Changes in gene expression align with behavioural differences in reproductive choices in a social... more Changes in gene expression align with behavioural differences in reproductive choices in a social beetle.
The reluctance of Israeli vine growers to adopt the mating disruption technique to control the mo... more The reluctance of Israeli vine growers to adopt the mating disruption technique to control the moth Lobesia botrana Den. & Schiff. has been attributed to the high cost of this method compared with that of traditional insecticide control. In this study, we tested the possibility of reducing the cost, Þrst by testing different pheromone formulations (and thus open the market for competition) and second by reducing the pheromone concentration used in vineyards. Comparisons were made between two pheromone formulationsÑShin-Etsu (Tokyo, Japan) at 165 g/ha and Concep (Sutera, Bend, OR) at 150 g/haÑand between two concentrations of Shin-Etsu, 165 and 110 g/ha. Pheromone dispensers were placed at the onset of the second moth generation. Comparison of the numbers of clusters infested with eggs and larvae of L. botrana showed no signiÞcant differences in the performance, either between the two formulations, or between the two tested concentrations. The results suggest that 1) the two formulations are equally effective, and 2) a low pheromone concentration is sufÞcient to maintain good control of small populations of L. botrana. However, when the population is high, pest control efÞcacy is not improved by increasing the pheromone concentration. Therefore, in the interest of reducing the relatively high cost of mating disruption, we emphasize that increasing the pheromone concentration does not provide improved control of high populations of L. botrana. The cost of mating disruption can be diminished by reducing the applied pheromone concentration and by using the least expensive pheromone formulations
Proceedings of The Royal Society B: Biological Sciences, Oct 22, 2000
The weevil Diaprepes abbreviatus shows three kinds of same-sex mountings: males mount other unpai... more The weevil Diaprepes abbreviatus shows three kinds of same-sex mountings: males mount other unpaired males, males mount males already engaged in copulation and females mount other females. Four hypotheses were evaluated in order to explain same-sex matings by males: (i) female mimicry by inferior males, (ii) dominance of larger males which a¡ects the behaviour of small males, (iii) sperm transfer in which smaller males gain some reproductive success by`hitchhiking' their sperm with the sperm of larger males, and (iv) poor sex recognition. Data from mate choice and sperm competition experiments rejected the female mimicry, dominance and sperm transfer hypotheses and supported the poor sex recognition hypothesis. We tested three hypotheses in order to explain female mounting behaviour: (i) females mimic male behaviour in order to reduce sexual harassment by males, (ii) females mount other females in order to appear larger and thereby attract more and larger males for mating, and (iii) female mimicry of males. The results of our mate choice experiments suggested that the female mimicry of males hypothesis best explains the observed female mounting behaviour. This result is also consistent with the poor sex recognition hypothesis which is the most likely explanation for male and female intrasexual mating behaviour in many insect species.
We used experimental manipulations to test adaptive explanations for the courtship display of the... more We used experimental manipulations to test adaptive explanations for the courtship display of the male widow spider, Latrodectus paUidus O. Pickard-Cambridge 1872. Two hypotheses have been suggested to explain a long and complex male display: a) Cooperation of males and females in the effort to physically stimulate the female. As the time of male arrival is not predictable, females may delay sexual readiness until the appearance of a courting male, b) Conflict between males and females regarding the display cost. Females impose on the males an energetically costly display that may last several hours as a test of their quality. To test both hypotheses, we manipulated the previous experience of either the male or the female. We presented naive or experienced males (males that had courted and were accepted by females but were prevented from copulating) to females that were either naive or experienced (had been courted by a male but prevented from copulating). We also presented naive males to mated females. Following the stimulation hypothesis, courted females were presumed to have been stimulated to mate and thus were expected to accept non-courting males as mates. Both naive and mated females, however, were expected to await male stimulation before allowing copulation. In contrast, the conllict of interest hypothesis predicts that the female tests each male for quality indicators and therefore a non-courting male should not be accepted as a mate. Mated females, however, should apply a less stringent test to courting males. Our results show that 1) naive females prevented males that did not perform a full courtship display from entering the nest and mounting; 2) naive males courted virgin females with the full display, independent of the female previous courting history; and 3) naive males shortened their courtship when presented with mated females. The results are consistent with the conllict of interest hypothesis.
The cypress bark beetle,Phloeosinus armatus, is a common element of the dying cypress tree system... more The cypress bark beetle,Phloeosinus armatus, is a common element of the dying cypress tree system in East-Mediterranean countries. Adult beetles congregate for breeding on this ephemeral resource. We studied three traits that characterize this beetle's sexual behavior and linked them to its reproductive success: mating system, mate choice, and parental care. We found that the females are the ‘pioneering sex’, excavating the mating chamber. The average female is slightly larger than the male, and female and male body size is correlated, demonstrating size-assortative mating. The time it takes for a male to enter the mating chamber is positively correlated with female size and negatively correlated with its own size, which is perhaps responsible for this assortative mating. Males remain in the gallery during the period of oviposition, gradually leaving soon after the eggs hatch. The number of eggs laid and tunnel length are positively correlated with male body size. Finally, in the presence of both parents, more eggs are laid than when the female alone is present, demonstrating the important contribution of biparental care for reproductive success. We suggest that the interaction between a monogamous mating system, assortative mating, and biparental care contributes to reproductive success.
An ecoinformatics approach was used to test how two noxious species in grapevines with varying ho... more An ecoinformatics approach was used to test how two noxious species in grapevines with varying host preferences and movement characteristics: the European grapevine moth (Lobesia botrana), and a parasitic fungus, the grape powdery mildew (Uncinula necator), are affected by local and landscape variables. Data were collected from 202 vineyards during four seasons: 2013, 2014, 2016 and 2017 and analysed using generalized mixed models. We hypothesized that the European grapevine moth would be affected most by the landscape variables, while the grape powdery mildew would be affected most by local ones. We found that the number of sprayings during the season was an important variable explaining variation in infestation levels between vineyards for both species. At the landscape scale, we found larger variations in the relationship between the studied variables and the two pests, but both were also affected by the surrounding land use including areas of deciduous orchards. Understanding the factors that affect the occurrence of various pests in the same environment might improve farmers' decision‐making.
Insect pests must reproduce in order to exist. In sexual organisms, sperm and ova need to synchro... more Insect pests must reproduce in order to exist. In sexual organisms, sperm and ova need to synchronically meet in a specific environment under conditions that may include temperature, time, food, day length, and many others. Mating events can therefore be predicted and as such open for manipulation.
The antagonistic sexual coevolution of the sexes (i.e., sexual conflict) is a key theme in the st... more The antagonistic sexual coevolution of the sexes (i.e., sexual conflict) is a key theme in the study of the evolution of mating systems. Specifically, studying the modifications of sexual behavior in the context of ecological conditions is fundamental for understanding the formation of a sexual system. The extremely crowded situation that prevails in the mating system of gregarious desert locusts is expected to result in a fierce sexual conflict. The goal of this work was to investigate core aspects of the sexual conflict during pre-copulatory interaction: (i) Female choosiness, (ii) preference functions (mate sampling strategy), (iv) antagonistic armament, (v) male endurance as an indicator of his fitness. We tested the pre-copulatory behavior of the gregarious desert locust (Schistocerca gregaria) under two distinguished conditions: (1) No-choice - a pair interaction (with no intra-male rivalry), and (2) choice – a female with two rival males. We investigate the sexual conflict in...
Female moths attract male moths by emitting to the atmosphere a series of pheromone filaments pro... more Female moths attract male moths by emitting to the atmosphere a series of pheromone filaments propagating downwind. The filaments appear to be aggregated into clusters (patches) while moving. In order to find the female moth, the male moth senses the concentration of the pheromone (e.g. odour) dispersed within the patches. Using the odour as a cue, the male moth may reach the vicinity of the female moth. The spatial and temporal variations of the odour advected by turbulence are random. This work addresses the problem of a male moth searching a female moth by tracing the randomly varying odour. We suggest an algorithm of searching the odour source. The algorithm uses a single instantaneous parameter that a navigator can measure: the time the moth crossed the odour patch during the last search. We describe mathematically a turbulent meandering patchy plume and the odour inside the plume. Using the proposed navigation algorithm, we simulate the path of the male moth searching the fema...
Mating and reproduction behaviors and strategies are fundamental aspects of an organism's evoluti... more Mating and reproduction behaviors and strategies are fundamental aspects of an organism's evolutionary and ecological success. In locusts, intra-as well as inter-phase reproductive interactions among gregarious and solitarious locust populations have a major impact on the locust population dynamics. However, practically all previous work on locust sexual behavior has been limited to the gregarious phase. Here we provide a first detailed description of pre-copulatory behavior of solitarious desert locusts. We compare our findings with those of previous reports of pre-copulatory behavior of gregarious locusts, focusing on the behavioral elements that serve in inter-sex signaling and communication. We also studied inter-phase (mixed pairs) reproductive interactions. Solitarious males were found to invest more in pre-copulatory courtship and signaling compared to their gregarious counterparts; and the solitarious females played a comparatively more dominant role in the inter-sex communication. The solitarious females were also less prone to demonstrate the typical rejection-related behavioral patterns displayed by the gregarious females. As a consequence of the particular characteristic behavior of each phase, the most successful among intra-and inter-phase pairs were gregarious males with solitary females. Least successful were solitary males encountered with gregarious females, indicating a strong asymmetry in inter-phase reproductive interactions. We discuss these results in the context of non-random or assortative mating in locust mixed or sympatric solitarious-gregarious populations.
We present a comprehensive discussion of pest management in organic greenhouse vegetable producti... more We present a comprehensive discussion of pest management in organic greenhouse vegetable production. Greenhouse structures and production practices vary greatly in different regions of the world. In northern Europe and North America, they are closed heated structures because of the long periods of cold weather and biological control is highly developed. In Israel, commercial greenhouses are made of netting or plastic, are not heated because the winters are generally mild in comparison with northern climes and hot in the summers, and biological control is used almost exclusively on some crops. In South America, greenhouses are simple structures covered with plastic material without nets or heating/cooling systems. We limit our discussion to properly closed and ventilated greenhouses, exclusive of structures that are opened for any period during the day or season. Our discussion covers greenhouse structure; the first line of defense, regulatory, and phytosanitary measures; various management methods; and finally specific management of primary pest groups, mites, thrips, hemipterans (aphids, mealybugs, and whiteflies), and small Lepidoptera.
t The pink bollworm, Pectinophoragossypiellais a key pest of cotton world-wide. In Israel mating ... more t The pink bollworm, Pectinophoragossypiellais a key pest of cotton world-wide. In Israel mating disruption sex pheromone is used in all cotton fields and recent repeated outbreaks of the pest populations has suggested a change in the population sex pheromone characteristics. The research goals were to (1) determine the change in pheromone characteristic of PBW females after long experience to Mating Disruption (MD), (2) to test the male’s antennae response (EAG) to pheromone characteristics of laboratory, naive females, and of field collected, MD experienced females, (3) to analyse the biosynthetic pathway for possible enzyme variations, (4) to determine the male behavioural response to the pheromone blend involved in the resistance to MD. The experiments revealed that (1) MD experienced females produced pheromone blend with higher ZZ ratio than lab reared (MD naive females) that typically produced ZZ:EE ratio of 1:1. (2) Male’s origin did not affect its response to pheromone characteristics of lab or field females. (3) A transcriptome study demonstrated many gene-encode enzymes in the biosynthetic pathway, but some of the transcripts were produced in differing levels in the MD resistant populations. (4) Male origin (field or lab) influenced males’ choice of mate with strong preference to females sharing the same origin. However, when MD was applied, males of both populations were more attracted to females originated form failed MD treated fields. We conclude that in MD failed fields a change in the population mean of the ratio of the pheromone components had occurred. Males in these fields had changed their search “image” accordingly while keeping the wide range of response to all pheromone characteristics. The change in the pheromone blend is due to different level of pheromone related enzyme production.
Sustainable Pest Management in Date Palm: Current Status and Emerging Challenges, 2015
This chapter covers general concepts of semiochemical implementations in pest management and the ... more This chapter covers general concepts of semiochemical implementations in pest management and the work done on the identification and use of semiochemicals for the management of date palm pests. Within the semiochemicals, pheromones are usually species specific and non-toxic to the environment. This makes pheromones in particular valuable components of integrated pest management as indicators of pest presence and as behavior modifiers, interfering with the proliferation of target pest. Control of pest populations can be achieved by a number of methods based on attractants, such as mating disruption, mass trapping, attract-and-kill, push-pull, or attract-and-infect. For any of these control tactics knowledge of the chemical ecology of pests and the identification of cues involved are essential. Isolation and identification of semiochemicals is a complicated process requiring: solvent extraction or head space collection by solid-phase microextraction (SPME) or other means, identification of active components by coupled gas chromatography-electroantennography (GC-EAG) and finally identification of chemical composition by gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR). A summary of known attractants of date pests is also provided. Currently effective attractants, pheromones, and/or host volatiles are known only for some of the major date palm pests. Case studies are described on sap beetles, the red palm weevil, Rhynchophorus ferrugineus, and the lesser date moth, Batrachedra amydraula. For red palm weevil and sap beetles, implementation of pheromones in combination with plant volatiles as a tool for monitoring is well accepted but essential information for optimization of their use is still missing. Moreover, development of semiochemical application as a control strategy, for most cases, is in its infancy and will remain a major challenge in future years. For other pests of palm trees, pheromones and other semiochemicals remain to be identified. Future challenges and perspectives for the implementation of semiochemicals towards sustainable pest control in date plantations are given.
Changes in gene expression align with behavioural differences in reproductive choices in a social... more Changes in gene expression align with behavioural differences in reproductive choices in a social beetle.
The reluctance of Israeli vine growers to adopt the mating disruption technique to control the mo... more The reluctance of Israeli vine growers to adopt the mating disruption technique to control the moth Lobesia botrana Den. & Schiff. has been attributed to the high cost of this method compared with that of traditional insecticide control. In this study, we tested the possibility of reducing the cost, Þrst by testing different pheromone formulations (and thus open the market for competition) and second by reducing the pheromone concentration used in vineyards. Comparisons were made between two pheromone formulationsÑShin-Etsu (Tokyo, Japan) at 165 g/ha and Concep (Sutera, Bend, OR) at 150 g/haÑand between two concentrations of Shin-Etsu, 165 and 110 g/ha. Pheromone dispensers were placed at the onset of the second moth generation. Comparison of the numbers of clusters infested with eggs and larvae of L. botrana showed no signiÞcant differences in the performance, either between the two formulations, or between the two tested concentrations. The results suggest that 1) the two formulations are equally effective, and 2) a low pheromone concentration is sufÞcient to maintain good control of small populations of L. botrana. However, when the population is high, pest control efÞcacy is not improved by increasing the pheromone concentration. Therefore, in the interest of reducing the relatively high cost of mating disruption, we emphasize that increasing the pheromone concentration does not provide improved control of high populations of L. botrana. The cost of mating disruption can be diminished by reducing the applied pheromone concentration and by using the least expensive pheromone formulations
Proceedings of The Royal Society B: Biological Sciences, Oct 22, 2000
The weevil Diaprepes abbreviatus shows three kinds of same-sex mountings: males mount other unpai... more The weevil Diaprepes abbreviatus shows three kinds of same-sex mountings: males mount other unpaired males, males mount males already engaged in copulation and females mount other females. Four hypotheses were evaluated in order to explain same-sex matings by males: (i) female mimicry by inferior males, (ii) dominance of larger males which a¡ects the behaviour of small males, (iii) sperm transfer in which smaller males gain some reproductive success by`hitchhiking' their sperm with the sperm of larger males, and (iv) poor sex recognition. Data from mate choice and sperm competition experiments rejected the female mimicry, dominance and sperm transfer hypotheses and supported the poor sex recognition hypothesis. We tested three hypotheses in order to explain female mounting behaviour: (i) females mimic male behaviour in order to reduce sexual harassment by males, (ii) females mount other females in order to appear larger and thereby attract more and larger males for mating, and (iii) female mimicry of males. The results of our mate choice experiments suggested that the female mimicry of males hypothesis best explains the observed female mounting behaviour. This result is also consistent with the poor sex recognition hypothesis which is the most likely explanation for male and female intrasexual mating behaviour in many insect species.
We used experimental manipulations to test adaptive explanations for the courtship display of the... more We used experimental manipulations to test adaptive explanations for the courtship display of the male widow spider, Latrodectus paUidus O. Pickard-Cambridge 1872. Two hypotheses have been suggested to explain a long and complex male display: a) Cooperation of males and females in the effort to physically stimulate the female. As the time of male arrival is not predictable, females may delay sexual readiness until the appearance of a courting male, b) Conflict between males and females regarding the display cost. Females impose on the males an energetically costly display that may last several hours as a test of their quality. To test both hypotheses, we manipulated the previous experience of either the male or the female. We presented naive or experienced males (males that had courted and were accepted by females but were prevented from copulating) to females that were either naive or experienced (had been courted by a male but prevented from copulating). We also presented naive males to mated females. Following the stimulation hypothesis, courted females were presumed to have been stimulated to mate and thus were expected to accept non-courting males as mates. Both naive and mated females, however, were expected to await male stimulation before allowing copulation. In contrast, the conllict of interest hypothesis predicts that the female tests each male for quality indicators and therefore a non-courting male should not be accepted as a mate. Mated females, however, should apply a less stringent test to courting males. Our results show that 1) naive females prevented males that did not perform a full courtship display from entering the nest and mounting; 2) naive males courted virgin females with the full display, independent of the female previous courting history; and 3) naive males shortened their courtship when presented with mated females. The results are consistent with the conllict of interest hypothesis.
The cypress bark beetle,Phloeosinus armatus, is a common element of the dying cypress tree system... more The cypress bark beetle,Phloeosinus armatus, is a common element of the dying cypress tree system in East-Mediterranean countries. Adult beetles congregate for breeding on this ephemeral resource. We studied three traits that characterize this beetle's sexual behavior and linked them to its reproductive success: mating system, mate choice, and parental care. We found that the females are the ‘pioneering sex’, excavating the mating chamber. The average female is slightly larger than the male, and female and male body size is correlated, demonstrating size-assortative mating. The time it takes for a male to enter the mating chamber is positively correlated with female size and negatively correlated with its own size, which is perhaps responsible for this assortative mating. Males remain in the gallery during the period of oviposition, gradually leaving soon after the eggs hatch. The number of eggs laid and tunnel length are positively correlated with male body size. Finally, in the presence of both parents, more eggs are laid than when the female alone is present, demonstrating the important contribution of biparental care for reproductive success. We suggest that the interaction between a monogamous mating system, assortative mating, and biparental care contributes to reproductive success.
An ecoinformatics approach was used to test how two noxious species in grapevines with varying ho... more An ecoinformatics approach was used to test how two noxious species in grapevines with varying host preferences and movement characteristics: the European grapevine moth (Lobesia botrana), and a parasitic fungus, the grape powdery mildew (Uncinula necator), are affected by local and landscape variables. Data were collected from 202 vineyards during four seasons: 2013, 2014, 2016 and 2017 and analysed using generalized mixed models. We hypothesized that the European grapevine moth would be affected most by the landscape variables, while the grape powdery mildew would be affected most by local ones. We found that the number of sprayings during the season was an important variable explaining variation in infestation levels between vineyards for both species. At the landscape scale, we found larger variations in the relationship between the studied variables and the two pests, but both were also affected by the surrounding land use including areas of deciduous orchards. Understanding the factors that affect the occurrence of various pests in the same environment might improve farmers' decision‐making.
Insect pests must reproduce in order to exist. In sexual organisms, sperm and ova need to synchro... more Insect pests must reproduce in order to exist. In sexual organisms, sperm and ova need to synchronically meet in a specific environment under conditions that may include temperature, time, food, day length, and many others. Mating events can therefore be predicted and as such open for manipulation.
The antagonistic sexual coevolution of the sexes (i.e., sexual conflict) is a key theme in the st... more The antagonistic sexual coevolution of the sexes (i.e., sexual conflict) is a key theme in the study of the evolution of mating systems. Specifically, studying the modifications of sexual behavior in the context of ecological conditions is fundamental for understanding the formation of a sexual system. The extremely crowded situation that prevails in the mating system of gregarious desert locusts is expected to result in a fierce sexual conflict. The goal of this work was to investigate core aspects of the sexual conflict during pre-copulatory interaction: (i) Female choosiness, (ii) preference functions (mate sampling strategy), (iv) antagonistic armament, (v) male endurance as an indicator of his fitness. We tested the pre-copulatory behavior of the gregarious desert locust (Schistocerca gregaria) under two distinguished conditions: (1) No-choice - a pair interaction (with no intra-male rivalry), and (2) choice – a female with two rival males. We investigate the sexual conflict in...
Female moths attract male moths by emitting to the atmosphere a series of pheromone filaments pro... more Female moths attract male moths by emitting to the atmosphere a series of pheromone filaments propagating downwind. The filaments appear to be aggregated into clusters (patches) while moving. In order to find the female moth, the male moth senses the concentration of the pheromone (e.g. odour) dispersed within the patches. Using the odour as a cue, the male moth may reach the vicinity of the female moth. The spatial and temporal variations of the odour advected by turbulence are random. This work addresses the problem of a male moth searching a female moth by tracing the randomly varying odour. We suggest an algorithm of searching the odour source. The algorithm uses a single instantaneous parameter that a navigator can measure: the time the moth crossed the odour patch during the last search. We describe mathematically a turbulent meandering patchy plume and the odour inside the plume. Using the proposed navigation algorithm, we simulate the path of the male moth searching the fema...
Mating and reproduction behaviors and strategies are fundamental aspects of an organism's evoluti... more Mating and reproduction behaviors and strategies are fundamental aspects of an organism's evolutionary and ecological success. In locusts, intra-as well as inter-phase reproductive interactions among gregarious and solitarious locust populations have a major impact on the locust population dynamics. However, practically all previous work on locust sexual behavior has been limited to the gregarious phase. Here we provide a first detailed description of pre-copulatory behavior of solitarious desert locusts. We compare our findings with those of previous reports of pre-copulatory behavior of gregarious locusts, focusing on the behavioral elements that serve in inter-sex signaling and communication. We also studied inter-phase (mixed pairs) reproductive interactions. Solitarious males were found to invest more in pre-copulatory courtship and signaling compared to their gregarious counterparts; and the solitarious females played a comparatively more dominant role in the inter-sex communication. The solitarious females were also less prone to demonstrate the typical rejection-related behavioral patterns displayed by the gregarious females. As a consequence of the particular characteristic behavior of each phase, the most successful among intra-and inter-phase pairs were gregarious males with solitary females. Least successful were solitary males encountered with gregarious females, indicating a strong asymmetry in inter-phase reproductive interactions. We discuss these results in the context of non-random or assortative mating in locust mixed or sympatric solitarious-gregarious populations.
We present a comprehensive discussion of pest management in organic greenhouse vegetable producti... more We present a comprehensive discussion of pest management in organic greenhouse vegetable production. Greenhouse structures and production practices vary greatly in different regions of the world. In northern Europe and North America, they are closed heated structures because of the long periods of cold weather and biological control is highly developed. In Israel, commercial greenhouses are made of netting or plastic, are not heated because the winters are generally mild in comparison with northern climes and hot in the summers, and biological control is used almost exclusively on some crops. In South America, greenhouses are simple structures covered with plastic material without nets or heating/cooling systems. We limit our discussion to properly closed and ventilated greenhouses, exclusive of structures that are opened for any period during the day or season. Our discussion covers greenhouse structure; the first line of defense, regulatory, and phytosanitary measures; various management methods; and finally specific management of primary pest groups, mites, thrips, hemipterans (aphids, mealybugs, and whiteflies), and small Lepidoptera.
t The pink bollworm, Pectinophoragossypiellais a key pest of cotton world-wide. In Israel mating ... more t The pink bollworm, Pectinophoragossypiellais a key pest of cotton world-wide. In Israel mating disruption sex pheromone is used in all cotton fields and recent repeated outbreaks of the pest populations has suggested a change in the population sex pheromone characteristics. The research goals were to (1) determine the change in pheromone characteristic of PBW females after long experience to Mating Disruption (MD), (2) to test the male’s antennae response (EAG) to pheromone characteristics of laboratory, naive females, and of field collected, MD experienced females, (3) to analyse the biosynthetic pathway for possible enzyme variations, (4) to determine the male behavioural response to the pheromone blend involved in the resistance to MD. The experiments revealed that (1) MD experienced females produced pheromone blend with higher ZZ ratio than lab reared (MD naive females) that typically produced ZZ:EE ratio of 1:1. (2) Male’s origin did not affect its response to pheromone characteristics of lab or field females. (3) A transcriptome study demonstrated many gene-encode enzymes in the biosynthetic pathway, but some of the transcripts were produced in differing levels in the MD resistant populations. (4) Male origin (field or lab) influenced males’ choice of mate with strong preference to females sharing the same origin. However, when MD was applied, males of both populations were more attracted to females originated form failed MD treated fields. We conclude that in MD failed fields a change in the population mean of the ratio of the pheromone components had occurred. Males in these fields had changed their search “image” accordingly while keeping the wide range of response to all pheromone characteristics. The change in the pheromone blend is due to different level of pheromone related enzyme production.
Sustainable Pest Management in Date Palm: Current Status and Emerging Challenges, 2015
This chapter covers general concepts of semiochemical implementations in pest management and the ... more This chapter covers general concepts of semiochemical implementations in pest management and the work done on the identification and use of semiochemicals for the management of date palm pests. Within the semiochemicals, pheromones are usually species specific and non-toxic to the environment. This makes pheromones in particular valuable components of integrated pest management as indicators of pest presence and as behavior modifiers, interfering with the proliferation of target pest. Control of pest populations can be achieved by a number of methods based on attractants, such as mating disruption, mass trapping, attract-and-kill, push-pull, or attract-and-infect. For any of these control tactics knowledge of the chemical ecology of pests and the identification of cues involved are essential. Isolation and identification of semiochemicals is a complicated process requiring: solvent extraction or head space collection by solid-phase microextraction (SPME) or other means, identification of active components by coupled gas chromatography-electroantennography (GC-EAG) and finally identification of chemical composition by gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR). A summary of known attractants of date pests is also provided. Currently effective attractants, pheromones, and/or host volatiles are known only for some of the major date palm pests. Case studies are described on sap beetles, the red palm weevil, Rhynchophorus ferrugineus, and the lesser date moth, Batrachedra amydraula. For red palm weevil and sap beetles, implementation of pheromones in combination with plant volatiles as a tool for monitoring is well accepted but essential information for optimization of their use is still missing. Moreover, development of semiochemical application as a control strategy, for most cases, is in its infancy and will remain a major challenge in future years. For other pests of palm trees, pheromones and other semiochemicals remain to be identified. Future challenges and perspectives for the implementation of semiochemicals towards sustainable pest control in date plantations are given.
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