WEEK 6-9 MATERIALS
WEEK 6-9 MATERIALS ENTM 21000-001
Popular in Introduction to Insect Behavior
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Date Created: 03/20/16
Question for this week Discuss the many ways insects are a vital key in an ecosystem of interactions between insects plants and other organisms and what might happen if they were removed Study Guide for Queen of Trees Video The first wasps that enter the figs through the one way passage are what gender To feed on the leaves of the fig a long horned beetle cuts the ow of latex by doing what to the leaves The katydid solves this problem in another way what does it do to feed on the leaves without latex What do the fermenting fruits bring for the mantis To prevent parasites from getting into the fig the fig tree does two things what are they How do nematodes get into the fig How does the parasitic driller wasp get into the fig How do the smaller parasitic banded wasps take advantage of the driller in getting access to the driller wasp eggs The ants look after eggs and nymphs of the Hilda bug and herd them Why What does the nymph have anatomically that the ants don t have The dried latex is used by bees for what purpose Cicadas do what to eliminate the surplus sugar to avoid getting their wings wet Females wasps can t emerge until what happens Male wasps mate with female wasps where What do males use to guide them into the female gall Nematodes can t kill the host too quickly why Female wasps exhibit what behavior to prepare to pollinate figs Why can t the hombill let one bee escape What is the final act of the males brief life Do both sexes leave the fig and y away What dangers lay in wait for wasps that disperse Can they disperse long distances Why do some figs remain full of parasites Fermented figs have what effect on butter ies and how does it increase their survival How does smoke keep the bees from stinging What do they do before leaving the hive Do bees also pollinate fig owers What two reasons creatures prevent germination of figs around a fig tree What three things help a female wasp get into a fig for fertilization How many females get inside each fig to lay eggs What does the female wasp do for the fig tree when she is in the fig Mosquito sperm have a quotsense of smellquot This unexpected discovery is reported in an article published in the online Early Edition of the Proceedings of the National Academy of Sciences for the week of Feb 3 by a team of Vanderbilt University biologists The scientists report that they have detected a suite of specialized chemical sensors called odorant receptors CBS in mosquito sperm These are the same as the sensors that play a central role in the mosquito39s olfactory system which is found on the insect39s antennaeThe researchers found that the odorant receptors in the sperm are expressed along their tails where they drive the rapid increase in the movement beating of the sperm tails quotThis discovery is really 39out of the box39 for usquot said LJ Zwiebel the Cornelius Vanderbilt Chair in Biological Sciences who directed the study quotIt is the first time that insect ORs have been found to function in nonsensory cells or tissue We think this could be an entirely new paradigm for how insect reproduction is regulated If it is it could provide a powerful new approach for controlling populations of insects of medical andor economic importancequot In nature evolution often reuses successful structures after they have arisen In this case it is likely that the CPS evolved first in the reproductive system and then were used to form the basis of the mosquito39s complex adult olfactory system If this is the case then it is also likely that the use of insect odorant receptors to modulate sperm behavior is a fundamental aspect of insect biology Female mosquitoes which live for about a month only mate once They store the male39s sperm in special organs called spermathecae After mating females require a blood meal to get the basic compounds they need to produce eggs That is why they bite humans and other animals and in so doing act as vectors for globally important diseases such as malaria and Dengue fever Once the eggs have developed they are fertilized by the sperm stored within the female39s reproductive tract quotThe sperm may need a chemical signal to become ready for fertilizationquot said Research Assistant Professor Jason Pitts quotThere are reports that within one day after insemination the sperm begin swimming around in the spermathecae There must be one or more signals that activate this movement and our findings suggest that odorant receptors may be the sensor that receives these signalsquot Pitts graduate student Chao Liu and postdoctoral fellow Xiaofan Zhou are cofirst authors of the paper The origin of the discovery was an observation the researchers made several years ago as part of their research into the olfaction system of the malaria mosquito Anopheles gambiae They found unusually high expression of a group of odorant receptors in the bodies of male mosquitoes This caught the researchers attention because they were receptors that females use so they didn39t expect them to be enhanced in males It took them several years to follow up on the observation When they did they tracked these receptors to the males39 testes and ultimately to the sperm themselves The finding sparked their interest further because of controversial research that has reported finding olfactory receptors in human sperm quotEvidence for the presence of these receptors in human sperm is very solid What is controversial is whether they play any role in human reproductionquot Pitts said Because of ongoing research that the Vanderbilt researchers have been conducting aimed at discovering new and more effective mosquito repellents they had developed the tools they needed to determine if the odorant receptors in the mosquito sperm were functional In particular they had identified specific chemical compounds that specifically activate insect odorant receptors as well as others that prevent them from activating Liu and Zhou used these compounds to design a novel videobased bioassay They found when the mosquito sperm were exposed to odorant receptor activators as well as chemical cues like fenchone a natural organic compound found in fennel the sperm tails started beating much more frequently However the sperm did not respond to the same compounds when they were simultaneously exposed to an agent that blocks the odorant receptors The researchers also showed the ability to activate sperm beating was absent in a mutant strain of Aedes aegypti mosquitoes that are genetically altered to lack functional odorant receptors quotThis provides compelling evidence that the odorant receptors are involved in the reproduction processquot said Zwiebel Their tests also found that cyclicAMP which has been shown to cause sperm beating in mammals also increased the rate of beating in mosquito sperm But its effect was not prevented by the OR blockers indicating that it was linked to a different set of receptors in the sperm quotWe know there is a lot more going on We have just scratched the surfacequot said Zwiebel The researchers have also tested three additional insect species the Asian Tiger mosquito Aedes albopictus the fruit fly Drosophila melanogaster and the jewel wasp Nasonia vitripennis and found that their sperm also contain odorant receptors According to the researchers this suggests that CBS have a general function in reproduction across most if not all species of insects Undergraduate researcher Juan Malpartida has begun surveying other insect species to find out whether the reproductive role of odorant receptors is indeed universal or if it is limited to specific insect groups At the same time the researchers will be exploring the possibility that their discovery can provide improved ways to control insect populations If they can find a compound that renders males sterile for example it could be used for the sterile insect method of biological control The method involves releasing overwhelming numbers of sterile males of an insect pest into the wild The sterile males compete with the wild males to mate with females to reduce the size of the next generation It has been successfully used to eradicate the screwworm fly from areas of North America and to control the Medfly and Mexican fruit fly However it is difficult to do correctly and it can be very expensive Story Source The above story is based on materials provided by Vanderbilt University Note Materials may be edited for content and length Journal Reference 1 R Jason Pitts Chao Liu Xiaofan Zhou Juan C Malpartida and Laurence J Zwiebel Odorant receptor mediated sperm activation in disease vector mosquitoes PNAS February 2014 DOI 101 O73pnas13229231 11 Sperm It s Not What s For DinnerPicture Winged Flies E bilimeki Female Ulidiid flies have a kinky habit After mating with a male they expel his sperm and eat it The odd behavior may help these lady flies choose which guy flies will father their young researchers reported online today April 11 in the journal Behavioral Ecology and Sociobiology Studying a species of quotpicturewinged flyquot known as Euxesta bilimeki researchers found that 100 percent of the 74 fy couples they studied spewed out ejaculate after mating Further study revealed that 25 percent of females harbored no gm afterward The findings suggest the fly dames were able to control how much sperm to expel in order to select which males fertilized their eggs And these fly gals are no romantics long periods of courtship before mating made females more likely to expel all the ejaculate results showed The researchers suggest that the female may simply be giving in to a determined male in order to stave off future advances but dispensing with his sperm before he can father her babies Another possibility is that the sperm provides nutrition for the female flies when food is scarce To test this theory the researchers fed female flies a diet of protein sugar and water sugar and water just water or nothing fasting flies Then they put the flies with males that could ejaculate or males that could not Flies that were fed nutrients sugar or proteins or plain water seemed to derive no benefit from eating the sperm But the fasting flies that ate sperm lived longer than those that were prevented from eating it suggesting the ejaculate provided a needed source of fluids These flies live in dry regions where evolution may have favored such behavior But studies reveal that females of many insect species receive no nutritional benefit from such quotnuptial giftsquot the researchers say The spermeating practice may simply be part of the mating effort Many questions remain and the researchers note that more experiments are needed before making conclusive statements about the function of the spermspewingandscarfing behavior In an odd twist on the dinner date some female flies eat sperm and now scientists know why Female Ulidiid flies Euxesta bilimeki expel and eat ejaculate because it allows them to decide who will be the best father of their offspring a new study says Also see quotFemale Flies Put Up a Fight to Keep Sex Short Just as lovers partners and spouses frequently exchange gifts and share meals during courtship and beyond so do many animal species Usually the male builds a nest or provides a food gift for the female in order to help convince her that his genes are high quality and that he would make a good father In these cases the female is directly choosing her mate and the offspring benefit both from the good genes of the parents and from the food or housing provided by the male Read about weird mating and courtship rituals But for some species of mammals birds and insects in which fertilization is internal the effects of female choice are less obvious to the male In a process called cryptic female choice a female can exert control over her baby daddy by expelling a male s sperm after copulation This method is especially effective in species like E bilimeki in which the female can store the male s sperm before using it to fertilize her eggs according to the study authors The Mating Game Researchers knew that female E bilimeki would expel and eat sperm but didn t know why To find out Christian Luis RodriguezEnriquez and colleagues at the Institute for Ecology in Vera Cruz Mexico watched 74 pairs of E bilimeki court and mate They found that all of the females expelled and ate at least some of the ejaculate that they d stored in specialized spermstorage organs See quotSperm Tracked in 3D A First When the team looked closer they found that onequarter of the females purged all of the ejaculate from their bodies This meant that the males with whom they recently mated would have no chance of fathering their offspring according to the study published recently in the journal Behavioral Ecoloqy and Sociology Since females mate multiple times the amount of ejaculate she expels can help increase or decrease the likelihood that a male will be the father of her offspring The more sperm she expels the less likely the male will pass on his genes So what makes an undesirable suitor A male fly that s too aggressive the study found The longer a male pursued a female before mating made the female more likely to expel and consume the ejaculate RodriguezEnriquez and colleagues hypothesize that this may be because the female grows tired of evading the male and copulates simply to avoid his amorous pursuits Expelling the sperm means that she doesn t have to worry about making babies with males who don t know the meaning of quotback off Plus she just might get some nutritious liquid in exchange for her hassle Sperm It s Not What s For Dinner Ulidiid flies live in the deserts of Mexico and the US Southwest where water and food are scarce That made researchers initially suspect that the female flies might be eating the ejaculate for sustenance Also see quotBeetles Are Thirsty for Sex To test this theory the team raised females on one of several different diets a very highquality diet containing protein sugar and water a highquality diet containing sugar and water water only and neither water nor food The females that were given no food or water for two days did live longer if they consumed expelled sperm after mating but this consumption had no effect on the survival or longevity of the wellfed flies But the starved and thirsty flies were no more likely than the wellfed flies to consume the ejaculate showing that they don t eat it for food Although mysteries remain about the spermeating flies the results show that females continue to play a crucial role in selecting the father of their offspring even after mating httpvoicesnationalgeographiccom20130417why femaleflieseatsperm SLOWER FRUIT FLY SPERM MAY WIN THE RACE Syracuse University It s assumed that faster sperm have an edge in the race to fertilize the egg but slower swimmers may have an advantage over their faster rivals The study recently published online in Current Biology and forthcoming in print on September 25 was conducted by a team of scientists led by corresponding author Stefan Lupold a postdoctoral researcher in the biology department at Syracuse University The team made the discovery using fruit ies Drosophila melanogaster that were genetically altered so that the heads of their sperm glow uorescent green or red under the microscope The fruit ies developed by biologist John Belote enable researchers to observe sperm in real time inside the female reproductive tract Sperm competition is a fundamental biological process throughout the animal kingdom yet we know very little about how ejaculate traits determine which males win contests says L pold a Swiss National Science Foundation Fellow working in the laboratory of biology professor Scott Pitnick This is the rst study that actually measures sperm quality under competitive conditions inside the female allowing us to distinguish the traits that are important in each of the reproductive phases The research is also significant because the scientists studied naturally occurring variations in sperm traits rather than manipulating the test populations for specific traits After identifying and isolating groups of males with similar ejaculate traits that remained constant across multiple generations the scientists mated single females with pairs of males from the different groups This approach allowed us to simultaneously investigate multiple ejaculate traits and also observe how sperm from one male change behavior depending upon that of rival sperm L pold says Female fruit ies mate about every three days Sperm from each mating swim through the female bursa into a storage area until eggs are released Eggs travel from the ovaries into the bursa to await the sperm However sperm battles actually take place within the storage area After each mating new sperm try to toss sperm from previous matings out of storage The female then ejects the displaced sperm from the reproductive system eliminating the ejected sperm from the mating game The researchers observed that longer and slowermoving sperm were better at displacing their rivals and were also less likely to be ejected from storage than their more agile counterparts The nding that longer sperm were more successful is consistent with earlier studies Liipold says However the nding that slower sperm also have an advantage is counterintuitive Why slower sperm have an advantage is still open to speculation It could be that when swimming back and forth in storage slower sperm hit the exit less frequently and are therefore less likely to be pushed out L pold says Or because sperm velocity is dependent on the density of sperm within the narrow storage area it could be that velocity isn t really the target of sexual selection in fruit ies but is rather a consequence of the amount of sperm packed into the storage organ The US National Science Foundation NSF and the Swiss National Science Foundation funded the study DOI 10lOl6jcub201206059 Reflection Question Consider the many ways that insects gather food and then narrow your discussion to a few that are not paralleled in human life and how those might have evolved Video Guide Life in the Undergrowth Silk and NonSpider Uses of Silk Illuminations Fungus Gnat Flies in Tasmanian Cave Larvae of the Fungus Gnat use light to attract prey How do they catch prey Light is located on what part of the body Silk comes from where When and why do they turn off the light Early uses of silk lacewings How do female lace wings protect their eggs using silk Silk comes out as a liquid and becomes hard how Webspinners Order Embioptera Produce their silk from what part of their body What unique feature of a webspinner s silken tunnels allow it to go undetected by the ant How does a webspinner get water Spider Webs What do trapdoor spiders do to avoid reacting to leaves hitting the trap lines Are spider webs made with one or several types of silk How do spiders start their web Why does she spin a scaffolding web first How do the final threads differ from the scaffolding threads When an insect strikes the web what are the coils of thread in the droplets used for What behavior does she exhibit to determine where the prey is Orb spiders and thieves in their webs Argyrodes dewdrop spiders How does the smaller spider Argyrodes get away with stealing a meal from the larger orb spider Nephila Hyptiotes spiders triangle web spiders do what behavior to keep the triangular web tight How does this behavior allow them to catch prey The gladiator spider backcombs using back legs the silk to make it fuzzy why She then snips the catch lines and holds the fuzzy silk just above the ground why How does the Australian redbacked spider use silk in a three dimensional web Bolas Spider How does the bola spider protect herself during the day How does the bolas spider catch prey Can bolas spiders change their pheromone mixture Why would they do this Social living spiders Why do some spiders live in quasisocial groups How do they immobilize their prey Where do they inject their venom Agiope Spiders Mating How does the male determine that the female is not going to attack Why does he snip some of her web Why does he pluck the single strand in the middle What does the female do to assure the male that she is receptive Wolf Spiders How does the male wolf spider use the female s drag line to determine her mating status What does he do to attract her when he is in visual range that triples his heart rate How does she respond to encourage him What does the male use his palps for in the mating process How does the female construct her egg case Why does she seek out sunny patches How do the spiderlings stay on the mom s back How do they use silk when they leave their mothers Question of the Week Why are ants so successful and if you had to design a way to eliminate them what behavior might use to your advantage Study Guide for Ants Little Creatures Who Run the World What group of insects gave rise to ants Social cockroaches and termite young are only able to digest wood if their parents pass on what to them The ant s strength came from not only their power jaws and the ability to sting but what Do workers usually breed Workers fight off infections by cleaning the grubs with from special glands Harvester ant colonies all over Arizona erupt on a few time of day and after what weather conditions to breed Who encourages them to take ight Do the males or the queens send out chemical signals After the mating frenzy who ies off to start the new colonies What happens to the individuals left behind Inside the piles when the outside temperatures are 40 degrees the ants survive huddled inside how do they melt the snow in the spring Sahara Dessert What time of day do the ants become active and how do they benefit by being active when other creatures are not Tropical rain forests 5 million kinds of insects live at what elevation in the rain forest the ground on the surface or high in the trees the canopy When Dr Wilson crushes the bodies of the fire ants and dips his stick into the Vial and lays a trail on the table how do the other live ants react Ants use how many chemical signal to communicate to alert nest mates to danger to lead them around to identify the castes of their nest mates Termites The first wave out from the termite nest is which group And what comes out of their nozzle shaped heads Soft white workers come out next what do they do African and Australian Bush How do the termite homes differ in these locations Kenyan raid ants find termites by following what laid down by scouts After invading a nest what do the ants do with the termite corpses when leaving the nest What ant lives in the largest colonies six feet under ground Why are they so feared ie what can they kill How are they able to overcome the slime defense of the large slug Do they ignore their trapped sisters after they leave the slug How do other organisms take advantage of the eeing insects in front of army of driver ants Do the ants climb to get prey Arizona desert Honey pot ants Do they only eat the honey or do they gather other food What do scouts do when they meet a stranger By the use of what behavior do they limit losses Describe how the stand What objects in the environment do they use to appear larger How does one colony judge another colony or in other words what do they use to determine if they should stay and fight or run If they sense an advantage what do they do What happens if they fail to assess the other s strength accurately and posturing does not work Malaysian Rainforest herdsman ants What do the herdsman ants do when the plants start to age and the bugs stop feeding on the plants What do they use to build their nest deep inside a hollow bamboo stem What happens to the young born of expectant mother bugs Cecropia plants and ants This plant provides the ants with home and white nodules which the ants do what with Peru relax we have seen this earlier in another video remember the Devil s garden Leaf cutter ants By being both nocturnal and diurnal they can graze a considerable area How many cows equal a full grown colony How does feeding habit of the leaf cutter ant ensure that the trees will be there for them in the future In other words how are they sustainable farmers What are the similarities between ants and humans with respect to their social behaviors Science Daily As climate warms bark beetles march on highelevation forests Date December 31 2012 Source University of WisconsinMadison Summary In a new study scientists report a rising threat to the whitebark pine forests of the northern Rocky Mountains as native mountain pine beetles climb ever higher attacking trees that have not evolved strong defenses to stop them Trees and the insects that eat them wage constant war Insects burrow and munch trees deploy lethal and disruptive defenses in the form of chemicals But in a warming world where temperatures and seasonal change are in flux the tide of battle may be shifting in some insects39 favor according to a new study In a report published today Dec 31 2012 in the Proceedings of the National Academy of Sciences a team of scientists from the University of WisconsinMadison reports a rising threat to the whitebark pine forests of the northern Rocky Mountains as native mountain pine beetles climb ever higher attacking trees that have not evolved strong defenses to stop them The whitebark pine forests of the western United States and Canada are the forest ecosystems that occur at the highest elevation that sustains trees It is critical habitat for iconic species such as the grizzly bear and plays an important role in governing the hydrology of the mountain west by shading snow and regulating the flow of meltwater quotWarming temperatures have allowed treekilling beetles to thrive in areas that were historically too cold for them most yearsquot explains Ken Raffa a UWMadison professor of entomology and a senior author of the new report quotThe tree species at these high elevations never evolved strong defensesquot A warming world has not only made it easier for the mountain pine beetle to invade new and defenseless ecosystems but also to better withstand winter weather that is milder and erupt in large outbreaks capable of killing entire stands of trees no matter their composition quotA subject of much concern in the scientific community is the potential for cascading effects of whitebark pine loss on mountain ecosystemsquot says Phil Townsend a UWMadison professor of forest ecology and also a senior author of the study The mountain pine beetle39s historic host is the lodgepole pine a tree common at lower elevations Typically the insects which are about the size of a grain of rice play a key role in regulating the health of a forest by attacking old or weakened trees and fostering the development of a younger forest However recent years have been characterized by unusually hot and dry summers and mild winters which have allowed insect populations to boom This has led to an infestation of mountain pine beetle described as possibly the most significant insect blight ever seen in North America Because lodgepole pine coevolved with the bark beetle it has devised stronger chemical countermeasures volatile compounds toxic to the beetle and other agents that disrupt the pine bark beetle39s chemical communication system Despite its robust defense system the lodgepole pine is still the preferred menu item for the mountain pine beetle suggesting that the beetle has not yet adjusted its host preference to whitebark pine quotNevertheless at elevations consisting of pure whitebark pine the mountain pine beetle readily attacks itquot says Townsend The good news he adds is that in mixed stands the beetle39s strongest attraction is to the lodgepole pine suggesting that at least in the short term whitebark pine may persist in those environments The study conducted in the Greater Yellowstone Ecosystem one of the last nearly intact ecosystems in the Earth39s northern temperate regions also revealed that the insects that prey on or compete with the mountain pine beetle are staying in their preferred lodgepole pine habitat That says Townsend is a concern because the treekilling bark beetles quotwill encounter fewer of these enemies in fragile highelevation standsquot Whitebark pine trees are an important food source for wildlife including black and grizzly bears and birds such as the Clark39s nutcracker named after the famed explorer and which is essential to whitebark pine forest ecology as the bird39s seed caches help regenerate the forests With their broad crowns the highelevation whitebark pines also act as snow fences helping to slowly release water into mountain streams and extending stream flow into mountain valleys well into the summer quotLoss of the canopy will lead to greater desiccation during the winter and faster melting in the summer due to loss of tree canopies for shadequot according to Townsend quotThis is possibly a short term effect of the loss of whitebark pinequot he explains quotIf and it is a big if other tree species replace it eventually this service may be replacedquot The new study was supported by the US National Science Foundation and the UWMadison College of Agricultural and Life Sciences Story Source The above post is reprinted from materials provided by University of WisconsinMadison The original item was written by Terry Devitt Note Materials may be edited for content and length Journal Reference 1 Kenneth F Raffa Erinn N Powell and Philip A Townsend Temperaturedriven range expansion of an irruptive insect heightened by weakly coevolved plant defenses Proceedings of the National Academy of Sciences 2012 DOI 101 O73pnas1 21 66661 10 Pivotal role of gut bacteria in insecttoinsect communication Date December 10 2015 Source Kansas State University Summary German cockroaches gather by acting on colonyspecific pheromones produced by specific fecal bacteria a new study shows The research helps to explain how cockroaches a particularly nasty species know to gather in a certain area If you39ve ever lived in a cockroachinfested dwelling you know that if you see one of the pesky insects many more are hiding just out of sight New research from a team including Kansas State University39s Ludek Zurek professor of entomology is helping explain how German cockroaches a particularly nasty species know to gather in a certain area Their communication system is mediated at least in part by the presence of certain gut microbes The roaches aggregate by tracing pheromones in feces from other roaches Zurek and colleagues determined that young German cockroaches or nymphs prefer the pheromones excreted from roaches with a certain gut bacterial profile Aggregating accelerates nymphal development and reproductive maturation and carries other benefits such as helping roaches locate mates avoid predators and find food sources quotThis result is another example demonstrating the importance of microbes in biology of eukaryotes including mediation of animal behaviorquot Zurek said German cockroaches are major pests of human homes worldwide They transmit pathogens contaminate food and cause allergies Researchers have long attempted to identify specific fecal aggregation pheromones and have been puzzled by widely varied chemical profiles Zurek and colleagues identified major fecal volatile carboxylic acids or VCAs that comprise pheromones and reflect the microorganism contents of a cockroach39s gut and in turn its local environment Introducing a synthetic blend of fecal VCAs into cockroaches that had no microorganisms in their digestive tracts resulted in increased aggregation response in young roaches and experiments indicated that roaches can discriminate among the odors from different microbes In addition to helping researchers understand the science that drives basic insect behaviors these results could lead to better pest control quotThis research can lead to practical applications such as devising more efficient traps for cockroaches based on the specific blend of volatile compounds originating from bacteriaquot Zurek said quotThis work adds a significant piece to our understanding of the role of microbes in shaping animal ecology and behavior and raises new questions about these relationships and how to exploit them for managing pests hallmarks of excellent researchquot said John Ruberson head of the entomology department The study quotGut bacteria mediate aggregation in the German cockroachquot was published in the Proceedings of the National Academy of Sciences Story Source The above post is reprinted from materials provided by Kansas State University The original item was written by Sarah Caldwell Hancock Note Materials may be edited for content and length Journal Reference 1 Ayako WadaKatsumata Ludek Zurek Godfrey Nalyanya Wendell L Roelofs Aijun Zhang Coby Schal Gut bacteria mediate aggregation in the German cockroach Proceedings of the National Academy of Sciences 2015 201504031 DOI 101 O73pnas1504031 1 12 Mown grass smell sends SOS for help 1n res1st1ng 1nsect attacks Date September 22 2014 Source Texas AampM Ag riLife Summary The smell of cut grass in recent years has been identified as the plant s way of signalling distress but new research says the aroma also summons beneficial insects to the rescue Such findings may help plant breeders know how to develop new varieties that are more resistant to insects and drought The smell of cut grass in recent years has been identified as the plant s way of signalling distress but new research says the aroma also summons beneficial insects to the rescue according to Dr Michael Kolomiets Texas AampM AgriLife Research plant pathologist in College Station Credit Texas AampM AgriLife Research photo by Kathleen Phillips The smell of cut grass in recent years has been identified as the plant s way of signalling distress but new research says the aroma also summons beneficial insects to the rescue When there is need for protection the plant signals the environment via the emission of volatile organic compounds which are recognized as a feeding queue for parasitic wasps to come to the plant that is being eaten and lay eggs in the pest insect said Dr Michael Kolomiets Texas AampM AgriLife Research plant pathologist in College Station The research stems from a look at the function of a large family of lipidderived molecular signals that regulate differential processes in humans animals and plants according to Kolomiets whose research was published in The Plant Journal In an effort to better understand these signals the US Department of Agriculture is granting Kolomiets 490000 in 2015 to study how the signals may also impact drought tolerance The molecular signals are less understood in plants than in animals and humans he noted People take certain drugs such as aspirin to suppress the activity of these signals because overproduction of these molecules may lead to headaches and pain and all sorts of disorders Kolomiets said It s the same group of metabolites that are produced by the plants but we know so little about them Yet a plant does communicate when attacked whether by blade of a mower or jaws of a predatory insect by producing defensive proteins and secondary metabolites either to repel the pest or make itself less appetizing he said What happens next is what scientists have been trying to figure out The best characterized molecule of the fatty acidderived signals is called jasmonic acid because it was first isolated as a volatile produced by jasmine Kolomiets said Jasmonic acid one of perhaps 600 oxylipin molecules identified in plants is known to have diverse functions Another volatile group derived from fatty acid is known as the green leaf volatiles To test how it functions in plant during insect attacks Kolomiets and his team used a mutant corn plant that could not produce the green leaf volatiles mowngrass smell when cut or torn And that s when they observed that the parasitic wasps didn t pay attention to plants without the green leaf volatile There are actually two roles for this molecule he said First it activates the jasmonate hormone which involves activation of defenses against insects on the plant Then this molecule since it is a volatile attracts parasitic wasps They come to the plant that is being chewed up by insect herbivores and lay eggs in the caterpillar s body We have proven that when you delete these volatiles parasitic wasps are no longer attracted to that planteven when an insect chews on the leaf So this volatile is required to attract parasitoids We have provided genetic evidence that green leafy volatiles have this dual function in the plant they activate production of insecticidal compounds but also they have indirect defense capability because they send an SOStype signal that results in attraction of parasitic wasps Kolomiets tested the phenomena both in the lab and in the field We did not have to do any artificial infestation because we had plenty of insects he said We have discovered that even under the field conditions when there s enough insect pressure then the plants are more susceptible to insect damage when they lack the green leaf volatiles Kolomiets hopes to continue the research by testing the impact of the presence of jasmonates and green leaf volatiles in other grassy crops such as sorghum This is just a tip of the iceberg We have found that this gene is required for many many different physiological processes such as drought tolerance he said We observed that mutant plants are drought susceptible as well as susceptible to insect feeding We are trying to identify the exact function of green leafy volatiles in drought tolerance and how it works Such findings may help plant breeders know how to develop new varieties that are more resistant to insects and drought he noted Story Source The above post is reprinted from materials provided by Texas AampM AgriLife The original item was written by Kathleen Phillips Note Materials may be edited for content and length Texas AampM AgriLife quotMown grass smell sends SOS for help in resisting insect attacksquot ScienceDaily ScienceDaily 22 September 2014 ltwwwsciencedailycomreleases201409140922145805htmgt Study sheds light on chemicals that insects use to communicate and survive Date January 13 2015 Source University of California Riverside Summary Most insects are covered with a thin layer of hydrocarbon molecules as a waterproofing barrier Embedded in this layer are compounds the insects use as chemical signals for a wide variety of functions such as communicating species and sex But isolating these chemicals and determining their absolute configuration and functions has been a challenge Now a team of scientists has devised a straightforward method for purifying these compounds Most insects such as the Argentine ant seen here are covered with a thin layer of hydrocarbon molecules as a waterproofing barrier Credit Mike Lewis CSR UC Riverside Most insects are covered with a thin layer of hydrocarbon molecules as a waterproofing barrier Embedded in this layer are compounds that the insects use as chemical signals for a wide variety of functions such as communicating species and sex In insects such as ants that live in colonies they also differentiate the different castes eg workers queens and drones But isolating these chemicals and determining their absolute configuration and functions has been a challenge because the chemicals occur in complex mixtures which are hard to separate Now a team of entomologists and chemists at the University of California Riverside has devised a straightforward method for purifying these compounds that could result in new quotgreenquot methods of controlling pest species like ants by disrupting the organization of their colonies The researchers devised a technique that combined known fractionation methods with reverse phase high performance liquid chromatography powerful tools in analysis Specifically they used their method to isolate 36 pure hydrocarbon molecules from the complex blends of 20 randomly chosen species in nine insect orders so that these compounds could be conclusively identified and the effects of the individual chemicals could be tested quotIn socalled social insects that live in large colonies such as ants and bees these chemicals have additional functionsquot explained Jocelyn G Millar a professor of entomology and chemistry whose lab led the research team quotThe queen in these colonies for example uses the chemicals to prevent her workers from laying eggs of their own ensuring that she remains the only reproducing female in the colonyquot The efforts of his research team were complicated by the fact that these chemicals can occur in righthanded R or lefthanded known as S from sinistro the Latin word for left forms Moreover Millar and his colleagues did not know whether some insects produce the R form and others produce the S or whether they all produced one form quotThis is critical information for biological activity because if you have the wrong form it is like trying to put your right hand into a lefthand glovequot Millar said quotThe wrong form of the chemical will simply not fit into its biological receptorquot His team was able to solve this problem by showing that all 20 insects that were tested had regardless of species sex and life stage the R form of these chemicals quotThis suggests strongly that nearly all insects are likely to produce the R form of these chemicalsquot Millar said quotKnowing this will be of great help in unravelling what these signals do and how they workquot Story Source The above post is reprinted from materials provided by University of California Riverside The original item was written by lqbal Pittalwala Note Materials may be edited for content and length Journal Reference 1 Jan E Bello J Steven McElfresh Jocelyn G Millar Isolation and determination of absolute configurations of insectproduced methylbranched hydrocarbons Proceedings of the National Academy of Sciences 2015 201417605 DOI 101073pnas1417605112 Question for the Week What are some instances where chemical communication is very advantageous and what are some of the instances where it would be harmful to an organism Secret Weapons Video Viewing Guide Eleodes Beetles and Quinones Why is one beetle attacked and killed by a swarm of ants while another can walk through the same path When confronted Elodes has a posture that indicates that something is going to happen its warning signal what is this posture What does the beetle do if the predator persists in the attack How does the grasshopper mouse attack and win the war with the beetle Millipedes and quinones What does the millipede do to ward off an attack WhipScorpion Vinegaroon What does the whip scorpion do when attacked from any direction Use its pinchers or something else Hemispherota Beetle on Palmetto In the first experiment with this beetle in the laboratory Dr Eisner determines that the beetle is very strong How strong does he find out that the beetle is when he pulls the palmetto leaf out from underneath the beetle How does the beetle hold on With hooks Glue Something else What does Eisner find out about the beetle s feet What does the electron microscope reveal about the feet What is the secret to its adherence and its secret defense chemical What unusual behavior does the larva use to protect itself Camphor Weed and Apiomerus What does the female do when she visits a camphorweed plant What does she do with the material she gather ie where does she store it What does she do with it during oviposition Saw y Larvae and Pine Where do the larvae store the pine resin What behavior does the larvae exhibit if attacked What does it do after the attack Milkweed and Monarch Butter ies Does the adult butter y eat milkweed to obtain toxins Utahathas and legume alkaloids Caterpillars compete for the seeds that are very toxic When crowded on plant there are winners and losers Why does it y during the day when other moths are not moving and why is it so brightly colored How does the male of this species use this alkaloid as an adult What happens when males are reared without alkaloid in their diet and are presented to females Fire ies Fire y females gain something else beside a meal when she eats a male fire y What does she gain and how does she use this Bombardier beetles What does the oscilloscope reveal about spraying of bombardier beetles Why do beetles emit their spray in this manner Think about the reaction chamber How does the spider overcome this infallible defense Female Flies Previous Lovers Affect Size of Later Children Posted by Mollie BloudoffIndelicato in Weird amp Wild on October 1 2014 A female fly s previous sexcapades can have a profound effect on how her future children look redefining the way scientists think about inheritance in insects Researchers at the University of New South Wales in Sydney Australia discovered that a mother s first sexual partner can determine the size of her later offspring even if he didn t sire them This odd evolutionary twist is caused by a secret compound in sperm See quotWhy Female Flies Eat Sperm Neriid flies Photograph by Russell Bonduriansky quotIt is strange and certainly unexpected said Angela Crean an evolutionary ecologist at the university who coauthored the study quotWe thought genetics is how inheritance works but that s just one mechanism of inheritance Everyone knows the story of how babies are made Sperm meets egg and creates a new lifeform which is half father and half mother However there are environmental factors that affect the development of the fetus like smoking in humans and other chemical exposures in the womb In the case of the fly semen is an environmental factor that holds the key to a baby fly s size whether or not the baby is related to the fly that supplied the semen according to a new study published in Ecology Letters To test this Crean manipulated the size of males by feeding them a diet that was either low in nutrients creating smaller males or high in nutrients which made the males bigger Also see quotWhy Genetically Modified Flies Don t Want Sex Then she let female flies get it on with their first sexual partners and deprived them of egglaying spots n flies eggs don t get fertilized until they re laid This means that females can potentially have sex with multiple partners without actually creating any baby flies Better Males Better Offspring After two weeks Crean mated the females with their second sexual partners and let them lay eggs When the lady flies were exposed to the semen of a small male and then had children with a big male their offspring ended up looking like the small male The opposite was also true And you thought you had daddy issues quotBetter quality males tend to produce better quality offspring said Fiona Clissold a nutritional ecophysiologist at the University of Sydney who was not involved with the paper quotThis study means if you re not a good quality male you can piggyback off someone else and pass on better traits The study looked at more than 500 flies but no one knows why these insects have evolved this ability or how it works The next step is to pinpoint the influential compound and figure out whether the same principle applies to other animals Crean says this finding could potentially impact human health but there s no way to test whether the same thing happens in our own species I quotIt seems unbelievable so you want to have a this is what causes that Crean said quotThat can be a bit of a needleinthehaystack approach at the moment because there are hundreds of compounds in semen The study is exciting because it suggests that there are more external factors that influence the evolution of a species Clissold said quotNothing is simple in biology she added httpvoicesnationalgeographiccom20141001fliesanimalsmating sexscienceoffspringinsects httpvoicesnationalgeographiccom20130910whygeneticallymodifiedfliesdontwantsex httpvoicesnationalgeographiccom2013O417whyfemaleflieseatsperm
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