A quest to find moth larvae/caterpillars - any tips?

Upon reading this I resolved to have a go at finding some moth larvae. But one issue arises: I have no idea how to. So, does anyone have tips for finding moth (or butterfly) larvae/caterpillars?
Where might they be found, what to photograph, projects for larvae observations, all detail is welcome and useful.

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If it is a tomato-growing area, look for Tomato hornworm. Tomato is solanum family…so I guess you can look into other solanum plants. Periwinkle, Impatens, Aroids, Ludwigia weeds may have caterpillars sometimes. It depends on your area too. Maybe can add where you are at. Butterflies have specific host plants. Have to research on the species and what the species eats. In my area, the usual plants are citrus plants, and various plants.
One problem with moths is after they emerge from cocoon, they fly inside the container and shed lots of scales and tiny hairs. Have to beware not to breathe in those dust particles. It may lead to rashes or severe allergies when contacted with the hairs of some moth caterpillars when it is still a caterpillar. Many butterflies species do not have such problems as causing rashes, only some moths species. A number of moth caterpillars have no hairs and can be handled but still will shed scales as moths.

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If it’s a conspicuous species like with a lot of eggar and tiger moths you can usually spot them resting in plain sight on foodplants or basking in the open during sunny days after their winter hibernation

noctuids are also fairly easy but you normally need to go out with a torch after dark to look on low growing plants where they’re usually quite obvious

geometrids are tricky since they blend in well with hostplants and their surroundings but can usually be found if you have a sharp eye and don’t mind foraging around shrubbery and trees

hawkmoths are also fairly easy to spot but I’ve only ever seen them feeding after dark where they’re most obvious since during the day they stay quite tucked away in foliage (except when they’re ready to pupate and they’ll be very conspicuous wandering around open areas)

for most of the micro moths (as a blanket term) they’re usually extremely tricky to find as caterpillars and most of them are tricky to distinguish but many of them live in rolled up leaves.

tussock and prominent moths are fairly easy to spot if you look for them like with hawkmoths

as a general, look for holes and chewed up parts of leaves as well as around unusually bare areas of a plant (sometimes confused with slug damage tho), search at torchlight for any nocturnal caterpillars, look for prepupal catties wandering around looking for a pupation site, look on fences, tree stumps, under rocks etc for any caterpillars around and if possible try and take a few home with their foodplant to raise into moths so you can figure out the species (don’t over collect and if they don’t do well with you release them back where you found them).

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As I take it your goal is hopefully to find some of the little-known or unknown kinds, I would especially look for rolled-up or chewed leaves, as @mothdragon advised. Even if you do not see any signs of caterpillars around the chewed leaves, some caterpillars only emerge at certain times, possibly nocturnal; so if yu find a host plant of interest, try coming back at different times of the day (or night). During my study of Hyalurga vinosa, I noticed that the same individual host plant might be covered with caterpillars at one time of day, and devoid of caterpillars at another. I also watched a caterpillar of this species disappear underground by seemingly crawling between the soil particles.

Another approach is to use a sweep net on vegetation and see if you pick up any caterpillars that way.

One important point is that the insects which feed on economically important plants (whether crop pests or weed biocontrols) tend to be the best studied; so if your goal is to find little-known kinds, focusing on plants lacking economic importance could be a fruitful approach.

Finally, if you can be out observing when moths are actively flying, you may be able to witness oviposition. This is one aspect that cannot be studied by the light or trap approach.

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You might also look for leaves with leaf mines, especially “blotch” mines because those are more likely to be the work of moths.

Rearing leaf miners is less work than rearing caterpillars. You don’t have to keep bringing them fresh leaves from the host plant.

Whatever approaches you choose, do not be surprised if the adult moth proves to be a species that has never been named and described.

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Looking for feeding damage as suggested is a good clue. I find another one is looking for droppings (frass). If you find those, check the leaves/trees above. Often you can find the culprit. Check the underside of leaves and keep in mind some caterpillars are so well camouflaged that they may be “hiding” in plain sight mimicking a petiole, bird droppings, or even flower parts.

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Caterpillars are relatively easy to spot when crawling around on walls alongside gardens/green spaces – at least, this is where I often seem to see them.

However, I don’t really recommend this as a method for finding them, since they are much harder to get ID’d without an association with a food plant.

I agree that feeding damage/faeces can be a good clue about where to look more closely.

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All suggestions given have been good.
My biggest tip is to take a lot of time looking. As in sit by host plants for a long while. Half hour can work.
They are masters of camouflage!
A small garden in bloom can host an abundance of observations, while you are patiently waiting for the caterpillars to show themselves to you.
These Wavy-lined and Southern Emeralds Complex Synchlora aerata were difficult to see… at first!



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Best way to do that is to plant native plants on your property. If not able to go to a field at dusk or dawn or even during the day when the sun is out and wait with camera in hand.
Also go out at night with a full moon. Lots of plants with light colored flowers look like they glow at night (evening primrose is one of them) and moths are particularly attracted to these flowering plants.

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What part of the world are you in? The original quote from Tutt was written in 1901. The situation in Britain, and I guess western Europe, has improved enormously since then. I doubt we have any macro-moths whose larvae are still unknown and a large proportion of micros are also now identifiable as larvae. For example
https://www.nhbs.com/2/series/micro-moth-field-tips

In less studied parts of the world there are still many moths and butterflies whose larvae are unknown. One way to go about it would be to find out which species lack this information, collect some female moths and keep them for a few days hoping one of them lays eggs. That way you will know you are getting the right caterpillars. Then rear the caterpillars, the difficulty being you won’t know what the preferred food plant is so you will need to give them choices based on what closely related moths eat.

And if you are in W. Europe where most larvae are known, there is still plenty to find out about the larval ecology - what range of food plants do they use, what growth form of the food plant do they prefer, where do they pupate, what parasites do they get?

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Thanks for all the ideas! I have not yet really been able to test them out, but hopefully I can make time for some moth-spotting soon.

other than waiting to find the culprit, is there some way to distinguish caterpillar damage from slug or other damage?
Same goes with @NancyinSunnyvale’s comment about leafmines: what is a “blotch” leafmine?
I am very much a beginner in these things, so thank you for any explanations.

@jhbratton, I am in New Zealand. I am not sure what the situation here is like, but feel like even if it is perfectly well known what each species’ caterpillar looks like and what it eats, the caterpillars are still underrepresented on inat. There are 5925 pages of lepidoptera observations in nz, but only 308 pages if you filter for “life stage annotation: larva”. (sorry to give such clumsy statistics. I couldn’t find a way to filter by annotation on the explore page, and neither could I get the identify page to tell me how many species were represented for a given search.) Likewise, there is only one observation of a nz cutworm caterpillar. There are 3554 observations of this species total. Of course, this could simply be because people aren’t annotating their observations of moth larvae as such.
Gosh, that went on a bit . . . sorry.
But I wouldn’t say no to discovering a new species either!

Leaf mines: When I search iNat for " Leaf Blotch Miner Moths Family Gracillariidae" observations in New Zealand, there are none. Strange.

But here are some examples of lepidopteran leaf mines found in N. America..

If you find a leaf mine on a plant that also occurs in Europe, it is likely you can get an ID for it on this site.

Thanks! It must have been a bug (pun intended) that no observations came up, because when I search for gracillariidae observations in NZ I get this:


That plant parasites website is super useful and seems really thorough too.
I will keep an eye out for leaf mines now that I know what they look like!

Try looking for droppings. Caterpillars tend to produce fairly dry pellets, star-shaped in the case of hawk moths. I think slug excrement is more squishy, but it isn’t a topic I have investigated in depth.

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