While I was blacklighting for moths, I have seen a lot of “moths” with weird mouthparts. While I’m still not sure if they were caddisflies or not, when looking up caddisflies in my area, I noticed that in general there isn’t many observations for them in the world, and the species count barely reaches 1000. So, what gives? Wikipedia says there is 15,000 described species, so I would expect more than a thousand… Is it that they are hard to ID? Or something else?
Where are you located? I see like 300k observations for Trichoptera, but I assume you mean maybe a particular genus or species?
I am located in Moscow, where there is like 200 observations (not counting the whole region). However, I was talking about the whole order. It seems to me that 350k is small for pretty noticeable creatures, but maybe I just have a bad point of reference haha.
This would be a perfect time for a top caddisfly IDer to chime in!
Looking at the leaderboard, none of the top 10 caddisfly IDers are very active on the forum these days.
Speaking of Russia, Marina is still #3 on the leaderboard of caddisfly IDers! She is dearly missed.
Hopefully another caddisfly expert will see this thread.
As far as I know, with some exceptions, adult caddisflies overall tend to be difficult to identify from photographs. Microscopic examination is needed for viewing many of the characters needed for ID.
Given that there has only ever really been one person identifying caddisflies ( grigorenko ) … that it’s less common to see them than other orders of insect … etc etc… 1000 of 15000 didn’t seem totally unsurprising to me…
But looking at other invert orders on iNat, relative to those described globally we have :
Thysanoptera = ~300 / ~6000 = 0.05
Trichoptera = ~1000 / ~15000 = 0.06
Diptera = ~20000 / ~150000 = 0.13
Hymenoptera = ~20000 / ~150000 = 0.13
Coleoptera = ~65000 / ~400000 = 0.16
Plecoptera = ~600 / ~3500 = 0.17
Araneae = ~15000 / ~55000 = 0.27
Lepidoptera = ~75000 / ~180000 = 0.42
Odonata = ~4000 / ~6500 = 0.6
Those are global numbers from Gemini google overview so may not be wholly reliable and I am rounding up or down wildly but…still …I would have also thought Trichoptera would be higher relative to the others - they are often relatively charismatic - I would expect the numbers to be closer to Plecoptera than Thysanoptera at least.
Yes, they are hard to identify from normal photos. The British keys to adults use numbers of spurs on the legs to divide them into major groups then rely largely on genitalia. So microscopy is needed but if you have the microscope, they are not very difficult, especially the males. It is a case of matching the drawings to what you see down the microscope. The larvae can also be identified but again it is microscopy to see patterns of hairs. No doubt after you have been concentrating on them for a few years and seen thousands, you can recognise many at a glance but they need a lengthy apprenticeship of plodding through the keys.
UK Caddis can be see here: https://uk.inaturalist.org/projects/trichoptera-caddisflies-of-britain-and-ireland-uk
It’s almost certainly due to their behaviour. The adults of most species are short-lived, nocturnal and often don’t feed at all - which means they’re much less likely to be encountered via casual recording. The large majority of observers don’t use special techniques (such as blacklighting) to actively look for insects - they just record whatever they happen to see.
Caddisflies aren’t usually seen perched on flowers, unlike many other commonly recorded insects. In my experience, a beating net or similar trapping technique is needed to regularly find them during the day. When I first started nature recording, most caddisflies looked almost identical to me. However, after submitting a few records to my national trichoptera recording scheme, it soon became apparent that many could be identified to species. There are certainly enough that can be identified from photos (even by non-experts) to make them worth recording (in the UK, anyway - maybe it’s different in other countries).
Even if caddisflies were always impossible to identify from photos, most casual recorders wouldn’t know that, and would just try to record them anyway. This might result in lots of unknown trichoptera observations (which is, in fact, the case anyway) - but not a general lack of records.
Yeah when I was in undergrad stream ecology, we had a caddisfly key book that was so heavy that you could kill someone with it. AFAIK ID’ing is incredibly difficult when you have the specimen in hand, so a photo is going to be much more so. I’m comfy with my obs remaining at trichoptera level.
I think one reason why they get overlooked by the general public is that the larval cases resemble debris more than anything else. I find them because I’m specifically looking for them, but someone less familiar with aquatic macroinverts might just see stream schmutz.
I’ll keep it brief and summarize what others have said, though I had these opinions beforehand anyway:
Short adult lifespan, often nocturnal and/or near sources of water.
Larvae are aquatic and are either hidden, camouflaged, or both.
Identifying both adults and larvae requires microscopy AND the knowledge of what to look for. Often requires either male genitalia or some can get by with just coloration and patterns and placement of minute body structures and setae.
As far as identification efforts on here, Trichoptera is a little more cryptic and there aren’t as many hyper-experts active on here. If you uploaded phenomenal macro shots of every body angle of every caddisfly you saw, and also dissected those that needed it, you’d probably have to do the leg work of researching the ID for your locality anyway.
That being said, these things can be learned! Keys and illustrations are out there, and the caddisflies sure are too, a useful microscope can be range from probably 90 USD to a couple hundred USD, but if you’re interesting in identifying cryptic stuff, totally worth it. Bonus is that for every individual you take the effort to ID all the way down to species, you’re increasing the likelihood that you report a new species for your area, or even for iNaturalist (speaking from experience).