# Talk:Plant defense against herbivory

The proposal is explained in the talk page of antifeedants. Bosula (talk) 22:33, 28 October 2025 (UTC)

The article, which is a nice read, is in places textbooky, see WP:NOTTEXTBOOK.  Here is an example where the article is teaching the reader about terpene chemistry.
"The [[terpenoids]], sometimes referred to as isoprenoids, are organic chemicals similar to [[terpene]]s, derived from five-carbon [[isoprene]] units. There are over 10,000 known types of terpenoids.<ref>...</ref> Most are multicyclic structures which differ from one another in both functional groups, and in basic carbon skeletons.<ref name=Terp>...</ref> Monoterpenoids, containing 2 isoprene units, are [[volatility (chemistry)|volatile]] [[essential oil]]s such as [[citronella oil|citronella]], [[limonene]], [[menthol]], [[camphor]], and [[pinene]]. Diterpenoids, 4 isoprene units, are widely distributed in [[latex]] and [[resins]], and can be quite toxic. Diterpenes are responsible for making ''[[Rhododendron]]'' leaves poisonous. Plant [[steroid]]s and [[sterol]]s are also produced from terpenoid precursors, including [[vitamin D]], [[glycosides]] (such as [[digitalis]]) and [[saponin]]s (which lyse [[red blood cell]]s of herbivores).<ref>...</ref>"

vs 

"Many [[terpenoids]], sometimes referred to as isoprenoids, serve as antifeedants.<ref name=Terp>...</ref>  These includeas the volatile monoterpenoids [[citronella oil|citronella]], [[limonene]], [[menthol]], [[camphor]], and [[pinene]]. Diterpenoids, derived from two monoterpenoid units, are widely distributed in [[latex]] and [[resins]], and can be quite toxic. Diterpenes making ''[[Rhododendron]]'' leaves poisonous. Plant [[steroid]]s and [[sterol]]s, also produced from terpenoid precursors, including [[vitamin D]], [[glycosides]] (such as [[digitalis]]) and [[saponin]]s (which lyse [[red blood cell]]s of herbivores).<ref>...</ref>"--Smokefoot (talk) 13:06, 29 October 2025 (UTC)

Thanks for your thoughts. Two immediate points: 1) an evolutionary biology article for the general reader cannot assume that readers are at all familiar with organic chemistry. Articles have to stand alone for at least a first reading, so that a reader who wants to know about plant defences could, for instance, print out the article and read it on train or plane, and feel reasonably informed about the subject without having to read a dozen other articles first. 2) Your version contains broken grammar. We might be better off as we are. Chiswick Chap (talk) 13:17, 29 October 2025 (UTC)
I agree 100% that the articles cannot assume too much.  But the agreement is not for me or for you, but for Big Brother Wikipedia (BBW).  And BBW says, present facts, dont explain them. Just sayin'.--Smokefoot (talk) 13:24, 29 October 2025 (UTC)
Terpenoids are produced in the plant from five-carbon isoprene units. There are over 10,000 known types of terpenoids. Monoterpenoids, containing 2 isoprene units, are volatile essential oils such as citronella, limonene, menthol, camphor, and pinene. Diterpenoids, 4 isoprene units, are widely distributed in latex and resins. Plant steroids, 6 isoprene units, include vitamin D, some glycosides (such as digitalis) and some saponins (which lyse red blood cells of herbivores.
How about this variant. I wouldn't mention both terpenoids and terpenes. Only just now I realised they are not always used synonymously. Best not to say they are mostly polycyclic and then next sentence start with the monoterpenes. Sterols are steroids so you can simplify that. Not all glycosides and saponins contain steroids, so best to say "some". Bosula (talk) 20:10, 29 October 2025 (UTC)

The article shows persimmon fruit.  Is there any evidence that the astringent taste plays a role as an antifeedant?  The article persimmon also skirts this issue.  This omission raises the issue that scientists attribute antifeedant roles to various attributes, but cause and effect can be tricky to establish. 
For chemists, an impactful family of antifeedants are the compounds released upon damage to garlic, horseradish, and some other plants of the genus Allium.  In some of these situations, the antifeedant precursor combines with its activating enzyme only upon mechanical breakup of the plant cells.
The function of rosin (sometimes called resin) and maybe latex has been speculated to be antifeedant (traps insects) or self-healing (covers scars).  The tendency of some pines to exude rosin upon scarring is the basis of an industry that produces terpentine and other solvents and fragrances.  Historically, it underpinned the naval stores industry.  But the point is that man provokes the antifeedant response on an industrial scale.--Smokefoot (talk) 13:24, 29 October 2025 (UTC)

Most of that is beyond the scope of this article, which can only sketch the barest outlines of antifeedant theory and evidence (which is why that should be a separate article, by the way) so as not to make the section a WP:COATRACK. I suggest you find sources for the matters you discuss and document them over there in that article. Chiswick Chap (talk) 13:31, 29 October 2025 (UTC)
If rosin traps insects, the I would not call it an antifeedant. Best to put it in the rosin article. The business with garlic is described in the allicin page. Bosula (talk) 20:21, 29 October 2025 (UTC)