Tag Archives: temporal

Cause and Effect

Temporally consistent species differences in parasite infection but no evidence for rapid parasite-mediated speciation in Lake Victoria cichlid fish (2020) Gobbin et al., Journal of Evolutionary Biology. https://doi.org/10.1111/jeb.13615

Image Credit: Kevin Bauman, CC BY 1.0

The Crux

Ecological speciation (see Did You Know?) can be driven by both abiotic (non-living) and biotic (living) factors. The biotic factors that tend to be studied in regards to ecological speciation are antagonistic in nature, such as competition for resources or interactions with predators. However, parasitism is another antagonistic species interaction that is ubiquitous in nature, and therefore might be expected to contribute to ecological speciation via its effects on host-parasite coevolutionary dynamics.

Though a number of studies have investigated the effects of parasites on ecological speciation, little is known about the role of parasites in adaptive radiations, which are bursts of speciation from a single ancestor to many descendent species that then adapt to fill new ecological niches. In other words, an ancestor will be adapted to a specific environment/food types, but its descendants adapt to live in different environments/eat different food. One of the best examples of an adaptive radiation are the Africa lake cichlids, which are the focus of today’s study. The authors wanted to understand if parasites may have contributed to/caused the adaptive radiation seen in African lake cichlids.

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The Challenges Facing Community Ecology

Community ecology, as a relatively new discipline, is fraught with challenges. Here, we look at why an hour spent talking about those challenges may make you feel like the PhD student pictured above (Image Credit: Lau Svensson, CC BY 2.0, Image Cropped)

Anyone who has forayed any small distance into academia will probably understand the following quote by Aristotle.

“The more you know, the more you realize you don’t know.”

According to Stewart Lee, participating in further education means embarking on a “quest to enlarge the global storehouse of all human understanding”. This might be true, yet venturing into academia also means that the more answers you learn to challenging scientific questions, the more questions get opened up. It’s the circle of academic life.

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Too Many Fish on the Sea Floor

When fish like this sand goby aggregate, the density of their nests can often have a big impact on their success
When fish like this goby aggregate, the density of their nests can often have a big impact on their success (Image Credit: Laszlo Ilyes, CC BY 2.0, Image Cropped)
Spatial and temporal patterns of nest distribution influence sexual selection in a marine fish (2018) Wong et al., Oikos, doi: 10.1111/oik.05058

The Crux

When we monitor the fluctuations of a population, we often look at vital rates, a huge part of which is reproductive success. The success that males have in siring offspring can be hugely influenced by the density of a population, particularly when it comes to a breeding ground.

Larger males will often outcompete smaller males on such grounds, however in many species these males will often reach reproductive limits, at which point smaller males can benefit. Smaller males may also fare better in less dense populations, where females lack other individuals to compare them to. Our study today looks at variations in reproductive success of a nest-breeding fish species over two levels of density.

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