Individual quality explains association between plumage colouration, arrival dates and mate acquisition in yellow warblers (Setophaga petechia)

Multi-character approach reveals a new mangrove population of the Yellow Warbler complex, Setophaga petechia, on Cozumel Island, Mexico

The Setophaga petechia complex includes 43 subspecies distributed within the new world, of which some are migratory and others are resident, with only two resident subspecies in the Mexican Caribbean: Setophaga petechia bryanti a mangrove subspecies belonging to the erithachorides group resident on the mainland of the Yucatan Peninsula and Setophaga petechia rufivertex endemic to Cozumel Island and belonging to the petechia group. Recently, a new population of individuals presenting intermediate phenotypic traits and living in mangrove ecosystems was discovered and reported for Cozumel Island. In this study, we used a multi-character approach including genetic (five ISSR genetic markers), morphometric (eight traits), phenotypic (four characteristics of males), and acoustic dataset (11 parameters) to understand the process of differentiation and the status of these new island individuals in relation to the two well-established subspecies using a total of 60 individuals (20 for each group). Through multivariate analyses based on different dataset used in our study, we show how the new population is related to the endemic island subspecies, S. p. rufivertex and to the mainland subspecies, S. p. bryanti while demonstrating finite differences. We conclude that the new population of S. petechia on Cozumel Island is a well-established population with high level of differentiation.

Rickettsia parkeri (Rickettsiales: Rickettsiaceae) Detected in Ticks of the Amblyomma maculatum (Acari: Ixodidae) Group Collected from Multiple Locations in Southern Arizona

Rickettsia parkeri is an emerging human pathogen transmitted by Amblyomma ticks in predominately tropical and subtropical regions of the western hemisphere. In 2014 and 2015, one confirmed case and one probable case of R. parkeri rickettsiosis were reported from the Pajarita Wilderness Area, a semi-arid mountainous region in southern Arizona. To examine more closely the potential public health risk of R. parkeri in this region, a study was initiated to investigate the pervasiveness of Amblyomma maculatum Koch group ticks in mountainous areas of southern Arizona and to ascertain the infection frequencies of R. parkeri in these ticks. During July 2016, a total of 182 adult ticks were collected and evaluated from the Pajarita Wilderness Area in Santa Cruz County and two additional sites in Cochise and Santa Cruz counties in southern Arizona. DNA of R. parkeri was detected in a total of 44 (24%) of these ticks. DNA of "Candidatus Rickettsia andeanae" and Rickettsia rhipicephali was detected in three (2%) and one (0.5%) of the samples, respectively. These observations corroborate previous collection records and indicate that established populations of A. maculatum group ticks exist in multiple foci in southern Arizona. The high frequency of R. parkeri in these tick populations suggests a public health risk as well as the need to increase education of R. parkeri rickettsiosis for those residing, working in, or visiting this area.

Conditions on the Mexican moulting grounds influence feather colour and carotenoids in Bullock's orioles (Icterus bullockii)

Carotenoid-based plumage coloration plays a critical role for both inter- and intrasexual communication. Habitat and diet during molt can have important consequences for the development of the ornamental signals used in these contexts. When molt occurs away from the breeding grounds (e.g., pre-alternate molt on the wintering grounds, or stopover molt), discerning the influence of habitat and diet can be particularly important, as these effects may result in important carryover effects that influence territory acquisition or mate choice in subsequent seasons. Several species of songbirds in western North America, including the Bullock's oriole (Icterus bullockii), migrate from the breeding grounds to undergo a complete prebasic (post-breeding) molt at a stopover site in the region affected by the Mexican monsoon climate pattern. This strategy appears to have evolved several times independently in response to the harsh, food-limited late-summer conditions in the arid West, which contrast strongly with the high productivity driven by heavy rains that is characteristic of the Mexican monsoon region. Within this region, individuals may be able to optimize plumage coloration by molting in favourable areas characterized by high resource abundance. We used stable isotope analysis (δ¹³C, δ¹⁵N) to ask whether the diet and molt habitat/location of Bullock's orioles influenced their expression of carotenoid-based plumage coloration as well as plumage carotenoid content and composition. Bullock's orioles with lower feather δ¹⁵N values acquired more colorful plumage (orange-shifted hue) but had feathers with lower total carotenoid concentration, lower zeaxanthin concentration, and marginally lower canthaxanthin and lutein concentration. Examining factors occurring throughout the annual cycle are critical for understanding evolutionary and ecological processes. Here, we demonstrate that conditions experienced during a stopover molt, occurring hundreds to thousands of kilometers from the breeding grounds, influence the production of ornamental plumage coloration, which may carryover to influence inter- and intrasexual signaling in subsequent seasons.