Tag Archives: invertebrate

Small Creatures, Large Effects

Arthropod predation of vertebrates structures trophic dynamics in island ecosystems (2021) Halpin et al., The American Naturalist, https://doi.org/10.1086/715702

Image credit: Bernard Dupont, CC BY-SA 2.0, via Wikimedia Commons

The Crux

Predator-prey dynamics are (I think) the most well-known species interaction out there. Not everyone is a scientist, but almost everyone has seen an image of a cheetah running down a gazelle, a great white shark exploding out of the water as it hammers a seal from below, or wolves teaming up on a much larger herbivore.

These interactions are not only fascinating and captivating, they are also key to structuring communities. For example, the damselflies that I worked with during my PhD occur in two different kinds of lakes: fish lakes and dragonfly lakes. The type of predator alters the lake significantly: damselflies that live in fish lakes are adapted to “hide” from their fish predators by not moving. Not moving in a dragonfly lake means that a dragonfly will eat you.

Though these interactions have been (justifiably) studied to an extreme extent, there are still knowledge gaps out there. Of interest for today’s study is the effect of invertebrate predators on vertebrate prey. While these invertebrate predator/vertebrate prey interactions have been studied in marine and freshwater environments, little work has been conducted in terrestrial systems. This is especially hard to do with invertebrate predators of vertebrate prey, because such predators tend to be hard to find, nocturnal, and they also hunt in more “concealed” environments like leaf litter. To overcome these challenges, today’s authors utilized the Phillip Island centipede (Cormocephalus coynei, which is NOT the centipede featured in this post’s image) and stable isotope analyses (see Did You Know) to understand how invertebrate predators structure food web dynamics.

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Hydrothermal Vents And Where To Find Them

The “Can­de­labra” black smoker at a wa­ter depth of 3,300 meters in the Log­atchev Hy­dro­thermal Field on the Mid-At­lantic Ridge (Image Credit: MARUM − Zentrum für Marine Umweltwissenschaften, Universität Bremen, CC BY 4.0, Image Cropped)

The deep sea is an unimaginably large and dark environment, and humanity’s attempt to learn about it is comically clumsy. Sampling the animals in the deep sea is often done “blindly”, by dragging nets along the ocean floor or through the water column, or bringing up cores of deep-sea sediment. The most sophisticated, precise and least destructive method is using underwater robots that have arms that can be controlled remotely to sample specific animals in real time, though naturally, this is also the most expensive.

These sampling efforts are comparable to sampling a rainforest with a helicopter. At night. With a map that a kindergartener drew. How long would it take to get a reliable record of all the different species of bird, beetle, monkey and flower found in the rainforest? How long to find a male and female of every species?

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Do Disturbances Promote Biodiversity in the Presence of an Invasive Species?

Image Credit: Paresh Poriya, CC BY 4.0, Image Cropped (also not featuring tunicates)

Testing ecological theories in the Anthropocene: alteration of succession by an invasive marine species (2021) Christianson et al., Ecosphere, https://doi.org/10.1002/ecs2.3471

The Crux

Ecological disturbances, such as fire, floods, or storms, might seem like a catastrophe at first glance, but often they open up space for new species to take the place of dominant ones, creating a more diverse ecosystem. When a disturbance occurs matters as well – if a storm hits right before a particular species starts to reproduce, that species could take advantage of the extra space and become dominant in a short time.

In the 1970s, John Sutherland and Ronald Karlson tested this theory, looking at the invertebrate community of a coastal dock in North Carolina, USA. They found that which species dominated depended on when the community began to grow (a proxy for when disturbance opened up new space).

The area has since seen the introduction of an invasive species of tunicate, Clavelina oblonga. This week’s authors wanted to test whether the original patterns seen in the 1970s still showed up in the presence of the invader.

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Life Under Lake Ice: A Mysterious (and Threatened) World

Image Credit: US National Park Service, Public Domain Mark 1.0, Image Cropped

Ice has become (pardon the pun) something of a hot topic lately.

Professional and amateur scientists alike have studied the timing of seasonal ice formation on lakes and rivers for hundreds of years, and the patterns that have emerged from these studies provide a window into the progression of climate change. Overwhelmingly, the data show that lakes and rivers are freezing up later in the winter and their ice cover is melting earlier in the spring than in the past.

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Shelley Adamo: Consider the Invertebrate

Shelley Adamo was recently asked to testify before the Canadian senate as to whether or not lobsters felt pain (Image Credit: Marco Verch, CC BY 2.0, Image Cropped)

Dr. Shelley Adamo is a full professor at Dalhousie University in Halifax, Nova Scotia, Canada. An internationally recognized expert in the field of ecoimmunology and comparative psychoneuroimmunology, Dr. Adamo has an enormous amount of scientific experience in both the lab and field. In addition to her stellar career in academia, she has also brought her expertise and knowledge to the public, as she was recently asked to testify before a Canadian senate committee to discuss whether or not insects feel pain.

During Shelley’s recent visit to my university, I took the opportunity to sit down and talk to her about appearing before the senate, the concept of pain in invertebrates, and the plight of the insect world in general.

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