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Juvenile Rank Acquisition Is Associated With Fitness Independent Of Adult Rank, Eli D. Strauss, Daizaburo Shizuka, Kay E. Holekamp

School of Biological Sciences: Faculty Publications

Social rank is a significant determinant of fitness in a variety of species. The importance of social rank suggests that the process by which juveniles come to establish their position in the social hierarchy is a critical component of development. Here, we use the highly predictable process of rank acquisition in spotted hyenas to study the consequences of variation in rank acquisition in early life. In spotted hyenas, rank is ‘inherited’ through a learning process called ‘maternal rank inheritance.’ This pattern is very consistent: approximately 80% of juveniles acquire the exact rank expected under the rules of maternal rank inheritance. …

Phenotypic Divergence In Two Sibling Species Of Shorebird: Common Snipe And Wilson’S Snipe (Charadriiformes: Scolopacidae), Tiago M. Rodrigues, Edward H. Miller, Sergei V. Drovetski, Robert M. Zink, Jon Fjeldså, David Gonçalves

School of Biological Sciences: Faculty Publications

Natural and social selection are among the main shapers of biological diversity but their relative importance in divergence remains understudied. Additionally, although neutral evolutionary processes may promote phenotypic divergence, their potential contribution in speciation is often overlooked in studies of comparative morphology. In this study, we investigated phenotypic differentiation in two allopatric shorebirds: the Palaearctic Common Snipe Gallinago gallinago and the Nearctic Wilson’s Snipe Gallinago delicata. Specimens of Common Snipe (n = 355 skins, n = 163 skeletons) and Wilson’s Snipe (n = 403 skins, n = 141 skeletons) in natural history collections were examined to quantify differences in skeletal …

Evolutionary Origin And Genetic Diversity Of Ring‐Necked Pheasants In The Upper Midwest United States, Hernán Vázquez-Miranda, Magdalena Jean Olson, Robert M. Zink

School of Biological Sciences: Faculty Publications

We compared mitochondrial cytochrome b sequences of ring‐necked pheasants (Phasianus colchicus) from Midwestern United States (SD and NE, USA) to a molecular phylogeographic hypothesis of pheasants in the native Eurasian range to understand which subspecies are represented by wild and captive released birds. We found that these birds represent 2 Eurasian lineages, which we refer to generally as northern Eurasian (Colchicus group) and eastern China (Torquatus group). These mitochondrial DNA lineages occur in different frequencies in the wild, with the latter being 3 times more common. This suggests that 1) the eastern China lineage is either …

Extreme Offspring Ornamentation In American Coots Is Favored By Selection Within Families, Not Benefits To Conspecific Brood Parasites, Bruce E. Lyon, Daizaburo Shizuka

School of Biological Sciences: Faculty Publications

Offspring ornamentation typically occurs in taxa with parental care, suggesting that selection arising from social interactions between parents and offspring may underlie signal evolution. American coot babies are among the most ornamented offspring found in nature, sporting vividly orange-red natal plumage, a bright red beak, and other red parts around the face and pate. Previous plumage manipulation experiments showed that ornamented plumage is favored by strong parental choice for chicks with more extreme ornamentation but left unresolved the question as to why parents show the preference. Here we explore natural patterns of variation in coot chick plumage color, both within …

Changes In The Diet And Body Size Of A Small Herbivorous Mammal (Hispid Cotton Rat, Sigmodon Hispidus) Following The Late Pleistocene Megafauna Extinction, Catalina P. Tomé, Emma A. Elliott Smith, S. Kathleen Lyons, Seth D. Newsome, Felisa A. Smith

School of Biological Sciences: Faculty Publications

The catastrophic loss of large-bodied mammals during the terminal Pleistocene likely led to cascading effects within communities. While the extinction of the top consumers probably expanded the resources available to survivors of all body sizes, little work has focused on the responses of the smallest mammals. Here, we use a detailed fossil record from the southwestern United States to examine the response of the hispid cotton rat Sigmodon hispidus to biodiversity loss and climatic change over the late Quaternary. In particular, we focus on changes in diet and body size. We characterize diet through carbon (δ¹³C) and nitrogen …

Reorganization Of Surviving Mammal Communities After The End-Pleistocene Megafaunal Extinction, Anikó B. Tóth, S. Kathleen Lyons, W. Andrew Barr, Anna K. Behrensmeyer, Jessica L. Blois, René Bobe, Matt Davis, Andrew Du, Jussi T. Eronen, J. Tyler Faith, Danielle Fraser, Nicholas J. Gotelli, Gary R. Graves, Advait M. Jukar, Joshua H. Miller, Silvia Pineda-Munoz, Laura C. Soul, Amelia Villaseñor, John Alroy

School of Biological Sciences: Faculty Publications

Large mammals are at high risk of extinction globally. To understand the consequences of their demise for community assembly, we tracked community structure through the end- Pleistocene megafaunal extinction in North America.We decomposed the effects of biotic and abiotic factors by analyzing co-occurrence within the mutual ranges of species pairs. Although shifting climate drove an increase in niche overlap, co-occurrence decreased, signaling shifts in biotic interactions. Furthermore, the effect of abiotic factors on cooccurrence remained constant over time while the effect of biotic factors decreased. Biotic factors apparently played a key role in continental-scale community assembly before the extinctions. Specifically, …

Gravid Tetragnathid Spiders Show An Increased Functional Response, Mary E. Boswell, John P. Delong

School of Biological Sciences: Faculty Publications

Spiders in the genus Tetragnatha feed on emerging aquatic insects, including mosquitoes and midges, but there is little known about the foraging behavior of these spiders. We hypothesized that female spiders actively developing egg sacs would increase food consumption to provide more energy to produce and provision their eggs. We tested this hypothesis by measuring foraging rates of Tetragnatha spiders kept in jars and provisioned with different levels of midges. We then tested for a difference in the functional response of spiders that did or did not lay egg sacs in their jars. Egg-laying and non-egg-laying spiders showed significantly different …

Predators Modify The Temperature Dependence Of Life-History Trade-Offs, Thomas M. Luhring, Janna M. Vavra, Clayton E. Cressler, John Delong

School of Biological Sciences: Faculty Publications

Although life histories are shaped by temperature and predation, their joint influence on the interdependence of life-history traits is poorly understood. Shifts in one life-history trait often necessitate shifts in another—structured in some cases by trade-offs— leading to differing life-history strategies among environments. The offspring size–number trade-off connects three traits whereby a constant reproductive allocation (R) constrains how the number (O) and size (S) of offspring change. Increasing temperature and size-independent predation decrease size at and time to reproduction which can lower R through reduced time for resource accrual or size-constrained fecundity. We investigated how O, S, and R in …

Song Recognition And Heterospecific Associations Between 2 Fairy-Wren Species (Maluridae), Allison E. Johnson, Christina Masco, Stephen Pruett-Jones

School of Biological Sciences: Faculty Publications

Although heterospecific associations beneficial to one or both species involved (e.g. commensalisms or mutualisms) are common, it is generally assumed that interactions between species are transient and not particular to individuals. However, long-term interactions between individuals of different species do occur. In such heterospecific social groups, discrimination between heterospecific individuals may be beneficial, allowing individuals to direct beneficial or aggressive behaviors towards appropriate targets. Here, we describe heterospecific groups composed of splendid and variegated fairy-wrens (Malurus splendens and M. lamberti) and provide the first experimental evidence that recognition of heterospecific group members occurs across species. In these species, …

Body Size Downgrading Of Mammals Over The Late Quaternary, Felisa A. Smith, Rosemary E. Elliott Smith, S. Kathleen Lyons, Jonathan L. Payne

School of Biological Sciences: Faculty Publications

Since the late Pleistocene, large-bodied mammals have been extirpated from much of Earth. Although all habitable continents once harbored giant mammals, the few remaining species are largely confined to Africa. This decline is coincident with the global expansion of hominins over the late Quaternary. Here, we quantify mammalian extinction selectivity, continental body size distributions, and taxonomic diversity over five time periods spanning the past 125,000 years and stretching approximately 200 years into the future. We demonstrate that size-selective extinction was already under way in the oldest interval and occurred on all continents, within all trophic modes, and across all time …

Reproductive Promiscuity In The Variegated Fairy-Wren: An Alternative Reproductive Strategy In The Absence Of Helpers?, Allison E. Johnson, Stephen Pruett-Jones

School of Biological Sciences: Faculty Publications

Cooperative breeding, in which auxiliary group members help rear related, but nondescendent young, is often explained by kin selection. Reproductive monogamy is predicted in cooperatively breeding systems, as monogamy increases intragroup relatedness and maximizes auxiliary inclusive fitness. While monogamy is observed across many systems, including eusocial insects and cooperatively breeding mammals, some cooperatively breeding birds exhibit high rates of extrapair paternity. Here we quantify paternity and examine the role of auxiliaries on extrapair paternity in the highly cooperative variegated fairy-wren, Malurus lamberti, a species with both male and female auxiliaries. Extrapair paternity occurred in 55.4% of nests, and 39.8% …

Spatially Biased Dispersal Of Acorns By A Scatter-Hoarding Corvid May Accelerate Passive Restoration Of Oak Habitat On California’S Largest Island, Mario B. Pesendorfer, T. Scott Sillett, Scott A. Morrison

School of Biological Sciences: Faculty Publications

Scatter hoarding by corvids (crows, jays, magpies, and nutcrackers) provides seed dispersal for many large-seeded plants, including oaks and pines. When hoarding seeds, corvids often choose nonrandom locations throughout the landscape, resulting in differential survival of seeds. In the context of habitat restoration, such disproportional storing of seeds in areas suitable for germination and establishment can accelerate expansion and recovery of large-seeded tree populations and their associated ecosystems. Here, we investigate the spatial preferences of island scrub jays Aphelocoma insularis during scatter hoarding of acorns (Quercus spp.) on Santa Cruz Island. We use a large behavioral data set on …

Biotic Interchange Has Structured Western Hemisphere Mammal Communities, Danielle Fraser, S. Kathleen Lyons

School of Biological Sciences: Faculty Publications

Aim.— Many hypotheses posit that species-rich tropical communities are dominated by speciesspecies interactions, apparent as competitive exclusion or character displacement, whereas species-poor temperate communities are dominated by species-environment interactions. Recent studies demonstrate a strong influence of macroevolutionary and biogeographic factors. We simultaneously test for the effects of species interactions, climate, and biotic interchange on Western Hemisphere mammal communities using a phylogenetic and functional diversity approach.

Location.— Western Hemisphere.

Time period.— Modern

Major taxa studied.— Mammalia

Methods.— Using Western Hemisphere mammal distributional and body mass data, we calculate body mass dispersion, phylogenetic diversity (Net Relatedness Index), and assemblage-averaged rates of co-occurrence …

The Maintenance Of Phenotypic Divergence Through Sexual Selection: An Experimental Study In Barn Swallows Hirundo Rustica, Rebecca Safran, Yoni Vortman, Brittany R. Jenkins, Joanna K. Hubbard, Matt Wilkins, Rachel J. Bradley, Arnon Lotem

School of Biological Sciences: Faculty Publications

Previous studies have shown that sexual signals can rapidly diverge among closely related species. However, we lack experimental studies to demonstrate that differences in trait-associated reproductive performance maintain sexual trait differences between closely related populations, in support for a role of sexual selection in speciation. Populations of Northern Hemisphere distributed barn swallows Hirundo rustica are closely related, yet differ in two plumage-based traits: ventral color and length of the outermost tail feathers (streamers). Here we provide experimental evidence that manipulations of these traits result in different reproductive consequences in two subspecies of barn swallow: (H. r. erythrogaster in North …

Range-Wide Patterns Of Geographic Variation In Songs Of Golden-Crowned Sparrows (Zonotrichia Atricapilla), Daizaburo Shizuka, M Ross Lein, Glen Chilton

School of Biological Sciences: Faculty Publications

Discrete geographic variation, or dialects, in songs of songbirds arise as a consequence of complex interactions between ecology and song learning. Four of the five species of Zonotrichia sparrows, including the model species White-crowned Sparrow (Z. leucophrys), have been studied with respect to the causes and consequences of geographic variation in song. Within White-crowned Sparrows, subspecies that migrate farther have larger range size of dialects. Here, we assessed geographic patterns of song variation in the fifth species of this genus, the Golden-crowned Sparrow (Z. atricapilla). We analyzed field-recorded songs from 2 sampling periods (1996–1998 and 2006–2013) …

Tiger Salamanders Disappearing In Region, Dennis M. Ferraro

School of Biological Sciences: Faculty Publications

"Where have all the salamanders gone?" 'This is a question I have been increasingly asked over the past five to six years from area residents. It seems we are observing a dramatic population decline of the western barred tiger salamander in parts of Southeast Nebraska. The western barred tiger salamander (Ambystoma mavortium) is one of only two salamanders in Nebraska. Over the past two years, none have been found in southeast Nebraska.

Salamanders, like all amphibians, are excellent indicator species. In many cases they act like the iconic canary in the mine shaft, telling us when to run …

Displaying To Females May Lower Male Foraging Time And Vigilance In A Lekking Bird, Sarah A. Cowles, Robert M. Gibson

School of Biological Sciences: Faculty Publications

Males of many species use courtship behavior to attract mates. However, by doing so males may face the associated costs of increased energetic expenditure, reduced foraging time, and elevated predation risk. We investigated the costs of display in lekking male Sharp-tailed Grouse (Tympanuchus phasianellus). We used lek-wide scan sampling to study how males allocated time among courtship display (‘‘dancing’’), agonism, foraging, and inactivity in relation to female numbers both within and across days. We also addressed the limited attention hypothesis and estimated visual attentiveness by videotaping 13 males and scoring head turns during these different activities. We found that the …

Interspecific Egg Rejection As Ecological Collateral Damage From Selection Driven By Conspecific Brood Parasitism, Bruce E. Lyon, Daizaburo Shizuka, John M. Eadie

School of Biological Sciences: Faculty Publications

Distinguishing between interspecific and intraspecific coevolution as the selective driver of traits can be difficult in some taxa. A previous study of an avian obligate brood parasite, the black-headed duck, Heteronetta atricapilla, suggested that egg rejection by its two main hosts (two species of coot) is an incidental by-product of selection from conspecific brood parasitism within the hosts, not selection imposed by the interspecific parasite. However, although both species of coot can recognize and reject eggs of conspecific brood parasites, which closely resemble their own, they paradoxically also accept a moderate fraction of duck eggs (40–60%), which differ strikingly …

The Network Motif Architecture Of Dominance Hierarchies, Daizaburo Shizuka, David B. Mcdonald

School of Biological Sciences: Faculty Publications

The widespread existence of dominance hierarchies has been a central puzzle in social evolution, yet we lack a framework for synthesizing the vast empirical data on hierarchy structure in animal groups. We applied network motif analysis to compare the structures of dominance networks from data published over the past 80 years. Overall patterns of dominance relations, including some aspects of non-interactions, were strikingly similar across disparate group types. For example, nearly all groups exhibited high frequencies of transitive triads, whereas cycles were very rare. Moreover, pass-along triads were rare, and double-dominant triads were common in most groups. These patterns did …

Spatiotemporal Variation In Flow-Dependent Recruitment Of Long-Lived Riverine Fish: Model Development And Evaluation, Daisuke Goto, Martin J. Hamel, Jeremy J. Hammen, Mathew L. Rugg, Mark A. Pegg, Valery E. Forbes

School of Biological Sciences: Faculty Publications

Abstract Natural flow regimes can play a major role as an overarching ecosystem driver in reproduction and recruitment of riverine fishes. Human needs for freshwater however have altered hydrology of many riverine systems worldwide, threatening fish population sustainability. To understand and predict how spatiotemporal dynamics of flow regimes influence reproductive and recruitment variability, and ultimately population sustainability of shovelnose sturgeon (Scaphirhynchus platorynchus), we develop a spatially explicit (1D) individual-based population model that mechanistically (via energetics-based processes) simulates daily activities (dispersal, spawning, foraging, growth, and survival). With field observations of sturgeon and habitat conditions in a major tributary of …

Across-Year Social Stability Shapes Network Structure In Wintering Migrant Sparrows, Daizaburo Shizuka, Alexis S. Chaine, Jennifer Anderson, Oscar Johnson, Inger Marie Laursen, Bruce E. Lyon

School of Biological Sciences: Faculty Publications

Migratory birds often form flocks on their wintering grounds, but important details of social structure such as the patterns of association between individuals are virtually unknown. We analysed networks of co-membership in short-term flocks for wintering golden-crowned sparrows (Zonotrichia atricapilla) across three years and discovered social complexity unsuspected for migratory songbirds. The population was consistently clustered into distinct social communities within a relatively small area (~ 7 ha). Birds returned to the same community across years, with mortality and recruitment leading to some degree of turnover in membership. These spatiotemporal patterns were explained by the combination of space …

Variable Facial Plumage In Juvenile Cliff Swallows: A Potential Offspring Recognition Cue?, Allison E. Johnson, Steven Freedberg

School of Biological Sciences: Faculty Publications

Although the ability to recognize related offspring is essential in the evolution of social behavior, the cues that birds use to identify their own offspring are not fully understood. The Cliff Swallow (Petrochelidon pyrrhonota) is a highly social species that nests in large colonies and exhibits a high incidence of both conspecific brood parasitism and extrapair fertilization, behaviors that can potentially lead to parents investing energy and resources in unrelated offspring, which reduces the parents’ genetic fitness. Because parents continue to feed offspring after they leave the nest, parents also risk investing in unrelated offspring by misidentifying their …

Experimental Confirmation That Avian Plumage Traits Function As Multiple Status Signals In Winter Contests, Alexis S. Chaine, Allison M. Roth, Daizaburo Shizuka, Bruce E. Lyon

School of Biological Sciences: Faculty Publications

Status signals are thought to reduce costs of overt conflict over resources by advertising social status or an individual’s ability to win contests. While most studies have focused on single badges of status, recent empirical work has shown that multiple status signals may exist. To provide robust evidence for multiple badges of status, an experimental manipulation is required to decouple signals from one another and from other traits linked to fighting ability. Such experimental evidence is lacking for most studies of multiple status signals to date. We previously found that two plumage traits in golden-crowned sparrows, Zonotrichia atricapilla, were correlated …

Melanin Concentration Gradients In Modern And Fossil Feathers, Daniel J. Field, Liliana D’Alba, Jakob Vinther, Samuel M. Webb, William Gearty, Matthew D. Shawkey

School of Biological Sciences: Faculty Publications

In birds and feathered non-avian dinosaurs, within-feather pigmentation patterns range from discrete spots and stripes to more subtle patterns, but the latter remain largely unstudied. A ,55 million year old fossil contour feather with a dark distal tip grading into a lighter base was recovered from the Fur Formation in Denmark. SEM and synchrotron-based trace metal mapping confirmed that this gradient was caused by differential concentration of melanin. To assess the potential ecological and phylogenetic prevalence of this pattern, we evaluated 321 modern samples from 18 orders within Aves. We observed that the pattern was found most frequently in distantly …

Antelope Mating Strategies Facilitate Invasion Of Grasslands By A Woody Weed, Shivani Jadeja, Soumya Prasad, Suhel Quader, Kavita Isvaran

School of Biological Sciences: Faculty Publications

Intra and interspecific variation in frugivore behaviour can have important consequences for seed dispersal outcomes. However, most information comes from among-species comparisons, and within-species variation is relatively poorly understood. We examined how large intraspecific differences in the behaviour of a native disperser, blackbuck antelope Antilope cervicapra, influence dispersal of a woody invasive, Prosopis juliflora, in a grassland ecosystem. Blackbuck disperse P. juliflora seeds through their dung. In lekking blackbuck populations, males defend clustered or dispersed mating territories. Territorial male movement is restricted, and within their territories males defecate on dung-piles. In contrast, mixed-sex herds range over large areas …

Different Modes Of Evolution In Males And Females Generate Dichromatism In Fairy-Wrens (Maluridae), Allison E. Johnson, J. Jordan Price, Stephen Pruett-Jones

School of Biological Sciences: Faculty Publications

Sexual dichromatism in birds is often attributed to selection for elaboration in males. However, evolutionary changes in either sex can result in plumage differences between them, and such changes can result in either gains or losses of dimorphism. We reconstructed the evolution of plumage colors in both males and females of species in Maluridae, a family comprising the fairy-wrens (Malurus, Clytomias, Sipodotus), emu-wrens (Stipiturus), and grasswrens (Amytornis). Our results show that, across species, males and females differ in their patterns of color evolution. Male plumage has diverged at relatively steady rates, whereas …

Male Field Crickets Infested By Parasitoid Flies Express Phenotypes That May Benefit The Parasitoids, Oliver M. Beckers, William E. Wagner

School of Biological Sciences: Faculty Publications

Parasites can cause changes in the phenotypes of their hosts that may benefit the parasite, the host, or both. To understand the evolutionary dynamics of host–parasite interactions it is necessary to first examine the effect of parasitic infestation on the host phenotype and whether the host or parasite benefits from these changes. The fly Ormia ochracea parasitizes the variable field cricket, Gryllus lineaticeps, and it uses male song to locate hosts for its lethal larvae. Adult flies preferentially orient to male songs with faster and longer chirps. We tested the effect of larval infestation on two types of host traits. …

Evidence For Air Movement Signals In The Agonistic Behaviour Of A Nocturnal Arachnid (Order Amblypygi), Roger D. Santer, Eileen A. Hebets

School of Biological Sciences: Faculty Publications

Many arthropods possess filiform hair sensilla (termed trichobothria in arachnids), which are extremely sensitive detectors of medium particle displacement. Electrophysiological evidence in some taxa suggests that these sensilla can detect air particle displacements resulting from intraspecific communication signals. However, it has not yet been shown for any species that the air particle displacements detected by the filiform hairs are themselves perceived as a ‘signal’ (i.e. that individuals make behavioural decisions based upon the responses of these organs to the displays of conspecifics). We investigate the agonistic behaviour of the whip spider Phrynus marginemaculatus and the role of its trichobothria in …

Glucocorticoid Hormone Levels Increase With Group Size And Parasite Load In Cliff Swallows, Samrrah A. Raouf, Linda C. Smith, Mary Bomberger Brown, John C. Wingfield, Charles R. Brown

School of Biological Sciences: Faculty Publications

Animals often cope with adverse events by releasing glucocorticoid hormones, which in turn promote increased energy assimilation. In captive animals, crowding also leads to increased glucocorticoid activity, probably because of increased levels of social competition. We investigated how group size and ectoparasite infestations affected endogenous levels of the glucocorticoid hormone, corticosterone, in colonial cliff swallows, Petrochelidon pyrrhonota, in southwestern Nebraska, USA. Parasites were removed from some colonies by fumigating nests. Baseline levels of corticosterone in breeding adults varied significantly with whether parasites were present, colony size (measured by total number of active nests at a site), and nesting stage. …

Terrestrial Behavior Of Ateles Spp., Christina J. Campbell, Filippo Aureli, Colin A. Chapman, Gabriel Ramos-Fernández, Kim Matthews, Sabrina E. Russo, Scott Suarez, Laura Vick

School of Biological Sciences: Faculty Publications

Spider monkeys (Ateles spp.) are well known for their highly arboreal lifestyle, spending much of their time in the highest levels of the canopy and rarely venturing to the ground. To investigate terrestriality by Ateles and to illuminate the conditions under which spider monkeys venture to the ground, we analyzed ad libitum data from 5 study sites, covering 2 species and 5 subspecies. Three of the sites are in Central/North America: Barro Colorado Island (BCI), Panama (Ateles geoffroyi panamensis), Santa Rosa National Park, Costa Rica (A. g. frontatus), and Punta Laguna, Mexico (A. g. yucatanensis). The 2 remaining sites are …