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R.h. Markham - One of the best experts on this subject based on the ideXlab platform.
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distribution of and association between the larger grain borer Prostephanus truncatus horn coleoptera bostrichidae and the maize weevil sitophilus zeamais motschulsky coleoptera curculionidae in maize stores
Journal of Stored Products Research, 2005Co-Authors: Kwame A Vowotor, William G. Meikle, J N Ayertey, R.h. MarkhamAbstract:Abstract Interspecific interactions between the larger grain borer Prostephanus truncatus and the maize weevil Sitophilus zeamais were studied during two storage seasons in maize stores, in Benin. Maize ears, randomly sampled from farmers’ grain stores, were ‘reared out’, i.e., kept for 4 weeks under controlled conditions for F 1 to emerge, and periodically sampled, in order to examine colonisation patterns of P. truncatus and S. zeamais . For both storage seasons, P. truncatus and S. zeamais populations were sparsely aggregated and not associated with each other. The degree and strength of association increased with each monthly sampling occasion with the Ochiai, Jaccard and Dice indices of association. By the fourth sampling occasion, P. truncatus was found on most ears and on some ears in very high numbers (>300 insects). Almost all ears with P. truncatus contained at least a few S. zeamais individuals, but many ears with S. zeamais contained no P. truncatus .
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Electrophoretic analysis of the prey spectrum of Teretrius nigrescens (Lewis) (Col., Histeridae), a predator of Prostephanus truncatus (Horn) (Col., Bostrichidae), in Mexico, Honduras, and Benin
Journal of Applied Entomology, 2003Co-Authors: M. Camara, C. Borgemeister, R.h. Markham, Hans-michael PoehlingAbstract:: Extensive collections of Teretrius nigrescens in Mexico, Honduras, and Benin, were electrophoretically analysed to elucidate the prey spectrum of the predator. Both polyacrylamide gel electrophoresis and cellulose acetate electrophoresis were used. Beetles were sampled with pheromone traps, using the synthetic aggregation pheromone of Prostephanus truncatus, and directly from farmers’ maize stores. The proportion of electrophoretically detected prey protein from adult T. nigrescens in pheromone traps was low: of the 1108 specimens analysed, only in 34 cases, prey protein could be clearly identified. More frequently, prey protein was detected in adult T. nigrescens sampled in maize stores in Mexico, Honduras, and Benin, with 87 samples showing distinct prey bands of the total 1214 predators analysed. Of the 241 T. nigrescens larvae sampled in maize stores in Benin, 136 showed distinct bands of prey protein. In all samples, P. truncatus was the most frequently detected prey species. The second most often identified prey species was Sitophilus zeamais. The results are discussed with regard to various methods for prey spectrum analysis and specifically the biology of T. nigrescens.
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Biological Control of the Larger Grain Borer, Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae)
Integrated Pest Management Reviews, 2002Co-Authors: W.g. Meikle, D. Rees, R.h. MarkhamAbstract:Biological control was first considered shortly after the accidental introduction of Prostephanus truncatus in Africa in the early 1980's. This article reviews first the history of the biological control efforts with a focus on the results and recommendations of the initial international meetings and foreign exploration projects, followed by a discussion of the more important biocontrol agents, in particular the histerid Teretrius nigrescens . Since the release of T. nigrescens in Africa a number of techniques have been employed by different research groups to measure the effect of the natural enemy on P. truncatus , including pheromone trapping, field experiments, gut analysis grain store surveys, simulation modelling, and statistical and economic analysis the conclusions of these various studies have been largely equivocal, and the results of studies with recent data suggest that uncertainty is growing. Further resources and time are needed both for a proper evaluation and for the further development of control strategies compatible with biological control.
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grain injury models for Prostephanus truncatus coleoptera bostrichidae and sitophilus zeamais coleoptera curculionidae in rural maize stores in west africa
Journal of Economic Entomology, 2000Co-Authors: Niels Holst, William G. Meikle, R.h. MarkhamAbstract:Prostephanus truncatus (Horn) and Sitophilus zeamais Motschulsky have been reported as the two most serious pests of stored maize in sub-Saharan Africa and smallholder farmers are in urgent need of guidelines for their proper management. In this article we investigate the injury rates attributable to these two species in terms of percentage weight loss and percentage grain damage, and we derive functional response models for the two species on maize. The models successfully described the progression of grain injury in an extensive data set compiled from previously published studies, comprising 46 time series of data relating maize injury and insect pest density. The grain injury models can be used in conjunction with predictive models of pest population dynamics to guide the development of integrated management strategies for postharvest maize pests in West Africa and comparable regions elsewhere.
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studies on predation of Prostephanus truncatus horn col bostrichidae and sitophilus zeamais mots col curculionidae at different densities on maize by teretriosoma nigrescens lewis col histeridae
Journal of Applied Entomology, 1999Co-Authors: J N Ayertey, C. Borgemeister, William G. Meikle, M. Camara, R.h. MarkhamAbstract:Laboratory experiments using whole cobs were conducted to examine the effect of varying densities of the larger grain borer, Prostephanus truncatus and the maize weevil, Sitophilus zeamais on rate of population increase by the histerid beetle, Teretriosoma nigrescens, a predator primarily of P. truncatus. Densities of all species of insects were determined at the end of the experiment, and an electrophoretic analysis of gut content was conducted on larval and adult T. nigrescens sampled during the experiments. Results indicated that T. nigrescens has a strong preference for P. truncatus and densities of T. nigrescens were associated only with densities of P. truncatus. The maize weevil played little role as an alternative prey or in interfering with T. nigrescens reproduction.
C. Borgemeister - One of the best experts on this subject based on the ideXlab platform.
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Electrophoretic analysis of the prey spectrum of Teretrius nigrescens (Lewis) (Col., Histeridae), a predator of Prostephanus truncatus (Horn) (Col., Bostrichidae), in Mexico, Honduras, and Benin
Journal of Applied Entomology, 2003Co-Authors: M. Camara, C. Borgemeister, R.h. Markham, Hans-michael PoehlingAbstract:: Extensive collections of Teretrius nigrescens in Mexico, Honduras, and Benin, were electrophoretically analysed to elucidate the prey spectrum of the predator. Both polyacrylamide gel electrophoresis and cellulose acetate electrophoresis were used. Beetles were sampled with pheromone traps, using the synthetic aggregation pheromone of Prostephanus truncatus, and directly from farmers’ maize stores. The proportion of electrophoretically detected prey protein from adult T. nigrescens in pheromone traps was low: of the 1108 specimens analysed, only in 34 cases, prey protein could be clearly identified. More frequently, prey protein was detected in adult T. nigrescens sampled in maize stores in Mexico, Honduras, and Benin, with 87 samples showing distinct prey bands of the total 1214 predators analysed. Of the 241 T. nigrescens larvae sampled in maize stores in Benin, 136 showed distinct bands of prey protein. In all samples, P. truncatus was the most frequently detected prey species. The second most often identified prey species was Sitophilus zeamais. The results are discussed with regard to various methods for prey spectrum analysis and specifically the biology of T. nigrescens.
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studies on predation of Prostephanus truncatus horn col bostrichidae and sitophilus zeamais mots col curculionidae at different densities on maize by teretriosoma nigrescens lewis col histeridae
Journal of Applied Entomology, 1999Co-Authors: J N Ayertey, C. Borgemeister, William G. Meikle, M. Camara, R.h. MarkhamAbstract:Laboratory experiments using whole cobs were conducted to examine the effect of varying densities of the larger grain borer, Prostephanus truncatus and the maize weevil, Sitophilus zeamais on rate of population increase by the histerid beetle, Teretriosoma nigrescens, a predator primarily of P. truncatus. Densities of all species of insects were determined at the end of the experiment, and an electrophoretic analysis of gut content was conducted on larval and adult T. nigrescens sampled during the experiments. Results indicated that T. nigrescens has a strong preference for P. truncatus and densities of T. nigrescens were associated only with densities of P. truncatus. The maize weevil played little role as an alternative prey or in interfering with T. nigrescens reproduction.
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flight initiation and flight activity in Prostephanus truncatus coleoptera bostrichidae
Bulletin of Entomological Research, 1998Co-Authors: D. Scholz, C. Borgemeister, R.h. Markham, Hans-michael PoehlingAbstract:In an outdoor experimental set-up, the number of Prostephanus truncatus (Horn) flying from maize cobs was recorded over 38 observation weeks. Flight activity in the field was recorded for 50 weeks with three pheromone traps, each placed at c. 100–300 m from the first experimental set-up. Multiple regression analyses revealed that both flight initiation and flight activity were partly influenced by mean temperatures, but were not directly related. Flight initiation was mainly dependent on population density. An additional experiment showed that sex ratios among pheromone trap catches were not correlated with the number of beetles caught; sex ratios were female-biased throughout the year. Seasonal fluctuations in flight activity recorded with pheromone traps are mainly dependent on changes in the number and sizes of beetle populations in a given area, as well as on breeding site availability and suitability.
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intraspecific competition in larvae of the larger grain borer Prostephanus truncatus horn within maize grains
International Journal of Tropical Insect Science, 1998Co-Authors: Kwame A Vowotor, C. Borgemeister, William G. Meikle, J N Ayertey, R.h. MarkhamAbstract:The effects of egg clutch size on development and survivorship of the larger grain borer, Prostephanus truncatus (Horn) (Col.: Bostrichidae) on maize were measured in the laboratory using single grains of the white maize variety, TZSR-W, at 30 ± 2°C and 70 ± 5% RH. Varying numbers of P. truncatus eggs (1, 2, 4, 8, or 16) were introduced into a hole drilled into a single maize grain. Destructive sampling was used at regular intervals to obtain data on immature developmental parameters, the location of immatures within the grain and the weight and sex of any emerged adults. First instars fed mainly on the floury endosperm tissue whereas the second and third instars preferred the germ tissue. Mortality due to competition was highest in first instars. At high initial densities (> 4 per kernel), some P. truncatus larvae reduced competition by moving out of the grain. A maximum of 6 adults emerged from a single grain. The mean number of adults that emerged per grain for initial egg densities of 8 and 16 were 3.3 and 3.5, respectively. Prostephanus truncatus adult weight at emergence was not significantly influenced by initial egg density except in the case of clutch size 16. The sex ratio of emerged adults was also unaffected by competition, and was always 1:1. Complete developmental period within grains ranged between 28 and 32 days.
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eag and behavioural responses of the larger grain borer Prostephanus truncatus and its predator teretriosoma nigrescens to the borer produced aggregation pheromone
Physiological Entomology, 1998Co-Authors: D. Scholz, C. Borgemeister, H M PoehlingAbstract:.Electroantennogram (EAG) and behavioural studies were conducted with Prostephanus truncatus (Horn) (Col.: Bostrichidae) and the predatory beetle, Teretriosoma nigrescens Lewis (Col: Histeridae) in regard to their responses to the components of the prey-produced aggregation pheromone. There were hardly any differences between species or sexes regarding perception thresholds. In field and olfactometer experiments, female P. truncatus were more responsive to the pheromone than males, and both sexes reacted more strongly to the minor pheromone component, T2, than to T1. Sex ratios among trap catches of T. nigrescens were slightly male-biased. The predator did not differentiate behaviourally between the pheromone components.
Fritz Schulthess - 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.
William G. Meikle - One of the best experts on this subject based on the ideXlab platform.
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distribution of and association between the larger grain borer Prostephanus truncatus horn coleoptera bostrichidae and the maize weevil sitophilus zeamais motschulsky coleoptera curculionidae in maize stores
Journal of Stored Products Research, 2005Co-Authors: Kwame A Vowotor, William G. Meikle, J N Ayertey, R.h. MarkhamAbstract:Abstract Interspecific interactions between the larger grain borer Prostephanus truncatus and the maize weevil Sitophilus zeamais were studied during two storage seasons in maize stores, in Benin. Maize ears, randomly sampled from farmers’ grain stores, were ‘reared out’, i.e., kept for 4 weeks under controlled conditions for F 1 to emerge, and periodically sampled, in order to examine colonisation patterns of P. truncatus and S. zeamais . For both storage seasons, P. truncatus and S. zeamais populations were sparsely aggregated and not associated with each other. The degree and strength of association increased with each monthly sampling occasion with the Ochiai, Jaccard and Dice indices of association. By the fourth sampling occasion, P. truncatus was found on most ears and on some ears in very high numbers (>300 insects). Almost all ears with P. truncatus contained at least a few S. zeamais individuals, but many ears with S. zeamais contained no P. truncatus .
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nonagricultural hosts of Prostephanus truncatus coleoptera bostrichidae in a west african forest
Annals of The Entomological Society of America, 2004Co-Authors: William G. Meikle, Barbara J Tigar, Christian Nansen, Susanne Harding, Atti TchabiAbstract:Prostephanus truncatus (Horn) is an important insect pest on stored maize, Zea mays L., and cassava, Manihot esculenta Crantz, in Africa, but weekly pheromone-baited trap catches in West and East Africa exceeding 1000 individuals suggest that this insect is also well established in nonag- ricultural areas. The magnitude of pheromone-baited trap catches on the African continent empha- sizes the importance of looking into the nonagricultural hosts of P. truncatus, because "wild" P. truncatus populations may be a threat to nearby food storage systems. In this study, we used a combination of 1) laboratory no-choice rearing tests on forest branches, roots, and seeds; 2) a behavioral experiment; 3) a review of published studies on the spatial ecology and host range of P. truncatus; and 4) a comparison of estimated P. truncatus production from potential forest hosts with the magnitude of pheromone trap catches, to discuss the possible role of different hosts in the P. truncatus ecology in West Africa. In no-choice tests, we evaluated the ability of P. truncatus to attack and reproduce on 1) fresh branches from 26 plant species, 2) dry branches from 13 species, 3) fresh roots from 18 species, 4) dry roots from two species, and 5) seeds from four species. Heavy attacks occurred on fresh branches from 11 tree species and fresh roots from four tree species. High reproductive rate was found on branches from four species and on roots from two species, and P. truncatus reproduction was also observed on teak, Tectona grandis Linn. F., seeds. We provided rough estimates of P. truncatus populations from different forest hosts and compared them with the spatial distribution pattern and the magnitude of pheromone-baited trap catches in a West African forest. The results from this study underscored the importance of further research into the possible role of girdled branches of Lannea nigritana (Sc. Elliot) Keay (Anacardiaceae), forest seeds, and roots in the P. truncatus ecology in West Africa.
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spatial analysis of Prostephanus truncatus bostrichidae coleoptera flight activity near maize stores and in different forest types in southern benin west africa
Annals of The Entomological Society of America, 2002Co-Authors: William G. Meikle, Christian Nansen, Sam KorieAbstract:Weekly Prostephanus truncatus (Horn) flight activity, measured as the density of captured beetles in pheromone baited traps, was monitored for 76 consecutive weeks at 16 sites inside the Lama forest in southern Benin and at four sites in maize farmland just outside the forest. Prostephanus truncatus flight activity was consistently higher and the flight activity pattern significantly different near maize stores than at sites inside the forest. Although P. truncatus is known to infest girdled branches of Lannea nigritana (Sc. Elliot) Keay, the P. truncatus flight activity was comparatively low at forest sites where this tree species dominated. The main peak in P. truncatus flight activity occurred earlier in the eastern part of the forest compared with other forest parts. Ordination analysis showed that comparatively higher flight activity in the eastern part of the forest was positively associated with the presence of teak plantations (Tectona grandis L. F.) at trap sites. The spatial distribution of weekly P. truncatus trap catches were found to be significantly aggregated during a 21-wk period, which largely coincided with the early increase in P. truncatus flight activity in the eastern part of the forest. Based on this evidence, it was suggested that P. truncatus individuals disperse from the eastern part of the forest to other forest parts and to nearby agricultural areas, rather than, as has been previously suggested, from maize stores to the forest environment.
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Sensitivity of Prostephanus truncatus (Coleoptera: Bostrichidae) Flight Activity to Environmental Variables in Benin, West Africa
Environmental Entomology, 2001Co-Authors: Christian Nansen, William G. Meikle, Sam Korie, Niels HolstAbstract:Based on pheromone trap catches, a model of weekly Prostephanus truncatus (Horn) flight activity was generated for southern Benin. Using response surface regression, the following environmental variables were examined: number of rainy days per week, precipitation, minimum and maximum temperatures, minimum relative air humidity, and daylength. A time-variable, year, was included to account for the variance between years. From step-wise exclusion of variables with the lowest contribution to the model fit, a model was generated which included three environmental variables (daylength, minimum relative air humidity, and minimum temperature) that explained 55% of the total variance, and the yearly variable explaining 8%. The response surface regression analysis of P. truncatus flight activity revealed the following: (1) it was positively correlated with daylength when daily minimum temperature and relative air humidity were low, (2) it was positively associated with minimum relative air humidity when lower than 75%, (3) it was negatively associated with minimum temperature, (4) unexplained yearly variation was important for the predictive strength of the model, (5) interactions of environmental variables contributed substantially to the model fit, and (6) precipitation, both as mm rain and as number of rainy days, had little influence on P. truncatus flight activity. Independent data showed that the model predicted P. truncatus flight activity well elsewhere in southern Benin, whereas in central Benin new coefficients for the same environmental variables were needed to produce an adequate prediction. The model did not fit pheromone baited trap catches from northern Benin.
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grain injury models for Prostephanus truncatus coleoptera bostrichidae and sitophilus zeamais coleoptera curculionidae in rural maize stores in west africa
Journal of Economic Entomology, 2000Co-Authors: Niels Holst, William G. Meikle, R.h. MarkhamAbstract:Prostephanus truncatus (Horn) and Sitophilus zeamais Motschulsky have been reported as the two most serious pests of stored maize in sub-Saharan Africa and smallholder farmers are in urgent need of guidelines for their proper management. In this article we investigate the injury rates attributable to these two species in terms of percentage weight loss and percentage grain damage, and we derive functional response models for the two species on maize. The models successfully described the progression of grain injury in an extensive data set compiled from previously published studies, comprising 46 time series of data relating maize injury and insect pest density. The grain injury models can be used in conjunction with predictive models of pest population dynamics to guide the development of integrated management strategies for postharvest maize pests in West Africa and comparable regions elsewhere.
D. Scholz - One of the best experts on this subject based on the ideXlab platform.
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flight initiation and flight activity in Prostephanus truncatus coleoptera bostrichidae
Bulletin of Entomological Research, 1998Co-Authors: D. Scholz, C. Borgemeister, R.h. Markham, Hans-michael PoehlingAbstract:In an outdoor experimental set-up, the number of Prostephanus truncatus (Horn) flying from maize cobs was recorded over 38 observation weeks. Flight activity in the field was recorded for 50 weeks with three pheromone traps, each placed at c. 100–300 m from the first experimental set-up. Multiple regression analyses revealed that both flight initiation and flight activity were partly influenced by mean temperatures, but were not directly related. Flight initiation was mainly dependent on population density. An additional experiment showed that sex ratios among pheromone trap catches were not correlated with the number of beetles caught; sex ratios were female-biased throughout the year. Seasonal fluctuations in flight activity recorded with pheromone traps are mainly dependent on changes in the number and sizes of beetle populations in a given area, as well as on breeding site availability and suitability.
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eag and behavioural responses of the larger grain borer Prostephanus truncatus and its predator teretriosoma nigrescens to the borer produced aggregation pheromone
Physiological Entomology, 1998Co-Authors: D. Scholz, C. Borgemeister, H M PoehlingAbstract:.Electroantennogram (EAG) and behavioural studies were conducted with Prostephanus truncatus (Horn) (Col.: Bostrichidae) and the predatory beetle, Teretriosoma nigrescens Lewis (Col: Histeridae) in regard to their responses to the components of the prey-produced aggregation pheromone. There were hardly any differences between species or sexes regarding perception thresholds. In field and olfactometer experiments, female P. truncatus were more responsive to the pheromone than males, and both sexes reacted more strongly to the minor pheromone component, T2, than to T1. Sex ratios among trap catches of T. nigrescens were slightly male-biased. The predator did not differentiate behaviourally between the pheromone components.
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trees or stores the origin of migrating Prostephanus truncatus collected in different ecological habitats in southern benin
Entomologia Experimentalis Et Applicata, 1998Co-Authors: C. Borgemeister, Atti Tchabi, D. ScholzAbstract:Migrating Prostephanus truncatus (Horn) (Col.: Bostrichidae) were collected weekly with pheromone-baited funnel traps at three different sites in southern Benin for 12 months. One site was located in a primary forest, one in a peri-urban area, and one in a region with intensive agriculture. The sex of the trapped beetles was determined. The gut-content of the specimens was analyzed for remains of lignin and starch, the former indicating recent feeding on woody, the latter on a starchy substrate, such as stored maize or dried cassava. At all locations, the sex ratio of migrating P. truncatus was significantly female-biased, with the greatest proportion of females trapped at the peri-urban site. At the forest site, most beetles had lignin in their guts, while the proportion of beetles containing starch was highest in the peri-urban site. Approximately equal proportions of beetles with either starch and lignin were trapped in the region with intensive agriculture. The results are discussed with regard to the population dynamics of P. truncatus in different habitats and the flight activity of the beetles.
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simulation model of Prostephanus truncatus coleoptera bostrichidae in rural maize stores in the republic of benin
Environmental Entomology, 1998Co-Authors: William G. Meikle, D. Scholz, Niels Holst, R.h. MarkhamAbstract:A distributed-delay, demographic simulation model of Prostephanus truncatus (Horn) populations in rural maize ( Zea mays L.) stores was developed and validated. Developmental and mortality parameters for eggs, larvae, and pupae, and the life span and fecundity data for adult insects, were estimated from published data and from laboratory experiments. The overall phenology of the simulated beetle dynamics reflected that of field data, although the model output tended to overestimate beetle population growth during the season and overall density late in the season. The model was developed as part of a low-cost tool for evaluating the major factors influencing population dynamics of stored-product pests and their natural enemies and to provide a conceptual framework for evaluating different control strategies in an integrated control context.
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Seasonal and weather factors influencing the annual flight cycle of Prostephanus truncatus (Coleoptera: Bostrichidae) and its predator Teretriosoma nigrescens (Coleoptera: Histeridae) in Benin
Bulletin of Entomological Research, 1997Co-Authors: C. Borgemeister, William G. Meikle, D. Scholz, C. Adda, P. Degbey, R.h. MarkhamAbstract:AbstractInvestigations were carried out in southern Benin on the annual flight cycle and the effects of weather variables on the flight activity of Prostephanus truncatus (Horn) and its natural enemy, Teretriosoma nigrescens Lewis. Two seasonal peaks in flight activity of P. truncatus were observed, one between the end of December and the beginning of January and a second one between May and June. Teretriosoma nigrescens showed a single delayed peak in June, approximately six weeks after the major peak of P. truncatus. Flight activity of P. truncatus was only weakly associated with weather characteristics (standardized regression coefficient for mean daily temperature b = 0.18, t = 2.87, P < 0.05)), whereas for T. nigrescens it was associated with precipitation (standardized regression coefficient for accumulated rainfall during the trapping period b = 0.38, t = 4.76, P < 0.05). The possibility that one of the P. truncatus peaks was associated with dispersal from crowded maize stores and the other with the search for natural woody host plants is discussed.
