Here are my other Brazos Bend and/or critter pages:
 ----------------------------------------------------------------                  OR,  FOR OTHER ANIMALS:
Alligators at Brazos Bend State Park Introduction                 Critters at Brazos Bend State Park Page 1
Snakes-nonvenomous 1-------------------------------------------     Critters at Brazos Bend State Park Page 3
Snakes-nonvenomous 2-------------------------------------------------Insects, non-toxic
Snakes-nonvenomous 3------------------------------------------------Spiders
Snakes-venomous------------------------------------------------------Mammals
Birds-Waders----Birds-Raptors---------------------------------    Lizards!--Turtles!
 Cookiecutter Shark Attack!  Hammer-headed Worms  Acid-Spitting Arthropod

-Today is 9/28/2021. I hadn't known anything about Apple Snails before July of this year.  Since then, I've read a lot about them, found them, filmed them, and tried to help control them.
I quickly gathered a lot of imagery and information about them, so...here it is.

07/08/2021 - 07/10/2021 A friend of mine told me about seeing Apple Snail egg clusters along the Live Oak Trail at BBSP.  He also mentioned that Limpkins had appeared in the area--since they are
known to eat adult apple snails.  I'd only recently learned that the egg masses of Apple Snails look like wads of pink bubble gum stuck on surfaces near water, because I'd seen one mass on a tree in
Houston, at Fiorenza park.  Just *one* mass, and at the time I didn't know what it was. I haven't seen any there since.  But, about a week ago, I noticed a few egg masses at Scobee field, but hadn't
thought much about how they got there and what they meant.  But then I started reading about them. And I went back to Scobee for another look, and took the pictures here. At some time recently,
most of that park must have been flooded. This makes sense because that entire area is *inside* the Barker Reservoir-a flood-control structure which is designed to capture water.  Anyway, I went
there between bouts of rain, so didn't have a lot of time this trip.  The pictures are all of the same area. Note where the eggs are.  The masses on the "bridges" over the ditch aren't a big surprise
(there's water in the ditch) but then there are masses on the tree, and on the picnic table. Water must have been higher. I didn't see any snails this trip.  Also, I dealt with all the egg clusters I took
pictures of (and more that I didn't get pictures of).
   

   

   
                                                                                                                                                       Egg Aftermath
Then I did more research.  The source I liked best--which seemed relevant to Texas was this one:  Identity, reproductive potential, distribution, ecology and management of invasive Pomacea maculata in the southern United States
(by Romi L. Burks et.al. 2017).  This book was also very informative:
Biology and Management of Invasive Apple Snails  ed. Ravindra C. Joshi, Robert H. Cowie, Leocadio S. Sebastian  2017.  It also contains the prevous study. I found the book in many places online.
Here's one link:   https://enaca.org/?id=931
This is what I've learned.  The term "Apple Snail" is too general.  Over time, it has led to some confusion while discussing these animals.  In the Southern U.S., the species Pomacea maculata is the most widespread.
 P. maculata were probably introduced here through mishandling of the snail by aquarium owners. The snails can keep enough air in their shell to allow them to float.  Then, if the body of water they are living in
became flooded (like in a hurricane. Harvey, for instance.) the water can carry them everywhere and anywhere.  Perhaps that's how they got to Scobee field.
P. maculata lay eggs on surfaces above the water line,  usually during dawn and dusk.  A normal clutch of eggs is about 1500-2100 and takes about 30 minutes to deposit.  The eggs hatch in about 2 weeks, and can yield
hundreds of hatchlings. The best hatching results if the eggs remain dry for 6 - 9 days. Any submergence during this time can affect the stability of the eggs.  The eggs are also toxic, possibly a by-product of the same
chemistry that allows them to incubate in open air. Their bright pink color may also serve as a warning against being eaten.  P. maculata apparently eats almost everything. Like many snails, P. maculata eats periphyton
(algae, detritus, etc. that cling to surfaces); but they also eat macrophytes (larger plants that are visible all the time...duckweed, rice, lotus).  In Louisiana, they are of major concern for rice farmers, as the snails will
eat young plants.  The snails will also eat crawfish eggs.  Although the eggs are toxic, the newly-hatched snails are fair game. It's possible the young snails could be eaten while they're growing by the predators that are
usually around--crustaceans, insects, fish, turtles, wading birds and some mammals. Some crawfish species seem to prefer P. maculata hatchlings to those of native snails.  The birds called Limpkins don't normally live in
Texas, but some have recently been observed here eating Apple Snails!! One more thing--P. maculata-like many snails-are inhabited by many parasites.  Some of these are dangerous to humans. One worm in particular--
Angiostrongylus cantonensis (aka Rat Lungworm) is pretty nasty.  It is generally spread to humans when they eat improperly-cooked snails.
The book I mentioned above gives a very good view of how many countries are trying to control the damage being done by the various species of "Apple Snails".  The studies are good examples of what major incursions
of the snails look like. They look BAD. A common method of early control is to destroy egg masses whenever they are found, and capturing and disposing of adult snails. In both cases, care should be taken to avoid being
contaminated by contact. Also, I haven't found very much descripton in what do do with snails after they're collected. It is illegal to transport the snails in many places--to prevent further contamination. I suppose crushing
them in place is an option (but not very humane...which might be why it isn't suggested often).  I've also seen references to freezing them....for a few days to be sure they're dead. It appears that P. maculata can also survive
short exposures to freezing temperatures.  Now, when I look at my pictures, it seems that  there isn't really much at that park there for adult snails to eat. The hatchlings might be able to live off periphyton for a while,
but there isn't much else. And, once the rain stops, those ditches are normally dry over the summer.  Between the wading birds coming in to clean out the wet ditches, and lack of water, perhaps the snails who have ended up
at Scobee will mostly die anyway.  To be sure, I did make sure to smush all the egg masses I took pictures off--plus more that I didn't.
On 07/10/21, I returned to Scobee Field. I went early, hoping that I could catch a snail laying eggs.  And, I did!  I shot some pictures of the snail at work, and some video clips as well. If you examine the pictures below,
you'll see how much more water there is.  It rained a lot Saturday.  The model airplane group that runs Scobee Field were having an activity there, so I didn't stay in their way (They were perfectly friendly. I just didn't want
to be in the way.)  There was one snail at work, so I filmed that one.  The video is here.  I was amazed when I saw how the eggs were carried out of the snail, and up to the wall.  There was a sort-sort of trench in the snail's
flesh. But, it wasn't a defined structure. It changed shape, and other dimples formed to carry separate clumps of eggs. Pictures in the bottom row below show this....trench.  The video shows it working. The final picture
shows an empty shell that was there. Something had eaten most of the snail out of it. There were lots of wading birds around that morning. One of the folks walking around suggested that raccoons might eat the snails.
That's encouraging, but I have a question (at least one, anyway). Since the eggs are toxic-which prevents most animals from eating them (the bright pink color might act as a warning (aposematic coloration)); then what happens
to animals that eat a snail that has eggs inside?  Also, the egg masses I saw, and the snails I found--were removed carefully.  They're gone. Since I always carry hand disninfectant, I used it after this.

   

   
                                                                                 Egg channels                                   The shell is not smooth everywhere.                 Something ate most of this one.

07/25/2021 and 08/01/21- I've been doing more research on our apple snail invaders since July. When I saw the inside of an adult Pomacea, I noticed orange masses or organs.
I figured that those were eggs. Since the deposited egg masses are toxic, I wondered if the eggs inside the snail were also toxic. And, if the eggs are toxic--how can any animals
--such as Limpkins--eat the adult snails?  After a lot of searching, I couldn't find any detailed description of how this situation is dealt with.  The first picture below was
taken on 7/24/21, but I'd seen inside other snails before then.  The other two pictures were taken 7/10/21, and show a snail that something had eaten. At the time, I hadn't
realized that the toxic egg masses had been left inside the shell.
   

I found a number of references saying that animals that eat the snails discard the albumen glands. But the only predator I saw named doing this was Snail Kites. But no clear descriptions.
I started searching for proof that Limpkins might discard these organs. I found a video on youtube that shows a Limpkin doing this!  After that, I started looking around BBSP for signs
of this behavior.
But let's pause a bit.  Limpkins?  Limpkins (Aramus guarauna) are long-necked wading birds with long, pointed beaks. They're about the size of Night Herons (maybe a bit larger).
According to Avibase, the World Bird Database, it is the only extant species in the genus Aramus and the family Aramidae. The "home range" of 4 subspecies of Limpkins is: Florida, Cuba,
 Jamaica ;  southern Mexico south to western Panama; Hispaniola and Puerto Rico; central and eastern Panama; South America, south west of the Andes to western Ecuador, and east of the Andes
south to northern Argentina. Like many wading birds, Limpkins can be generalist predators but according to many sources, the greatest component of their diet is:  Apple Snails. If we examine the
list of regions  in their "home range", we can see something missing-- TEXAS.  That's right.   In fact, their home range is far from Texas. 
Texas is now being invaded by Apple Snails.  If only Limpkins were in Texas!  Well...they ARE in Texas. In fact, they have been hanging around in the lake next door to BBSP for some months now. 
That lake is infested with snails. Unfortunately, the snails have made their way to the BBSP side of the fence, along Live Oak Trail. But the Limpkins have been picking them off there, also. 
Discarded snail shells litter the trail. I went down Live Oak Trail on 7/18, and I saw something interesting among some discarded shells. I took a few pictures. Next to one
of the shells is a pink mass. I think that mass is one of the "albumen glands" that was discarded by the Limpkin that ate that snail. The trail was really wet, so I didn't go further.
First 3 images below show shells on the trail, and a pink mass neer them. The last image was taken there on 8/1/21, and shows pink material in the discarded shell.
  

I returned to Live Oak Trail the next week (7/25).  I'd been around the other trails, and entered Live Oak from the East end and walked West.  I was doing snail egg removal. It was Noon,
and it was hot, so I didn't expect to see anything.  A Limpkin appeared on the South side of the trail, near the fence, and hunted the area near the fence.  I stayed back, and hardly moved. 
It came to the trail, walked on it a bit, then went back under the fence and eventually up the levee and across.  I got pictures and a bit of video!  This is all edited into this video.
  

Next weekend (8./01). I'd been out on the other trails first. I met a couple park visitors I'd sent to Live Oak trail and they told me they'd hadn't seen any Limpkins, but had seen snail egg masses,
 and even a few live snails. So I was on Live Oak Trail again, at about 12:30pm.  I'd gotten almost to one of the "bridges" when I saw a Limpkin up in a tree between the trail and the
road--that is, North of the trail. I watched it for about 20 minutes, until thunder from approaching rain clouds convinced me to start back to my car.  I got a brief look at another Limpkin
in a tree near the one I'd been watching.  They both moved, and seemed to start hunting, but I didn't want to get caught in rain that seemed to be approaching. I got photos and video
clips.  Again, this has all been edited into this video.
   

And, I found another snail shell that seemed to have remnants of a discarded "albumen gland" in it.  I also found another paper that seems to have been inspired by the habit of snail predators
discarding the "albumen gland":  "Apple Snail Perivitellin Precursor Properties Help Explain Predators’ Feeding Behavior" 2016 by Cadierno, Dreon, Heras. While it discusses Pomacea canaliculata and
 not our problem (P. maculata), I think it's still related. This study is where I got the term "albumen gland" for the organ which produces the snail eggs. Perivitellin serves as a nutrition source for snail
 embryos (similar function to egg yolk ). While the paper is a bit technical for me to fully understand, for me it verified:   a) that the organs are toxic, and therefore consumption of the entire snail
could be dangerous;  b) that experienced predators do discard toxic parts of the snail, rendering it safe to eat. From the paper: " Therefore, as the noxious perivitellin precursors are exclusively
confined within the AG, this explains why it is the only usually discarded organ, even when this behavior implies a large loss of the total energy and nutrients available from the soft-body biomass
(Estoy et al. 2002). Finally, we propose that the reddish-pink gland color may contribute to this behavior, helping the visual-hunting predators of adult snails to associate the bright AG color with the
noxious compounds it carries."(page 466 "AG"=albumen gland)  This could be trouble for our local predators (such as alligators) that might consume entire snails.  Raccoons might be able to identify
and remove the glands, but they'd have to learn about the danger first (that might be what ate the snail in the picture above). It's potentially good news that Limpkins are eating snails here. It will
be better news if they establish a breeding population in Texas. They can help control the spread of the Pomacea. But, regardless of predation, and it seems to me that the snails will remain.  I think
the most we can hope for is that the predators that have followed the snails (and other local predators) and the snails will reach a "balance" where the snails will not overpower the environment.
There must be reasons why Limpkins haven't made the journey here before.   If lack of snails was a factor...where they're here now. But, if there are other environmental reasons (such as temperature)
 the Limpkins may not stay.  I hope they do.

My Big Apple Snail Followup, written 09/28/2021-------------------------------------------------------------------------------------------------

At Scobee Field on 7/24/2021--The ditches dried, though the dirt was still damp. I noticed a snail shell in a hole in the mud. Since I'd read about these snails can aestivate, 
I took pictures of the shell before I moved anything. I had already seen many snail shells lying out of the water in other locations, and they'd all been empty(dead).
But just in case, I took many pictures of this one. The depression, or hole, or whatever, was intriguing.
   
          Snail in the dried ditch                       Shells of dead small snails litter the area            Snail in the hole shot with flash                 Snail in the hole shot without flash

Then I turned the shell over.  The snail was alive!  I could tell by the sealed operculum.  I took pictures of the snail and the depression. The hole wasn't elaborate, but it seems
like the snail made it.  As of this date (9/29/2021) I haven't found any description of how Pomacea aestivate naturally. Do they dig burrows, or dig anything? I've read of
one experiment shows that it's possible for these snails to survive TEN MONTHS without water, as long as they can maintain a seal to converve internal moisture. The snail had
"backed into" the hole, so perhaps it could dig by manipulation of its foot.

   
      Snail flipped over. It's alive!                          Flipped snail next to the hole                          Closer view of the hole                      Snail near the hole, view shifted a bit.        

At Scobee Field on 8/17/2021--The ditches had some water again. I found an adult snail moving around in the water at one of the culverts. In this case, there were strings of amphibian
eggs in the water, too.  I think they belonged to a species of toad. I've read that Pomacea will consume amphibian eggs as well as the various types of plants. So, I watched (and filmed) the
snail as it moved around the ditch and over the eggs many times. I didn't see any sign that this adult snail paid any attention to the eggs at all. The snail didn't pause, the eggs remained intact.
The video clips I captured are included in the edited video.  Here's the video link.

   
  Snail in the ditch with amphibian eggs. 1        Snail in the ditch with amphibian eggs. 2     Snail in the ditch with amphibian eggs. 3   

At Scobee Field on 9/18/2021--A small bit of water appeared in the ditches. The pictures below show that the water hadn't been there long. But when I looked into that shallow
puddle, I found 5 adult snails. Where did they come from? How did they get there? I started filming, and this time I captured more interesting behavior. 
   
  Very shallow puddle in the same ditch.               Live snails moving in the water!                   The water hasn't been there long.            Two snails moving around mower tracks.

Apple Snails (and some other species of snails) have gills and a lung. This explains why the snails can go over land, or climb trees--etc.  While I watched the snails moving around the 
shallow puddle I noticed them probing with their "siphon".  But the probe went straight up until it broke the surface of the water, where it opened. The siphon had become a snorkel!
   
    Pinched-closed siphon reached up.            Pinched-closed siphon breached the surface.               Siphon begins to open.                               Siphon opening expands.      

   
         Siphon is now a snorkel.                                   Siphon is now a snorkel.                        Breathing through the snorkel.                      Close the opening and submerge.   

I noticed something else while the snorkel was being used. With the snorkel deployed, the head of the snail moved in and out; as if acting like a pump.  The series of images below
are frame grabs from the video. They show how the head moved in and out.  This is also shown in the same edited video clip.   Here's the video link.

   
    Snail's eyes, antennae, and face.              "Air Pump" cycle, snorkel up, head is out.       "Air Pump" cycle, snorkel up, head is in.        "Air Pump" cycle, snorkel up, head is out.

Although these snails are pretty tough, there are already natural allies here that may help control them--that is, help stop them from taking over the environment. After all, they do
have a natural habitat (continent of South America), and are part of the ecosystem there. So, here are some of the animals on the Home Team:
1) Raccoons have been observed eating the adult snails--and they discard the toxic albumin glands.   Here's a link to the article "Observations of Raccoon (Procyon lotor) Predation on the Invasive Maculata 
Apple Snail (Pomacea maculata) in Southern Louisiana".  And, here's a link to connected video showing raccoons with snails.  The links were good when I used them. Can't guarantee they still are. 
2) Remains of Apple Snails have been found in stomach contents of alligators harvested in Louisiana. In article "ALLIGATOR MISSISSIPPIENSIS (American Alligator). NOVEL NON-NATIVE PREY".
Link to the article (in Herpetological Review, pages 627-628). 
3) At least one native species of ant will attack snail egg masses. Surprise!! Not fire ants (although they might consider it). Article: "Observations of Acrobat Ants (Crematogaster sp.) Preying on the Eggs 
of the Invasive Giant Applesnail (Pomacea maculata)"   Link to the article is here.  Link to a related video is here. 
4) A native sunfish--Redear Sunfish (Lepomis microlophus) AKA "shellcracker" is known to eat small snails of many kinds, including young Pomacea. TPWD link here. 
5) Limpkins!  These birds are not native here, but have moved in to Texas, at least for the summer, and they are specialists in eating Apple Snails. As far as I know, Limpkins have not been seen nesting
here yet, so they might not have established a population here--so far. 
6)  Crawfish.  Some crawfish are voracious. Native Red Swamp Crawfish (Procambarus clarkii) are for sure, and I've read that they will also eat young Pomacea. Which is good, since I've also read that
adult Pomacea snails can ravage crawfish habitat and also eat their young. So that's a few of the animals that can help control the growth of Apple Snail populations. Along with these...are people.  Scientists
around the world have been trying create some kind of control but have not yet found one. In the meantime, collecting and destroying adult snails, and scraping snail eggs off and into the water can help.  I have done 
a bit of this at Scobee (removed about...70 snails total and maybe a hundred or so egg masses I think).  And also at Brazos Bend State Park (only found about 20 snails, but have removed about 400 egg masses off
the trees along Live Oak Trail there.)  This is not much compared to the efforts of some other groups of people at some other ponds and lakes. The images below are from Brazos Bend State Park on 09/05/2021.
They will give some idea of the number of masses possible on the trail. I've found 180 masses along a 100-yard stretch in two hours.  A short video demonstration of scraping technique is in the same edited video.
   
    7 egg masses, with old smears others.           4 egg masses, with old smears others.            4 egg masses, maybe different species       9 egg masses, with old smears from others

   
  5 egg masses, from the picture of 9            13 egg masses, with old smears from others   12 egg masses, with old smears from others     Scraping with paint roller handle step 1

   
  Scraping with paint roller handle step 2      Scraping with paint roller handle step 3      Scraping with paint roller handle step 4        Rinsing toxic egg goo off of scraper.

Go back to my home page, Welcome to rickubis.com
Go to the RICKUBISCAM page.