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Location: In a lawn 20 km south of Vienna, Austria

Date & Time: 13th of May 2024 at around 2pm

Estimated size of the ellipsoid, foamy cone: y-axis 10mm, x-& z-axis 6-7mm

Estimated length of the insect within the foamy cone: 4-5mm

Please excuse the poor quality of the second picture - focus was off a bit and I was using an old smart phone..

enter image description here

enter image description here

I discovered some bubbly, foamy cone attached to a blade of grass which I never noticed/seen before. It looks like the insect inside that foamy cone is maybe in its nymph or molt stage.

I have to admit that due to my curious nature I took another blade of grass to gently scrape away some of the foam to see what's inside - I attached another photo showing how it looks when it is still intact.

I tried searching the web with all sorts of combinations of 'insect', 'nymph', 'foam' and the like but unfortunately couldn't find anything that comes close. It also seems that its shell/molt is also present within the foamy cone.

Anyone can share some insights on what that could be/evolve to?

I also find that foam amazing - is this quite common?

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2 Answers 2

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This is a very cool question! Thank you for providing a image and location

The insect which made the spittle is in the Subfamily Aphrophorinae, which contains most if not all spittlebugs.

Spittlebugs damage plants by biting into them and sucking all of their nutrients out. The Spittlebug then uses the plant nutrients to create the spit which it will feed on when it emerges from its egg.

Spittlebugs damage plants by piercing plant tissue and sucking out juices. The damage stunts plant growth, distorts leaves and interferes with fruit production. Effective spittlebug control focuses on reaching these pests before they're covered in protective foam.
Source: https://www.gardentech.com/insects/spittlebugs

The species is best identified by range, as the only spittlebug in the Vienna area is the Meadow Spittlebug (Philaenus spumarius)

Philaenus spumarius, the meadow froghopper or meadow spittlebug, is a species of insect belonging to the spittlebug family Aphrophoridae. In Italy and America, it is economically important as one of the vectors of Pierce's disease (Xylella fastidiosa)
Source: https://wikipedia.org

The brownish thing inside the spit is the molt of the spittlebug.

Spittlebugs overwinter as tiny white eggs in plant stems. The eggs hatch in early to mid-spring. Over the next month or two, the nymph feeds within it spittle, molting two to four times. The nymph finally molts to an adult in late spring or early summer, emerging from its froth.
https://hort.extension.wisc.edu/articles/spittlebugs/

You should refrain from touching the spittle as it carries disease and touching it will spread bacteria:

...With a wide geographic range and the ability to thrive in climates spanning from Hawaii to just south of the Arctic Circle, the spittlebug is also a serious agricultural threat because it can carry bacteria from plant to plant while it feeds.
“Thirteen hundred host plants means 1,300 opportunities to spread pathogenic bacteria in natural and agricultural environments, a sobering wake-up call,” said the study’s lead author Vinton Thompson, a research associate in the Museum’s Division of Invertebrate Zoology.

The bug is also impactful as being a significant carrier of the devastating Pierce's Disease:

Philaenus spumarius is economically important as one of the vectors of Pierce's disease (Xylella fastidiosa)

Here are some examples of the meadow spittlebug: enter image description here enter image description here enter image description here

Image one reference: https://www.inaturalist.org/photos/83085896, Photo 83085896, (c) Thomas Barbin, some rights reserved (CC BY-NC), uploaded by Thomas Barbin
Image two reference: https://www.inaturalist.org/photos/140353568, Photo 140353568, (c) Paul van de Velde, some rights reserved (CC BY)
Image three reference: https://www.inaturalist.org/photos/77769829, Photo 77769829, (c) Mason Maron, all rights reserved, uploaded by Mason Maron

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    $\begingroup$ Can you provide a reference for the claim that "touching the spittle as it carries disease and touching it will spread bacteria"? That seems quite surprising, are you saying that they act as a substrate for specific bacteria that can be harmful to humans? $\endgroup$
    – terdon
    May 16 at 14:07
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    $\begingroup$ @terdon Absolutely! I just did. It doesn't carry diseases harmful to humans but diseases harmful to plants. Sorry for the mixup, and thanks for pointing that out :) $\endgroup$
    – Arrow
    May 16 at 16:00
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The larvae of "froghoppers" are called "spittlebugs" because they make these little balls that look like foamy spit to protect themselves:

https://hort.extension.wisc.edu/articles/spittlebugs/

https://en.wikipedia.org/wiki/Froghopper

I won't attempt to identify the particular species in your picture, maybe someone else will, but the "meadow spittlebug/froghopper" seems to be a quite common one in Europe as well.

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  • $\begingroup$ Thank you for your answer - could you also include your thoughts on which stage this froghopper might be and if the greyish object is indeed its shed/molt/shed in your answer? In the linked article it mentions 'immatures, or nymphs'.. $\endgroup$
    – iLuvLogix
    May 14 at 14:34
  • $\begingroup$ What I found amazing: "The immature bugs feed face down on the stem, and as excess sap is excreted out the anus, A spittlebug nymph peeks out from a mass of bubbles on a strawberry leaf. A spittlebug nymph peeks out from a mass of bubbles on a strawberry leaf. it is mixed with a substance secreted by epidermal glands that enhances surface viscosity and stabilizes the foam to make it last longer. This mixture is forced out of the abdomen under pressure and as it is mixed with air, it forms bubbles. Some species can produce as many as 80 bubbles per minute. " Very impressive.. $\endgroup$
    – iLuvLogix
    May 14 at 14:37
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    $\begingroup$ @iLuvLogix It would definitely be a nymph, but sorry, I'd be completely guessing at which nymph stage it might be. $\endgroup$
    – Bryan Krause
    May 14 at 14:41

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