For the past few days, I have been sorting and identifying macroinvertebrates from some samples collected from the decomposition bags. Doing so made me appreciate lugging a microscope to Costa Rica, since the scopes here are horrendous. The dishes pictured here contain macroinvertebrates, mostly insect larva, that I’ve sorted to family.
I don’t like being in the lab.
Here’s some photos of the apple snail eggs I mentioned that had been laid in one of my enclosures.
This Hemidactylus frenatus makes a clicking noise at night to communicate with other geckos. They are found all over the buildings of the station and are an invasive animal.
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Brightly colored but highly camouflaged, this orthopteran was chowing down on some Thalia, which seems to be a favorite food source for invertebrates around here. There are other grass hoppers that hang around on Paspalum repens, a floating grass in the wetland, in large numbers. This guy was alone by my account.
This is the biggest we’ve seen so far. Incidentally, it was fairly docile and only managed to produce a large, smelly spot on Paul’s shirt once.
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My wetland plant identification database is growing. This is Caperonia castaneifolia. It’s stem is thick and hollow (at least the portion that’s submerged).
At the moment, this sedge (Cyperus articulatus) appears to dominant the Palo Verde wetland. I wonder if it will be replaced by another sedge later in the season.
There are tons of apple snail eggs (Pomacea flagulata) attached to the stems of emergent vegetation. I’ve found some clumps of eggs on Thalia geniculata, Cyperus articulatus, Echinodorus paniculatus and in my own plots on Eichhornia crassipes as well as some PVC pipe I’m using. There is a lot of variation in height from the water’s surface and size of egg cluster and I’ve only seen one instance where there are two clusters to a single stem. I wonder how the snail choose a location in terms of plant species and height on the stem.
The eggs are pinkish in color and are vary conspicuous. I’ve encountered one instance where the eggs appeared to have suffered a predation attempt, although I would suspect that egg predation would generally be complete and if not, the left-overs would sink away. Additionally, a cluster that I brought back to the lab appears to have been eaten by a raccoon that raided my snail bucket one night – it also made off with 2 of my adult snails (one of which was splattered on the ground) and punctured a whole in another (which is still alive).
I sacrificed this cluster to get an idea of how the snails develop. Within the cluster, there is an outer layer of empty eggs encased in hard, brittle, shell-like material. Beyond the empty layer, individual snail-lets (?) develop in separated compartments.
These beetles look ridiculous. They are everywhere in the wetland, however, and I suspect they are feeding on my water hyacinth. I have found a few papers on the use of two weevil species as a biocontrol for Eichhornia, but I haven’t keyed this species out. Although this one was being blown across the water by the wind, I have seen many on my Eichhornia.
This is what the water hyacinth in the Palo Verde wetland currently looks like. Seedlings existed throughout the wetland underwater, attached and rooted. In areas where there has been high traffic (because of my work or because of cattle), the seedlings have release from the sediment and float. When I first noticed them, they had two leaflets and a couple of roots, and I was unsure on their identification. A week later and it is obvious. The seedlings are generally smaller than a silver dollar.
