This is a plea to everyone uploading larval records of moths and butterflies to please include the host plant (if known) in your record. This can be done simply by adding a comment, or even better by adding the Host Plant ID observation field. This information is incredibly valuable for understanding the ecology of these species and helping to inform conservation efforts. iNaturalist has become an amazing tool for reporting larval records, making distribution and phenology data available to researchers on a scale previously impossible. But in the vast majority of cases (95-99%), larval records make no mention of the host plant. Surprisingly, even some of the most prolific larval contributors and iNat curators donāt bother to include host plants. Please, please take the couple extra seconds to add this information when known. So much valuable information is being lost!
Iāve checked that all of mine have host species added. I know my plants but hexapods elude me. This observation of a larva in Juncus pallidus is one of my favourites. They were abundant across that valley at that date with evidence of presence in most sick looking Juncus pallidus culms
Or if you donāt know the ID of the host plant, make a separate observation for it and add a link to the larva observation (either as a comment or in an observation field). I try to add Host Plant ID (or Visited Flower of) observation fields for others but can only do so much if there are only highly-cropped images of the insect.
I usually use the āfeeding onā observation field, sometimes the caterpillar is feeding on a different plant than the one their eggs were on, so host isnāt appropriate. Sometimes the caterpillar is just on a plant and not feeding on it, in that case the plant shouldnāt be added?
I use the āName of Associated Plantā if Iām not sure if an insect is just resting on it or if it could be feeding/using it as a host (isnāt the host plant the one that the insect is feeding on, rather than what its eggs were laid on?). But I have no idea if thatās the best field to use vs others- there are so many available.
If you think you know the ID of the host plant, still make a separate observation for it! You have the tool already in your hand!
Yes! I try to do this when known. Iāve noticed lots of identifiers donāt look down at the Host Plant ID observation field and only look at the comments and then ask what plant it was on. Same with galls.
Great point. I donāt always know the identity of the plant, and have gotten a lot of help from those more knowledgeable about plant ID.
Yes, if it is feeding on the plant, that plant is serving as a host. Maybe not the primary host, but most larvae feed on a number of hosts. And good point about actually observing feeding. This is important to distinguish caterpillars feeding on a plant from those who wander from their host plant, which is especially common once they have finished feeding and are getting ready to pupate.
Seconded, although also with apologies to the folks whose observation fields I miss when Iām in the Identify window and moving quickly.
I just wish the taxon observation fields (Host Plant ID, etc.) had an NA option that could be used for caterpillars not on plants. It would make it easier to filter for the observations that need that observation field added from those where the caterpillars are clearly off-host.
In India we have a project for lepidopteran host plants, and its pretty successful I would say. Every user can contribute by joining the project and adding the observation fields- host plant and whether its wild or cultivated
someone can take the initiative to start such a project in your respective areas, its sure to get good attention eventually
If anyone is curious, this is the project
https://www.inaturalist.org/projects/host-plants-for-lepidoptera-of-india
Iām not sure, its a bit of a grey area for me, I suppose in the grader scheme of things, if a caterpillar feeds on a plant then theres a good chance eggs will be deposited onto that plant somewhere, even if they are polyphagus? Maybe I just donāt know enough about the process?
Guilty as chargedā¦ Iāve made a note to do so, am going back through the old records and will encourage friends to do likewise. Thanks for the nudge!
Sorry, but our project has been using āInsect Host Plantā for this for years now. Not sure why we should switch to using someone elseās preferred field.
Iām pretty good at IDāing butterflies, but Iām not a botanist. Even if I had better plant ID skills, people frequently take closeups of larvae, and not enough of the plant is visible for positive ID.
The other problem is that in our area, the bulk of the larval observations are of 3 species:
- Monarch
- Black Swallowtail
- Cabbage White
And Iām not going to waste my time adding Host plant fields for those observations.
The process is extremely variable among species. Some Leps specifically deposit their eggs on the plant thatās used as a host, others ābroadcastā eggs while flying so they might land anywhere, and the caterpillars have to search for the host (think fall-flying Leps that use annuals as hosts- the caterpillars that hatch out in the spring will be feeding on plants that donāt exist yet when the adult is laying eggs). Not to mention that when moths are trapped around lights near the end of their life, theyāll lay the eggs right there near the light, regardless of whether the host is available. So a plant next to a light source that attracts moths could have just about any speciesā eggs laid on it. I suspect if an egg is on a plant that thatās the host plant more often than not, but itās far from a certain bet.
In a spectacular example of being off-host, someone recently posted a caterpillar that had eaten its way into a flip-flop
There is an excellent guide to insects and their host plants for the Eastern US called āPollinators of Native Plants: Attract, Observe and Identify Pollinators and Beneficial Insects with Native Plants,ā written by Heather N. Holm. This is the first comprehensive book to illustrate the specific relationships between native pollinators and native plants. Organized by plant communities, the book profiles over 65 perennial native plants of the Midwest, Great Lakes region, Northeast and southern Canada and the pollinators, beneficial insects and flower visitors the plants attract. Published in 2014.
That looks useful! Hereās a link to her books, with links to other titles from her publisher https://www.pollinatorsnativeplants.com/