This is a guest post by Dr. Monica Mowery.
Title Image Credit: Sean McCann, CC BY 2.0, Image Cropped
Dispersal and life history of brown widow spiders in dated invasive populations on two continents (2022) Mowery et al., Animal Behaviour, https://doi.org/10.1016/j.anbehav.2022.02.006
As I write this, I can hear invasive myna birds chirping in the trees outside, and see yellow pollen from the invasive Acacia trees floating through the air. What makes these species able to thrive far away from their native habitat? Despite the knowledge of how harmful invasive species can be, humans continue to transport species to new environments, both intentionally and unintentionally. Yet even with the explosive growth of both invasive species and invasion ecologists, we still don’t know a lot about which traits make the most successful invaders that can thrive and spread to new places.
One way to investigate this is to compare invasive populations that have just arrived at a new place with populations that have been in an area for a long time. To better understand invasive species, we need to figure out how traits shift in invasive populations, as some individuals survive transport, establish, and spread to new habitats, expanding their range. When this happens, traits can change, or shift, as the species adapt to the new environment. Such traits, such as body size, number of offspring, and dispersal ability, may be particularly important during range expansion. This study is an investigation into how traits of invasive spiders shift on a broad geographic scale on two continents.
Image Credit: Andreas Kay, CC BY-NC-SA 2.0, Image Cropped
Specifc parasites indirectly influence niche occupation of non‑hosts community members (2018) Fernandes Cardoso et al., Oecologia, https://doi.org/10.1007/s00442-018-4163-x
One of the oldest questions in community ecology is why do some species seem to co-occur with one another, while others don’t? Two hypotheses have been put forward to explain why this happens: environmental filtering and niche partitioning. Environmental filtering is when some abiotic feature of a given environment – such as the temperature or oxygen levels – prohibits some species from ever living in the same location as another. A very broad (and overly simplistic) example of this is that you would never see a shark living in the same habitat as a lion, because the shark needs to live in the ocean and the terrestrial Savannah of Africa where lions are found “filter” the sharks out. Niche partitioning, on the other hand, involves species adapting to specialize on a given part of the environment, thus lessening competition for a niche by dividing it up. You can see this with some of Darwin’s Finches, which adapted differently-sized beaks to feed on differently-sized seeds. They all still eat seeds, but they are not eating the same seeds.
Interactions with other organisms, either direct or indirect, can also influence which species co-occur. If one species can out-compete another, they likely won’t be able to co-occur because the better competitor will take most of the resources, forcing the other out. This can all change, however, if a third organism affects the competitive ability of the superior competitor, allowing the inferior competitor to persist despite its lesser ability.
Today’s authors used two spider species to study community assembly and how it may be affected by a fungal parasite. Chrysso intervales (hereafter inland spiders) builds webs further away from rivers, while Helvibis longicauda builds webs close to the river (hereafter river spiders). Interestingly, only the river spiders are infected with the fungal parasite, thus they investigated how interactions between the two spiders may be mediated by this fungal parasite. Read more
Image credit: Bernard Dupont, CC BY-SA 2.0, Image Cropped
If you follow anyone in the fields of ecology or biology, chances are you’ve seen or heard of #PruittData, #PruittGate, #SpiderGate, or some other similar hashtag. We at Ecology for the Masses decided that we wanted to add our voice to the discussion, not to disparage anyone, but to take the opportunity to discuss ethics in science and data reporting.
Body coloration of an animal can be useful for not only attracting prey, but also avoiding being eaten. One important question is whether or not this coloration can simultaneously serve both purposes? (Image Credit: Chen-Pan Liao, CC BY-SA 3.0, Image Cropped).
Multifunctionality of an arthropod predator’s body coloration (2019) Liao et al., Functional Ecology, https://dx.doi.org/10.1111/1365-2435.13326
One topic that has interested ecologists for decades is that of animal body coloration, and what function that coloration can serve for the animal. Despite this fascination and the work that has been done to study this aspect of animal biology, the actual mechanisms driving the evolution and maintenance of body color are not well understood. Many different aspects of an organism’s life can shape and affect body color, such as avoiding predators, attracting mates, and whatever resources an organism has available to create specific colors. In addition, many of these aspects often compete with one another, such that a color that is good for attracting mates may also make you more easily-spotted by a predator.
Spiders provide an excellent system in which to study the evolutionary significance of body colors, as previous work has shown that body color affects mate attraction, predator avoidance, and prey attraction. The authors of today’s study wanted to know if these complex color patterns could serve more than one function in the spider’s life.
EDIT: This paper is one of many papers by Jonathan Pruitt which is currently under investigation for suspected data manipulation. More on that at the link below.
#PruittData and the Ethics of Data in Science
Leadership can play an important role of a population dynamics, but is it the strength of the leaders or the willingness of the followers that has more influence? (Image Credit: Bernard Dupont, CC BY-SA 2.0)
Selection for Collective Aggressiveness Favors Social Susceptibility in Social Spiders (2018) Pruitt et al., Current Biology, doi: 10.1016/j.cub.2017.11.038.
Socially-influential leaders can have a large effect on the actions of any group. Think of that one person in your life that everyone looks to when it’s time to make a decision; whether it’s something trivial like where to go for dinner, or something more important like whether or not to take that job on the other side of the country, these individuals make a large impact in their social circles. This can also be seen in the natural world, like the alpha of a wolf pack, or the matriarchs of an elephant troop or an orca pod. These focal individuals greatly influence the actions and success of their groups.
In order to determine not only how important these influential individuals are, but also how much the “social susceptibility” of the followers matters, the researchers in this paper used a species of social spider in two different habitat types. By using both arid and wet environments and analyzing both sides of the influence coin, this study was able to accurately determine the importance of both influencing and being influenced in different ecosystems.