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I saw a dozen or more clusters of what I think are insect eggs attached to a few vertical sticks protruding from a small pond, and a few more to stalks of grass nearby. Location is in Hsinchu County, Taiwan, end of March, fairly good weather these days in the neighborhood of 15-22 C.

Each cluster consist of a group of roughly 150 spherical hot pink colored eggs stuck to a surface, each about 2.5 to 3 mm in diameter. One group was deposited almost completely around a stalk of grass on land next to the pond, and several others were deposited on the side of a stick from a fallen branch sticking out of the water.

Questions:

  1. Is it possible to identify what kind of insect produces such clusters of eggs?
  2. Is there any explanation possible for the "hot pink" color? I suppose it could be a general "don't eat me" signal like these big juicy red bugs but it's such an artificial looking color, I've never seen it anywhere in nature, at least that I can remember.

cluster of hot pink insect eggs? each egg 2.5 to 3 mm

click images below for full size:

cluster of hot pink insect eggs? each egg 2.5 to 3 mm clusters of hot pink insect eggs? each egg 2.5 to 3 mm


update: This answer suggests that snails are the likely culprits, and so I returned to the scene of the crime today and caught them red-handed, or in this case "pink-footed".

Click for full size; the larger snail is about 5 centimeters in diameter.

suspicious-looking snails in the pond with pink eggs nearby suspicious-looking snails in the pond with pink eggs nearby

two VERY suspicious-looking snails in the pond with pink eggs nearby caught red-handed, or in this case "pink-footed"

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    $\begingroup$ Great post that received a great answer!! :). +1 to both! I've closed as duplicate due to a very similar post from Singapore a year ago. I think linking these 2 posts in this way is most efficient for site bookkeeping. However, if you think that your post and/or species is sufficiently different and maintaining your question as a unique post is useful, then I could possibly be persuaded to reopen. (though, again, I think linking as dupe works best). $\endgroup$ – theforestecologist Mar 30 at 6:02
  • $\begingroup$ @theforestecologist I'm all for keeping all our pink egg questions in one basket ;-) Based on the answer I revisited the pond a few hours ago I took some much better photos of the snails there which are likely the culprits. I was going to accept the answer and then post a supplementary answer with them, but maybe I will just update this question with two more photos. Since it's now closed and it complements rather than complicates the existing answer, does that sound okay? $\endgroup$ – uhoh Mar 30 at 6:13
  • $\begingroup$ I think making a clearly "Updated" portion of your answer with photos of the snail species is appropriate. However, if you think your new info/photos suggests a different species than the one suggested in the previous answer, I'd be happy to open the post back up -- a unique ID to species is reason enough to let you post a unique answer :). $\endgroup$ – theforestecologist Mar 30 at 6:33
  • $\begingroup$ @theforestecologist I've added the additional snapshots above and left a message under (at)tyersome's answer. I'm no expert but it certainly looks like these are those. Thanks! $\endgroup$ – uhoh Mar 30 at 7:09
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Those appear to be the eggs of a species of apple snail in the genus Pomacea, probably the introduced invasive golden apple snail (Pomacea canaliculata), but there are at least two other candidates1,2.

You can learn more about this species and the problems it causes from this Columbia University webpage.

For comparison — Figure 3 from "The identity, distribution, and impacts of non-native apple snails in the continental United States"3. enter image description here Egg masses of introduced and native Pomacea in the continental U.S. a. P. haustrum, b. P. diffusa, c. P. canaliculata, d. P. paludosa, e. P. insularum. Scale Bar:5 cm.

References:

1: Yang, Q. Q., Liu, S. W., He, C., & Yu, X. P. (2018). Distribution and the origin of invasive apple snails, Pomacea canaliculata and P. maculata (Gastropoda: Ampullariidae) in China. Scientific reports, 8(1), 1-8.

2: Yang, Q. Q., & Yu, X. P. (2019). A New Species of Apple Snail in the Genus Pomacea (Gastropoda: Caenogastropoda: Ampullariidae). Zoological Studies, 58(13).

3: Rawlings, T. A., Hayes, K. A., Cowie, R. H., & Collins, T. M. (2007). The identity, distribution, and impacts of non-native apple snails in the continental United States. BMC Evolutionary Biology, 7(1), 97.

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    $\begingroup$ Wow, thank you! I never would have imagined that those were snail eggs. I don't have a close-up but I did notice that the pond is full of small snails. Below the big image there are two smaller images that will display full size when clicked. If you look at the one on the left there are dozens and dozens of snails at the bottom of the pond and there are snail trails everywhere. I don't suppose it's just a coincidence. This is probably not the first invasive snail I've posted here either! What are these four large snails doing? $\endgroup$ – uhoh Mar 29 at 18:36
  • $\begingroup$ Type "b" looks like eggs of the variety in the aquarium trade in the US. I found they needed to have a very humid atmosphere to hatch. $\endgroup$ – blacksmith37 Mar 30 at 1:01
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    $\begingroup$ Thanks again for your answer! I've revisited the pond and took some photos of the snails in proximity to the eggs. Apart for being covered in algae the do seem to match the shape of the "golden apples" though in this case with the algae they look more like green apples! $\endgroup$ – uhoh Mar 30 at 7:08

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