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Fritz Schulthess - One of the best experts on this subject based on the ideXlab platform.
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Molecular markers reveal narrow genetic base and culturing-associated genetic drift in Teretrius nigrescens Lewis populations released for the biological control of the larger grain borer in Africa.
Bulletin of entomological research, 2013Co-Authors: B.a. Omondi, Daniel K. Masiga, J. Van Den Berg, Fritz SchulthessAbstract:In biological control, successful establishment of a natural enemy species depends on its adaptability in the introduced range including its ability to re-establish desired ecological interactions with the pest. These are affected by genetic parameters hitherto largely unresolved in biological control. The larger grain borer (LGB), Prostephanus truncatus, an invasive species from meso-America, is the most important post-harvest pest of maize in Africa. We studied the genetic structure of Teretrius nigrescens, a predatory beetle previously released for the control of the pest in Africa, to test the hypothesis that establishment patterns were a result of ecotype-environment mismatch and to follow up on our earlier reports of distinct lineages of the predator. We studied 13 populations of T. nigrescens, using 16 polymorphic microsatellite markers. Five genetic populations with a hierarchical structure and significant isolation by distance were detected. The most diverse population was found in southern Mexico, consistent with earlier lineage coexistence observations. Populations introduced to Africa maintained genetic similarity to local geographic populations of their area of origin. The more successful Benin releases were also more genetically diverse. Loss of rare alleles and a higher frequency of existing private alleles in some populations indicated population expansions following bottleneck events. Sustainable biological control should accommodate pest and natural enemy species, and monitor genetic changes associated with introduction and release.
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Phylogeographic structure of Teretrius nigrescens (Coleoptera: Histeridae) predator of the invasive post harvest pest Prostephanus truncatus (Coleoptera: Bostrichidae).
Bulletin of entomological research, 2011Co-Authors: B.a. Omondi, J. Van Den Berg, Daniel K. Masiga, Fritz SchulthessAbstract:The invasive larger grain borer Prostephanus truncatus (Horn) is the most important pest of farm-stored maize in Africa. It was introduced into the continent from Mesoamerica in the late 1970s and by 2008 had spread to at least 18 countries. Classical biological control using two populations of the predator Teretrius nigrescens Lewis achieved long-term and cost effective control in warm-humid areas, but not in cool and hot-dry zones. The present study investigated the phylogenetic relationships between geographical populations of the predator. Ten populations of T. nigrescens were studied using randomly amplified polymorphic DNA polymerase chain reaction (RAPD-PCR), sequence analysis of mitochondrial Cytochrme oxydase 1 (mtCOI) gene and ribosomal internally transcribed spacers (ITS) 1, 5.8S and ITS2. The mtCOI variation revealed two clades associated with geographical regions in Central America. It also reveals a significant isolation by distance between populations and considerable genetic shifts in laboratory rearing. RAPD-PCR did not reveal any potential SCAR diagnostic markers. The ITS variation mainly involved insertions and deletions of simple sequence repeats even within individuals. This study reveals the existence of two different mitochondrial lineages of the predator, associated with the geographical origin of populations distinguishable by fixed mutations on the mtCOI gene. The populations of T. nigrescens released in Africa belonged to two different clades from Meso America, namely south (released in West Africa) and north (released in eastern Africa). However, more polymorphic markers are required to clarify the observations in demographic time scales.
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The flight activity of Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae) and Teretrius nigrescens Lewis (Coleoptera: Histeridae) in Kenya
Journal of Stored Products Research, 2011Co-Authors: B.a. Omondi, J. Van Den Berg, Nanqing Jiang, Fritz SchulthessAbstract:The invasive storage pest, the larger grain borer (LGB) Prostephanus truncatus (Horn), was introduced into the maize-deficit, semi-arid areas of the eastern region in Kenya in the early 1980s. In spite of containment efforts and the introduction of the predator Teretrius nigrescens Lewis from Mexico, LGB has spread to the main maize production zone in western Kenya during the past five years. The present work presents results from a 28-month monitoring effort of LGB and its predator, using pheromone traps at five locations along an east-west transect across Kenya. LGB occurred in all regions with highest trap catches in the high potential maize production zones in Western Kenya. T. nigrescens had not spread to western Kenya and trap catches were very low and mostly zero in Eastern Kenya, even in the area where it was released during the 1990s, suggesting that it became locally extinct after initial establishment. LGB flight activity was closely related to relative humidity, temperature and vapour pressure deficit. A model based on climatic factors accurately predicted seasonal trends of LGB flight behaviour in Kakamega and Mombasa but not in Kitale and Thika. It was concluded that models that rely on the direct effect of climate cannot predict LGB flight accurately enough to allow assessment of the impact of T. nigrescens on a regional basis. It is suggested that other factors such as the availability of stored grain and thus the indirect effect of climate via enhanced or reduced crop production play a major role in the flight activity of LGB and T. nigrescens.
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Isolation and characterization of microsatellite markers from Teretrius nigrescens Lewis (Coleoptera: Histeridae), predator of the storage pest Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae)
Molecular ecology resources, 2009Co-Authors: A. B. Omondi, L. C. Orantes, J. Van Den Berg, Daniel K. Masiga, Fritz SchulthessAbstract:Teretrius nigrescens is a predator of the larger grain borer (LGB) Prostephanus truncatus, an invasive post-harvest pest in Africa. We describe the isolation and characterization of 24 novel polymorphic microsatellite markers and their testing on a population from Honduras. Alleles per locus ranged between 2 and 12, and observed heterozygosity between 0.037 and 0.646. Six loci deviated significantly from Hardy-Weinberg equilibrium and showed evidence of null alleles. These markers will be useful for studies of the predator's population structure and characterizing populations for control of LGB.
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Biological control of the larger grain borer Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae) by its predator Teretrius nigrescens (Lewis) (Coleoptera: Histeridae) in Togo and Benin
Biological Control, 2004Co-Authors: Heinrich Schneider, C. Borgemeister, Hans-michael Poehling, Mamoudou Sétamou, Hippolyte Affognon, Albert Bell, Matthias E. Zweigert, Fritz SchulthessAbstract:Abstract Populations of the exotic bostrichid storage pest Prostephanus truncatus and its introduced histerid predator Teretrius nigrescens were monitored biweekly with pheromone traps at 124 sites in southern Togo and in the four agro-ecological zones of Benin, i.e., from south to north: the humid forest savanna (HFS), the forest–savanna mosaic (FSM), the southern Guinea savanna (SGS), and the northern Guinea savanna together with the Sudan savanna (NGS/SS), from mid 1995 to late 1997. Grain losses, pest and predator numbers as well as infestations by Sitophilus zeamais were, in addition, assessed monthly in nearby grain stores. In southern Togo and Benin, a comparison with previous trap catches showed a steady decline in P. truncatus numbers after introduction of T. nigrescens in 1992. At the same time, grain losses decreased to levels corresponding with the average losses reported prior to the arrival of P. truncatus , which were mainly caused by S. zeamais . P. truncatus trap catches were lowest in the HFS and around double in the three northern zones while T. nigrescens in traps decreased rapidly from FSM to NGS/SS. The latter was probably due to the later arrival of T. nigrescens in those regions; thus, the pest–predator system might not yet be at equilibrium. Similar to previous studies, yearly fluctuations in P. truncatus flight behavior could not only be attributed to T. nigrescens , but were also a result of changing weather patterns. Moreover, it is suggested that the role of wild woody habitats in suppressing the pest via its predator T. nigrescens has so far been underestimated.
Daniel K. Masiga - One of the best experts on this subject based on the ideXlab platform.
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Molecular markers reveal narrow genetic base and culturing-associated genetic drift in Teretrius nigrescens Lewis populations released for the biological control of the larger grain borer in Africa.
Bulletin of entomological research, 2013Co-Authors: B.a. Omondi, Daniel K. Masiga, J. Van Den Berg, Fritz SchulthessAbstract:In biological control, successful establishment of a natural enemy species depends on its adaptability in the introduced range including its ability to re-establish desired ecological interactions with the pest. These are affected by genetic parameters hitherto largely unresolved in biological control. The larger grain borer (LGB), Prostephanus truncatus, an invasive species from meso-America, is the most important post-harvest pest of maize in Africa. We studied the genetic structure of Teretrius nigrescens, a predatory beetle previously released for the control of the pest in Africa, to test the hypothesis that establishment patterns were a result of ecotype-environment mismatch and to follow up on our earlier reports of distinct lineages of the predator. We studied 13 populations of T. nigrescens, using 16 polymorphic microsatellite markers. Five genetic populations with a hierarchical structure and significant isolation by distance were detected. The most diverse population was found in southern Mexico, consistent with earlier lineage coexistence observations. Populations introduced to Africa maintained genetic similarity to local geographic populations of their area of origin. The more successful Benin releases were also more genetically diverse. Loss of rare alleles and a higher frequency of existing private alleles in some populations indicated population expansions following bottleneck events. Sustainable biological control should accommodate pest and natural enemy species, and monitor genetic changes associated with introduction and release.
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Phylogeographic structure of Teretrius nigrescens (Coleoptera: Histeridae) predator of the invasive post harvest pest Prostephanus truncatus (Coleoptera: Bostrichidae).
Bulletin of entomological research, 2011Co-Authors: B.a. Omondi, J. Van Den Berg, Daniel K. Masiga, Fritz SchulthessAbstract:The invasive larger grain borer Prostephanus truncatus (Horn) is the most important pest of farm-stored maize in Africa. It was introduced into the continent from Mesoamerica in the late 1970s and by 2008 had spread to at least 18 countries. Classical biological control using two populations of the predator Teretrius nigrescens Lewis achieved long-term and cost effective control in warm-humid areas, but not in cool and hot-dry zones. The present study investigated the phylogenetic relationships between geographical populations of the predator. Ten populations of T. nigrescens were studied using randomly amplified polymorphic DNA polymerase chain reaction (RAPD-PCR), sequence analysis of mitochondrial Cytochrme oxydase 1 (mtCOI) gene and ribosomal internally transcribed spacers (ITS) 1, 5.8S and ITS2. The mtCOI variation revealed two clades associated with geographical regions in Central America. It also reveals a significant isolation by distance between populations and considerable genetic shifts in laboratory rearing. RAPD-PCR did not reveal any potential SCAR diagnostic markers. The ITS variation mainly involved insertions and deletions of simple sequence repeats even within individuals. This study reveals the existence of two different mitochondrial lineages of the predator, associated with the geographical origin of populations distinguishable by fixed mutations on the mtCOI gene. The populations of T. nigrescens released in Africa belonged to two different clades from Meso America, namely south (released in West Africa) and north (released in eastern Africa). However, more polymorphic markers are required to clarify the observations in demographic time scales.
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Isolation and characterization of microsatellite markers from Teretrius nigrescens Lewis (Coleoptera: Histeridae), predator of the storage pest Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae)
Molecular ecology resources, 2009Co-Authors: A. B. Omondi, L. C. Orantes, J. Van Den Berg, Daniel K. Masiga, Fritz SchulthessAbstract:Teretrius nigrescens is a predator of the larger grain borer (LGB) Prostephanus truncatus, an invasive post-harvest pest in Africa. We describe the isolation and characterization of 24 novel polymorphic microsatellite markers and their testing on a population from Honduras. Alleles per locus ranged between 2 and 12, and observed heterozygosity between 0.037 and 0.646. Six loci deviated significantly from Hardy-Weinberg equilibrium and showed evidence of null alleles. These markers will be useful for studies of the predator's population structure and characterizing populations for control of LGB.
J. Van Den Berg - One of the best experts on this subject based on the ideXlab platform.
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Phylogeographic structure of Teretrius nigrescens (Coleoptera: Histeridae) predator of the invasive post harvest pest Prostephanus truncatus (Coleoptera: Bostrichidae).
Bulletin of entomological research, 2011Co-Authors: B.a. Omondi, J. Van Den Berg, Daniel K. Masiga, Fritz SchulthessAbstract:The invasive larger grain borer Prostephanus truncatus (Horn) is the most important pest of farm-stored maize in Africa. It was introduced into the continent from Mesoamerica in the late 1970s and by 2008 had spread to at least 18 countries. Classical biological control using two populations of the predator Teretrius nigrescens Lewis achieved long-term and cost effective control in warm-humid areas, but not in cool and hot-dry zones. The present study investigated the phylogenetic relationships between geographical populations of the predator. Ten populations of T. nigrescens were studied using randomly amplified polymorphic DNA polymerase chain reaction (RAPD-PCR), sequence analysis of mitochondrial Cytochrme oxydase 1 (mtCOI) gene and ribosomal internally transcribed spacers (ITS) 1, 5.8S and ITS2. The mtCOI variation revealed two clades associated with geographical regions in Central America. It also reveals a significant isolation by distance between populations and considerable genetic shifts in laboratory rearing. RAPD-PCR did not reveal any potential SCAR diagnostic markers. The ITS variation mainly involved insertions and deletions of simple sequence repeats even within individuals. This study reveals the existence of two different mitochondrial lineages of the predator, associated with the geographical origin of populations distinguishable by fixed mutations on the mtCOI gene. The populations of T. nigrescens released in Africa belonged to two different clades from Meso America, namely south (released in West Africa) and north (released in eastern Africa). However, more polymorphic markers are required to clarify the observations in demographic time scales.
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The flight activity of Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae) and Teretrius nigrescens Lewis (Coleoptera: Histeridae) in Kenya
Journal of Stored Products Research, 2011Co-Authors: B.a. Omondi, J. Van Den Berg, Nanqing Jiang, Fritz SchulthessAbstract:The invasive storage pest, the larger grain borer (LGB) Prostephanus truncatus (Horn), was introduced into the maize-deficit, semi-arid areas of the eastern region in Kenya in the early 1980s. In spite of containment efforts and the introduction of the predator Teretrius nigrescens Lewis from Mexico, LGB has spread to the main maize production zone in western Kenya during the past five years. The present work presents results from a 28-month monitoring effort of LGB and its predator, using pheromone traps at five locations along an east-west transect across Kenya. LGB occurred in all regions with highest trap catches in the high potential maize production zones in Western Kenya. T. nigrescens had not spread to western Kenya and trap catches were very low and mostly zero in Eastern Kenya, even in the area where it was released during the 1990s, suggesting that it became locally extinct after initial establishment. LGB flight activity was closely related to relative humidity, temperature and vapour pressure deficit. A model based on climatic factors accurately predicted seasonal trends of LGB flight behaviour in Kakamega and Mombasa but not in Kitale and Thika. It was concluded that models that rely on the direct effect of climate cannot predict LGB flight accurately enough to allow assessment of the impact of T. nigrescens on a regional basis. It is suggested that other factors such as the availability of stored grain and thus the indirect effect of climate via enhanced or reduced crop production play a major role in the flight activity of LGB and T. nigrescens.
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Isolation and characterization of microsatellite markers from Teretrius nigrescens Lewis (Coleoptera: Histeridae), predator of the storage pest Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae)
Molecular ecology resources, 2009Co-Authors: A. B. Omondi, L. C. Orantes, J. Van Den Berg, Daniel K. Masiga, Fritz SchulthessAbstract:Teretrius nigrescens is a predator of the larger grain borer (LGB) Prostephanus truncatus, an invasive post-harvest pest in Africa. We describe the isolation and characterization of 24 novel polymorphic microsatellite markers and their testing on a population from Honduras. Alleles per locus ranged between 2 and 12, and observed heterozygosity between 0.037 and 0.646. Six loci deviated significantly from Hardy-Weinberg equilibrium and showed evidence of null alleles. These markers will be useful for studies of the predator's population structure and characterizing populations for control of LGB.
Denis J. Wright - One of the best experts on this subject based on the ideXlab platform.
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Biological control of the larger grain borer Prostephanus truncatus (Coleoptera: Bostrichidae) in Kenya using a predatory beetle Teretrius nigrescens(Coleoptera: Histeridae).
Bulletin of entomological research, 2003Co-Authors: M.g. Hill, F.l.o. Nang'ayo, Denis J. WrightAbstract:The establishment of the predatory histerid beetle, Teretrius nigrescens Lewis, following its field release in south eastern Kenya in 1992, and its impact on populations of the larger grain borer, Prostephanus truncatus (Horn), in woodland habitats is evaluated. Pheromone trap catch data show a single strong peak of P. truncatus from November to January, coincident with the short rains. Comparisons of P. truncatus pheromone trap catches before and after predator establishment, and in areas with and without T. nigrescens, show a sustained decline of over 80% in P. truncatus abundance over a 5-year period, following the establishment T. nigrescens. Concurrent laboratory studies of the impact of T. nigrescens on populations of P. truncatus raised on a wood substrate showed a 77% reduction in the growth of the pest population. These results are compared with published findings of the impact of T. nigrescens as a biological control agent of P. truncatus in west Africa.
M.g. Hill - One of the best experts on this subject based on the ideXlab platform.
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Biological control of the larger grain borer Prostephanus truncatus (Coleoptera: Bostrichidae) in Kenya using a predatory beetle Teretrius nigrescens(Coleoptera: Histeridae).
Bulletin of entomological research, 2003Co-Authors: M.g. Hill, F.l.o. Nang'ayo, Denis J. WrightAbstract:The establishment of the predatory histerid beetle, Teretrius nigrescens Lewis, following its field release in south eastern Kenya in 1992, and its impact on populations of the larger grain borer, Prostephanus truncatus (Horn), in woodland habitats is evaluated. Pheromone trap catch data show a single strong peak of P. truncatus from November to January, coincident with the short rains. Comparisons of P. truncatus pheromone trap catches before and after predator establishment, and in areas with and without T. nigrescens, show a sustained decline of over 80% in P. truncatus abundance over a 5-year period, following the establishment T. nigrescens. Concurrent laboratory studies of the impact of T. nigrescens on populations of P. truncatus raised on a wood substrate showed a 77% reduction in the growth of the pest population. These results are compared with published findings of the impact of T. nigrescens as a biological control agent of P. truncatus in west Africa.
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Ecological Studies on the Larger Grain Borer, Prostephanus truncatus (Horn) (Col.: Bostrichidae) and their Implications for Integrated Pest Management
Integrated Pest Management Reviews, 2002Co-Authors: M.g. Hill, C. Borgemeister, C. NansenAbstract:In this article, we review studies of the ecology of the larger grain borer, Protephanus truncatus , both outside and within the maize storage systems. Laboratory studies have shown that P. truncatus can breed on a wide range of woody substrates (branches, roots, and seeds). Pheromone trap catches in different habitats strongly suggest that P. truncatus is well-established in certain non-agricultural environments, presumably breeding in dead or dying wood. In Meso-America, West and East Africa, P. truncatus reproduction in the field has been documented in branches ring-barked by cerambycid beetles. Within a maize store, P. truncatus densities can increase from very small initial colonies of probably less than 200 individuals to densities in excess of 1000 beetles per kg after about 4–6 months of storage. Insect parasitoids are very often found in smallholders' grain stores attacked by P. truncatus , but they do not contribute significantly to population regulation. Declines in maize store population levels in Benin from 1993 to 1996, and in adult abundance in pheromone traps in the natural environment in Kenya, have been attributed to predation by the introduced predator, Teretrius nigrescens , but in recent years pheromone trap catches in West Africa suggest that the situation may be complex. Several environmental factors, notably temperature, humidity, and daylength, and their interactions, have been correlated with P. truncatus flight activity, as well as, in West Africa, the emptying of maize stores. Laboratory experiments have shown food quality also affects flight activity. Factors terminating dispersal and flight are most likely attraction to the male-released aggregation pheromone. Short range attraction to plant volatiles has also been recorded. In Africa the highest densities of P. truncatus tend to occur in humid lowlands, which contrasts with the situation in meso-America where P. truncatus tend to occur in greatest numbers in cooler upland regions. Pheromone trap catches can be significant predictors of the risk of stores becoming infested. Coupled with the development of a rule-based model of flight activity, these studies may offer the prospect of predicting the risk of store infestation based upon temperature and humidity measurements.
