Unintelligent Design - Creating Problems

Leopard marking its territory

Simulations reveal interplay between scent marking and disease spread: Accounting for individual animal movement could boost understanding of emerging infectious diseases -- ScienceDaily

In a paper published in PLOS Computational Biology a couple of days ago, Lauren White of the University of Maryland's National Socio-Environmental Synthesis Center, Annapolis, MD, and colleagues have shown how a solution to the problem of parasitic infections, can create an opportunity for parasites to spread infections in a classic twist of an arms race.

Animals are liable to pass infections between them by physical contact, so one solution to this problem is for some species to be solitary and live within a territory. However, this solution only works if individuals are able to signal the borders of territories to other members of their species. Unlike birds, which often use song or calls, many species use scent markings placed at strategic positions.

This solution to the problem of parasites only works if potential invaders sniff the scent marking. This then creates an opportunity for the parasite if it can be deposited in the scent, to be sniffed at by another individual.

Abstract
Although movement ecology has leveraged models of home range formation to explore the effects of spatial heterogeneity and social cues on movement behavior, disease ecology has yet to integrate these potential drivers and mechanisms of contact behavior into a generalizable disease modeling framework. Here we ask how dynamic territory formation and maintenance might contribute to disease dynamics in a territorial, solitary predator for an indirectly transmitted pathogen. We developed a mechanistic individual-based model where stigmergy—the deposition of signals into the environment (e.g., scent marking, scraping)—dictates local movement choices and long-term territory formation, but also the risk of pathogen transmission. Based on a variable importance analysis, the length of the infectious period was the single most important variable in predicting outbreak success, maximum prevalence, and outbreak duration. Host density and rate of pathogen decay were also key predictors. We found that territoriality best reduced maximum prevalence in conditions where we would otherwise expect outbreaks to be most successful: slower recovery rates (i.e., longer infectious periods) and higher conspecific densities. However, for slower pathogen decay rates, stigmergy-driven movement increased outbreak durations relative to random movement simulations. Our findings therefore support a limited version of the “territoriality benefits” hypothesis—where reduced home range overlap leads to reduced opportunities for pathogen transmission, but with the caveat that reduction in outbreak severity may increase the likelihood of pathogen persistence. For longer infectious periods and higher host densities, key trade-offs emerged between the strength of pathogen load, the strength of the stigmergy cue, and the rate at which those two quantities decayed; this finding raises interesting questions about the evolutionary nature of these competing processes and the role of possible feedbacks between parasitism and territoriality. This work also highlights the importance of considering social cues as part of the movement landscape in order to better understand the consequences of individual behaviors on population level outcomes.

Author summary
Making decisions about conservation and disease management relies on our understanding of what allows animal populations to be successful, which often depends on when and where animals encounter each other. However, disease ecology often focuses on the social behavior of animals without accounting for their individual movement patterns. We developed a simulation model that bridges the fields of disease and movement ecology by allowing hosts to inform their movement based on the past movements of other hosts. As hosts navigate their environment, they leave behind a scent trail while avoiding the scent trails of other individuals. We wanted to know if this means of territory formation could heighten or dampen disease spread when infectious hosts leave pathogens in their wake. We found that territoriality can inhibit disease spread under conditions that we would normally expect pathogens to be most successful: when there are many hosts on the landscape and hosts stay infectious for longer. This work points to how incorporating movement behavior into disease models can provide improved understanding of how diseases spread in wildlife populations; such understanding is particularly important in the face of combatting ongoing and emerging infectious diseases.

White LA, VandeWoude S, Craft ME (2020)
A mechanistic, stigmergy model of territory formation in solitary animals: Territorial behavior can dampen disease prevalence but increase persistence.
PLoS Comput Biol 16(6): e1007457. https://doi.org/10.1371/journal.pcbi.1007457

Copyright: © 2020 White et al.
Published open access.
Reprinted under a Creative Commons Attribution 4.0 International License (CC BY 4.0)

Brilliant! What a triumph of design for any intelligence to come up with! Untill that is, we back-track the sequence of events involved here:

1. Create a parasite to make an animal ill. This then is a designed problem to be solved.
2. Create territorial behaviour to solve the problem it just created when it created the parasite. This is then a designed problem for the parasite.
3. Create the ability to use scent markings to overcome the problem of territorial behaviour that it created earlier as a solution to the problem of parasites that it created.
4. The animal now has the original problem of a parasite that was created to make it ill.

This not a problem for evolutionary biology to explain because these evolutionary arms races are predicted by the theory of evolution by natural selection, where utilitarian solutions will be adopted if they result in more descendants, so each species involved will tend to evolve a solution which is in it's own interests, regardless of and oblivious too, whatever problem this might be creating for the other species.

However, as the work of a single, omniscient designer, arms races like this make no sense at all, since the same designer would be designing problems for itself to solve, apparently for no discernible ultimate benefit.

Intelligent [sic] design advocates consider this to be the work of a highly intelligent designer. Since this is a fundamentalist Christian notion, proponents are forbidden by religious dogma from proposing several different designers working in competition and in isolation from one another, since that would be heretical. Similar constraints apply to Islamic and Jewish creationist of course despite all pretending that intelligent [sic] design is real science, not religion at all.

Don't you just love the way scientists keep on refuting creationism without even trying! Tweet

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