MOVING ON ...

Box elder bugs (Boisea trivittata) feeding on the sap of a Himalayan blackberry plant

Today I ended work at the Vineyard Drainage. Although it looked promising and there were rumors of three or more turtles living there, I found just one. Hence, the sample was too small for the effort we wore putting out. The good news is that today Kate and I did a survey of a site near the confluence of this waterway and Santa Rosa Creek and it looks promising. In the meantime there is other work to do, especially telemetry work to see how the turtles are responding to work to clear the channel of debris.

INTUITION, SCIENCE, AND ART

One of the fascinating things I do as a biologist is to also try to understand how this kind of mouthpart evolved. For example, the previous insect the Aeshnidae (dragonfly) naiad (nymph) had a completely different set of mouthparts but they come from a common antecedent or ancestor. I will save that for a later discussion.

In the meantime, there is there are some interesting discoveries I did make along the Vineyard Drainage. I found a new Odonate naiad and made an interesting discovery about the affect of preservatives on specimens. Specifically, I have several samples that have bits and pieces of insects, especially wings that do not look like any insect Kate and I know live in the region. However, I know insect colors are ephemeral and fade particularly quickly when they die. Recently I was taking photographs of pinned and mounted dragonflies. They look dreary because they lose all of their color. Upon finishing the project on Monday I recalled how preserving specimens changes their colors as well. Hence, I collected some Water Striders ((Gerris remigis) to see the response of their rather dreary colors to being preserved in alcohol. I choose them is that I keep finding what looks like their body and wing parts in the stomach contents of western pond turtles - but the colors are brown rather than grey. Sure enough, the color changes when I preserve them in alcohol after exposing them to a tad bit of acid similar to stomach acid. In fact, it matches the mysterious wing and body parts that seemed like those from insects from their family! Because I am taking time to work with possible food resources in the ecosystem and choose to follow my intuitive mind, I uncovered some very interesting information. Before deciding to follow my passion for wildlife ecology, I was a fine artist, photographer, and commercial artist. As an artist, I was always combining analysis with intuition and open to serendipity. It seems this works in science as well.

Hemiptera or "true bugs"and haustellate mouthparts

Above is a frontal view of the face of a water strider (Gerris remigis) and the beak-like projection is the rostrum. The water strider is a predator and it feeds by injecting enzymes into the prey, the enzymes liquefy the interior of the insect, and the water strider sucks the liquid out. The water strider is a member of the order or group of insects called Hemiptera or true bugs whose feeding style always includes the sucking up of fluids, the technical term is haustellate.

Lastly, the water strider is part of a group called “true bugs” (Hemiptera) that suck a variety of juices, some from plants and others from animals.  For example, Box Elder Beetles get fluids from plants while the water strider gets it from other insects (mostly).

An elegant yet simple solution

Most invertebrates do not have an internal skeleton or endoskeleton as we do. Rather they have an external skeleton called and exoskeleton. Now, if you are a biochemist or an expert in this field, move on because I am going to oversimplify things. For the rest of you this is important. 

An animal like and insect, lobster, or crayfish has its skeleton on the outside and the organs hang on the inside. Therefore, the skeleton must do the work of our skeleton and skin. It must offer support, protection, and be a waterproof bag that keeps the animal from drying out.

Hence, the outer portion of the exoskeleton is supportive and a protective shield. To make this hard shield strands of chitin, a long chain of molecules are interwoven with protein molecules. If you want to think of it is alternating threads of two strong materials with different properties that combine to form a hard outer shield that is also a skeleton. Then to keep moisture in, there is a lining of epithelial cells (the same kind that are the lining of you mouth and the rest of your alimentary canal). A good analogy a foil container of juice; it is hard on the outside and then lined with plastic.

In keeping with the analogy of the foil juice container, how do people get access to the juice? Yep, we poke a hole in the foil pouch and suck out the juice just as true bugs and spiders do. I find it interesting how I am was at first repulsed by this feeding style but then when I discovered I do it as well it was not as vexing. After all, we are all animals! 

It is what it is

One more thing regarding feeding styles. For the most part, insects that eat other insects or others have only two ways to get to the protein they need penetrate the hard exoskeleton shell. Hence they have two choices, either penetrate the exoskeleton and suck the juice out or crush the exoskeleton and pick it apart to get the protein. How do you get lobster meat? I could go on but enough said. Folks like me have no problem with the variety of feeding styles we animals use and others – well it troubles them and nothing will make it easier. For example, I tried this analogy on my friend Barton, but he still thinks its gross and we are still friends. I sometimes think biologists like me have some sort of genetic anomaly that makes us see the world so differently.