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Showing posts from July, 2023

Mud-Dauber

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A yellow-legged mud-dauber on the window of my truck. Notice the thin, elongated connection or pedicel between the middle and rear segments of the body. In one of the first posts that I published on this blog, I talked about insect specialization and the relationship between insect and native plant diversity. Because herbivorous insects will often specialize on eating one particular species or group of plants, an area with a high diversity of native plants will also tend to have a high diversity of insects. In that same post, I also talked about how this relationship can be extended to the diversity of insect parasites, which also tend to specialize. Last week, while starting up the truck I use at work, a common and rather visually striking example of this process of diversification through parasitism landed on the driver-side window - a yellow-legged mud-dauber ( Spheliphron caementarium ). The yellow-legged mud-dauber is a member of the Sphecidae family of wasps, appropriately know

The Ambystoma Complex

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A salamander belonging to the Ambystoma complex, found in Lichfield County, CT If you took a biology class in middle or high school, you were probably introduced to something called the biological species concept. First proposed in the 1940s by Ernst Myer, the biological species concept defines a species as a group of organisms that are actually or potentially capable of breeding with each other, but not with organisms outside the group. In other words, if two organisms can breed with each other, then they are part of the same species; if they cannot, they are different species. Simple, right? Well, not really. The biological species concept is often taught and used as a kind of default definition for what a species is because it's so simple and because it emphasizes the documented importance of reproductive isolation in the development of the diversity we see across the tree of life. The problem is that its only really applicable to organisms that reproduce sexually - an organis

Halteres

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  A crane fly we caught in a light trap at work; the halteres are the bulbous, drumstick-looking structures on the back, just behind the wings. Have you ever wondered what makes a fly a fly?  The complicated answer is a set of similar physiological characteristics, specific evolutionary relationships, and a dash of arbitrary line drawing by human taxonomists.  The simple answer is halteres!  Halteres are a pair of small, club-like structures located just behind the forewings in members of the order Diptera, also known as the "true flies." They function like gyroscopes, providing the fly with information about its position in space. As the fly beats its wings, its halteres beat in time with them, moving along a single, vertical axis. If the fly's body starts to tilt, the halteres maintain their inertia and continue to beat in that original plane. This puts strain on the halteres, which is sensed by receptors at their base and translated by the nervous system into informati

Friends

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  I was returning home from work the other day when I heard something moving in a small pile of rocks near the side of my building. Looking over, I saw two eastern garter snakes ( Thamnophis sirtalis sirtalis ) retreating into a hole between the rocks, along with two others sunning themselves on top of the pile. When I moved to get a closer look, these two snakes also retreated between the rocks. That these snakes would be sunning themselves so close together, and then retreating into the same hiding place when disturbed, may seem a bit odd. After all, we don't usually think of snakes as very sociable creatures and there has been very little research into the social dynamics of snakes due to this very prejudice. All that has started to change over the past few decades, however, with some truly interesting results.  Garter snakes have long been known to gather together in large numbers during at least two times of the year. First, during the winter, garter snakes living in colder re