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Can You Afford to be Picky?

The better, the choosier: A meta-analysis on interindividual variation of male mate choice (2022) Pollo et al. , Ecology Letters, https://doi.org/10.1111/ele.13981

Image credit: barloventomagico, CC BY-NC-ND 2.0

The Crux

Choosing who to reproduce with (mate choice – see Did You Know?) is a major player when it comes to the evolution of a species, yet it can be tough to know when individuals (and which individuals) should be choosy in their partners. A general trend is that when there are a plethora of potential mates available, too many for a given animal to mate with, they must make decisions on who to mate with. For many species, females tend to be the choosy sex, given the limited number of reproductive resources that are available to them (i.e., eggs) and how many males are usually available to mate.

Despite this commonality of female mate choice, male mate choice is also widespread in the animal kingdom. It is therefore important to know how different factors affect how a male chooses his mates. One factor that may play a key role is male quality, or the ability of a male to acquire mates. It could be that males that vary in their quality also vary in how picky they are. Today’s authors used a meta-analysis, or a “study of studies”, to understand how males make their decisions.

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Sunstruck

Viruses are weird – they are non-living, yet still contain genetic information and are dependent on a live host to actually replicate and survive. Unlike many other parasites, since viruses are basically just a string of DNA or RNA, they actually need to actually get inside the cells of their host and hijack some of the components of these cells to allow them to replicate. After infection they are (at least partially) in the driving seat and can control and manipulate how some cells behave.

This means that viruses often have the capacity to also alter the behaviour of their host – which can be particularly beneficial to help ensure that the virus can also spread from one host to another. A good example is rabies, whereby the virus triggers infected individuals to become exceptionally aggressive – a surefire way to probably lead to them biting another individual and allowing infection to occur via the bite wound.

Sometimes the behavioural changes can be more nuanced – in this case caterpillars infected by a baculovirus start perceiving then sun in a positive light (pun definitely intended). Infected caterpillars become attracted to sunlight and feel compelled to move towards it (this process is known as phototaxis). Unfortunately in this case is is drawing them to an untimely death. Having the caterpillars die near the tree canopy is beneficial for the virus, as its a better scouting ground for newer hosts.

Read more: Baculoviruses hijack the visual perception of their caterpillar hosts to induce climbing behaviour thus promoting virus dispersal


Tanya Strydom is a PhD candidate at the Université de Montréal, mostly focusing on how we can use machine learning and artificial intelligence in ecology. Current research interests include (but are not limited to) predicting ecological networks, the role species traits and scale in ecological networks, general computer (and maths) geekiness, and a (seemingly) ever growing list of side projects. Tweets (sometimes related to actual science) can be found @TanyaS_08.

The Lazy Bird Gets the Worm

A fine-scale analysis reveals microgeographic hotspots maximizing infection rate between a parasite and its fish host (2021) Mathieu-Bégné et al., Functional Ecology, https://doi.org/10.1111/1365-2435.13967

Image credit: Viridiflavus via Wikimedia Commons, CC BY-SA 3.0

The Crux

Interactions between hosts and parasites can be broken down into two broad stages: the encounter filter and the compatibility filter. The encounter filter determines whether a parasite actually comes in contact with a host, through either a spatial or temporal overlap. After the encounter filter comes the compatibility filter, the stage at which a parasite either successfully infects a host and takes the resources needed, or is successfully repelled by the host. Though the encounter filter must come before the compatibility filter, most studies tend to focus on the compatibility filter. Yet for a parasite to successfully encounter a host, many obstacles must first be overcome.

Parasites tend to be very small, and hosts tend to be rare. Furthermore, many hosts move around the environment and/or are only available to a parasite at specific times of the year. Finally, in many cases the environment that a single host can occupy is huge. With all of these difficulties facing parasites, it is not surprising that they have evolved many different strategies to effectively find hosts.

However, some species don’t appear to display these strategies. For them to succeed, it is possible that they distribute themselves in a non-random (see Did You Know?) fashion in the environment, clumping together to form “hot-spots” of infection. Other studies have investigated this “hot-spot” phenomenon before, but tended to focus on larger spatial scales, anywhere from hundreds to thousands of meters. Today’s authors wanted to understand if investigations at much smaller spatial scales (i.e., ~10 meters or less) could provide further insight into the spatial aggregation of parasites.

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Mainstream

Bird and whale song are a way for males to attract members of the opposite sex, and (as the variety of bird calls you might hear out in the garden indicates) these songs vary between species. Similar to how people can have different tastes in music, there is also variation in the the style of the songs between individuals of the same species. This can lead to ‘cultural revolutions’ where some individuals can influence and change the mating calls of the other individuals in the population if they want to stay relevant.

This poses an interesting question of if and how animals value and appreciate aesthetic beauty and how similar that is to how humans view ‘aesthetic beauty’ – and of course implies that bird and whales must have some kind of Billboard 100 chart floating around!

The idea of cultural evolution in non-human animals is a growing topic of discussion but if you want to know more about how whale songs change check out the link below.

Read more: Global cultural evolutionary model of humpback whale song


Tanya Strydom is a PhD candidate at the Université de Montréal, mostly focusing on how we can use machine learning and artificial intelligence in ecology. Current research interests include (but are not limited to) predicting ecological networks, the role species traits and scale in ecological networks, general computer (and maths) geekiness, and a (seemingly) ever growing list of side projects. Tweets (sometimes related to actual science) can be found @TanyaS_08.

Location Location Location

Biotic interactions are more often important at species’ warm versus cool range edges, Paquette & Hargreaves, 2021 Ecology. https://doi.org/10.1111/ele.13864

Image credit: Trey Ratcliff, CC BY-NC-SA 2.0

The Crux

In nature, we usually refer to the given area in which a species is found as a species range. The size of these vary, even between species that are very similar in appearance. For example, many of the dragonflies and damselflies I worked with during my PhD research could be found all over the state of Arkansas, but others had more limited ranges, and could only be found in the more southern lakes that I visited. Often, species are limited to these areas because the environmental conditions, such as temperature, are favorable to them, and the change in those conditions beyond the boundaries of their range will lead to them suffering. Knowing which factors limit the range of a given species is important for management policies, as knowing the temperature limits can inform predictions about the effects of climate change, while knowledge of natural enemies (like predators) can help with the containment of invasive species.

Previous work on the constraints experienced by species at their range limits tend to focus on abiotic factors (temperature, precipitation, etc.), as these data are easily quantified and there are very extensive records available. However, biotic factors (interactions with predators/competitors, the availability of prey) can also limit the range of a species. Though biotic factors are important, they are more difficult to quantify than abiotic factors, and are often species-specific. That is, the effect of a competitor on limiting the range of one species won’t be the same on another species. Interestingly, biotic interactions may be more important in warmer range limits, while the abiotic may be more important in the cooler range limits. Today’s authors used data from a number of studies to test just that idea.

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The Summer of the Russian (Fish) invasion

Title Image Credit: Earl Steele, CC BY-NC-ND 2.0, Image Cropped

Every time fighter jets fly overhead here in Central Norway, either my wife or I nearly always make a dry remark about the Russians finally invading. It’s a slightly dark reference to former Norwegian occupations, but not something that’s likely to occur anytime soon.

Yet this summer, the papers were filled with constant sensational references to very real and ongoing Russian invasions. Luckily, they’re referring to the pink (or humpback) salmon, and not to any human army marching across the borders.

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Does A Modern Ecologist Need To Become A Bayesian?

Image Credit: 2010 Jee & Rani Nature Photography, CC BY-SA 4.0, Image Cropped

This question comes from Marney Pratt (@marney_pratt) as she noted that a recent paper tracking trends in ecology papers shows the use of Bayesian statistics increasing over time. (Before we get going, if you want a refresher about what exactly Bayesian thought entails, check out this previous post.) Anderson et al. say:

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Welcome to the Jungle: Living With Your Study Species

At the start of the pandemic, working from home became essential for many of us – breaking down the physical separation of work and life and instead creating one very long day at the office. For many research groups, this meant having to make key decisions on what to do with vital animals, plants, and tissue cultures. For me, it meant over a year living with hundreds of bush crickets. Now that the summer has returned and more COVID restrictions have been lifted, the insects recently returned to our lab. Here I share some thoughts on this element of the last year, and what I have learnt about time management in academia.

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Some (Don’t) Like it Hot

Do latitudinal and bioclimatic gradients drive parasitism in Odonata? (2021) da Silva et al., International Journal for Parasitology. https://doi.org/10.1016/j.ijpara.2020.11.008

Image Credit: Adam Hasik, image cropped

The Crux

If there is one thing that people know about me and my research it’s that I love parasites. They’re everywhere, and more than half of all animals are parasites. They also make ecosystems more stable and link organisms within food webs to one another. For example, some parasites connect prey animals and their predators by making it easier for the predator to find and/or eat the prey. Though they can be found all over the world, there are a variety of environmental factors that make it more likely for a parasite to be found in a given environment. Today’s study focuses on one particular hypothesis related to the effects of the environment, the latitudinal diversity gradient (LDG, see Did You Know).

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Eternal Flame

Dinosaurs in the arctic – plausible. Dinosaurs thriving in the arctic – absolutely crazy…

The notion that dinosaurs were reptilian-esque, scaly, and cold-blooded creatures has probably played a role in shaping the idea that we shouldn’t expect to find dinosaurs at higher (colder) latitudes. But as our picture of dinosaurs has changed (think feathers and possibly endothermic (warm-blooded)) over time, it is probably not that surprising to learn that dinosaurs may have done well in colder (and darker) latitudes.

The discovery of not only adult dinosaurs but their young up in fossil deposits in Alaska tells us exactly that. This means that these dinosaurs were not just migrants moving through these regions but were able to reproduce. The other cool thing? It wasn’t just one, but a large collection of species that had babies represented in the fossil record. This means that a lot of dinosaurs were actually able to reproduce – which suggests that they were well-adapted to polar regions.

Just another lesson in how much we still have to learn about these beasts from the past.

You can read the full article here: https://doi.org/10.1016/j.cub.2021.05.041

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