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Johannes L. M. Steidle - One of the best experts on this subject based on the ideXlab platform.
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microdissection and whole chromosome painting confirm karyotype transformation in cryptic species of the Lariophagus Distinguendus forster 1841 complex hymenoptera pteromalidae
PLOS ONE, 2019Co-Authors: V E Gokhman, Lars Krogmann, Johannes L. M. Steidle, Marcelo De Bello Cioffi, Christian Konig, Marie Pollmann, Cornelia Gantert, Nadezda Kosyakova, Thomas LiehrAbstract:Karyotypes of two cryptic species of parasitoid Hymenoptera with n = 5 and 6 belonging to the Lariophagus Distinguendus (Forster, 1841) complex, which includes cosmopolitan parasitoids of coleopteran stored-product pests, were studied using glass-needle based microdissection, reverse and cross-species fluorescence in situ hybridisation (FISH). This experiment strongly indicates that the largest metacentric chromosome in the karyotype with n = 5 originated from a particular fusion between the only acrocentric and a smaller metacentric chromosome of the set with n = 6, therefore confirming our previous hypothesis based on the karyotypic analysis using chromosome morphometrics. This study represents the first successful application of both microdissection and whole chromosome painting for the reconstruction of karyotypic rearrangements in closely related species of parasitoids, as well as in the order Hymenoptera in general.
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Reproductive isolation due to prezygotic isolation and postzygotic cytoplasmic incompatibility in parasitoid wasps.
Ecology and Evolution, 2019Co-Authors: Kerstin Konig, Christian Konig, Marie Pollmann, Elena Krimmer, Petra Zundel, Yuval Gottlieb, Johannes L. M. SteidleAbstract:: The reproductive barriers that prevent gene flow between closely related species are a major topic in evolutionary research. Insect clades with parasitoid lifestyle are among the most species-rich insects and new species are constantly described, indicating that speciation occurs frequently in this group. However, there are only very few studies on speciation in parasitoids. We studied reproductive barriers in two lineages of Lariophagus Distinguendus (Chalcidoidea: Hymenoptera), a parasitoid wasp of pest beetle larvae that occur in human environments. One of the two lineages occurs in households preferably attacking larvae of the drugstore beetle Stegobium paniceum ("DB-lineage"), the other in grain stores with larvae of the granary weevil Sitophilus granarius as main host ("GW-lineage"). Between two populations of the DB-lineage, we identified slight sexual isolation as intraspecific barrier. Between populations from both lineages, we found almost complete sexual isolation caused by female mate choice, and postzygotic isolation, which is partially caused by cytoplasmic incompatibility induced by so far undescribed endosymbionts which are not Wolbachia or Cardinium. Because separation between the two lineages is almost complete, they should be considered as separate species according to the biological species concept. This demonstrates that cryptic species within parasitoid Hymenoptera also occur in Central Europe in close contact to humans.
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molecular and cytogenetic differentiation within the Lariophagus Distinguendus forster 1841 species complex hymenoptera pteromalidae
Comparative Cytogenetics, 2019Co-Authors: Christian Konig, Lars Krogmann, Johannes L. M. Steidle, Marie Pollmann, Cornelia Gantert, Sina Paschke, Ronja Reinisch, Justus Weber, V E GokhmanAbstract:: Several strains of the apparently well-known cosmopolitan synanthropic parasitoid of coleopteran stored-product pests, LariophagusDistinguendus (Forster, 1841) from Western Europe, were studied using DNA sequencing and chromosomal analysis. The presence of at least two cryptic species with different COI sequences and chromosome numbers (n = 5 and 6) was supported. The species with n = 6 is associated with the drugstore beetle Stegobiumpaniceum (Linnaeus, 1758), whereas the other one with n = 5 mostly develops on the granary weevil Sitophilusgranarius (Linnaeus, 1758). A phylogenetic study revealed that the karyotype with n = 6 represents an ancestral character state in this complex. Consequently, the chromosome set with n = 5 which is characteristic of a particular internal clade, apparently originated via chromosomal fusion which was probably preceded by a pericentric inversion. If this is true, inverted chromosome segments could accumulate a number of genetic loci responsible for certain interspecific differences.
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Lost in space? Host-finding ability of the parasitoids Lariophagus Distinguendus and Anisopteromalus calandrae in empty grain storage facilities to control residual pest populations
BioControl, 2016Co-Authors: Steffi Niedermayer, Lars Krogmann, Johannes L. M. SteidleAbstract:We studied the ability of the parasitoid species Lariophagus Distinguendus (Förster) and Anisopteromalus calandrae (Howard) (Hymenoptera: Pteromalidae) to locate populations of the granary weevil Sitophilus granarius (L.) (Coleoptera: Dryophtoridae) in grain residues. Experiments were conducted under laboratory and storage-like conditions. Generally both parasitoid species were able to find hosts up to 10 m from the release spot. Under laboratory conditions with excluded air movement and a centered light source, host finding was largely random, declining with increasing distance of baits from the release spot. Under storage-like conditions, host finding was strongly reduced and was not influenced by distance. A. calandrae seems to have been influenced by positive phototaxis. L. Distinguendus showed a weaker host-finding success than A. calandrae , which was increased by a higher number of wasps from 10–50 per release. This resulted in a 5-fold higher number of parasitizations. It is discussed that host finding of residual pest populations by L. Distinguendus and A. calandrae in empty storages is difficult to predict and influenced by light and air conditions. Based on our results, we provide recommendations for the release of parasitoids against residual pest populations.
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Lariophagus Distinguendus hymenoptera pteromalidae forster past present and future the history of a biological control method using l Distinguendus against different storage pests
Insects, 2016Co-Authors: Steffi Niedermayer, Marie Pollmann, Johannes L. M. SteidleAbstract:Legal requirements and consumer demands for residue-free products pose a big challenge for pest control in grain stores. One possible alternative to chemical insecticides is biological pest control with the pteromalid wasp Lariophagus Distinguendus against the weevils Sitophilus granarius, S. oryzae (Coleoptera: Dryophtoridae), and many other storage pest beetles. The use of this wasp as a biocontrol agent was already suggested in 1919 by Prof. Dr. Hase [1]. Despite many studies on host-finding and behavioral biology, the applied aspect was neglected until 1994. Nowadays the wasps are commercially available and can now even be reared on-site, facilitating their use tremendously. This review highlights the milestones in L. Distinguendus research, gives insights in current studies, and ventures a glimpse into the future.
Joachim Ruther - One of the best experts on this subject based on the ideXlab platform.
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elucidating structure bioactivity relationships of methyl branched alkanes in the contact sex pheromone of the parasitic wasp Lariophagus Distinguendus
Insects, 2013Co-Authors: Stephan Kuhbandner, Jan E Bello, Kenji Mori, Jocelyn G Millar, Joachim RutherAbstract:The exoskeletons of insects are covered by complex mixtures of cuticular hydrocarbons (CHCs) which are involved in social and sexual communication. However, little is known about the relationship between the structures of CHCs and their behavioral activity. The key component of the contact sex pheromone of the parasitoid Lariophagus Distinguendus is 3-methylheptacosane (3-MeC27), which is present in CHC profiles of both females and newly emerged males. The CHCs of females and young males elicit wing-fanning behavior in older males. However, as young males age, 3-MeC27 disappears from their CHC profiles and they no longer elicit wing-fanning responses from other males. We applied enantiopure 3-MeC27 and structurally related CHCs (with respect to chain length or methyl-branch position) to the cuticle of aged male dummies and recorded the wing-fanning behavior of responding males. Only the two enantiomers of 3-MeC27 restored the dummies’ attractiveness. The addition of structurally related CHCs or various n-alkanes to bioactive dummies of young males and females significantly decreased wing-fanning by test males. Hence, L. Distinguendus males respond specifically but not enantioselectively to 3-MeC27, and perceive the CHC profiles as a whole. Both removal (as is the case with 3-MeC27 in aging males) and addition of individual compounds may disrupt the behavioral response.
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composition of cuticular lipids in the pteromalid wasp Lariophagus Distinguendus is host dependent
Bulletin of Entomological Research, 2012Co-Authors: Stephan Kuhbandner, Steffi Niedermayer, Johannes L. M. Steidle, K Hacker, Joachim RutherAbstract:The insect cuticle is covered by a thin layer of hydrocarbons not only preventing desiccation but also playing an important role in the sexual communication of several species. In the pteromalid wasp Lariophagus Distinguendus, a parasitoid of grain infesting beetles, female cuticular hydrocarbons (CHCs) elicit male courtship behaviour. We analyzed the CHC profiles of male and female L. Distinguendus wasps reared on different beetle hosts by coupled gas chromatography- mass spectrometry (GC-MS). Statistical analysis of the data revealed significant differences between strains reared on different hosts, while spatially isolated strains reared on the same host produced similar profiles. CHC profiles of parasitoids reared on Stegobium paniceum were statistically distinguishable from those of wasps reared on all other hosts. A host shift from Sitophilus granarius to S. paniceum resulted in distinguishable CHC profiles of L. Distinguendus females after only one generation. Considering the role of CHCs as contact sex pheromones, our data suggest that host shifts in parasitic wasps might lead to reproductive isolation of host races due to the modification of the cuticular semiochemistry.
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Deciphering the signature of cuticular lipids with contact sex pheromone function in a parasitic wasp.
The Journal of experimental biology, 2012Co-Authors: Stephan Kuhbandner, Kenji Mori, Sergej Sperling, Joachim RutherAbstract:The surface of insects is covered by a complex mixture of cuticular hydrocarbons (CHCs) to prevent desiccation. In many species these lipids also have communicative functions, but often it is unknown which components are crucial for the behavioural response. Furthermore, it is often ignored that polar lipids also occur on the insects' cuticle and might interact with CHCs. In the parasitic wasp Lariophagus Distinguendus, CHCs function as a contact sex pheromone eliciting wing-fanning in males. Interestingly, not only females but also newly emerged males have the pheromone, resulting regularly in homosexual courtship. However, males deactivate the pheromone within the first two days after emergence. This deactivation is accompanied by the disappearance of 3-methylheptacosane (3-MeC27) and some minor components from the CHC profile of males. Here we show that 3-MeC27 is a key component of the contact sex pheromone which, however, triggers courtship behaviour only if an olfactory background of other cuticular lipids is present. Males responded to (S)-3-MeC27 enantioselectively when applied to filter paper but on three-dimensional dummies both enantiomers were behaviourally active, suggesting that physical stimuli also play a role in sexual communication of the wasps. Finally, we report that triacylglycerides (TAGs) are also essential components of the pheromone, and present evidence that TAGs actually occur on the cuticle of L. Distinguendus. Our data provide novel insights into the semiochemical function of cuticular lipids by showing that the bioactivity of CHCs may be influenced by the stereochemistry and a synergetic interaction with long time ignored TAGs.
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costs of female odour in males of the parasitic wasp Lariophagus Distinguendus hymenoptera pteromalidae
Naturwissenschaften, 2008Co-Authors: Joachim Ruther, Sven SteinerAbstract:The display of female traits by males is widespread in the animal kingdom. In several species, this phenomenon has been shown to function adaptively as a male mating strategy to deceive sexual rivals (female mimicry). Freshly emerged males of the parasitic wasp Lariophagus Distinguendus (Hymenoptera: Pteromalidae) are perceived by other males as if they were females because of a very similar composition of cuticular hydrocarbons which function as a sex pheromone in this species inducing courtship behaviour in males. Within 32 h, however, males deactivate the pheromone and are no longer courted by other males. In this paper, behavioural experiments were performed to test hypotheses on potential costs and benefits associated with the female odour in young males. We did not find any benefits, but demonstrated that young males were significantly more often outrivaled in male–male contests when competing with two older males for a female. Also, young males were significantly more often mounted in homosexual courtship events during these contests. Thus, display of female traits by males is not necessarily beneficial, and in fact, can be disadvantageous. We suggest that these costs have favoured the evolution of the pheromone deactivation mechanism in L. Distinguendus males. The function of cuticular hydrocarbons as a female courtship pheromone in L. Distinguendus might have evolved secondarily from a primary function relevant for both genders, and the deactivation of the signal in males might have caused a shift of specificity of the chemical signal from the species level to the sex level.
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mating with sperm depleted males does not increase female mating frequency in the parasitoid Lariophagus Distinguendus
Entomologia Experimentalis Et Applicata, 2008Co-Authors: Sven Steiner, Nina Henrich, Joachim RutherAbstract:Sexual conflicts due to divergent male and female interests in reproduction are common in parasitic Hymenoptera. The majority of parasitoid females are monandrous, whereas males are able to mate repeatedly. Thus, accepting only a single mate might be costly when females mate with a sperm-depleted male, which may not transfer a sufficient amount of sperm. In the present study, we investigated the reproductive performance in the parasitoid Lariophagus Distinguendus Forst. (Hymenoptera: Pteromalidae) and studied whether mating with experimentally sperm-depleted males increases the tendency of females to remate. Males were able to mate with up to 17 females offered in rapid succession within a 10-h test period. The resulting female offspring, as an indirect measure of sperm transfer, remained constant during the first six matings and then decreased successively with increasing number of copulations by the males. Experimentally sperm-depleted males continued to mate even if they transferred only small amounts or no sperm at all. Unlike males, the majority of females mated only once during a 192-h test period. A second copulation was observed only in a few cases (maximum 16%). The frequency of remating was not influenced by the mating status of the first male the females had copulated with, suggesting that these events are not controlled by sperm deficiency of the females. Furthermore, we investigated male courtship behaviour towards mated females. Male courtship intensity towards mated females decreased with increasing time. However, females that had mated with an experimentally sperm-depleted male did not elicit stronger or longer-lasting behavioural responses in courting males than those that had mated with a virgin male. As the observed behaviours in L. Distinguendus are known to be elicited by a courtship pheromone, these results suggest that females no longer invest in pheromone biosynthesis after mating (as indicated by ceasing behavioural responses of courting males), irrespective of whether they have received a sufficient amount of sperm or not. We discuss the results with respect to a possible mating strategy of sperm-depleted males.
Steffi Niedermayer - One of the best experts on this subject based on the ideXlab platform.
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Lost in space? Host-finding ability of the parasitoids Lariophagus Distinguendus and Anisopteromalus calandrae in empty grain storage facilities to control residual pest populations
BioControl, 2016Co-Authors: Steffi Niedermayer, Lars Krogmann, Johannes L. M. SteidleAbstract:We studied the ability of the parasitoid species Lariophagus Distinguendus (Förster) and Anisopteromalus calandrae (Howard) (Hymenoptera: Pteromalidae) to locate populations of the granary weevil Sitophilus granarius (L.) (Coleoptera: Dryophtoridae) in grain residues. Experiments were conducted under laboratory and storage-like conditions. Generally both parasitoid species were able to find hosts up to 10 m from the release spot. Under laboratory conditions with excluded air movement and a centered light source, host finding was largely random, declining with increasing distance of baits from the release spot. Under storage-like conditions, host finding was strongly reduced and was not influenced by distance. A. calandrae seems to have been influenced by positive phototaxis. L. Distinguendus showed a weaker host-finding success than A. calandrae , which was increased by a higher number of wasps from 10–50 per release. This resulted in a 5-fold higher number of parasitizations. It is discussed that host finding of residual pest populations by L. Distinguendus and A. calandrae in empty storages is difficult to predict and influenced by light and air conditions. Based on our results, we provide recommendations for the release of parasitoids against residual pest populations.
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Lariophagus Distinguendus hymenoptera pteromalidae forster past present and future the history of a biological control method using l Distinguendus against different storage pests
Insects, 2016Co-Authors: Steffi Niedermayer, Marie Pollmann, Johannes L. M. SteidleAbstract:Legal requirements and consumer demands for residue-free products pose a big challenge for pest control in grain stores. One possible alternative to chemical insecticides is biological pest control with the pteromalid wasp Lariophagus Distinguendus against the weevils Sitophilus granarius, S. oryzae (Coleoptera: Dryophtoridae), and many other storage pest beetles. The use of this wasp as a biocontrol agent was already suggested in 1919 by Prof. Dr. Hase [1]. Despite many studies on host-finding and behavioral biology, the applied aspect was neglected until 1994. Nowadays the wasps are commercially available and can now even be reared on-site, facilitating their use tremendously. This review highlights the milestones in L. Distinguendus research, gives insights in current studies, and ventures a glimpse into the future.
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die hohenheimer box entwicklung einer methode zur vor ort massenzucht der erzwespe Lariophagus Distinguendus gegen vorratsschadlinge
2013Co-Authors: Steffi Niedermayer, Johannes L. M. SteidleAbstract:Biological pest control is an important tool in stored products protection. To improve the biological control of the granary weevil Sitophilus granarius L. (Coleoptera: Curculionidae), a rearing box for the parasitic wasp Lariophagus Distinguendus (Forster) (Hymenoptera: Pteromalidae) has been developed. The box contains breeding substrate as well as populations of hosts and parasitoids and is placed directly in the storage site. A special outlet prevents hosts from leaving the box while freshly emerged parasitoids are released continuously over several months. A repeated shipment of wasps has thereby become obsolete.
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the hohenheimer box a new way to rear and release Lariophagus Distinguendus to control stored product pest insects
Biological Control, 2013Co-Authors: Steffi Niedermayer, Johannes L. M. SteidleAbstract:Abstract To improve the biological control of stored product pests, the present paper reports on the development of a rearing box for parasitoids of pest insects. The box contains breeding substrate and populations of hosts and parasitoids and is placed in storage sites, where parasitoids are released continuously over several months. The box was developed to rear Lariophagus Distinguendus (Forster) (Hymenoptera: Pteromalidae) to control the granary weevil Sitophilus granarius (L.) (Coleoptera: Curculionidae). Due to sanitary reasons, the bean weevil Acanthoscelides obtectus Say (Coleoptera: Bruchidae) was chosen as an alternative host. Rearing experiments revealed that the cowpea Vigna unguiculata unguiculata (L.) Walp. is most suitable as host substrate. For the outlet of the rearing device, a wire gauze mesh size of 0.8–1.0 mm was found suitable to release wasps while holding back the bean weevils. The size of the starting populations of hosts and parasitoids was determined experimentally in a storage building. An amount of 5 ml weevils plus 21–60 adult parasitoids on 2 kg of cowpeas produced an average of 56 and 62 wasps per week respectively, from June to September. Wasps reared in the boxes had the same number of offspring on granary weevils as wasps from regular lab-cultures. This study demonstrates the feasibility of a rearing box for parasitoids of stored product pests that releases large numbers of wasps over several months. We consider our study as a guideline for the development of similar rearing boxes also for other parasitoid-pest systems in stored products protection throughout the world.
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The Hohenheimer Box – A new way to rear and release Lariophagus Distinguendus to control stored product pest insects
Biological Control, 2013Co-Authors: Steffi Niedermayer, Johannes L. M. SteidleAbstract:Abstract To improve the biological control of stored product pests, the present paper reports on the development of a rearing box for parasitoids of pest insects. The box contains breeding substrate and populations of hosts and parasitoids and is placed in storage sites, where parasitoids are released continuously over several months. The box was developed to rear Lariophagus Distinguendus (Forster) (Hymenoptera: Pteromalidae) to control the granary weevil Sitophilus granarius (L.) (Coleoptera: Curculionidae). Due to sanitary reasons, the bean weevil Acanthoscelides obtectus Say (Coleoptera: Bruchidae) was chosen as an alternative host. Rearing experiments revealed that the cowpea Vigna unguiculata unguiculata (L.) Walp. is most suitable as host substrate. For the outlet of the rearing device, a wire gauze mesh size of 0.8–1.0 mm was found suitable to release wasps while holding back the bean weevils. The size of the starting populations of hosts and parasitoids was determined experimentally in a storage building. An amount of 5 ml weevils plus 21–60 adult parasitoids on 2 kg of cowpeas produced an average of 56 and 62 wasps per week respectively, from June to September. Wasps reared in the boxes had the same number of offspring on granary weevils as wasps from regular lab-cultures. This study demonstrates the feasibility of a rearing box for parasitoids of stored product pests that releases large numbers of wasps over several months. We consider our study as a guideline for the development of similar rearing boxes also for other parasitoid-pest systems in stored products protection throughout the world.
Matthias Scholler - One of the best experts on this subject based on the ideXlab platform.
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Potential of Hymenopteran larval and egg parasitoids to control stored-product beetle and moth infestation in jute bags.
Bulletin of Entomological Research, 2014Co-Authors: Charles Adarkwah, Christian Ulrichs, S. Schaarschmidt, Benjamin Kongyeli Badii, Isaac Kwahene Addai, Daniel Obeng-ofori, Matthias SchollerAbstract:The control of stored-product moths in bagged commodities is difficult because the developmental stages of the moths are protected by the bagging material from control measures such as the application of contact insecticides. Studies were carried out to assess the ability of Hymenopteran parasitoids to locate their hosts inside jute bags in the laboratory. The ability of different parasitoids to penetrate jute bags containing rice was investigated in a controlled climate chamber. Few Habrobracon hebetor (Say) (Hymenoptera: Braconidae) passed through the jute material while a high percentage of Lariophagus Distinguendus (Forster), Anisopteromalus calandrae (Howard) (Hymenoptera: Pteromalidae), Theocolax elegans (Westwood) (Hymenoptera: Pteromalidae) and Trichogramma evanescens Westwood (Hymenoptera: Trichogrammatidae) were able to enter the Petri-dishes. Significantly more L. Distinguendus and T. elegans entered compared to H. hebetor . There was significant difference in the mean percentage parasitoids invading depending on species. Head capsules and/or thorax widths were measured in order to determine whether the opening in the jute material would be large enough for entry of the parasitoids. These morphometric data differed depending on parasitoid species and sex. The parasitoid Venturia canescens (Gravenhorst) (Hymenoptera: Ichneumonidae) did not enter the bags, but located host larvae inside the jute bags and parasitized rice moths Corcyra cephalonica larvae by stinging through the jute material. Venturia canescens significantly reduced the number of C. cephalonica adults emerging from the bagged rice; therefore, it could be released in storage rooms containing bagged rice for biological control of C. cephalonica . The use of parasitoids to suppress stored-product insect pests in bagged commodities could become a valuable supplement to the use of synthetic pesticides.
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potential of Lariophagus Distinguendus forster hymenoptera pteromalidae to suppress the maize weevil sitophilus zeamais motschulsky coleoptera curculionidae in bagged and bulk stored maize
Biological Control, 2012Co-Authors: Charles Adarkwah, D Obengofori, C Buttner, Christoph Reichmuth, Matthias SchollerAbstract:Abstract Grains are often stored in jute bags in developing countries, especially in Africa, as well as in small quantities in bulk. Parasitoids suitable for biological control of stored-product pests should be able to find their hosts in bulk grain or in jute bags over a certain distance in a warehouse containing stacks of bagged grain. The potential of using Lariophagus Distinguendus for the biological control of Sitophilus zeamais was assessed in maize stored in jute bags and bulk grain. The ability of the parasitoid to penetrate the jute cloth and the grain mass and parasitize its host was studied under controlled conditions of 25 ± 1 °C and 65 ± 5% RH. Experiments were carried out in small 5-kg jute bags containing 28 d old S. zeamais larvae within infested maize kernels, and in cylinders filled with maize grains and containing caged hosts at different depths. L. Distinguendus parasitized S. zeamais in the jute bags and in the storage cylinders at various depths. In the jute bag experiment, out of the 60 L. Distinguendus adults released, a mean ± SD of 7.03 ± 1.78% and 6.34 ± 1.01% of the 40 females and of the 20 males released, respectively, entered the jute bags. Significantly, no differences were found between the female and male L. Distinguendus that entered the bags. Mean reduction of S. zeamais in the jute bags by parasitoids was 81%. The parasitic wasps also significantly reduced the emergence of S. zeamais in bulk maize. At depths of 20–45 cm from the grain surface, mean reduction of S. zeamais was 74%, while from 95 to 100 cm, mean reduction was 34%. When results from depths lower than 50 cm were pooled and compared with pooled data from depths higher than 90 cm, there was a significant reduction in parasitism at depths of more than 90 cm. For depths below 50 cm a mean of 5.3 L. Distinguendus adult offspring per cage emerged compared with a mean of 2.6 at depths of more than 90 cm. These results support the approach to utilize L. Distinguendus as a component in the integrated control of S. zeamais in bagged or bulk stored maize.
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Biological control of cultural heritage pest Coleoptera and Lepidoptera with the help of parasitoid Hymenoptera
Journal of Entomological and Acarological Research, 2011Co-Authors: Matthias Scholler, Sabine ProzellAbstract:Natural enemies are known from many cultural heritage pests, but their potential for biological control has been marginally exploited only. In this publication, examples of practical and commercial application of parasitoids of beetles and moths are compiled as well as laboratory research that contributes to the development of guidelines for parasitoid releases. One the one hand there are parasitoids found to occur simultaneously with the pests in buildings, on the other hand there are parasitoids that were never found to be associated with the respective pests but accept them if brought into the cultural heritage environments. An example for the latter is the egg parasitoid Trichogramma evanescens euproctidis , a parasitoid of moth eggs including those of the cloth moth Tineola bisselliella . In semi-field trials it was shown that inundative releases of the egg parasitoids are necessary and that effectiveness is reduced on thick cloth with long strand. Trichogramma release units have to be placed directly on the cloth to be protected. A naturally occuring parasitoid of Anobiid beetles is the pteromalid larval parasitoid Lariophagus Distinguendus . This parasitoid was applied against the drugstore beetle Stegobium paniceum in historic libraries and against spider beetles (Ptininae) in historic buildings. A simulation model for the population-dynamics of L. Distinguendus and the golden spider beetle Niptus hololeucus is presented. Finally, monitoring of the Braconid larval parasitoid Spathius exarator used for indirect monitoring of the common furniture beetle Anobium punctatum is described. The future potential of parasitoids to control cultural heritage pests is discussed.
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fecundity and ability of the parasitoid Lariophagus Distinguendus hymenoptera pteromalidae to find larvae of the granary weevil sitophilus granarius coleoptera curculionidae in bulk grain
Journal of Stored Products Research, 2002Co-Authors: Johannes L. M. Steidle, Matthias SchollerAbstract:Abstract Fecundity and host finding behavior in the storage environment were examined for the parasitoid Lariophagus Distinguendus (Forster), a potential agent for biological control of stored-product pest beetles. Larvae of the granary weevil, Sitophilus granarius (L.), in wheat were used as hosts. The fecundity varied considerably among strains of different geographical origin, from 1.3±2.4 to 92.5±23.6 offspring per female parasitoid. Host finding ability was examined in a small acrylic cylinder (about 42 kg wheat), a silo-bin (20.5 t wheat grain), and the flat storage grain bin in a commercial facility (3000 t rye). Experiments in the cylinder and the silo-bin revealed that the number of hosts found by the parasitoids decreases with increasing depth. Moreover, parasitoids were more likely to find hosts in the cylinder than under field storage conditions in a silo-bin. This indicates that the density of parasitoids per unit volume of the grain might be an important factor in determining how deep they penetrate a grain layer. In the silo-bin and the commercial grain store, parasitoids were able to find and parasitize hosts located up to 4 m vertically and horizontally from the release point. The significance of these results with respect to the suitability of L. Distinguendus for biological control of the granary weevil is discussed.
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olfactory host location and learning in the granary weevil parasitoidLariophagus Distinguendus hymenoptera pteromalidae
Journal of Insect Behavior, 1997Co-Authors: Johannes L. M. Steidle, Matthias SchollerAbstract:The sources of volatiles that attract the parasitoid Lariophagus Distinguendus(Forst.) to its hosts, the larvae of the granary weevil Sitophilus granarius(L.) infesting grains of Triticum aestivumL., were investigated in bioassays. The influence of oviposition experience on the responsiveness of the parasitoids to the sources of volatiles was considered. The potential sources of attractants are the host larvae, their feces, and the grain infested by the host. Weevil larvae were not attractive. Feces were attractive to females without and females with oviposition experience. Infested grains from which the larvae and feces were removed were slightly attractive to inexperienced, but very attractive to experienced females. Healthy and artificially damaged grains were attractive to experienced parasitoids only. Refering to the “variable response model,” we discuss the effect of experience on the response of the parasitoids to the several stimuli. Stimuli from different trophic levels are used by the foraging parasitoids: feces of the host larvae is an important source of attractants, but also the grains, particularly after experience.
Lise Stengaard Hansen - One of the best experts on this subject based on the ideXlab platform.
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survival and development of a stored product pest sitophilus zeamais coleoptera curculionidae and its natural enemy the parasitoid Lariophagus Distinguendus hymenoptera pteromalidae on transgenic bt maize
Pest Management Science, 2013Co-Authors: Lise Stengaard Hansen, Gabor L Lovei, Andras SzekacsAbstract:Background The effect of transgenic maize (Zea mays L.) containing a lepidopteran-specific Bt toxin on a stored-product pest, Sitophilus zeamais Motschulsky, and its parasitoid, Lariophagus Distinguendus Forster, was examined in the laboratory to test the impact of transgenic maize on stored-product pests and their biological control. Results Weevils were not harmfully affected by transgenic Bt maize in their development characteristics (development time, body mass), and females emerging from transgenic maize kernels were larger. However, significantly fewer parasitoid females emerged from weevils that developed in transgenic kernels, although parasitoids did not develop more slowly and were not different in size or mass from their conspecifics emerging from hosts in non-transgenic maize kernels. Conclusion The emergence of female parasitoids was reduced in transgenic Bt maize, and this effect cannot be explained by the known lepidopteran-specific toxicity of Bt Cry1Ab toxin.
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Combining larval parasitoids and an entomopathogenic fungus for biological control of Sitophilus granarius (Coleoptera: Curculionidae) in stored grain
Biological Control, 2007Co-Authors: Lise Stengaard Hansen, Tove SteenbergAbstract:Abstract The potential of combining different natural enemies for biological control of Sitophilus granarius (L.) in grain was investigated in a laboratory study. We compared the effect of two species of larval parasitoids, Lariophagus Distinguendus Forster and Anisoptermalus calandrae (Howard), alone or in combination with a surface treatment of the grain with the entomopathogenic fungus Beauveria bassiana (Bals.) Vuillemin against S. granarius in units containing 9 kg of wheat over a period of 26 weeks. In the untreated units, the pest population increased about 5000 times. The highest level of pest suppression (>99.9%) was obtained in units with L. Distinguendus, followed by units with A. calandrae. In units with both parasitoids and the entomopathogen, the pest suppression level was 83–98%. Although the parasitoids were negatively affected by the fungus, they still exerted some degree of control compared to the untreated units.
