic structure in S. mangiferae supports the hypothesis that the population genetics of this species has been impacted by anthropogenic transportation of mangoes and weevils.

     

Control of mango seed weevils (Sternochetus mangiferae) using the African Weaver Ant (Oecophylla longinoda Latreille) (Hymenoptera: Formicidae)

The mango seed weevil, Sternochetus mangiferae (Fabricius), is among the major threats to mango production in Tanzania. Sternochetus mangiferae is primarily a quarantine pest whose presence inside the fruits restricts access to new foreign markets and leads to rejections of fruits destined for export. Management options for the pest have largely been dependent on field sanitation and application of synthetic insecticides with some success. Thus, more sustainable methods are needed to substitute insecticides, as this may also open up opportunities for organic markets. We conducted field experiments for two fruiting seasons in a mango plantation at Mlandizi, Kibaha district, along the coastal belt of Tanzania to evaluate and compare the effectiveness of the predaceous ant Oecophylla longinoda Latreille with foliar insecticidal sprays of Dudumida (70 WDG Imidacloprid) in controlling S. mangiferae. Mango seed weevil infestation was assessed fortnightly based on infestation marks on developing fruits starting eight weeks after fruit set to early ripening phase. Between 50 and 64 fruits were sampled, well labelled in jute bags, secured and transported to the laboratory at Kibaha Biological Control Unit (KBCU) for incubation at room temperature using rearing transparent containers. Two weeks later, the fruits were dissected and inspected for the presence of S. mangiferae developmental stages. Field and laboratory results indicated that fruits from trees that were occupied by O. longinoda and from those treated with insecticide showed significantly (P < 0.0001) lower incidences and infestation rates by S. mangiferae than from untreated trees. Furthermore, there were no significant differences between the insecticide and the weaver ant treatments. We conclude that in our experiments, O. longinoda is an efficient biological control agent for a long‐term control programme and is comparable to insecticide (Dudumida) in suppressing S. mangiferae and may be used in Tanzanian mango plantations.     

Population structure of the melon fly, Bactrocera cucurbitae, in Reunion Island

The melon fly, Bactrocera cucurbitae (Coquillett) (Diptera: Tephritidae) is an agricultural pest of major significance worldwide that primarily attacks cucurbit crops. In Reunion Island, it represents the main tephritid pest on cucurbits. In this paper, we provide a genetic characterization of populations of B. cucurbitae from Reunion Island and investigate their geographical origin using ten microsatellite loci at two mitochondrial gene fragments. Microsatellites reveal the occurrence of three different genetic clusters of B. cucurbitae in Reunion Island, all clearly distinguishable from their African and Asian relatives. These three clusters are sympatric and show no signs of recent bottlenecks. Levels of gene flow among clusters are relatively high, yet gene flow also occurs with populations from the African continent and, to a lesser extent, from Asia. The B. cucurbitae clusters show distinct distributions across eastern and western locations in Reunion Island (but not at different altitudes or between wild and cultivated host plants or between sampling periods), and their abundance is also correlated with the average amount of rainfall. Microsatellite and sequence analyses suggest Africa as the most probable source area for populations of B. cucurbitae in Reunion Island.     

Habitat selection in amphidromous Gobiidae of Reunion Island: Sicyopterus lagocephalus (Pallas, 1770) and Cotylopus acutipinnis (Guichenot, 1863)

Freshwater populations of the Indo-pacific region are characterized by a large proportion of amphidromous species. In this paper, we analyse habitat selection by two amphidromous sympatric Gobiidae: Sicyopterus lagocephalus and Cotylopus acutipinnis in Reunion Island. A sampling method using Point Abundance Sampling (PAS) was conducted in 12 rivers. We used mixed logistic models in order to examine the presence probability of species according to location, downstream-upstream gradient, microhabitat variables (depth, velocity and predominant substrata) and presence of conspecifics and sympatric species. Presence probabilities varied between the sampled rivers. We observed a positive attraction between identical developmental stages of both species, which suggests that social interactions or similar preferences for environmental cues influenced their distribution. The presence probabilities of both species’ juveniles decreased from downstream to upstream. We showed that traditional microhabitat variables weakly explained the spatial distribution of both S. lagocephalus and C. acutipinnis, in Reunion Island. We suggest that weak habitat selection for these species is consistent with the amphidromous life style because of the unpredictability of juvenile settlement and the extreme hydrological variations in tropical rivers.     

First evidence of ethylene production by Fusarium mangiferae associated with mango malformation

Malformation is arguably the most crucial disease of mango (Mangifera indica L.) at present. It is receiving great attention not only because of its widespread and destructive nature but also because of its etiology and control is not absolutely understood. Recently, Fusarium mangiferae is found to be associated with mango malformation disease. There are indications that stress ethylene production could be involved in the disease. Here we have shown the first direct evidence of production of ethylene in pure culture of F. mangiferae obtained from mango. The study also revealed that all the isolates dissected from mango acquire morphological features of F. mangiferae showing most similarity to the features of species with accepted standard features. The isolates of F. mangiferae from mango were observed to produce ethylene in significant amounts, ranging from 9.28–13.66 n mol/g dry wt/day. The findings presented here suggest that F. mangiferae could contribute to the malformation of mango by producing ethylene and probably stimulating stress ethylene production in malformed tissue of mango. Ethylene might be produced through 2-oxoglutarate-dependent oxygenase-type ethylene-forming-enzyme (EFE) pathway in Fusarium sp, which needs to be investigated.     

First Occurrence of <Emphasis Type="Italic">Sternochetus mangiferae</Emphasis> (Fabricius) (Coleoptera: Curculionidae) in Brazil

Specimens of the mango stone weevil Sternochetus mangiferae (Fabricius) (Coleoptera: Curculionidae) were found in fruits of mango from a tree in the residential area of the Rio de Janeiro, RJ. This is the first report of the S. mangiferae in Brazil, currently regulated as an absent quarantine pest in the country. A taxonomist specialized in Curculionidae confirmed the identification based on morphological diagnostics characteristics. This detection is a relevant finding, because Brazil is a major producer and exporter of mango and the main areas of mango for exportation are located very far from this detection point. This pest damages seed and embryo of mango fruits and it causes reduction of fruit size and its premature dropping. The detection was notified to the Plant Health Department, division of the Brazilian Ministry of Agriculture, Livestock and Food Supply (MAPA), which is the National Plant Protection Organization of Brazil.     

Genetic and ecological differences between <Emphasis Type="Italic">Asphondylia yushimai</Emphasis> and the ivy gall midge, <Emphasis Type="Italic">Asphondylia</Emphasis> sp. (Diptera: Cecidomyiidae), with a new distribution record of the former from Hokkaido and South Korea

The soybean pod gall midge, Asphondylia yushimai, is known to utilize Laurocerasus zippeliana (Rosaceae) and Osmanthus heterophyllus (Oleaceae) as autumn–spring hosts. In addition, ivy, Hedera rhombea (Araliaceae), was thought to be a candidate for an additional autumn–spring host. However, our genetic analysis indicated that no haplotypes of the ivy fruit gall midge, Asphondylia sp., were identical to any of the haplotypes of A. yushimai. Furthermore, the life-history traits of the ivy fruit gall midge, such as voltinism, host-plant range, lower development threshold temperature (LDT), and developmental speed, were clearly different from those of A. yushimai. Thus, the results from genetic analysis and life-history traits revealed that the ivy fruit gall midge was not identical to A. yushimai and that H. rhombea is not an additional autumn–spring host plant for A. yushimai. We also discovered through morphological observation and genetic analysis that A. yushimai is distributed in Hokkaido and South Korea, and that the ivy fruit gall midge exhibits host plant alternation, utilizing both the fruit of Phytolacca americana (Phytolaccaceae) and the flower buds of Paederia foetida (Rubiaceae) as spring–autumn hosts.     

A new <Emphasis Type="Italic">Gephyraulus</Emphasis> species (Diptera: Cecidomyiidae) inducing flower bud galls on the European sea rocket <Emphasis Type="Italic">Cakile maritima</Emphasis> Scop. (Brassicaceae)

The European sea rocket Cakile maritima Scop. (Brassicaceae) is a common herb growing on sandy coastlines worldwide and is considered a useful plant because of its medicinal importance, its edibility, and potential as an oilseed crop. However, C. maritima is an invasive plant over a wide range, e.g., eastern South America, North America, northern Iran, Australia and New Zealand, and has a limited number of associated herbivorous insects. During investigations on gall midges (Diptera: Cecidomyiidae) in Egypt, we found a gall midge inducing flower bud galls on C. maritima and preventing fruit production, which suggested that this gall midge is a potential pest of this plant. In this paper, we describe this gall midge species, Gephyraulus zewaili Elsayed and Tokuda sp. nov., as new to science by comparing its morphology with that of close congeners. Partial sequence data of the mitochondrial DNA cytochrome oxidase subunit I gene are also provided.     

Tripius gyraloura n. sp. (Aphelenchoidea: Sphaerulariidae) parasitic in the gall midge Lasioptera donacis Coutin (Diptera: Cecidomyiidae)

A new nematode, Tripius gyraloura n. sp., is described from the arundo gall midge, Lasioptera donacis Coutin (Diptera: Cecidomyiidae). This gall midge is being considered as a biological control agent for use in North America against the introduced giant reed Arundo donax (L.) (Poaceae: Cyperales). Thus the present study was initiated to investigate a nematode parasite that was unknown at the time studies with L. donacis were initiated. The new species has a rapid development in the fly host and the mature parasitic female nematodes evert their uterine cells in the hosts’ hemolymph. Because large numbers of nematodes sterilise the host, eradication of the parasite from laboratory colonies of the midge may be necessary before populations of the fly are released.     

Role of stressed mango host conditions in attraction of and colonization by the mango bark beetle Hypocryphalus mangiferae Stebbing (Coleoptera: Curculionidae: Scolytinae) and in the symptom development of quick decline of mango trees in Pakistan

The mango sudden death syndrome has become a serious threat to the mango industry and caused significant decline in mango production worldwide. The bark beetle Hypocryphalus mangiferae (Stebbing) (Coleoptera: Curculionidae: Scolytinae) has been suggested as a potential vector of the disease based primarily on field observations with little or no supporting empirical data. In this study, we investigated the role of infected mango trees in host attraction and colonization by H. mangiferae to determine if beetle attack and colonization contributes to the disease progression on mango trees. Initially, the role of various stress factors on beetle attraction and disease progression was assessed under lathe house conditions from 2008 to 2009. Results suggest that symptomatic or recently inoculated mango trees (without any obvious symptoms) are preferentially colonized by H. mangiferae. Although not significant, high numbers of beetles attacked stressed or wounded mango trees, compared to healthy or dead mango trees. Disease symptoms after beetle colonization, such as bark splitting, wilting and oozing, were further evaluated. These symptoms showed positive correlation with the degree of disease severity and host plant condition. Furthermore, two fungi, Ceratocystis fimbriata and Lasiodiplodia theobromae, were frequently isolated from the beetle and beetle-colonized trees. Based on these findings, they suggests that H. mangiferae can vector multiple fungi associated with mango sudden decline disease and play a significant role in outbreaks of this disease.     

Effect of different eriophyid and tetranychid mango mite species on development,longevity, fecundity and predation of Typhlodromus mangiferus Zaher and El-Brolossy (Acari: Phytoseiidae)

Effects on development, longevity, fecundity and predation of the predatory phytoseiid mite Typhlodromus mangiferus Zaher and El-Brolossy were studied in the laboratory at different temperatures and relative humidities using four prey mite species: the motile stages of the eriophyid mango bud mite Aceria mangiferae Sayed, the eriophyid leaf coating and webbing mite Cisaberoptus kenyae Keifer, the eriophyid mango rust mite Metaculus mangiferae (Attiah) and nymphs of the tetranychid mango red mite Oligonychus mangiferus (Rahman and Sabra). The increase of different temperatures and decrease of relative humidities from 25°C and 60% to 30°C and 55% and 35°C and 50% shortened development and increased reproduction and prey consumption. The developmental durations were almost similar when the predator was fed on eriophyids compared to that on tetranychid. The maximum reproduction (2.70, 2.08, 1.97 and 1.66 eggs/ ♀ /day) was recorded at the highest temperature and the lowest relative humidity, while the minimum reproduction (1.7, 1.54, 1.53, and 1.06 eggs/ ♀ /day) was noted at the lowest temperature and highest relative humidity with all mango prey species. Life table parameters indicated that feeding of T. mangiferus on A. mangiferae led to the highest reproduction rate (rm = 0.204 and 0.139 females/female/day), while feeding on O. mangiferus gave the lowest reproduction rate (rm = 0.137 and 0.116) at 35°C and 50% relative humidity and 25°C and 60% relative humidity, respectively. T. mangiferus seems to be a voracious predator of both mango eriophyid and tetranychid mites. The adult female daily consumed about 127 A. mangiferae, 97 C. kenyae, 86 M. mangiferae, and 18 O. mangiferus at 35°C and 50% relative humidity, while it devoured only 99.81, 86, 81, and 15 individuals, respectively at 25°C and 60% relative humidity. The present study revealed that each injurious mite is thought to be profitable prey species to T. mangiferus as a facultative predator.     

Natural and human‐mediated selection in a landrace of Thai rice (Oryza sativa)

Landrace rice in Thailand consists of managed populations grown under traditional and long‐standing agricultural practices. These populations evolve both in response to environmental conditions within the local agro‐ecosystem and in response to human activities. Single landraces are grown across varying environments and recently have experienced temporal changes in local environments due to climate change. Here we assess the interplay between natural selection in a changing climate and human‐mediated selection on the population genetic structure of Muey Nawng, a local landrace of Thai rice. Genetic diversity and population structure of landrace rice were assessed by a STRUCTURE analysis of 20 microsatellite loci. The first exon–intron junction of the waxy gene was sequenced to determine genotypes for glutinous or non‐glutinous grain starch. Muey Nawng rice is genetically variable and is structured based on starch grain types and the level of resistance to gall midge pest. A strong positive correlation was found between genetic diversity and the percentage of gall midge infestation. Variation in the waxy locus is correlated with starch quality; selection for non‐glutinous rice appears to involve additional genes. The dynamics of genetic diversity within Muey Nawng rice depends on three factors: (a) a genetic bottleneck caused by strong selection associated with gall midge infestation, (b) selection by local farmers for starch quality and (c) variation introduced by farmer practices for cultivation and seed exchange. These results, when taken in total, document the ability of landrace rice to quickly evolve in response to both natural and human‐mediated selection.     

Genetic,physiological and molecular interactions of rice and its major dipteran pest,gall midge

The gall midge, Orseolia oryzae, is a major dipteran pest of rice affecting most rice growing regions in Asia, Southeast Asia and Africa. Chemical and other cultural methods for control of this pest are neither very effective nor environmentally safe. The gall midge problem is further compounded by the fact that there are many biotypes of this insect and new biotypes are continuously evolving. However, resistance to this pest is found in the rice germ plasm. Resistance is generally governed by single dominant genes and a number of non-allelic resistance genes that confer resistance to different biotypes have been identified. Genetic studies have revealed that there is a gene-for-gene interaction between the different biotypes of gall midge and the various resistance genes found in rice. This review discusses different aspects of the process of infestation by the rice gall midge and its interaction with its host. Identification of the gall midge biotypes by conventional methods is a long and tedious process. The review discusses the PCR-based molecular markers that have been developed recently to speed up the identification process. Similarly, molecular markers have been developed for two gall midge resistance genes in rice – Gm2 and Gm4t – and these markers are now being used for marker-assisted selection. The mapping, tagging and map-based gene cloning of one of these genes – Gm2 – has also been discussed. This revised version was published online in June 2006 with corrections to the Cover Date.     

A new species of gall midge (Diptera: Cecidomyiidae) damaging flower buds of goji berry Lycium barbarum (Solanaceae)

Larvae of a previously undescribed gall midge species have been feeding within malformed flower buds of goji berry Lycium barbarum L. (Solanaceae) in China, preventing fruit development and causing damage to the fruit industry. The new species is named Gephyraulus lycantha Jiao & Kolesik, its morphology is described, the COI mitochondrial gene segment is sequenced, and the biology is outlined. In order to taxonomically accommodate the new gall midge, the scope of the genus Gephyraulus is broadened and now encompasses also species that lack dorso-apical sensoria on the female cercus.LSID: urn:lsid:zoobank.org:pub:17B243CF-5235-405B-AA60-8E872C848367.     

Can polyploidy confer invasive plants with a wider climatic tolerance? A test using Solidago canadensis

Polyploidy can cause variation in plant functional traits and thereby generate individuals that can adapt to fluctuating environments and exploit new environments. However, few empirical studies have tested for an association between ploidy level and climatic tolerance of invasive cytotypes relative to conspecific native‐range cytotypes. Here, we used an invasive plant Solidago canadensis to test whether invasive populations had a higher proportion of polyploids, greater height and stem‐base diameter, and occupied a wider range of climatic conditions than conspecific native‐range populations. We also tested whether the invasive populations had overcome genetic founder effects. We sampled a total of 80 populations in parts of the invaded range in China and native range in North America for in situ measurements of plant height and stem‐base diameter in the field and for population genetic and cytotype analyses. To examine climatic correlates, we augmented our field‐sampled data with occurrence records obtained from Global Biodiversity Information Facility. All, except one, of the populations that we sampled in China occurred in a humid subtropical climate. In contrast, the North American populations occurred in humid continental, humid subtropical, and semi‐arid climatic zones. All populations of S. canadensis in China were purely hexaploid, while the North American populations were diploid, tetraploid, and hexaploid. The invasive hexaploids were significantly taller and had a larger stem‐base diameter than native hexaploids. Native hexaploids were significantly taller and had larger stem‐base diameter than native diploids. Climatic correlate assessment found that invasive and native populations occupied different climatic envelopes, with invasive populations occurring in warmer and less seasonal climates than native populations. However, there was no significant correlation between ploidy level and climatic envelope of S. canadensis. Molecular phylogeography data suggest reduced genetic founder effects in the invaded range. Overall, these results suggest that polyploidy does not influence S. canadensis climatic tolerance.     

The non-native chironomid Eretmoptera murphyi in Antarctica: erosion of the barriers to invasion

Antarctica is the continent least affected by invasive species, but climate change and increasing human activity are increasing this threat. Antarctic terrestrial ecosystems generally have low biodiversity with simple community structures and little competition for resources. Consequently, species with pre-adaptations or capabilities that allow them to tolerate polar conditions may have disproportionately large ecosystem impacts when introduced to Antarctica compared with other regions of the Earth. Here we investigate the invasion risk associated with the flightless chironomid midge, Eretmoptera murphyi, which was accidentally introduced from South Georgia (54°S) to Signy Island, South Orkney Islands (61°S), probably during plant transplantation experiments in the 1960s. Larval size class distribution analysis indicated that E. murphyi has a 2 year life cycle on Signy Island, supporting previous suggestions. Estimates of litter turnover show that recent large increases in E. murphyi population density and extent are likely to increase nutrient cycling rates on Signy Island substantially. Existing physiological adaptations may allow E. murphyi to colonise higher latitude locations. Growth rate and microhabitat climatic modelling show that temperature constraints on larval development on Anchorage Island (68°S) are theoretically similar to those on Signy Island even though it is ~750 km further south. Establishment of this non-native midge at climatically similar intervening locations along the western Antarctic Peninsula is therefore plausible. Currently, lack of effective natural dispersal mechanisms is probably limiting the spread of the midge. However, dispersal to other areas of the Antarctic Peninsula may occur via human-assisted transportation, highlighting the importance of appropriate biosecurity measures.     

危害芒果叶片的瘿蚊科--中国新纪录属和一新种(双翅目,瘿蚊科)

记述了福建厦门危害芒果叶片的瘿蚊科--中国新纪录属和一新种:普瘿蚊属Procontarinia Kieffer ＆ Cecconi,1906;壮铗普瘿蚊Procontarinia robusta sp.nov..正模♂,福建厦门杏林,2001-09-12,张清源饲养自叶瘿.副模16♂♂,23♀♀,同正模,2001-09-12～16.新种触角鞭节基颈很短,被毛;第1、2鞭节不愈合;抱器基节和端节都不细长;肛下板端部凹陷很浅;虫瘿外面无刺,不呈海胆状等区别于P.echinogalliperda(Mani,1947).模式标本保存于南开大学生物系昆虫标本室.     

Mango stem end rot pathogens - Fruit infection by endophytic colonisation of the inflorescence and pedicel

The stem end rot pathogens of mango (Mangifera indica), (Dothiorella dominicana, Dothiorella mangiferae, Lasiodiplodia theobromae (Syn. Diplodia natalensis Phomopsis mangiferae, Cytosphaera mangiferae, Pestalotiopsis sp. and Dothiorella‘long’), as well as other fungi (including Alternaria alternata), were found to occur endophytically in the stem tissue of mango trees prior to inflorescence emergence. On samples from trees with a record of low stem end rot levels, colonisation did not extend into the most recently produced flush of stem tissue. At a site with a history of high stem end rot levels, sequential monitoring of inflorescence tissue between flowering and harvest by plating out small (c. 8 mm³) tissue pieces revealed, that at least some of the pathogens - Dothiorella spp., P. mangiferae, Pestalotiopsis sp. and C. mangiferae gradually colonised the inflorescence, reaching the pedicel tissue of young fruit - 8 wk after flowering. Subsequently, detection frequency of the pathogens in inflorescence tissue declined, possibly because of interference from copper residues (from field sprays) accumulating on tissue samples. The detection frequency of A. alternata also increased as Dothiorella spp. declined, however these changes could not be attributed to antagonistic interactions between the two fungi. Using larger tissue pieces (1–2 mm thick transverse sections, or a square of tissue 25 mm²× 3 mm thick) in isolations, endophytic colonisation by Dothiorella spp. and P. mangiferae was detected in stem, inflorescence and pedicel tissues of mature-fruit-specimens from two different sites, one unsprayed, and the other regularly sprayed with copper. The fungi were detected more frequently in the samples from unsprayed trees. Fruit from the sprayed orchard subsequently developed a high level of stem end rot caused by D. dominicana, while a lower level of stem end rot developed in unsprayed fruit, possibly because the latter fruit were also extensively diseased by anthracnose (Colletotrichum gloeosporioides Penz.). Endophytic colonisation of inflorescence and pedicel tissue was found to be a primary route of infection for fruit which develop stem end rot during ripening.