Re: [ECOLOG-L] Mosquitoes as keystone species?
If interested regarding your debate and information on the importance of mosquitoes, especially their control - you may want to look at the following articles - based on a 7-year study (before and after) of a mosquito control program - Hershey, A.E., A.R. Lima, G.J. Niemi, and R.R. Regal. 1998. Effects of Bacillus thuringiensis israelensis (Bti) and methoprene on non-target macroinvertebrates in Minnesota wetlands. Ecological Applications 8:41-60. Niemi, G.J., A.E. Hershey, L. Shannon, J.M. Hanowski, A. Lima, R.P. Axler, and R.R. Regal. 1999. Ecological effects of mosquito control on zooplankton, insects, and birds. Environmental Toxicology and Chemistry 18:549-559. -Original Message- From: Ecological Society of America: grants, jobs, news [mailto:ecolo...@listserv.umd.edu] On Behalf Of Ted Linda Mosquin Sent: Friday, July 10, 2009 9:23 AM To: ECOLOG-L@LISTSERV.UMD.EDU Subject: Re: [ECOLOG-L] Mosquitoes as keystone species? Hello Amanda: There is a considerable literature, particularly from the 20th Century on the role played by various mosquito species in pollinating woodland flowers, particularly the small orchid species (Platanthera) but other northern orchid genera as well. Many of these orchids have an ambush device which comes in the form of a pollinarium (very sticky pollen sacs) which get affixed to a visiting female mosquito's body as she probes for the nectar offered by these orchids. Mosquitoes are weak insects and can't dislodge these pollen structures so one can often catch a few females flying around with them. Some years ago I wrote a summary article on pollination of northern orchids. It has been published in Legacy, a Natural History of Ontario edited by John B. Theberge. It might be found on the web. You should be able to find the book on E-bay, or Amazon. _ Ted Mosquin Amanda Quillen wrote: Can anyone speak about the capacity of mosquitoes themselves as pollinators? I know they spend much more time eating nectar than blood (which only the females do when they are breeding). I wondered if anyone happened to know how effective they are as pollinators. Also, could it be helpful to consider pollinators or insects as a keystone group? Removing the occupiers of a niche could certainly effect the whole system. -Original Message- From: Ecological Society of America: grants, jobs, news [mailto:ECOLOG- l...@listserv.umd.edu] On Behalf Of James Crants Sent: Thursday, July 09, 2009 10:00 PM To: ECOLOG-L@LISTSERV.UMD.EDU Subject: Re: [ECOLOG-L] Mosquitoes as keystone species? I agree with you the rest of your post, except to say that not all mosquitoes are human-feeders, and not all are WNV-vectors (only those that bite both birds and mammals are). Fewer bees probably does equate with fewer flowering plants. In the same spirit, I should add that many flowering plants are long- lived perennials, many use pollinators other than bees (possibly in addition to bees), and many are capable of pollinating themselves or producing seeds asexually (and, if you want to call clonal growth reproduction, a whole lot of them do that, too). So their abundances cannot be expected to track bee abundances very closely. On the other hand, if flowering plant abundance IS strongly correlated with bee abundance across space or time in your study system, it could be the bee populations that are tracking the plant populations. This is what makes ecology so challenging! No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.5.387 / Virus Database: 270.13.9/2229 - Release Date: 07/10/09 07:05:00
Re: [ECOLOG-L] Mosquitoes as keystone species?
William Brogan wrote: However, other herbicides such as Atrazine are not very lethal to amphibians in concentrations that are likely to be observed in surface waters. Not very lethal is not the name of the game. If a chemical causes them to become intersex and be otherwise messed up endocrinologically or neurologically, or by any other important sublethal effect, that's enough damage to affect the population. Killing non-target organisms is not the only way to severely damage them!! 1880's: There's lots of good fish in the sea W.S. Gilbert 1990's: Many fish stocks depleted due to overfishing, habitat loss, and pollution. 2000's: Marine reserves, ecosystem restoration, and pollution reduction MAY help restore populations. \ \ \ \ \ - - _ - \ \ \ \ \ - _ -\ - -( O \ _ - -_ __ / - -/ -/// _ __ ___/ /// / Judith S. Weis, Professor Department of Biological Sciences Rutgers University, Newark NJ 07102 jw...@andromeda.rutgers.edu Phone: 973 353-5387 FAX 973 353-5518 http://newarkbioweb.rutgers.edu/department/FacultyProfiles/weis.html
Re: [ECOLOG-L] Mosquitoes as keystone species?
Can anyone speak about the capacity of mosquitoes themselves as pollinators? I know they spend much more time eating nectar than blood (which only the females do when they are breeding). I wondered if anyone happened to know how effective they are as pollinators. Also, could it be helpful to consider pollinators or insects as a keystone group? Removing the occupiers of a niche could certainly effect the whole system. -Original Message- From: Ecological Society of America: grants, jobs, news [mailto:ECOLOG- l...@listserv.umd.edu] On Behalf Of James Crants Sent: Thursday, July 09, 2009 10:00 PM To: ECOLOG-L@LISTSERV.UMD.EDU Subject: Re: [ECOLOG-L] Mosquitoes as keystone species? I agree with you the rest of your post, except to say that not all mosquitoes are human-feeders, and not all are WNV-vectors (only those that bite both birds and mammals are). Fewer bees probably does equate with fewer flowering plants. In the same spirit, I should add that many flowering plants are long- lived perennials, many use pollinators other than bees (possibly in addition to bees), and many are capable of pollinating themselves or producing seeds asexually (and, if you want to call clonal growth reproduction, a whole lot of them do that, too). So their abundances cannot be expected to track bee abundances very closely. On the other hand, if flowering plant abundance IS strongly correlated with bee abundance across space or time in your study system, it could be the bee populations that are tracking the plant populations. This is what makes ecology so challenging!
Re: [ECOLOG-L] Mosquitoes as keystone species?
Hello Amanda: There is a considerable literature, particularly from the 20th Century on the role played by various mosquito species in pollinating woodland flowers, particularly the small orchid species (Platanthera) but other northern orchid genera as well. Many of these orchids have an ambush device which comes in the form of a pollinarium (very sticky pollen sacs) which get affixed to a visiting female mosquito's body as she probes for the nectar offered by these orchids. Mosquitoes are weak insects and can't dislodge these pollen structures so one can often catch a few females flying around with them. Some years ago I wrote a summary article on pollination of northern orchids. It has been published in Legacy, a Natural History of Ontario edited by John B. Theberge. It might be found on the web. You should be able to find the book on E-bay, or Amazon. _ Ted Mosquin Amanda Quillen wrote: Can anyone speak about the capacity of mosquitoes themselves as pollinators? I know they spend much more time eating nectar than blood (which only the females do when they are breeding). I wondered if anyone happened to know how effective they are as pollinators. Also, could it be helpful to consider pollinators or insects as a keystone group? Removing the occupiers of a niche could certainly effect the whole system. -Original Message- From: Ecological Society of America: grants, jobs, news [mailto:ECOLOG- l...@listserv.umd.edu] On Behalf Of James Crants Sent: Thursday, July 09, 2009 10:00 PM To: ECOLOG-L@LISTSERV.UMD.EDU Subject: Re: [ECOLOG-L] Mosquitoes as keystone species? I agree with you the rest of your post, except to say that not all mosquitoes are human-feeders, and not all are WNV-vectors (only those that bite both birds and mammals are). Fewer bees probably does equate with fewer flowering plants. In the same spirit, I should add that many flowering plants are long- lived perennials, many use pollinators other than bees (possibly in addition to bees), and many are capable of pollinating themselves or producing seeds asexually (and, if you want to call clonal growth reproduction, a whole lot of them do that, too). So their abundances cannot be expected to track bee abundances very closely. On the other hand, if flowering plant abundance IS strongly correlated with bee abundance across space or time in your study system, it could be the bee populations that are tracking the plant populations. This is what makes ecology so challenging! No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.5.387 / Virus Database: 270.13.9/2229 - Release Date: 07/10/09 07:05:00
Re: [ECOLOG-L] Mosquitoes as keystone species?
Conor, I believe the product used now is Malathion: Malathion is a man-made organophosphate insecticide that is commonly used to control mosquitoes and a variety of insects that attack fruits, vegetables, landscaping plants, and shrubs. It can also be found in other pesticide products used indoors and on pets to control ticks and insects, such as fleas and ants. Malathion is the active ingredient in mosquitocontrol products including Fyfanon and Atrapa. These products contain over 95% malathion and are often applied undiluted. However, they may be diluted with a petroleum solvent similar to kerosene before application, in which case petroleum solvent will make up most of the pesticide solution. As an anecdote, I have noticed in my own neighborhood that the lack of spraying this year (due to city budget cuts) has resulted in an increase in fleas that are available to parasitize my dog. I would be curious what the current sentiment is toward possible malathion effects on frog populations. I know this probably has been debated before. Not sure about the Keystone concept but certainly mosquitos have had profound effects on human ecology/history. An excellent short treatment of this can be found in: *Mosquito: The Story of Man's Deadliest Foe* by Andrew Spielman Very interesting read, apparently mosquitoes saved Rome from invaders many times... Todd On Wed, Jul 8, 2009 at 9:48 PM, Conor Flynn conorrobertfl...@gmail.comwrote: Our field crew is working in the extensive wetlands surrounding Alamosa, CO and we've noticed something interesting: there are no mosquitoes in or near Alamosa. This is because the city sprays for them regularly. We're not complaining... but we have also noticed fewer grasshoppers, bees, and frogs than we might otherwise expect. Are these (and other) species directly affected by the insecticide (which chemicals are used post-DDT?) and/or are mosquitoes ecologically important -- even keystone -- species? What happens when you remove a parasite from the foodweb? Our field crew is, among other things, cataloging the vegetation in the area -- could we expect to see e.g. fewer flowering plants? Anything else we could look for? Is anyone doing research on this quasi-Silent Spring phenomenon or know more about the possible ramifications of parasite/pest control?
Re: [ECOLOG-L] Mosquitoes as keystone species?
Conor_Flynn wrote: we've noticed something interesting: there are no mosquitoes in or near Alamosa. This is because the city sprays for them regularly. We have also noticed fewer grasshoppers, bees, and frogs than we might otherwise expect. Michael Cooperman wrote: I don't know what chemical your county uses for mosquito control but probably it is not specific to mosquitoes and would affect other insects just as strongly. Interesting these comments suggesting great harm to both mosquitoes and non-target insects appeared just after Mitch Cruzan said: Critical thinking/reading is a primary goal of all graduate programs and is something we introduce undergraduates to in advanced courses. A critical thinker would say it wildly speculative for anyone to claim, without extensive direct evidence, that: 1) There really are no mosquitoes and fewer grasshoppers, bees, and frogs in Alamosa, Colorado. 2) Mosquito spraying is the underlying cause of these declines. Paul Cherubini El Dorado, Calif.
Re: [ECOLOG-L] Mosquitoes as keystone species?
Paul, Forgive me if I am wrong here, but aren't these kinds of observations the very ones that lead to the formation of hypotheses-which will then be later falsified or confirmed? Although one might consider such wild speculation, would you not agree that such questions and observations are foundational to the further understanding of the possible impacts of humans on the environment, and if not, underlying ecological phenomena? -Todd Johnson sttd...@gmail.com Paul Cherubini wrote: Interesting these comments suggesting great harm to both mosquitoes and non-target insects appeared just after Mitch Cruzan said: Critical thinking/reading is a primary goal of all graduate programs and is something we introduce undergraduates to in advanced courses. A critical thinker would say it wildly speculative for anyone to claim, without extensive direct evidence, that: 1) There really are no mosquitoes and fewer grasshoppers, bees, and frogs in Alamosa, Colorado. 2) Mosquito spraying is the underlying cause of these declines. Paul Cherubini El Dorado, Calif. Conor_Flynn wrote: we've noticed something interesting: there are no mosquitoes in or near Alamosa. This is because the city sprays for them regularly. We have also noticed fewer grasshoppers, bees, and frogs than we might otherwise expect. Michael Cooperman wrote: I don't know what chemical your county uses for mosquito control but probably it is not specific to mosquitoes and would affect other insects just as strongly.
Re: [ECOLOG-L] Mosquitoes as keystone species?
It is not clear what Paul means by extensive direct evidence. Flynn indicated that he had a team of colleagues working over several years who made this observation. Isn't this extensive direct evidence? Nor is it unreasonable to postulate that maybe the reason that there are fewer mosquitoes is that they were killed. Bill Silvert, trying to think critically. - Original Message - From: Paul Cherubini mona...@saber.net To: ECOLOG-L@LISTSERV.UMD.EDU Sent: Thursday, July 09, 2009 1:10 PM Subject: Re: [ECOLOG-L] Mosquitoes as keystone species? Conor_Flynn wrote: we've noticed something interesting: there are no mosquitoes in or near Alamosa. This is because the city sprays for them regularly. We have also noticed fewer grasshoppers, bees, and frogs than we might otherwise expect. A critical thinker would say it wildly speculative for anyone to claim, without , that: 1) There really are no mosquitoes and fewer grasshoppers, bees, and frogs in Alamosa, Colorado. 2) Mosquito spraying is the underlying cause of these declines.
Re: [ECOLOG-L] Mosquitoes as keystone species?
Paul, I agree completely. Then why on earth is the city spraying without any evidence that it is having any effect? What a waste of taxpayer's money. Charles Davis
Re: [ECOLOG-L] Mosquitoes as keystone species?
In the quoted text below, Michael Cooperman says only that whatever chemical Conor's county uses to control mosquitoes probably affects other insects as strongly as it affects mosquitoes. The implication is that he agrees it's plausible that the chemical used to control mosquitoes near Alamosa would result in decreased abundances of non-target species (grasshoppers, bees, and frogs). If he wanted to publish that statement, I'd say he would need proof that (1) some kind of chemical spray is used near Alamosa to reduce the abundance of mosquitoes, and (2) some chemical sprays people use to reduce the abundance of mosquitoes also reduce the abundances of non-target species (preferably including citations specific to any particular species he might mention). He would only need to prove that the abundances of grasshoppers, bees, frogs, and mosquitoes had declined near Alamosa, and that chemical sprays were the cause of these declines, if he'd actually said these things. If he did, it's not in the quote below. In any case, since Michael's statement is not in a scientific paper, but rather on an internet forum, I don't think the same standards apply. Yes, it's best to keep your critical thinking cap on when replying to something on Ecolog, but if we had to cite sources or conduct original research for every statement we made here, who would bother? Might as well apply that same effort to writing peer-reviewed publications. Jim Crants On Thu, Jul 9, 2009 at 11:10 AM, Paul Cherubini mona...@saber.net wrote: Conor_Flynn wrote: we've noticed something interesting: there are no mosquitoes in or near Alamosa. This is because the city sprays for them regularly. We have also noticed fewer grasshoppers, bees, and frogs than we might otherwise expect. Michael Cooperman wrote: I don't know what chemical your county uses for mosquito control but probably it is not specific to mosquitoes and would affect other insects just as strongly. Interesting these comments suggesting great harm to both mosquitoes and non-target insects appeared just after Mitch Cruzan said: Critical thinking/reading is a primary goal of all graduate programs and is something we introduce undergraduates to in advanced courses. A critical thinker would say it wildly speculative for anyone to claim, without extensive direct evidence, that: 1) There really are no mosquitoes and fewer grasshoppers, bees, and frogs in Alamosa, Colorado. 2) Mosquito spraying is the underlying cause of these declines. Paul Cherubini El Dorado, Calif.
Re: [ECOLOG-L] Mosquitoes as keystone species?
Bill Silvert wrote: Flynn indicated that he had a team of colleagues working over several years who made this observation. Flynn made no mention of the number of years they had been observing. Nor is it unreasonable to postulate that maybe the reason that there are fewer mosquitoes is that they were killed. Flynn did not say fewer mosquitoes, he said there are no mosquitoes in or near Alamosa Paul Cherubini El Dorado, Calif.
Re: [ECOLOG-L] Mosquitoes as keystone species?
Michael Cooperman wrote: I respectfully disagree with you. It is not wild speculation to posit widely applied broad-cast insecticides have impacts to non-target organisms, You said the mosquito chemical: would affect other insects just as strongly which is speculation. Paul Cherubini El Dorado, Calif.
[ECOLOG-L] ECOLOG responsiveness to direct questions Re: [ECOLOG-L] Mosquitoes as keystone species?
Flynn's questions are: 1. Are these (and other) species directly affected by the insecticide (which chemicals are used post-DDT?) and/or are mosquitoes ecologically important -- even keystone -- species? 2. What happens when you remove a parasite from the foodweb? 3. Our field crew is, among other things, cataloging the vegetation in the area -- could we expect to see e.g. fewer flowering plants? 4. Anything else we could look for? 4. Is anyone doing research on this quasi-Silent Spring phenomenon or know more about the possible ramifications of parasite/pest control? Either these are good questions relevant to the mission of this list, and as such deserving of answers, or they are not. In the absence of such answers, or a polite reply that he should seek his answers elsewhere (an implied declaration that the questions are not relevant), what would be Flynn's reasonable conclusions with respect to the subscribers of this list? WT - Original Message - From: Paul Cherubini mona...@saber.net To: ECOLOG-L@LISTSERV.UMD.EDU Sent: Thursday, July 09, 2009 9:10 AM Subject: Re: [ECOLOG-L] Mosquitoes as keystone species? Conor_Flynn wrote: we've noticed something interesting: there are no mosquitoes in or near Alamosa. This is because the city sprays for them regularly. We have also noticed fewer grasshoppers, bees, and frogs than we might otherwise expect. Michael Cooperman wrote: I don't know what chemical your county uses for mosquito control but probably it is not specific to mosquitoes and would affect other insects just as strongly. Interesting these comments suggesting great harm to both mosquitoes and non-target insects appeared just after Mitch Cruzan said: Critical thinking/reading is a primary goal of all graduate programs and is something we introduce undergraduates to in advanced courses. A critical thinker would say it wildly speculative for anyone to claim, without extensive direct evidence, that: 1) There really are no mosquitoes and fewer grasshoppers, bees, and frogs in Alamosa, Colorado. 2) Mosquito spraying is the underlying cause of these declines. Paul Cherubini El Dorado, Calif. No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.5.375 / Virus Database: 270.13.8/2227 - Release Date: 07/09/09 05:55:00
Re: [ECOLOG-L] Mosquitoes as keystone species?
Taking to heart the ad nauseum admonishments to think critically regarding this issue, I put on my well worn critical thinking cap and, using skills from a long ago recieved degree in toxicology, cursorily looked up the list of insecticides used by the Alamosa mosquito abatement program. It took exactly 3 clicks of the mouse. Malathion, which is known by USEPA to have a strong mortality effect on bees, is in fact used by the folks from the Alamosa district. Permethrin/pyperonyl butoxide mixtures, likewise, are used by the district and are also well documented as toxic to bees. As to whether or no there are no mosquitos or no honeybees in the area, I'm not here to say. As others have pointed out, that's something for the local entomologists and toxicologists to ascertain, at some financial and temporal expense. But knowing what we know about malathion and permethrin/piperonyl butoxide formulations, it would seem to me to be a supreme lack of critical reasoning to 'assume' that the malathion in use in that district had no effect on the target mosquito species (elsewise, as someone else snarkily pointed out, what a waste of money it's been for all the mosquito districts in North America to have used it for all these decades!! They should go down and get their money back!!!) or the very well documented non target species, honeybees. As for non target effects on grasshoppers, rhinoceri, or other non target species, and whether mosquitos could be keystone species, I'll leave that up to the rest of the audience. I haven't the time. But really, I reply mainly to point out that these effects are not unknown quantities to the field of toxicologythey're pretty well documented, and taught in introductory courses in that discipline. To pooh-pooh the possibility that reduction of honeybee numbers might have something to do with pesticide use in this case seems, well, pretty silly, to say the least. C Rosamond Date: Thu, 9 Jul 2009 12:55:14 -0700 From: mona...@saber.net Subject: Re: [ECOLOG-L] Mosquitoes as keystone species? To: ECOLOG-L@LISTSERV.UMD.EDU Michael Cooperman wrote: I respectfully disagree with you. It is not wild speculation to posit widely applied broad-cast insecticides have impacts to non-target organisms, You said the mosquito chemical: would affect other insects just as strongly which is speculation. Paul Cherubini El Dorado, Calif. _ Hotmail® has ever-growing storage! Don’t worry about storage limits. http://windowslive.com/Tutorial/Hotmail/Storage?ocid=TXT_TAGLM_WL_HM_Tutorial_Storage_062009
Re: [ECOLOG-L] Mosquitoes as keystone species?
On Thu, Jul 9, 2009 at 7:57 AM, Michael Coopermanmichael.cooper...@noaa.gov wrote: Hello Conor, Thank you for sharing these observations. Unfortunately, these are not simple questions to answer, as it would take a prolonged and rigorous discourse on many of the disciplines of ecology to address all the issues. I don't know what chemical your county uses for mosquito control but probably it is not specific to mosquitoes and would affect other insects just as strongly. Just a point of clarification, and not to start or prolong a discussion of the relative merits and different insect control tactics, but there are mosquito control options that have few (or fewer) non-target effects. Particularly on terrestrial insects such as grasshoppers or bees. http://www.epa.gov/opp1/health/mosquitoes/larvicides4mosquitoes.htm I agree with you the rest of your post, except to say that not all mosquitoes are human-feeders, and not all are WNV-vectors (only those that bite both birds and mammals are). Fewer bees probably does equate with fewer flowering plants. Are mosquitoes ecologically important? In some places it is a resounding yes -- for example, in places where malaria is abundant, mosquitoes as the primary vector for malaria were a major control on human populations (i.e., mosquitoes promoted a high death rate). Are they a key stone in your community? Probably not, but if you lump them with the rest of the insects that are locally scarce due to pesticides, you could reasonably expect a significant ecological response. For example, the birds and bats which rely on insects for food are likely to be affected. But, on the other hand, mosquitoes are a primary vector for West Nile Virus and WNV kills many species of birds -- hence, eliminating mosquitoes could be a benefit to the bird community. Hopefully you see my point -- the interactions that go on in a situation such as this are hugely complex and dynamic, so its tough to give a simple yes/no kind of answer. I realize I've probably frustrated you more than helped, but that's kind of the way ecology goes (in my opinion). Keep up with the good observations, and let your local community know what you are seeing (i.e., a letter to the editor of your local paper). I bet you'll find more people than just yourself care. Michael Cooperman Post-doctoral Fellow of the National Research Council in residence at NOAA-Fisheries, NE Fisheries Science Center. Conor Flynn wrote: Our field crew is working in the extensive wetlands surrounding Alamosa, CO and we've noticed something interesting: there are no mosquitoes in or near Alamosa. This is because the city sprays for them regularly. We're not complaining... but we have also noticed fewer grasshoppers, bees, and frogs than we might otherwise expect. Are these (and other) species directly affected by the insecticide (which chemicals are used post-DDT?) and/or are mosquitoes ecologically important -- even keystone -- species? What happens when you remove a parasite from the foodweb? Our field crew is, among other things, cataloging the vegetation in the area -- could we expect to see e.g. fewer flowering plants? Anything else we could look for? Is anyone doing research on this quasi-Silent Spring phenomenon or know more about the possible ramifications of parasite/pest control?
Re: [ECOLOG-L] Mosquitoes as keystone species?
Conor, I am a graduate student in Rick Relyea's lab at the University of Pittsburgh. Our lab has been looking at the direct and indirect impacts of many types of pesticides on amphibians for the better part of this decade. We have found that the direct impacts of pesticide exposure on amphibians varies considerably depending on the mode of action of the pesticide, as well as the species of amphibian. For example, we have found that some herbicides, such as Roundup, are incredibly deadly to amphibians at concentrations well below EPA standards. It's not the chemical itself, but the surfactant that is highly toxic to many species of amphibians, but does not . However, other herbicides such as Atrazine are not very lethal to amphibians in concentrations that are likely to be observed in surface waters. Malathion is likely to be the insecticide that would be sprayed on crops and wetlands for pest control and can be directly lethal to amphibians at doses that could follow a direct overspray application. Our lab is just discovering that endosulfan, another commonly applied insecticide, is incredibly lethal to amphibians in concentrations as low as 1 ppb, way below the estimated environmental concentrations according the the EPA. If Endosulfan use in the area is high, I would not be surprised if it was at least partially responsible for declines in amphibian populations. I hope this helps with the quasi-silent spring bit of your question. For additional information please see: For direct impacts of malathion: Relyea, RA. 2004. Synergistic impacts of malathion and predatory stress on six species of North American tadpoles. * Environmental Toxicology and Chemistry*; (23) 1080-1084. For direct/indirect impacts of a suite of herbicides/insecticides: Relyea, RA. 2009. A cocktail of contaminants: how mixtures of pesticides at low doses effect aquatic communities. *Oecologia*; (159) 363-376. Relyea, RA Will Brogan On Thu, Jul 9, 2009 at 12:10 PM, Paul Cherubini mona...@saber.net wrote: Conor_Flynn wrote: we've noticed something interesting: there are no mosquitoes in or near Alamosa. This is because the city sprays for them regularly. We have also noticed fewer grasshoppers, bees, and frogs than we might otherwise expect. Michael Cooperman wrote: I don't know what chemical your county uses for mosquito control but probably it is not specific to mosquitoes and would affect other insects just as strongly. Interesting these comments suggesting great harm to both mosquitoes and non-target insects appeared just after Mitch Cruzan said: Critical thinking/reading is a primary goal of all graduate programs and is something we introduce undergraduates to in advanced courses. A critical thinker would say it wildly speculative for anyone to claim, without extensive direct evidence, that: 1) There really are no mosquitoes and fewer grasshoppers, bees, and frogs in Alamosa, Colorado. 2) Mosquito spraying is the underlying cause of these declines. Paul Cherubini El Dorado, Calif. -- William R. Brogan III University of Pittsburgh Department of Biology 101 Clapp Hall Pittsburgh, PA 15224 Not everything that counts can be counted, and not everything that can be counted counts. -Albert Einstein
Re: [ECOLOG-L] Mosquitoes as keystone species?
I agree with you the rest of your post, except to say that not all mosquitoes are human-feeders, and not all are WNV-vectors (only those that bite both birds and mammals are). Fewer bees probably does equate with fewer flowering plants. In the same spirit, I should add that many flowering plants are long-lived perennials, many use pollinators other than bees (possibly in addition to bees), and many are capable of pollinating themselves or producing seeds asexually (and, if you want to call clonal growth reproduction, a whole lot of them do that, too). So their abundances cannot be expected to track bee abundances very closely. On the other hand, if flowering plant abundance IS strongly correlated with bee abundance across space or time in your study system, it could be the bee populations that are tracking the plant populations. This is what makes ecology so challenging!
Re: [ECOLOG-L] Mosquitoes as keystone species?
I'll admit that my knowledge of mosquitoes is not great, but I wouldn't necessarily go so far as to label them a keystone species. Since there are several different genera of mosquitoes in North America (let alone species!), is the term keystone species even appropriate? Can the concept be extended to higher taxa (i.e. if we remove this genus, family, etc., will it have an effect on the ecosystem disproportionate to its abundance?). If so, what becomes the basis for comparison (seeing as different genera may have vastly different numbers of species, and so on)? Most importantly, mosquitoes are generally rather abundant, and so I would suspect that any impacts that mosquito declines would have on a given ecosystem are a result of the loss of such an abundant organism as opposed to an organism that affects its ecosystem disproportionately relative to its abundance (the definitition of a keystone species). Assuming, however, that the keystone concept can be applied to mosquitoes, could they be labeled as such? While mosquitoes are certainly an ecologically important species, I would expect not. To me, a keystone species evokes imagery of an ecosystem collapsing when it is removed (much like a stone arch would collapse if it's keystone were removed). Textbook examples include the removal of wolves resulting in overpopulation of deer and elk, which results in extensive mortality of browse vegetation (notably Quaking Aspen), and declines in sea otters leading to explosive overabundance of sea urchins which essentially clear cut kelp beds. As far as I know, mosquito predation or parasitism doesn't play a significant role in keeping any other species in check. Mosquitoes are an important prey item for numerous species, so perhaps they can qualify for this reason. However, many mosquito predators are not mosquito specialists (frogs, birds, bats), and if mosquitoes disappeared from an area these predators would simply prey more extensively on other species. I guess the biggest issue that I have with the notion is that, from what I understand, keystone species are a rare phenomenon but most common in low diversity communities where, if the keystone is removed, no other species is present that can fill the niche. As far as I know, Diptera (or any biting insects and/or insects with aquatic larvae to serve as a similar prey base) are ubiquitous and species-rich throughout North America (except perhaps in the Arctic). I would suspect that the declines of other species in Alamosa are more likely a result of the non-selectivity of the insecticide(s) used, or a combination of other unknown phenomena, rather than the absence of mosquitoes as the primary cause (though it may certainly contribute). Of course I won't claim any of my statements to be conclusive, or even highly probable; I'll defer that to entomologists, particularly those with extensive knowledge of mosquito ecology. Good discussion topic though! Conor Flynn wrote: Our field crew is working in the extensive wetlands surrounding Alamosa, CO and we've noticed something interesting: there are no mosquitoes in or near Alamosa. This is because the city sprays for them regularly. We're not complaining... but we have also noticed fewer grasshoppers, bees, and frogs than we might otherwise expect. Are these (and other) species directly affected by the insecticide (which chemicals are used post-DDT?) and/or are mosquitoes ecologically important -- even keystone -- species? What happens when you remove a parasite from the foodweb? Our field crew is, among other things, cataloging the vegetation in the area -- could we expect to see e.g. fewer flowering plants? Anything else we could look for? Is anyone doing research on this quasi-Silent Spring phenomenon or know more about the possible ramifications of parasite/pest control?
[ECOLOG-L] Mosquitoes as keystone species?
Our field crew is working in the extensive wetlands surrounding Alamosa, CO and we've noticed something interesting: there are no mosquitoes in or near Alamosa. This is because the city sprays for them regularly. We're not complaining... but we have also noticed fewer grasshoppers, bees, and frogs than we might otherwise expect. Are these (and other) species directly affected by the insecticide (which chemicals are used post-DDT?) and/or are mosquitoes ecologically important -- even keystone -- species? What happens when you remove a parasite from the foodweb? Our field crew is, among other things, cataloging the vegetation in the area -- could we expect to see e.g. fewer flowering plants? Anything else we could look for? Is anyone doing research on this quasi-Silent Spring phenomenon or know more about the possible ramifications of parasite/pest control?
