I read that the pheromone glands of butterflies are in their wings. Is this true and how do we isolate these pheromones?
I do not know about butterfly pheromone gland location. But the most reliable method to extract these pheromones is probably as follows: isolate the gland and crush it in a small vial with solvent. The pheromone is very likely to be hydrophobic (see literature), thus hexane would be a good bet to extract it. If it is polar, you can use methanol for example.
I do not know about butterfly pheromone gland location. But the most reliable method to extract these pheromones is probably as follows: isolate the gland and crush it in a small vial with solvent. The pheromone is very likely to be hydrophobic (see literature), thus hexane would be a good bet to extract it. If it is polar, you can use methanol for example.
Yes, it's true for some species like Ephestia (on forewings) or Bicyclus anynana (on both fore- and hindwings) but in some other lepidopteran, glands are located at the tip of abdomen (inside) like in Heliothis virescens. For extraction, the method described by Loïc is the simplest one.
If you don't know where the gland is, cut your insect in pieces (head, thorax, abdomen, wings) and test the extract on behaviour of the opposite sex.
I worked on a number of Lepidoptera pest spp., finding distinctly different hydrocarbon patterns in body and wing extracts using hexane. There were sexual dimorphic patterns there. It is not surprising that butterflies would have glands and probably pheromone components like field-crop pest Lepidoptera. There have been a LOT of pioneering work done on these insects i the last 40 years, mostly published in J. Chemical Ecology. Few people were previously interested in butterfly sexual behavior.
Extremely variable depending on families. I think that pheromones glands on the wings are restricted to some Pyralidae (sensu lato) and among butterflies Nymphalidae and Lycaenidae. Some other families have their glands at the base of the wings but not directly on them (Ctenuchinae, for that I published a little study some years ago, check on my profile and download:Schneider D, Legal L, Dierl W and Wink M (1999) Androconial hairbrushes of the Syntomis (Amata) phegea (L.) Group (Lepidoptera, Ctenuchinae): A synapomorphic Character supported by sequence data of the mitochondrial 16S rRNA gene. Zeitschrift fur Naturforschung C (Journal of bioscience). Vol.54c, 1119-1139. ) also among Papilionidae most of Troidini.(Surely not an exhaustive list).
Vivek please tell us on which family you want to work and may be David, Olivier or me have most precise ideas.
Cheers from luc
Many papers published over the last 40 years on Lepidoptera would give good clues about the types of volatile compounds to look for. All Leps investigated so far have long-chain unbranched hydrocarbons, almost all with odd numbered backbones, with "families" of hydrocarbons with structurally similar methyl branches. Very little has been done with butterflies by agricultural scientists, because there are few economic pests. These probably have species-specific patterns within related species, as in tsetse flies, cockroaches, honeybees and many other families. Field-pest Leps may use long-chain 10-20 carbon unsaturated acetates or esters of longer-chain alcohols, ketones, aldehydes, long-chain epoxy hydrocarbons with one or two methyl branches, even long chain branched hydrocarbons with only double bonds (my favorites from Dipteran flies!). The beetle families tend to use smaller complex molecules with 4,5 or 6-membered rings. There is virtually no limit to the brilliance of organic chemistry in insects! Warning Note- a female insect may use only a few of the plethora of compounds present in her pheromone gland for actual sex-attractant/stimulant communication: Someone has to sort all this out.
There are too many papers published in the Journal of Chemical Ecology to cite. Sadly, I will have to throw away my 30-year collection of these Journals because nobody wants them anymore. But analytical organic microchemistry will go on, because we invented it for young, smart entomologists to use.
Good luck and good hunting from David
If there is not former information on the location of scent glands in your species, an interesting first step would be trying the different parts of the body separately (fore-, hind wings, thorax, abdomen, perhaps legs...). This will provide further aditional information that might be interesting by itself.
This work has been ongoing in Moths for 50 years, particularly for economic pest species: Most female moths call with abdominal gland eversion at night. There are many moth pheromones used in traps, and it would be interesting to see which butterflies are most Moth-like in calling behavior. Perhaps this could give leads to butterfly bioactive compounds.
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