ANNEX XX
ABSTRACTS 3RD RCM TUCUMAN
Evaluation of genetic sexing strain, Bactrocera dorsalis Salaya1 for its species complex members and molecular characterization of Y-chromosome sequences of Bactrocera dorsalis
Nidchaya Aketarawong1, Siriwan Isasawin1, Anna R. Malacrida2, Giuliano Gasperi2, Sujinda Thanaphum1
1Department of Biotechnology, Faculty of Science, Mahidol University, THAILAND
2Department of Biology and Biotechnology, University of Pavia, ITALY
Abstract:
Bactrocera dorsalis strain Salaya 1 is a translocation-based genetic sexing character based on a brown-white pupal color dimorphism. This strain showed successful mating competitiveness with wild B. dorsalis s.s. under semi-natural condition (Fried competitiveness value (C) = 1.33). A mass release of sterile Salaya 1 males in the field resulted in suppression of an indigenous pest population (from 23 flies/trap/day to less than 1 fly/trap/day). Consequently, fruit damage was reduced from 30% to 5%. According to results, the Salaya 1 strain has been applied to wild B. carambolae, a member of B. dorsalis species complex, in order to test mating competitiveness under the semi-natural condition. However, we found that C-value was low, suggesting that incompatible mating occurs between the genetic sexing Salaya 1 strain and wild B. carambolae. The new genetic sexing strain is therefore being further developed for pest management using the sterile insect technique.
In the meantime, we have a collaborative research project between University of Pavia and Mahidol University. This project aims to study Y-chromosome sequences of B. dorsalis s.s. We focus on the Y-chromosome because it plays a key role in determining the development of male individuals and may contain genes involving male fertility. Five DNA fragments were isolated from the genome of B. dorsalis s.s. (Seiberdorf strain). After amplification of several B. dorsalis s.s. strains, we found that four fragments may be a male-specific sequence and another one may be a male-enriched sequence. More experiments such as in situ hybridization will be performed to identify the location of those sequences.
Molecular genetic resolution of pest species within the Bactrocera dorsalis complex
Karen F. Armstrong1, L. M. Boykin1, A. Chomic1, M. K. Schutze2, A. R. Clarke2
1Lincoln University, NEW ZEALAND
2School of Earth, Environmental and Biological Sciences, Queensland University of Technology, G.P.O. Box 2434, Brisbane 4000, Queensland, AUSTRALIA
Abstract:
As part of a comprehensive genetic analysis a comparative transcriptome approach was taken to identify genetic differences amongst the pest taxa B. dorsalis ss, B. papayae, B. philippinensis, B. invadens and B. carambolae. The aim was to identify novel, potentially discriminatory gene regions based on the presence of group-specific SNPs (single nucleotide polymorphisms) which might support the species status of these groups or otherwise.
After filtering out non-insect EST’s (9% other organisms; 35% not annotated) ~37,000 EST’s were screened for private SNPs, each of which then manually checked for authenticity. Of many candidate markers identified 22 primer pairs have been designed and further explored to date; B. occipitalis was included as a “good species” out group. Ten loci produced useful data. These together with data from three of the previous loci using the same specimens, excluding B. invadens, were examined for character-based (private SNPs) and phylogenetic-based evidence of differences between groups. Diagnostic differences were observed in several loci for B. carambolae (11 loci), B. occipitalis (8 loci), B. philippinensis (5 loci) and B. dorsalis/B. papayae (5 loci). No loci suggested differences between B. dorsalis and B. papayae. Clusters in maximum likelihood analysis reflected these separations, although the inter-group relationships were not consistent between loci. Species tree analysis has yet to be completed.
In conclusion, while a species tree may clarify these relationships as might the inclusion of further loci, based on the data to date used in isolation in the context of a phylogenetic species concept, there is still no evidence to suggest that B. dorsalis and B. papayae and possibly B. philippinensis are discrete taxa. Bactrocera philippinensis does appear to have some characters that differentiate it from the others. However, this information on its own, with such small genetic distances and sampling from a narrow geographic base, would be hard to interpret as anything more than a population variant emphasised by geographic distance from the interbreeding populations in mainland Asia.
Pheromones as an indispensible instruments for distiction of Anastrepha fraterculus by age and geographic origin
Radka Břízová1,2*, Lucie Vaníčková3, Blanka Kalinová1, Michal Hoskovec1, Ruth Rufino Do Nascimento3
1Institute of Organic Chemistry and Biochemistry of the Czech Academy of Science, Prague, CZECH REPUBLIC..
2Institute of Chemical Technology Prague, CZECH REPUBLIC
3Universidade Federal de Alagoas, Maceio, BRAZIL
Abstract:
Males of Anastrepha fraterculus form leks and release sex pheromone to attract females during the reproductive behavior. 20 substances were identified in mature male emanations. Of these substances, 6 compounds were antennally active. In young males, the active compounds are present only in trace quantities. Their concentration increases with age and reaches a maximum at the time of sexual maturity. It is very likely that only these substances are part of the male sex pheromone signal.
In order to estimate whether the variability in pheromone communication correlates with reproductive isolation observed between some A. fraterculus populations, the emanations of mature males of “Piracicaba”, “Tucuman”, “Vacaria” and “Peru” populations were compared. Semi-quantitative analyses showed both qualitative and qualitative differences in signal quality. The biggest difference was observed in the “Peru” population.
Population structure of the Andean morphotype of the Anastrepha fraterculus complex
Nelson A. Canal, Julio C. Carranza, Daniel Zabala, María del Rosario Castañeda
Universidad del Tolima, COLOMBIA
Abstract:
The South American Fruit Fly is an important pest of fruits in Latin America, however, seven morphotypes have been found in the nominal species Anastrepha fraterculus. Specimens from Colombia belong to the Andean morphotype, together with specimens from the Venezuelan highlands. Data on morphology, biology, ecology or genetics of this biological entity are lacking.
Specimens from nine localities in Colombia were collected, from two different hosts and a wide range of altitudinal distribution of the species. The main objective was to study the morphological, cytogenetic and genetic structure of the population of the biological entity through its geographical distribution. There were not statistical differences among populations based on adult morphometry, however, the range of the measurements of the taxonomic characters are wider than previously reported. The karyotype of the species was described; it differs from the other known karyotypes of the complex and it is variable among Colombian populations.
Studies of the mitochondrial genes COI and COII show eight populations in a clade differing from other populations from Latin America; the ninth population, from the South of the country, near Ecuador, was grouped apart from the other eight and it appear to be related to Ecuadorian populations, however, its karyotype and morphometry are related to other populations from Colombia and not from Ecuador.
For quarantine purposes, A. fraterculus from Colombia belongs to a single species along the Highland Mountains, from the South-West to North- East and the specimens from the South have to be studied more deeply. Aspects of biology, ecology, quarantine status, chemical ecology, among other aspects, have to be studied for this widely unknown morphotype.
Population studies of Anastrepha obliqua (MacQuart, 1835)
María del Rosario Castañeda, Daniel Zabala, F. M. Patarroyo, Julio C. Carranza, Nelson A. Canal
University of Tolima, COLOMBIA
Abstract:
The West Indian Fruit Fly Anastrepha obliqua is distributed from Mexico to South Peru and North-East Brazil, and it is an important pest of mango and other fruits, with quarantine restrictions. The species is close to A. fraterculus and like this last species, and due to a wide distribution, some studies have shown population variability and it has been suggested that a complex of cryptic species may be present in the biological entities. It is important to clear this fact to support future SIT activities and/or quarantines at international markets.
Morphological, cytogenetic and genetic studies were performed, based on Colombian populations and including specimens from Brazil and Mexico or data from previous studies. Genetic variability was found, supported by 100 bootstrap. Cytogenetic variability was found especially in the size of sexual chromosomes and shape of C-band. Morphometric analyses show some divergent populations. Results obtained show population variability; however results are not clear at this moment because differences found are not as remarkable as the variability found within A. fraterculus.
Field cage mating compatibility test of Bactrocera dorsalis complex of the north and the south of Thailand
Suksom Chinvinijkul1, Sunyanee Srikachar2, Weerawan Amornsak3, Sujinda Thanaphum4
1Department of Agricultural Extension, Ministry of Agriculture and Cooperatives, Chatuchak, Bangkok 10900, THAILAND
2Department of Agriculture, Ministry of Agriculture and Cooperatives, Chatuchak, Bangkok 10900, THAILAND
3Department of Entomology, Faculty of Agriculture, Kasetsart University, Bangkhen Campus, Chatuchak, Bangkok 10900, THAILAND
4Department of Biotechnology, Faculty of Science, Mahidol University, Salaya Campus, Salaya, Nakhon Pathom, THAILAND
Abstract:
The sexual compatibility among Bactrocera dorsalis complex (Diptera: Tephritidae) populations from the northern and southern extremes of geographical distribution of Thailand was assessed in field cages.
Six wild colonies of Bactrocera dorsalis, Bactrocera papayae and Bactrocera carambolae from Chiang Mai (north) and Nakhon Si Thammarat (south) were collected from infested fruits and maintained at the fruit fly mass rearing facility in Pathumthani province. Identified flies of different populations were genetically studied, including a pheromone analysis. Intra–specific and inter-specific mating compatibility of the 2nd - 4th generation flies was investigated at the intra-regional and inter-regional level. Bactrocera dorsalis, B. papayae and B. carambolae males 23, 28 and 28 day old and females 21, 28 and 28 day old, respectively, were used in these studies. Twenty individuals of each sex of two different colour marked populations were released into the field cages. A potted mango tree approximately 180 cm height in each octagonal field cage was set up for the experiment. Five mated pairs in each replicate were randomized and individually assessed for fecundity. Sexual compatible mating was quantified with the following indices: the Relative Isolation Index (RII), Isolation Index (ISI), Male Relative Performance Index (MRPI), and Female Relative Performance Index (FRPI).
Results of the intra-species mating compatibility tests showed that B. dorsalis from the north and the south preferred to mate within region (RII=1.73), higher potential to mate appeared in males from the north than the south (MRPI=0.09), but females from the south showed higher mating (FRPI=-0.15). Bactrocera papayae showed inter-regional mating compatibility between north and south (RII=1.04), with males from the south and females from the north showing higher propensity to mate (MRPI=-0.13, FRPI=0.03). Bactrocera carambolae showed the same trend in mating as B. dorsalis that preferred to mate within region (RII=2.41), with both males and females from the south showing higher potential to mate (MRPI=-0.22, FRPI=-0.27).
The inter-species mating tests between B. dorsalis and B. papayae from the north showed non-selective mating (RII= 0.98), with both males and females of B. dorsalis from the north showing higher potential (MRPI=0.19, FRPI=0.38), while in the south (RII=1.94) both males and females of B. papayae showed higher potential in mating (MRPI=-0.51, FRPI=-0.48). Inter-regional mating between B. dorsalis and B. papayae from the south showed selectivity by both males and females of B. dorsalis (RII=2.50, MRPI=0.58, FRPI=0.66).
Bactrocera dorsalis showed high potential species selectivity in the north with B. carambolae (RII=2.04, MRPI=0.18, FRPI=0.32) and high inter-regional selectivity by B. dorsalis from the south (RII=5.50, MRPI=0.48, FRPI=0.90).
Bactrocera papayae and B. carambolae showed non-selectivity in the north (RII=0.77), with males of B. carambolae and females of B. papayae showing higher potential (MRPI=-0.37, FRPI=0.55), but selectivity in the south with males of B. papayae and females of B. carambolae showing higher potential (RII=1.92, MRPI=0.28, FRPI=-0.17).
Meanwhile infested star apple fruits from Chantaburi province (east), which was recorded as the host and place that B. carambolae was presented in Thailand, were collected for reference.
The Ceratitis FAR complex: biogeography, host plant spectrum and morphometrics
J. Van Cann1, M. Virgilio2, H. Delatte3, K. Jordaens1, 2, M. De Meyer2
1University of Antwerp, Antwerp, BELGIUM
2Royal Museum for Central Africa, Tervuren, BELGIUM
3CIRAD, UMR PVBMT, St Pierre, La Réunion, FRANCE
Abstract:
Earlier studies on morphological and genetic differentiation of the FAR complex are shortly reviewed. They revealed the existence of five genotypes within the Ceratitis FAR complex, comprising two groupings within Ceratitis rosa (‘cold’ and ‘hot’), two within Ceratitis fasciventris (‘dark’ and ‘pale’) and Ceratitis anonae. These different groupings were confirmed by morphological differences in the male secondary characters, in particular the leg ornamentation.
Distributional data for C. rosa and C. fasciventris were re-examined. For C. fasciventris the two types are largely separated in a West-Central group (‘dark’ type) and an eastern group (‘pale’). However, isolated occurrences of the ‘dark’ type are found in Angola, Malawi and Tanzania. For C. rosa the two types seem to be separated along temperature clines with the ‘cold’ type restricted to lower latitudes (most part of South Africa) and higher altitudes. For the ‘cold’ type, precipitation also seems to have an impact on the distribution.
Host plant information is inconclusive. All types are polyphagous with a large overlap of host plants, especially regarding those of economic significance. In C. rosa there is a tendency for the ‘cold’ type to be found more in fruits grown in temperate climates, compared to the ‘hot’ type.
Morphometric studies, based on wing landmarking, indicate a clear sexual dimorphism. There is also an indication of separation between the three established taxa (C. fasciventris, C. anonae, C. rosa) and to a lesser extent, between the five genotypes.
Chemical studies of the sex pheromone of five Brazilian populations of Anastrepha fraterculus (Diptera: Tephritidae)
Ruth R. do Nascimento1, Lucie Vanicková1,2, Adriana L. Mendonça1, Alana L. Mendonça1, Beatriz Jordão Paranhos3, Blanka Kalinová2, Antônio Euzébio Goulart Sant´Ana1
1Universidade Federal de Alagoas, BRAZIL
2Institute of Organic Chemistry and Bichemistry of the Czech Academy of Prague, CZECH REPUBLIC
3Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA), BRAZIL