Global urban environmental change drives adaptation in white clover.

Urbanization transforms environments in ways that alter biological evolution. We examined whether urban environmental change drives parallel evolution by sampling 110,019 white clover plants from 6169 populations in 160 cities globally. Plants were assayed for a Mendelian antiherbivore defense that also affects tolerance to abiotic stressors. Urban-rural gradients were associated with the evolution of clines in defense in 47% of cities throughout the world. Variation in the strength of clines was explained by environmental changes in drought stress and vegetation cover that varied among cities. Sequencing 2074 genomes from 26 cities revealed that the evolution of urban-rural clines was best explained by adaptive evolution, but the degree of parallel adaptation varied among cities. Our results demonstrate that urbanization leads to adaptation at a global scale

Global urban environmental change drives adaptation in white clover

Urbanization transforms environments in ways that alter biological evolution. We examined whether urban environmental change drives parallel evolution by sampling 110,019 white clover plants from 6169 populations in 160 cities globally. Plants were assayed for a Mendelian antiherbivore defense that also affects tolerance to abiotic stressors. Urban-rural gradients were associated with the evolution of clines in defense in 47% of cities throughout the world. Variation in the strength of clines was explained by environmental changes in drought stress and vegetation cover that varied among cities. Sequencing 2074 genomes from 26 cities revealed that the evolution of urban-rural clines was best explained by adaptive evolution, but the degree of parallel adaptation varied among cities. Our results demonstrate that urbanization leads to adaptation at a global scale

Sexual dimorphism, bite force and diet in the diamondback terrapin

International audienc

Multimodal courtship efficacy of Schizocosa retrorsa wolf spiders: implications of an additional signal modality

Here, we simultaneously examine both content and efficacy-based sources of selection on the visual and seismic multimodal courtship display of the wolf spider Schizocosa retrorsa. Immature field-collected S. retrorsa were reared in the laboratory on either high-quantity diet (HD) or low-quantity diet (LD) treatments. On maturation, females of each diet treatment were run in simultaneous mate choice trials with both a HD and an LD male (content-based selection). Simultaneous mate choice trials were conducted across different signaling environments (efficacy-based selection) in a fully crossed 2 � 2 design with visual treatments of light/dark (visual signal present/absent) and seismic treatments of filter paper substratum/granite substratum (seismic signal present/absent). Male copulation success did not differ across either signaling environment or diet treatment. However, copulation success was related to male leg waving displays as males who engaged in more bouts of leg waving were more likely to copulate regardless of experimental manipulations. The observation that copulation success was independent of signaling environment suggests the use of an additional courtship signal modality. Copyright 2010, Oxford University Press.