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Boom-Bust Cycles: Equilibrium is Out, Dare to be Different!

Wed, 16 Sep 2026 05:00:00 GMT

Louis T. Bubrig and Amanda K. Gibson: Read the article

Bubrig et al. modeled host-parasite interactions where the host population experienced recurring bottlenecks: turns out that bottlenecks can hugely benefit hosts in their quest to rid themselves of parasites!

When studying how different species interact with each other, it is straightforward to picture that they exist at an equilibrium. For our purposes, we consider equilibrium as an expected numerical balance between each interacting species within an ecosystem. In an equilibrium model, when numbers depart from this balance, they eventually return to it. Equilibrium gives a tidy scenario where you can measure how species will react to a changing climate because they will undoubtedly settle back into a familiar numerical balance. The diversity of our world’s ecosystems provides us with a variety of species with different life histories, some of which go against this idea of a balanced ecosystem. In light of this fact, how can we understand and model species interactions that reject equilibrium?

Prevalent exceptions to the trend of returning to equilibrium are species that experience boom-bust life cycles. These species may have a booming increase in population followed by a bust, a decline in their population size. That bust could be caused by a disturbance to the population, including disease, natural disaster, or lack of resources. Imagine a hypothetical species named species A. At the start of a year, there are plenty of resources allowing species A to grow to a population of 1,000. After six months, resources are dwindling, and the lack of available food causes the population to decrease to 100. This demonstrates one instance of a boom-bust. Imagine that after six months, resources are plentiful again. This becomes a boom-bust cycle, as species A can then rapidly increase again by taking up all the resources, followed by a population bust as their resources become scarcer. The word disturbance seems inherently negative, but many species seek out disturbances. These species exploit unstable environments and temporary resources. To understand the spread of disease and interaction changes in these species that thrive within boom-bust cycles, studies need to focus on non-equilibrium dynamics.

A common species interaction is between a host and its parasite. Bubrig and Gibson set out to create a mathematical model to predict parasite prevalence for host species that experience boom-bust life cycles. For this model, a parasite is an organism that can be transmitted between members of the host species, and parasite prevalence is the percentage of hosts that are infected. A decrease in the host population was referred to as a bottleneck. Parasite prevalence was assumed to be 100% when no bottleneck occurred. To observe the effect of host bottleneck occurrences on parasite prevalence, Bubrig and Gibson modeled recurring bottlenecks, bottlenecks at an increased frequency, and bottlenecks at an increased severity.

To determine what could happen when multiple bottlenecks happened consecutively, they set the model to perform recurring bottlenecks that were kept at a consistent frequency and severity. After repeated bottlenecks, parasites lost the ability to fully infect the host population and were kept at a maximum value that was lower than the initial 100%. The reason for this is that after a bottleneck event, the hosts reproduce faster than the parasites can spread throughout the uninfected portion of the host population. The hosts now have more space to reproduce, and parasites have a further distance between hosts to travel.

With the understanding that recurring bottlenecks give the host an advantage, the next step is to see if increases in frequency and severity of the bottlenecks may exaggerate this effect. For this portion of the model, parasite prevalence may become so low that parasite extinction can occur. First, a higher frequency means more bottlenecks occurring in a shorter period. As frequency increased, parasite prevalence had an increasingly difficult time recovering, as host birth rate was higher than parasite transmission. In this situation, parasite extinction became slightly more likely. Next, higher severity means that each bottleneck reduces the population to a smaller value. As the host population decreased to lower and lower values, the parasite prevalence decreased as well. Parasite extinction became significantly more likely, as removing more individuals from the population increases the chances of eliminating all the infected individuals.

This paper holds open the door for further research on non-equilibrium modeling. This model should encourage the collection of experimental data on specific host species that experience boom-bust cycles. Bubrig and Gibson were transparent about some of the areas where their paper can be expanded upon, and future researchers should walk through that open door. While a straightforward problem may seem ideal to solve, complexities are what allow the Earth to be so essential, productive, and beautiful. Understanding these complexities will benefit our knowledge of non-equilibrium host-parasite dynamics, but to similar importance, will allow us to better protect these delicate ecosystems.

Mel Grillo is a second-year PhD student in the Bolnick Eco-Evo-Immuno Dynamics Lab at the University of Connecticut. Their research focuses on analyzing untargeted metabolomics datasets to understand within and among population differences in threespine stickleback (Gasterosteus aculeatus). Mel believes that decoding the metabolome will greatly aid our understanding of phenotypes. Beyond their research, Mel plays the piano and watches too much reality television.

Nominations for the IDEA Award

Fri, 11 Sep 2026 05:00:00 GMT

The American Society of Naturalists, the Society for the Study of Evolution, and the Society of Systematic Biologists announce the call for nominations for the ASN/SSE/SSB IDEA Award. The IDEA Award will be given to a person at any career stage who has strengthened the ecology and evolutionary biology community by promoting access and inclusion in our fields. The award can also be presented to a group. The recipient(s) will be invited to present a plenary lecture at the annual Evolution meeting. Each recipient will also receive a plaque and a $1000 honorarium (shared among recipients if more than one).

Eligibility

No contemporary officer, editor, member of the AIC committee, or meeting organizer of the three societies is eligible for the award. Membership in any of the three societies is not required to nominate someone or be nominated for this award.

Resubmissions (with or without updates) of previous nominees who did not receive the award are welcomed.

How to submit a nomination

Nominations should be submitted by November 1, 2026.

Nomination packages should include:

Nomination Letter: A single letter of support (maximum 2 pages) including biographical information (name, title, organization) of the person or group being nominated, along with a description of the activities supporting the nomination. The letter should focus on the nature of the impact the nominee has had on access and inclusion in our community. In the letter, nominators should also address the breadth of the nominee’s impact, the scale and timeframe of their efforts, and the extent to which the nominee has a plan to assess the impact of their activities. Specifically, how have the candidate’s efforts increased access and inclusion in the ecology and evolutionary biology community?
For self-nominations, an additional letter of support from another person who is familiar with the activities of the nominee is welcome, but not required. At the end of the letter, the nominator must include this statement: “To the best of my/our knowledge, this nominee has adhered and does adhere to the SSE/ASN/SSB Code of Ethics.” Nominators should choose one code for this statement. The ASN Code of Ethics is available here.
Biosketch: A brief biosketch or list of activities (maximum 3 pages) for the person/group nominated that highlights their work increasing inclusion and access. This document should focus on the activities relevant to the nomination and should include relevant materials (citations, websites, workshops, social media accounts and activities, etc.).
Code of Ethics: A statement confirming that you have reviewed the ASN, SSE, or SSB Code of Ethics and that to your knowledge, the nominee has not violated the Code of Ethics.
Optional supplementary material: Any material you believe clarifies or captures the scope, breadth, and timeline of the activities of the nominee relevant to this award (maximum 3 pages).

Please contact committee chair Susana Wadgymar at suwadgymar [at] davidson [dot] edu with any questions.

DEADLINE: November 1, 2026

Click here to apply!

Evaluation Criteria

The evaluation committee will use the following criteria to assess nominees. The nominators should include information addressing these points in the nomination letter:

The specific activities of the nominee
Timeline of nominee’s activities (when/over what years was the nominee active?)
The impacts of the nominee’s activities (who is impacted and how)
The scale at which the nominee’s activities is directed (e.g., local, regional, national, international)
Assessment of impact (has the nominee demonstrated their impact via formal assessments, etc.?)
Communication of the nominee’s activities (have the nominee’s activities been communicated to the ecology and evolutionary biology community, broader scientific community, or the general public?)
Ability of nominee’s activities to serve as a model for other fields
Growth of the nominee/nominee’s activities over time (has the nominee shown sustained commitment to their activity over time? Has the activity expanded, evolved, or changed over time with the nominee’s input?)

Successful nominees need not excel in all categories. The award has previously been made to the founders of new groups as well as career professionals.

Award

The recipient(s) will be invited to present a plenary lecture at the annual Evolution meeting. Each recipient will also receive a plaque and a $1000 honorarium (shared among recipients if more than one).

Past Recipients

Past recipients are listed here.

About the IDEA Award

The IDEA Award was created in 2019 by the American Society of Naturalists (ASN), the Society for the Study of Evolution (SSE), and the Society of Systematic Biologists (SSB). The IDEA Award is given to a person or group at any career stage who has strengthened the ecology and evolutionary biology community by promoting access and inclusiveness in our fields. The recipient will receive a plaque at the annual meeting of the joint societies and a $1000 honorarium.

Presidential Award for Outstanding Service to the Community, 2026

Mon, 31 Aug 2026 05:00:00 GMT

We are pleased to announce Dr. Bob Montgomerie as the recipient of the 2026 special Presidential Award for Outstanding Service to the Community in recognition of the tremendous work he did in establishing The American Naturalist’s data editors program.

The American Naturalist was early in requiring the data underlying a manuscript be deposited upon publication. However, little had been done to verify that the data actually supported the conclusions drawn in the paper. There was simply no easy way to ensure compliance without a dedicated data editor. Under the encouragement of then-editor Dan Bolnick, Bob developed an effective process to evaluate and improve data repositories of all papers published in the journal. That model is now becoming the standard for other journals in our field and beyond.

Bob, along with his assistant data editors, helped set the standard for verifiably reproducible code and data, first with The American Naturalist and then at other journals. This was a significant undertaking on behalf of ASN and Am Nat, and we are deeply grateful.

Nominations for Honorary Lifetime Membership in the American Society of Naturalists

Fri, 28 Aug 2026 05:00:00 GMT

The Honorary Lifetime Membership is the oldest and most prestigious award given of the American Society of Naturalists. It is intended to recognize senior scientists whose careers epitomize the goals of the Society.

A list of present and former Honorary Lifetime Members can be found here:

https://www.amnat.org/awards.html#Lifetime

Honorary lifetime memberships in ASN, limited to twelve individuals, are intended to recognize senior scientists whose distinguished research careers epitomize the goal of the Society. New honorary members are chosen through a Society-wide nomination process and selection by the ASN Executive Committee at each year’s annual meeting. We urge members to propose inductees. To do so, please fill out this Google form with a statement of your nominee’s suitability for this recognition, preferably accompanied by a CV. Those who do not have Google accounts can provide the same information by email to the incoming ASN President (Jen Lau, jenlau@iu.edu). We encourage you to keep in mind the global reach of the Society, as well as its broad conceptual scope.

Many thanks,
Becky Fuller
President, ASN

Pardon our dust...

Thu, 20 Aug 2026 05:00:00 GMT

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