{"id":5117,"date":"2020-01-22T19:25:31","date_gmt":"2020-01-22T23:25:31","guid":{"rendered":"https:\/\/drealfmgrenada.com\/?p=5117"},"modified":"2020-01-22T19:25:31","modified_gmt":"2020-01-22T23:25:31","slug":"mosquitoes-are-drawn-to-flowers-as-much-as-people-and-now-scientists-know-why","status":"publish","type":"post","link":"https:\/\/drealfmgrenada.com\/index.php\/2020\/01\/22\/mosquitoes-are-drawn-to-flowers-as-much-as-people-and-now-scientists-know-why\/","title":{"rendered":"Mosquitoes Are Drawn To Flowers As Much As People \u2014 And Now Scientists Know Why"},"content":{"rendered":"

UW News-<\/strong>Without their keen sense of smell, mosquitoes wouldn\u2019t get very far. They rely on this sense to find a host to bite and spots to lay eggs.<\/p>\n

And without that sense of smell, mosquitoes could not locate their dominant source of food: nectar from flowers.<\/p>\n

\"\"<\/a><\/p>\n

Aedes<\/u>\u00a0mosquitoes feeding from\u00a0Platanthera<\/u>\u00a0flowers.Kiley Riffell<\/span><\/p>\n<\/div>\n

\u201cNectar is an important source of food for all mosquitoes,\u201d said\u00a0Jeffrey Riffell<\/a>, a professor of biology at the University of Washington. \u201cFor male mosquitoes, nectar is their only food source, and female mosquitoes feed on nectar for all but a few days of their lives.\u201d<\/p>\n

Yet scientists know little about the scents that draw mosquitoes toward certain flowers, or repel them from others. This information could help develop less toxic and better repellents, more effective traps and understand how the mosquito brain responds to sensory information \u2014 including the cues that, on occasion, lead a female mosquito to bite one of us.<\/p>\n

Riffell\u2019s team, which includes researchers at the UW, Virginia Tech and UC San Diego, has discovered the chemical cues that lead mosquitoes to pollinate a particularly irresistible species of orchid. As they report in a\u00a0paper<\/a>\u00a0published in the Proceedings of the National Academy of Sciences, the orchid produces a finely balanced bouquet of chemical compounds that stimulate mosquitoes\u2019 sense of smell. On their own, some of these chemicals have either attractive or repressive effects on the mosquito brain. When combined in the same ratio as they\u2019re found in the orchid, they draw in mosquitoes as effectively as a real flower. Riffell\u2019s team also showed that one of the scent chemicals that repels mosquitoes lights up the same region of the mosquito brain as\u00a0DEET<\/a>, a common and controversial mosquito repellant.<\/p>\n

\"\"<\/a><\/p>\n

The researchers used bags placed over the orchids to collect samples of their scents in the field.Kiley Riffell<\/span><\/p>\n<\/div>\n

Their findings show how environmental cues from flowers can stimulate the mosquito brain as much as a warm-blooded host \u2014 and can draw the mosquito toward a target or send it flying the other direction, said Riffell, who is the senior author of the study.<\/p>\n

The blunt-leaf orchid, or\u00a0Platanthera obtusata<\/em>, grows in cool, high-latitude climates across the Northern Hemisphere. From field stations in the Okanogan-Wenatchee National Forest in Washington state, Riffell\u2019s team verified past research showing that local mosquitoes pollinate this species, but not its close relatives that grow in the same habitat. When researchers covered the flowers with bags \u2014 depriving the mosquitoes of a visual cue for the flower \u2014 the mosquitoes would still land on the bagged flowers and attempt to feed through the canvas.<\/p>\n

Orchid scent obviously attracted the mosquitoes. To find out why, Riffell\u2019s team turned to the individual chemicals that make up the blunt-leaf orchid\u2019s scent.<\/p>\n

\u201cWe often describe \u2018scent\u2019 as if it\u2019s one thing \u2014 like the scent of a flower, or the scent of a person,\u201d said Riffell. \u201cScent is actually a complex combination of chemicals \u2014 the scent of a rose consists of more than 300 \u2014 and mosquitoes can detect the individual types of chemicals that make up a scent.\u201d<\/p>\n

\"\"<\/a><\/p>\n

Using a gas chromatogram to separate the individual chemicals that make up a flower\u2019s scent while simultaneously recording electrical activity from a mosquito\u2019s antenna to see which chemicals stimulate the mosquito\u2019s antenna.Kiley Riffell<\/span><\/p>\n<\/div>\n

Riffell describes the blunt-leaf orchid\u2019s scent as a grassy or musky odor, while its close relatives have a sweeter fragrance. The team used gas chromatography and mass spectroscopy to identify dozens of chemicals in the scents of the\u00a0Platanthera<\/em>\u00a0species. Compared to its relatives, the blunt-leaf orchid\u2019s scent contained high amounts of a compound called\u00a0nonanal<\/a>, and smaller amounts of another chemical, lilac aldehyde.<\/p>\n

Riffell\u2019s team also recorded the electrical activity in mosquito antennae, which detect scents. Both nonanal and lilac aldehyde stimulated antennae of mosquitoes that are native to the blunt-leaf orchid\u2019s habitat. But these compounds also stimulated the antennae of mosquitoes from other regions, including\u00a0Anopheles stephensi<\/em>, which spreads malaria, and\u00a0Aedes aegypti<\/em>, which spreads dengue, yellow fever, Zika and other diseases.<\/p>\n

Experiments of mosquito behavior showed that both native and non-native mosquitoes preferred a solution of nonanal and lilac aldehyde mixed in the same ratio as found in blunt-leaf flowers. If the researchers omitted lilac aldehyde from the recipe, mosquitoes lost interest. If they added more lilac aldehyde \u2014 at levels found in the blunt-leaf orchid\u2019s close relatives \u2014 mosquitoes were indifferent or repelled by the scent.<\/p>\n

Using techniques developed in Riffell\u2019s lab, they also peered directly into the brains of\u00a0Aedes increpitus\u00a0<\/em>mosquitoes, which overlap with blunt-leaf orchids, and a genetically modified strain of\u00a0Aedes aegypti<\/em>\u00a0previously developed<\/a>\u00a0by Riffell and co-author\u00a0Omar Akbari<\/a>, an associate professor at UC San Diego. They imaged calcium ions \u2014 signatures of actively firing neurons \u2014 in the antenna lobe, the region of the mosquito brain that processes signals from the antennae.<\/p>\n

These brain imaging experiments revealed that nonanal and lilac aldehyde stimulate different parts of the antenna lobe \u2014 and even compete with one another when stimulated: The region that responds to nonanal can suppress activity in the region that responds to lilac aldehyde, and vice versa. Whether this \u201ccross talk\u201d makes a flower attractive or repelling to the mosquito likely depends on the amounts of nonanal and lilac aldehyde in the original scent. Blunt-leaf orchids have a ratio that attracts mosquitoes, while closely related species do not, according to Riffell.<\/p>\n

\u201cMosquitoes are processing the ratio of chemicals, not just the presence or absence of them,\u201d said Riffell. \u201cThis isn\u2019t just important for flower discrimination \u2014 it\u2019s also important for how mosquitoes discern between you and I. Human scent is very complex, and what is probably important for attracting or repelling mosquitoes is the ratio of particular chemicals. We know that some people get bit more than others, and maybe a difference in ratio explains why.\u201d<\/p>\n

\"\"<\/a><\/p>\n

A mosquito tethered to the underside of a microscope stage for calcium imaging of its antenna lobe.Kiley Riffell<\/span><\/p>\n<\/div>\n

The team also discovered that lilac aldehyde stimulates the same region of the antenna lobe as DEET. That region may process \u201crepressive\u201d scents, though further research would need to verify this, said Riffell. It\u2019s too soon to tell if lilac aldehyde may someday be an effective mosquito repellant. But if it is, there is an added bonus.<\/p>\n

\u201cIt smells wonderful,\u201d said Riffell.<\/p>\n

Lead author is\u00a0Chlo\u00e9 Lahond\u00e8re<\/a>, who conducted the research as a UW postdoctoral fellow and is now a research assistant professor at Virginia Tech. Additional co-authors are\u00a0Cl\u00e9ment Vinauger<\/a>, a former UW postdoctoral researcher and current assistant professor at Virginia Tech; UW biology graduate students\u00a0Ryo Okubo<\/a>\u00a0and\u00a0Jeremy Chan<\/a>; and UW postdoctoral researcher\u00a0Gabriella Wolff<\/a>. The research was funded by the National Institutes of Health, the Air Force Office of Scientific Research and the University of Washington.<\/p>\n

For more information, contact Riffell at 206-685-2573 or\u00a0jriffell@uw.edu<\/a>.<\/em><\/p>\n

University of Washington\u00a0<\/strong><\/p>\n","protected":false},"excerpt":{"rendered":"

UW News-Without their keen sense of smell, mosquitoes wouldn\u2019t get very far. They rely on this sense to find a host to bite and spots to lay eggs. And without that sense of smell, mosquitoes […]<\/a><\/p>\n<\/div>","protected":false},"author":1,"featured_media":5118,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[21,45],"tags":[],"class_list":{"0":"post-5117","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-environment","8":"category-health"},"jetpack_publicize_connections":[],"jetpack_featured_media_url":"https:\/\/i0.wp.com\/drealfmgrenada.com\/wp-content\/uploads\/2020\/01\/Lahondere-et-al-Image2-1140x1081-1.jpg?fit=1140%2C1081&ssl=1","jetpack_likes_enabled":true,"jetpack_sharing_enabled":true,"rttpg_featured_image_url":{"full":["https:\/\/i0.wp.com\/drealfmgrenada.com\/wp-content\/uploads\/2020\/01\/Lahondere-et-al-Image2-1140x1081-1.jpg?fit=1140%2C1081&ssl=1",1140,1081,false],"landscape":["https:\/\/drealfmgrenada.com\/wp-content\/uploads\/2020\/01\/Lahondere-et-al-Image2-1140x1081-1.jpg",1140,1081,false],"portraits":["https:\/\/drealfmgrenada.com\/wp-content\/uploads\/2020\/01\/Lahondere-et-al-Image2-1140x1081-1.jpg",1140,1081,false],"thumbnail":["https:\/\/i0.wp.com\/drealfmgrenada.com\/wp-content\/uploads\/2020\/01\/Lahondere-et-al-Image2-1140x1081-1.jpg?resize=150%2C150&ssl=1",150,150,true],"medium":["https:\/\/i0.wp.com\/drealfmgrenada.com\/wp-content\/uploads\/2020\/01\/Lahondere-et-al-Image2-1140x1081-1.jpg?fit=300%2C284&ssl=1",300,284,true],"large":["https:\/\/i0.wp.com\/drealfmgrenada.com\/wp-content\/uploads\/2020\/01\/Lahondere-et-al-Image2-1140x1081-1.jpg?fit=1024%2C971&ssl=1",1024,971,true],"1536x1536":["https:\/\/i0.wp.com\/drealfmgrenada.com\/wp-content\/uploads\/2020\/01\/Lahondere-et-al-Image2-1140x1081-1.jpg?fit=1140%2C1081&ssl=1",1140,1081,true],"2048x2048":["https:\/\/i0.wp.com\/drealfmgrenada.com\/wp-content\/uploads\/2020\/01\/Lahondere-et-al-Image2-1140x1081-1.jpg?fit=1140%2C1081&ssl=1",1140,1081,true],"mh-magazine-slider":["https:\/\/i0.wp.com\/drealfmgrenada.com\/wp-content\/uploads\/2020\/01\/Lahondere-et-al-Image2-1140x1081-1.jpg?resize=1030%2C438&ssl=1",1030,438,true],"mh-magazine-content":["https:\/\/i0.wp.com\/drealfmgrenada.com\/wp-content\/uploads\/2020\/01\/Lahondere-et-al-Image2-1140x1081-1.jpg?resize=678%2C381&ssl=1",678,381,true],"mh-magazine-large":["https:\/\/i0.wp.com\/drealfmgrenada.com\/wp-content\/uploads\/2020\/01\/Lahondere-et-al-Image2-1140x1081-1.jpg?resize=678%2C509&ssl=1",678,509,true],"mh-magazine-medium":["https:\/\/i0.wp.com\/drealfmgrenada.com\/wp-content\/uploads\/2020\/01\/Lahondere-et-al-Image2-1140x1081-1.jpg?resize=326%2C245&ssl=1",326,245,true],"mh-magazine-small":["https:\/\/i0.wp.com\/drealfmgrenada.com\/wp-content\/uploads\/2020\/01\/Lahondere-et-al-Image2-1140x1081-1.jpg?resize=80%2C60&ssl=1",80,60,true]},"rttpg_author":{"display_name":"adminrfm","author_link":"https:\/\/drealfmgrenada.com\/index.php\/author\/adminrfm\/"},"rttpg_comment":0,"rttpg_category":"Environment<\/a> Health<\/a>","rttpg_excerpt":"UW News-Without their keen sense of smell, mosquitoes wouldn\u2019t get very far. They rely on this sense to find a host to bite and spots to lay eggs. And without that sense of smell, mosquitoes [...]","_links":{"self":[{"href":"https:\/\/drealfmgrenada.com\/index.php\/wp-json\/wp\/v2\/posts\/5117","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/drealfmgrenada.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/drealfmgrenada.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/drealfmgrenada.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/drealfmgrenada.com\/index.php\/wp-json\/wp\/v2\/comments?post=5117"}],"version-history":[{"count":1,"href":"https:\/\/drealfmgrenada.com\/index.php\/wp-json\/wp\/v2\/posts\/5117\/revisions"}],"predecessor-version":[{"id":5119,"href":"https:\/\/drealfmgrenada.com\/index.php\/wp-json\/wp\/v2\/posts\/5117\/revisions\/5119"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/drealfmgrenada.com\/index.php\/wp-json\/wp\/v2\/media\/5118"}],"wp:attachment":[{"href":"https:\/\/drealfmgrenada.com\/index.php\/wp-json\/wp\/v2\/media?parent=5117"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/drealfmgrenada.com\/index.php\/wp-json\/wp\/v2\/categories?post=5117"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/drealfmgrenada.com\/index.php\/wp-json\/wp\/v2\/tags?post=5117"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}