Caterpillars on wrong host plant

I’ve made an observation of California Oak Moth caterpillars hatching on Manzanita leaves. And I’ve made an observation of a California Oak Moth laying eggs on a manzanita leaf.
I can find those observations by searching my ID, * Phryganidia californica*, and the term “manzanita”
https://www.inaturalist.org/observations/138079672
https://www.inaturalist.org/observations/138067497
But I’d like to begin to keep a record of when I find eggs and caterpillars on the wrong host plant. How do I find a list of all the tags or observation fields that already exist for iNat? I don’t want to contribute to the over proliferation of observation fields such as the “Host,” “Host Plant,” “Host Plant ID,” redundancy.

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I’ve noticed overlap in manzanita and white oak as larval food plants for a few moths in AZ and NM. Dalcerides is one example. I wonder how they are compatible.

I wonder also, but I could find no evidence of herbivory by the caterpillars on the manzanita. In these cases I suspect that because all oaks were defoliated, the manzanita was just an alternative surface for the egglaying. I’m pretty sure it was a dead end for those caterpillars.

I’m not sure if I understand why you don’t want to use these observation fields. Is it because there are several that could apply? (There is also “Interaction->Herbivore of”). Two options would be to create a traditional project for insects on the wrong host plant, or to create a unique tag to identify such observations.

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Well, because I don’t think the manzanita is a “host” plant.

I guess to be more clear I want to know if one can generate a list of existing iNat observation fields and tags? If an appropriate one exists, I would prefer to use that rather than create a new one that is equivalent.

Because people create redundant tags and observation fields, other folks end up having to do extra work when contributing to projects for example. Galls of North America uses “Host Plant ID” and Galls of California uses “Host,” which means I have to type in the genus and species of the host plant twice in order to submit my gall observation.

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My parents have been getting eggs of oak moths hatching on their house. I think the larvae might have some windborne dispersal potential by “ballooning” with a thread of silk so it is not necessarily a dead end, just a safe place to develop and hatch before drifting to a new location (and/or killing time while the oaks leaf back out). And potentially late into an outbreak, parasites might be abundant on the defoliated oaks, so laying on non-host substrates might even be advantageous.

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I found a black swallowtail caterpillar on seaside goldenrod, though I cannot confirm if it was eating it. https://www.inaturalist.org/observations/97270414

I don’t know how to technically go about keeping track of this on iNaturalist though.

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https://www.inaturalist.org/observation_fields

There’s a lot, and most of them aren’t very useful, but maybe you can find something in there.

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Interesting, I find a reference for it on a wide range of oaks, on chinquapin, and, oddly, on eucalyptus, but nothing on manzanita.

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That’s a good question. I agree that finding eggs on a plant doesn’t necessarily mean that the plant is a host plant. Associating the plant with the eggs in our observations could still be useful.

I try not to create new fields, if I can help it, since there are so many already. Still, I’ve just been looking and haven’t so far found an “egg substrate” taxon field or an “egg laid on” taxon field. The closest I’ve come is " Epiphytic on" but that’s not quite right. Unless anyone else knows of such a field by a different name, I think it would make sense to create it.

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Ah, of course - that makes sense. Yes, I agree that host plant is not the most appropriate for cases like this. I think a custom tag is probably your best bet to keep track of your own observations. Tags are completely uncontrolled so you can use whatever you like. They are more for personal use than observation fields, which I agree would benefit from standardisation. If you want to collate others’ observations too, then a traditional project would be the way to go.

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When I worked on butterflies (briefly), I observed repeatedly that the young females would lay their eggs strictly on the host plants, but as they got old, they started to lay their eggs on any possible surface, not neccessarily directly beside the host plant, and not neccessarily similar to the host plant. I thought that maybe this is a natural mechanism? First you ensure species survival, and after that maybe give evolution a tiny chance?

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That’s a good point about the parasites. I’m finding lots of Spined Soldier Bugs (known to feed on eggs and small larvae) on oaks where the moth larvae are, and some trees where hundreds of larvae have been killed off by some disease, possibly Nosema phryganidiae a microsporidian.

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Thanks! That’s what I was looking for!!

Thanks for that excellent reference. What a depressing intro though… I agree with them that changes in commercial agriculture are the major problem, at least when comparing the Salinas Valley to neighboring valleys such as the upper Carmel Valley.