Publications by EEOB faculty November 13 - November 30

November 26, 2014

Mating Patterns and Pollinator Communities of the Invasive Shrub Lonicera maackii: A Comparison between Interior Plants and Edge Plants

Kelly Barriball, Karen Goodell, and Oscar J. Rocha. 2014. International Journal of Plant Sciences. 175(8). Article DOI: 10.1086/677678

It is known that outcrossing rates and mating structure are important factors determining the genetic structure of populations. Moreover, the composition and abundance of pollinator communities visiting flowers determine the distances over which the pollen is likely to be dispersed, which in turn affects the genetic structure of plant populations. For invasive plants, high outcrossing rates produce genetically diverse propagules for the colonization of uninvaded areas and facilitate the establishment of novel gene combinations that may affect their invasive ability. Here, we examine how differences in pollinator communities visiting flowers of the invasive shrub Lonicera maackii (Caprifoliaceae), growing along the edge and in the interior of a woodlot, affect their outcrossing rates and mating structure.

Goodell Lab

Environmental proxies of antigen exposure explain variation in immune investment better than indices of pace of life

Nicholas P. C. Horrocks, Arne Hegemann, Stéphane Ostrowski, Henry Ndithia, Mohammed Shobrak, Joseph B. Williams, Kevin D. Matson and B. I. Tieleman. 2014. Oecologia. DOI: 10.1007/s00442-014-3136-y .

Investment in immune defences is predicted to covary with a variety of ecologically and evolutionarily relevant axes, with pace of life and environmental antigen exposure being two examples. These axes may themselves covary directly or inversely, and such relationships can lead to conflicting predictions regarding immune investment. If pace of life shapes immune investment then, following life history theory, slow-living, arid zone and tropical species should invest more in immunity than fast-living temperate species. Alternatively, if antigen exposure drives immune investment, then species in antigen-rich tropical and temperate environments are predicted to exhibit higher immune indices than species from antigen-poor arid locations. To test these contrasting predictions we investigated how variation in pace of life and antigen exposure influence immune investment in related lark species (Alaudidae) with differing life histories and predicted risks of exposure to environmental microbes and parasites. We used clutch size and total number of eggs laid per year as indicators of pace of life, and aridity, and the climatic variables that influence aridity, as correlates of antigen abundance. We quantified immune investment by measuring four indices of innate immunity. Pace of life explained little of the variation in immune investment, and only one immune measure correlated significantly with pace of life, but not in the predicted direction. Conversely, aridity, our proxy for environmental antigen exposure, was predictive of immune investment, and larks in more mesic environments had higher immune indices than those living in arid, low-risk locations. Our study suggests that abiotic environmental variables with strong ties to environmental antigen exposure can be important correlates of immunological variation.

Williams Lab

Comparative phylogeography of mutualists and the effect of the host on the genetic structure of its partners

Anahí Espíndola, Bryan C. Carstens, and Nadir Alvarez. Biological Journal of the Linnean Society. 2014. 113(4): 1021-1035. DOI: 10.1111/bij.12393

Whether or not species participating in specialized and obligate interactions display similar and simultaneous demographic variations at the intraspecific level remains an open question in phylogeography. In the present study, we used the mutualistic nursery pollination occurring between the European globeflower Trollius europaeus and its specialized pollinators in the genus Chiastocheta as a case study. Explicitly, we investigated if the phylogeographies of the pollinating flies are significantly different from the expectation under a scenario of plant-insect congruence. Based on a large-scale sampling, we first used mitochondrial data to infer the phylogeographical histories of each fly species. Then, we defined phylogeographical scenarios of congruence with the plant history, and used maximum likelihood and Bayesian approaches to test for plant-insect phylogeographical congruence for the three Chiastocheta species. We show that the phylogeographical histories of the three fly species differ. Only Chiastocheta lophota and Chiastocheta dentifera display strong spatial genetic structures, which do not appear to be statistically different from those expected under scenarios of phylogeographical congruence with the plant. The results of the present study indicate that the fly species responded in independent and different ways to shared evolutionary forces, displaying varying levels of congruence with the plant genetic structure. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 113, 1021-1035.

Carstens Lab

A review of the zumpti species group of the genus Harpyrhynchoides (Acariformes: Harpirhynchidae)—ectoparasites of passerines

Andre V Bochkov, and Hans Klompen. Zootaxa. 3884(5): 401-418. DOI: 10.11646/zootaxa.3884.5.1

The zumpti species group of the genus Harpyrhynchoides (Harpirhynchidae), parasites of passerines, is revised. A key to the species of this group is provided and data on host associations and geographic distribution of its constituent species are summarized. This group includes six previously recognized species: Harpyrhynchoides alaudinus Bochkov, 2000, H.brevis (Ewing, 1911) comb. nov ., H. heatherae Bochkov and Galloway, 2013, H. rubeculinus (Cherny and Sixl, 1971), H. vulgaris Bochkov and Galloway, 2004, and H. zumpti (Fain, 1972). Three species from North American passerines are described as new: H. setophaga sp. nov . from Setophaga ruticilla (Parulidae), H. xanthocephalus sp. nov . from Xanthocephalus xanthocephalus (Icteridae), and H. spizella sp. nov . from Spizella passerina (Emberizidae). Additionally, H. brevis is redescribed based on samples from Coccothraustes vespertinus (type host) and Loxia curvirostra (Passeriformes: Fringillidae) from North America. Harpyrhynchoides kirgizorum Fain et al . 1999 syn. nov . is synonymized with H. zumpti .

Acarology Lab

Historical Species Distribution Models Predict Species Limits in Western Plethodon Salamanders.

Tara A Pelletier, Charlie Crisafulli, Steve Wagner, Amanda J Zellmer, and Bryan C Carstens. 2014. Systematic Biology. doi: 10.1093/sysbio/syu090

Allopatry is commonly used to predict boundaries in species delimitation investigations under the assumption that currently allopatric distributions are indicative of reproductive isolation, however, species ranges are known to change over time. Incorporating a temporal perspective of geographic distributions should improve species delimitation; to explore this, we investigate three species of western Plethodon salamanders that have shifted their ranges since the end of the Pleistocene. We generate species distribution models (SDM) of the current range, hindcast these models onto a climatic model 21Ka, and use three molecular approaches to delimit species in an integrated fashion. In contrast to expectations based on the current distribution, we detect no independent lineages in species with allopatric and patchy distributions (P. vandykei and P. larselli). The SDMs indicate that probable habitat is more expansive than their current range, especially during the last glacial maximum (21Ka). However, with a contiguous distribution, two independent lineages were detected in P. idahoensis, possibly due to isolation in multiple glacial refugia. Results indicate that historical SDMs are a better predictor of species boundaries than current distributions, and strongly imply that researchers should incorporate species distribution modeling and hindcasting into their investigations and the development of species hypotheses.

Carstens Lab