In tsetse both sexes feed exclusively on the blood of vertebrates for a few minutes every 23 day... more In tsetse both sexes feed exclusively on the blood of vertebrates for a few minutes every 23 days. Tsetse flies seek cover from high temperatures to conserve energy and plants provide shelter for tsetse in all the biotopes they occupy. Recently, tsetse have taken cover in ...
The larch bud moth (LBM) Zeiraphera diniana Guenée causes defoliation on larch in the Alps at 8- ... more The larch bud moth (LBM) Zeiraphera diniana Guenée causes defoliation on larch in the Alps at 8- to 10-year intervals, after which populations crash. There are two LBM host races, one on larch and the other on cembran pine. These host races are morphologically indistinguishable as adults but they differ genetically in larval color types. Furthermore, females of each host race produce distinct pheromone blends and show oviposition preferences for their respective hosts. It is not clear to what extent host choice contributes to assortative mating in the LBM. Here, we compare the olfactory sensitivities of the two host races to the odors of fresh foliage of the host plants using the electroantennogram (EAG) technique, and the responses of the two host races to volatiles collected from the two host plants as analyzed by gas-chromatography-linked antennographic detection (GC-EAD). Both sexes of the larch and cembran host races show the same EAG responses to vapors of fresh larch and cemb...
... Corresponding Author Contact Information , E-mail The Corresponding Author , K. De Souza b ..... more ... Corresponding Author Contact Information , E-mail The Corresponding Author , K. De Souza b ... Lepidopteran sex pheromones have attracted considerable interest in crop pest control (Howse ... disruption of male moth orientation leading to mating disruption (Sanders, 1997) and ...
In tsetse both sexes feed exclusively on the blood of vertebrates for a few minutes every 23 day... more In tsetse both sexes feed exclusively on the blood of vertebrates for a few minutes every 23 days. Tsetse flies seek cover from high temperatures to conserve energy and plants provide shelter for tsetse in all the biotopes they occupy. Recently, tsetse have taken cover in ...
The development of sex-specific traits, including the female-specific ability to bite humans and ... more The development of sex-specific traits, including the female-specific ability to bite humans and vector disease, is critical for vector mosquito reproduction and pathogen transmission. Doublesex (Dsx), a terminal transcription factor in the sex determination pathway, is known to regulate sex-specific gene expression during development of the dengue fever vector mosquito Aedes aegypti. Here, the effects of developmental siRNA-mediated dsx silencing were assessed in adult females. Targeting of dsx during A. aegypti development resulted in decreased female wing size, a correlate for body size, which is typically larger in females. siRNA-mediated targeting of dsx also resulted in decreased length of the adult female proboscis. Although dsx silencing did not impact female membrane blood feeding or mating behavior in the laboratory, decreased fecundity and fertility correlated with decreased ovary length, ovariole length, and ovariole number in dsx knockdown females. Dsx silencing also resulted in disruption of olfactory system development, as evidenced by reduced length of the female antenna and maxillary palp and the sensilla present on these structures, as well as disrupted odorant receptor expression. Female lifespan, a critical component of the ability of A. aegypti to transmit pathogens, was also significantly reduced in adult females following developmental targeting of dsx. The results of this investigation demonstrate that silencing of dsx during A. aegypti development disrupts multiple sex-specific morphological, physiological, and behavioral traits of adult females, a number of which are directly or indirectly linked to mosquito reproduction and pathogen transmission. Moreover, the olfactory phenotypes observed connect Dsx to development of the olfactory system, suggesting that A. aegypti will be an excellent system in which to further assess the developmental genetics of sex-specific chemosensation.
Sexual dimorphism, a poorly understood but crucial aspect of vector mosquito biology, encompasses... more Sexual dimorphism, a poorly understood but crucial aspect of vector mosquito biology, encompasses sex-specific physical, physiological, and behavioral traits related to mosquito reproduction. The study of mosquito sexual dimorphism has largely focused on analysis of the differences between adult female and male mosquitoes, particularly with respect to sex-specific behaviors related to disease transmission. However, sexually dimorphic behaviors are the products of differential gene expression that initiates during development and therefore must also be studied during development. Recent technical advancements are facilitating functional genetic studies in the dengue vector Aedes aegypti, an emerging model for mosquito development. These methodologies, many of which could be extended to other non-model insect species, are facilitating analysis of the development of sexual dimorphism in neural tissues, particularly the olfactory system. These studies are providing insight into the neurodevelopmental genetic basis for sexual dimorphism in vector mosquitoes.
Drosophila have evolved strong mutualistic associations with yeast communities that best support ... more Drosophila have evolved strong mutualistic associations with yeast communities that best support their growth and survival, resulting in the development of novel niches. It has been suggested that flies recognize their cognate yeasts primarily based on the rich repertoire of volatile organic compounds (VOCs) derived from the yeasts. Thus, it remained an exciting avenue to study whether fly spp. detect and discriminate yeast strains based on odor alone, and if so, how such resolution is achieved by the olfactory system in flies. We used two fly species known to exploit different niches and harboring different yeasts, D. suzukii (a pest of fresh fruit) and D. melanogaster (a saprophytic fly and a neurogenetic model organism). We initially established the behavioral preference of both fly species to six Drosophila-associated yeasts; then chemically analyzed the VOC profile of each yeast which revealed quantitative and qualitative differences; and finally isolated and identified the phy...
We employed the Solid Phase Micro Extraction (SPME) and other analytical methods to collect the h... more We employed the Solid Phase Micro Extraction (SPME) and other analytical methods to collect the headspace volatiles from human and animal hosts of Culex quinquefasciatus. Analysis of adsorbed headspace volatiles by Gas chromatography linked antennal detection (GC-EAD) revealed at least four compounds that consistently elicited the responses from the antenna. Chemical identity of these compounds was established by GC-MS. We carried out extensive single sensillum recordings (SSR) on the adult Culex antenna in order to find out if these compounds are detected by specific olfactory receptor neurons (ORNs). One of the sensillum types, ABII-2, indeed detected the dominant compound in host odor spectrum with a remarkable sensitivity. Of the two ORNs present in this sensillum, second ORN detects indole, an aromatic compound that has been previously shown to elicit various physiological responses in many mosquito species. We extended the SSR analysis by exposing each type of antennal sensill...
Southern house mosquito, Culex quinquefasciatus Say, transmits many serious diseases including We... more Southern house mosquito, Culex quinquefasciatus Say, transmits many serious diseases including West Nile Virus that is now emerging as the dominant vector borne diseases across Northern America. Olfaction plays a critical role in feeding and survival. A variety of odorant molecules released from hosts and habitats are detected by olfactory receptors (Ors) expressed on antennal Olfactory Receptor Neurons (ORNs). A comprehensive account of chemical landscape, reception and perception underlying the complex Culex-host interaction will be presented in the poster. Additionally, unique host shifts in Culex where adults alternate host feeding based on availability and abundance of host population will be discussed.
In tsetse both sexes feed exclusively on the blood of vertebrates for a few minutes every 23 day... more In tsetse both sexes feed exclusively on the blood of vertebrates for a few minutes every 23 days. Tsetse flies seek cover from high temperatures to conserve energy and plants provide shelter for tsetse in all the biotopes they occupy. Recently, tsetse have taken cover in ...
The larch bud moth (LBM) Zeiraphera diniana Guenée causes defoliation on larch in the Alps at 8- ... more The larch bud moth (LBM) Zeiraphera diniana Guenée causes defoliation on larch in the Alps at 8- to 10-year intervals, after which populations crash. There are two LBM host races, one on larch and the other on cembran pine. These host races are morphologically indistinguishable as adults but they differ genetically in larval color types. Furthermore, females of each host race produce distinct pheromone blends and show oviposition preferences for their respective hosts. It is not clear to what extent host choice contributes to assortative mating in the LBM. Here, we compare the olfactory sensitivities of the two host races to the odors of fresh foliage of the host plants using the electroantennogram (EAG) technique, and the responses of the two host races to volatiles collected from the two host plants as analyzed by gas-chromatography-linked antennographic detection (GC-EAD). Both sexes of the larch and cembran host races show the same EAG responses to vapors of fresh larch and cemb...
... Corresponding Author Contact Information , E-mail The Corresponding Author , K. De Souza b ..... more ... Corresponding Author Contact Information , E-mail The Corresponding Author , K. De Souza b ... Lepidopteran sex pheromones have attracted considerable interest in crop pest control (Howse ... disruption of male moth orientation leading to mating disruption (Sanders, 1997) and ...
In tsetse both sexes feed exclusively on the blood of vertebrates for a few minutes every 23 day... more In tsetse both sexes feed exclusively on the blood of vertebrates for a few minutes every 23 days. Tsetse flies seek cover from high temperatures to conserve energy and plants provide shelter for tsetse in all the biotopes they occupy. Recently, tsetse have taken cover in ...
The development of sex-specific traits, including the female-specific ability to bite humans and ... more The development of sex-specific traits, including the female-specific ability to bite humans and vector disease, is critical for vector mosquito reproduction and pathogen transmission. Doublesex (Dsx), a terminal transcription factor in the sex determination pathway, is known to regulate sex-specific gene expression during development of the dengue fever vector mosquito Aedes aegypti. Here, the effects of developmental siRNA-mediated dsx silencing were assessed in adult females. Targeting of dsx during A. aegypti development resulted in decreased female wing size, a correlate for body size, which is typically larger in females. siRNA-mediated targeting of dsx also resulted in decreased length of the adult female proboscis. Although dsx silencing did not impact female membrane blood feeding or mating behavior in the laboratory, decreased fecundity and fertility correlated with decreased ovary length, ovariole length, and ovariole number in dsx knockdown females. Dsx silencing also resulted in disruption of olfactory system development, as evidenced by reduced length of the female antenna and maxillary palp and the sensilla present on these structures, as well as disrupted odorant receptor expression. Female lifespan, a critical component of the ability of A. aegypti to transmit pathogens, was also significantly reduced in adult females following developmental targeting of dsx. The results of this investigation demonstrate that silencing of dsx during A. aegypti development disrupts multiple sex-specific morphological, physiological, and behavioral traits of adult females, a number of which are directly or indirectly linked to mosquito reproduction and pathogen transmission. Moreover, the olfactory phenotypes observed connect Dsx to development of the olfactory system, suggesting that A. aegypti will be an excellent system in which to further assess the developmental genetics of sex-specific chemosensation.
Sexual dimorphism, a poorly understood but crucial aspect of vector mosquito biology, encompasses... more Sexual dimorphism, a poorly understood but crucial aspect of vector mosquito biology, encompasses sex-specific physical, physiological, and behavioral traits related to mosquito reproduction. The study of mosquito sexual dimorphism has largely focused on analysis of the differences between adult female and male mosquitoes, particularly with respect to sex-specific behaviors related to disease transmission. However, sexually dimorphic behaviors are the products of differential gene expression that initiates during development and therefore must also be studied during development. Recent technical advancements are facilitating functional genetic studies in the dengue vector Aedes aegypti, an emerging model for mosquito development. These methodologies, many of which could be extended to other non-model insect species, are facilitating analysis of the development of sexual dimorphism in neural tissues, particularly the olfactory system. These studies are providing insight into the neurodevelopmental genetic basis for sexual dimorphism in vector mosquitoes.
Drosophila have evolved strong mutualistic associations with yeast communities that best support ... more Drosophila have evolved strong mutualistic associations with yeast communities that best support their growth and survival, resulting in the development of novel niches. It has been suggested that flies recognize their cognate yeasts primarily based on the rich repertoire of volatile organic compounds (VOCs) derived from the yeasts. Thus, it remained an exciting avenue to study whether fly spp. detect and discriminate yeast strains based on odor alone, and if so, how such resolution is achieved by the olfactory system in flies. We used two fly species known to exploit different niches and harboring different yeasts, D. suzukii (a pest of fresh fruit) and D. melanogaster (a saprophytic fly and a neurogenetic model organism). We initially established the behavioral preference of both fly species to six Drosophila-associated yeasts; then chemically analyzed the VOC profile of each yeast which revealed quantitative and qualitative differences; and finally isolated and identified the phy...
We employed the Solid Phase Micro Extraction (SPME) and other analytical methods to collect the h... more We employed the Solid Phase Micro Extraction (SPME) and other analytical methods to collect the headspace volatiles from human and animal hosts of Culex quinquefasciatus. Analysis of adsorbed headspace volatiles by Gas chromatography linked antennal detection (GC-EAD) revealed at least four compounds that consistently elicited the responses from the antenna. Chemical identity of these compounds was established by GC-MS. We carried out extensive single sensillum recordings (SSR) on the adult Culex antenna in order to find out if these compounds are detected by specific olfactory receptor neurons (ORNs). One of the sensillum types, ABII-2, indeed detected the dominant compound in host odor spectrum with a remarkable sensitivity. Of the two ORNs present in this sensillum, second ORN detects indole, an aromatic compound that has been previously shown to elicit various physiological responses in many mosquito species. We extended the SSR analysis by exposing each type of antennal sensill...
Southern house mosquito, Culex quinquefasciatus Say, transmits many serious diseases including We... more Southern house mosquito, Culex quinquefasciatus Say, transmits many serious diseases including West Nile Virus that is now emerging as the dominant vector borne diseases across Northern America. Olfaction plays a critical role in feeding and survival. A variety of odorant molecules released from hosts and habitats are detected by olfactory receptors (Ors) expressed on antennal Olfactory Receptor Neurons (ORNs). A comprehensive account of chemical landscape, reception and perception underlying the complex Culex-host interaction will be presented in the poster. Additionally, unique host shifts in Culex where adults alternate host feeding based on availability and abundance of host population will be discussed.
Uploads