Ecological stoichiometry of the black widow spider and its prey from desert, urban and laboratory populations
Urbanization can change the nutrient availability for organisms that live within cities. Ecological stoichiometry (ES) is a way to identify nutrient requirements and limitations of organisms by measuring carbon (C), nitrogen (N), and phosphorus (P). ES can show when their are imbalances in your diet (e.g., C:N ratios). Spiders usually are N limited because they contain significantly more body N than their prey.
The Western black widow spider is polyphagous (eats lots of different types of organisms) and is cannibalistic. In Phoenix, AZ, these spiders have less diversity in their diet relative to desert spiders.
In their recent publication, Patricia Trubl & J. Chadwick Johnson (@Lhesperus) measured ES (molar ratios of C: N, C: P, and N: P) of black widows and their prey from replicate field (urban and desert) habitats, and a laboratory-reared population (single species diet and cannibalism diet) to document stoichiometric variation.
They found that desert spiders had lower C: P and N: P, than urban spiders but C: N did not differ. Cannibalism by laboratory-reared spiders lowered C: P and N: P ratios, but not C: N ratios (Figure 1). This means that cannibalism allowed spiders to reach their optimal ES ratios when their bland diet would otherwise make them worse off.
I am interested in urban ecology and evolution. Urbanization can have drastic impacts on local ecosystems, both negative and positive, and creates a new environment for organisms to experience. To understand the impacts that urbanization plays on organisms, I look through the lense of population genetics and molecular evolution.
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