After doing a quick literature search about apple snails, I decided to blog about some fascinating discoveries that have been made about these caenogastropods including mating behaviors, nuptial gifts, and learned predator avoidance. This allows the apple snail to be amphibious, breathing both under and above the water line (Pomacea 2009). One characteristic unique to this family is the presence of both a ctenidium (gill) and an air sac that functions as a lung. Apple snails are members of the family Ampullariidae. Dash is a species of freshwater Caenogastropod, of the phylum Mollusca, commonly known as the Apple Snail (Figure 2). (Photo by: Alexandra Arjo – Reproduced with permission)Īfter observing and learning a little bit about marine snails in lab, I decided I wanted to learn more about the natural ecology of my pet snail. Dash puts out his siphon once in a while, so I was happy to learn what it was for.įigure 1 (above): Marine snail in subclass Caenogastropoda (Photo by: Aimee Taylor) The arrow is pointing at an organ called the siphon, which I learned helps “inhale” oxygen rich water to bring it over the gills for respiration. Figure 1 is an example of a marine snail we looked at in lab from the subclass Caenogastropoda. This is a valuable experience as it allows us to not only look at the organism, but also infer its ecology from morphology and the way the organism moves. The lab portion of the class allows us to explore hands on activities with live invertebrates from virtually all of the animal phyla. I signed up for EVE 112 at UC Davis hoping to learn more about my new friend, Dash. When I was younger I always had small snails in my freshwater aquarium so I was excited to have a new snail to take care of. Sea slugs engage in penis fencing snails stab one another with penis darts.It was the day after my birthday when my friend Tyler called me on the phone and said, “I got you something! I’m on my way over.” He arrived at the front door with a huge snail in a bag of water. And all to inject a little bit of romance.Ĭorrection, March 12, 2014: The caption in this post originally stated that snails engage in penis fencing. For males and females locked in an arms race, though, it could be said to run in circles-vicious ones at that. The course of true love never did run smooth. Others have evolved ways of digesting the injected sperm and using it to repair their wounds, minimizing the damage. Astonishingly, some female bedbugs have evolved modified spermaleges that mimic those of males, to reduce harassment. In an arms race, though, neither side can win-each can only gain a temporary advantage-and, as expected, females are fighting back. Male bedbugs regularly jump other males by mistake-which is such a problem that males in one species have evolved their own damage-control spermaleges. Males will often jump on and penis-stab anything that comes their way, even females of other species, often killing them in the process-a phenomenon that has driven some species to evolve apart. In Harpactea sadistica spiders, the male bites the female, then stabs her with needle-like genitals, ejaculating into the wound. Male giant squid inject sperm packets into females’ arms-although occasionally they end up inseminating themselves, literally shooting themselves in the foot. Male Myzostoma worms secrete corrosive enzymes from their penis, dissolving a hole in the female’s skin into which they ejaculate. This has been such a successful strategy for males that it has evolved repeatedly across the animal kingdom. Males can both prevent females from excluding their sperm and also from preferring other males. But in the cold language of statistics, this may be worth it for the male-a healthy female is no good if she doesn’t bear his offspring. The female is injured in the process, reducing her number of offspring. By injecting sperm directly into females’ body fluid, male bedbugs bypass the female’s adaptations to control access to her eggs. Penis-stabbing, though, shifts the goalposts entirely.
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