Winner and loser effects influence subsequent mating interactions in crayfish.

In species whose social structure includes dominance relationships, individuals are likely to engage in frequent agonistic interactions with conspecifics, and these interactions can have substantial effects on participants. For example, 'winner' and 'loser' effects, whereby winning or losing a contest increases the probability of winning or losing subsequent encounters, have been described in many species. However, a smaller body of research has shown that winning or losing a contest can lead to additional behavioral changes that affect other domains of an individual's social experiences. Here, we report on an experiment designed to evaluate the effects of prior contests on subsequent mating interactions in the crayfish (Faxonius virilis). We presented males with mating opportunities either immediately following or 7 days after a contest with a conspecific male. We predicted that winners would be more likely to mate than losers, because of either or both winner/loser effects and differences in male competitiveness. We found that, when presented with a mating opportunity immediately following a contest, winning males were more likely to mate than were losing males. We also found that these differences had eroded within 7 days, such that there was no significant difference in the proportions of winners and losers that mated after that period. We concluded that the changes in mating behavior that we observed immediately after a contest were likely due to relatively short-term winner and loser effects, rather than any differences in the males' competitiveness, which would presumably be of longer duration.

Outcomes of agonistic interactions alter sheltering behavior in crayfish.

'Winner' and 'loser' effects have been demonstrated in a broad range of species, but such investigations are often limited to the effects of prior contest outcomes on future agonistic interactions. Much less is known about the impacts of winning or losing contests on other aspects of individual behavior, like courtship interactions and sheltering behavior. In this investigation, I examined the effect of prior contest outcomes on sheltering behavior in the crayfish Faxonius virilis. I predicted that winners of contests would spend less time inside shelters and more time exploring, while losers of contests would spend more time inside shelters and less time exploring. I compared individual sheltering behavior before and after staged dyadic encounters between competitively mismatched individuals. This experiment revealed strong effects on the behavior of contest losers, which showed significant increases in the amount of time spent inside the shelter immediately after the contest. However, there was no significant change in the sheltering behavior of contest winners. These results reinforce the idea that contest outcomes can affect individual behaviors other than agonistic behavior, and suggest that losing a contest may motivate individual crayfish to engage in less-risky behavior, at least for a brief period after the contest.

Behavioral Auditory Processing in Children and Young Adults with Autism Spectrum Disorder.

BACKGROUND: Auditory-processing deficits are common in children and adults who are diagnosed with autism spectrum disorder (ASD). These deficits are evident across multiple domains as exhibited by the results from subjective questionnaires from parents, teachers, and individuals with ASD and from behavioral auditory-processing testing. PURPOSE: Few studies compare subjective and behavioral performance of adults and children diagnosed with ASD using commercially available tests of auditory processing. The primary goal of the present study is to compare the performance of adults and children with ASD to age-matched, neurotypical peers. The secondary goal is to examine the effect of age on auditory-processing performance in individuals with ASD relative to age-matched peers. RESEARCH DESIGN: A four-group, quasi-experimental design with repeated measures was used in this study. STUDY SAMPLE: Forty-two adults and children were separated into four groups of participants: (1) 10 children with ASD ages 14 years or younger; (2) 10 age-matched, neurotypical children; (3) 11 adolescents and young adults with ASD ages 16 years and older; and (4) 11 age-matched, neurotypical adolescents or young adults. DATA COLLECTION AND ANALYSIS: Data from each participant were collected in one test session. Data were analyzed with analysis of variance (ANOVA), repeated measures ANOVA, or nonparametric analyses. Effect sizes were calculated to compare performance between those with ASD and those who were neurotypical within each age group. RESULTS: Across all the questionnaires and the majority of the behavioral test measures, participants with ASD had significantly poorer ratings or auditory-processing performance than age-matched, neurotypical peers. Adults had more favorable performance than children on several of the test measures. Medium to large effect sizes corroborated the significant results. CONCLUSION: Overall, the questionnaires and behavioral tests used in this study were sensitive to detecting auditory-processing differences between individuals diagnosed with ASD and those who are considered neurotypical. On most test measures, children performed more poorly than adults. The findings in this study support that both children and adults with ASD exhibit auditory-processing difficulties. Appropriate school and work accommodations will be necessary to ensure appropriate access to speech in challenging environments.

Effects of Auditory Training on Electrophysiological Measures in Individuals with Autism Spectrum Disorder.

BACKGROUND: Identifying objective changes following an auditory training program is central to the assessment of the program's efficacy. PURPOSE: This study aimed (1) to objectively determine the efficacy of a 12-week auditory processing training (APT) program in individuals with autism spectrum disorder using auditory evoked potentials (AEPs) and (2) to identify the top central AEP predictors of the overall score on the Test of Auditory Processing Skills-3 (TAPS-3), the primary behavioral outcome measure of the APT program published in our earlier article. RESEARCH DESIGN: A one-group pretraining, posttraining design was used. STUDY SAMPLE: The sample included 15 children and young adults diagnosed with autism spectrum disorder. Participants underwent the APT program consisting of computerized dichotic training, one-on-one therapist-directed auditory training, and the use of remote microphone technology at home and in the classroom. DATA COLLECTION AND ANALYSIS: All participants underwent pre- and posttraining auditory brain stem responses (ABRs), complex auditory brain stem responses (cABRs), and auditory late responses (ALRs). Test results from ABRs and ALRs were grouped based on scores obtained in their dominant and nondominant ears. Paired t-tests were used to assess the efficacy of the training program, and least absolute shrinkage and selection operator regression was used to assess the relationship between ALRs and the TAPS-3 overall summed raw score reported in our earlier article. RESULTS AND CONCLUSIONS: When compared with pretraining results, posttraining results showed shorter ABR latencies and larger amplitudes. The cABRs showed decreased latencies of the frequency following waves, a reduction in pitch error, and enhancement of pitch strength and phase shift. ALR results indicated shorter latencies and larger amplitudes. Our earlier article showed that the TAPS-3 overall score was significantly higher after training. This study showed that the top three ALR predictors of TAPS-3 outcomes were P1 amplitude in the dominant ear, and N1 amplitude in the dominant and nondominant ears.

Effects of Auditory Training and Remote Microphone Technology on the Behavioral Performance of Children and Young Adults Who Have Autism Spectrum Disorder.

BACKGROUND: Individuals who have a normal pure-tone audiogram but are diagnosed with autism spectrum disorder (ASD) often exhibit poorer speech recognition and auditory processing when compared with neurotypical peers with normal pure-tone audiograms. PURPOSE: The purpose of this study was to determine the efficacy and effectiveness of a 12-week auditory processing training (APT) program that was designed to address the deleterious effects of background noise and auditory processing deficits that are common among individuals diagnosed with ASD. RESEARCH DESIGN: A repeated measures design was used. STUDY SAMPLE: The sample consisted of 15 high-functioning children and young adults who had a formal diagnosis of ASD and who were recruited from local clinics and school districts. INTERVENTION: Participants completed the 12-week APT program consisting of computerized dichotic training, one-on-one therapist-directed auditory training, and the use of remote microphone (RM) technology at home and in the classroom. DATA COLLECTION AND ANALYSIS: Participants completed a comprehensive test battery to assess general auditory processing skills, speech recognition in noise, acceptance of background noise, spatial processing, binaural integration abilities, self-perceived difficulties, and observed behaviors. Testing was conducted before (n = 15), immediately after (n = 15), and 12 weeks after (n = 7) the completion of the APT program. Paired t-tests, repeated measures analysis of variance, or nonparametric tests were used to analyze the data. RESULTS: On average, the APT program significantly enhanced general auditory processing abilities, including binaural integration and subjective listening abilities in the classroom. When the RM was used, significantly improved speech recognition and improved acceptance of background noise was measured relative to a condition with no technology. CONCLUSIONS: Following the APT program, the participants exhibited the greatest improvements in testing that required binaural integration and auditory working memory. The use of the RM technology was able to address the deleterious effects of noise on speech recognition in noise and acceptance of noise levels.

Learning in herbivorous insects: dispersing aphids spend less time evaluating familiar than novel non-host plant species.

For many organisms, dispersal may be a high-risk activity, and dispersers are likely to have behavioral, physiological, or other adaptations that increase the probability they will successfully settle in new habitat. Dispersing aphids, for example, are small-bodied, relatively weak flyers that must navigate through a complex landscape where non-host species may be much more common than suitable hosts are. While previous research has focused on how dispersing aphids locate and evaluate host species, little is known about how they interact with the non-host species they encounter while host searching. Here, I report on an experiment to test the hypothesis that dispersers of Aphis fabae spend less time evaluating non-host species with which they have had prior experience than novel non-host species. Aphids consistently spent less time in contact with familiar non-host species than novel non-host species, but the magnitude of this effect varied for different non-host species. Aphids that had previously encountered rose spent less time interacting with rose than with raspberry or goldenrod, and aphids that had previously encountered raspberry spent less time interacting with raspberry than with goldenrod. Aphids that had previously encountered goldenrod showed a less pronounced and statistically non-significant reduction in time spent interacting with goldenrod relative to either raspberry or rose. The ability to recognize previously encountered non-hosts may allow aphids to navigate more efficiently through an environment in which they face many more non-hosts than hosts, and therefore increase the probability that a disperser will ultimately locate and settle on an appropriate host plant.

The effects of food stoichiometry and temperature on copepods are mediated by ontogeny.

Climate change is warming the oceans, increasing carbon dioxide partial pressure and reducing nutrient recycling from deep layers. This will affect carbon (C) and phosphorus (P) availability in the oceans, thus, altering the balance between the nutrient content of consumers and their food resource. The combined effects of food quality and temperature have been investigated for adult copepods; however, nauplii, the early developmental stages of copepods, often far outnumber adults, grow more rapidly and have a higher phosphorus body content and demand than later life stages. Consequently, ontogeny may affect how copepods respond to the combined stressors of increasing temperature and altered food stoichiometry. We conducted temperature-controlled experiments (24, 28 and 32 °C) where Parvocalanus crassirostris was fed either a P-replete or a P-limited phytoplankton food source. Reduced survival of nauplii and copepodites at the highest temperature was ameliorated when fed P-replete food. At higher temperatures, copepodite growth remained stable, but internal C:P stoichiometry diverged in the direction of phytoplankton C:P, suggesting that increased temperature affected copepodite stoichiometric homeostasis. In contrast, naupliar P content increased with temperature and naupliar growth was P limited, suggesting nauplii required additional phosphorus at higher temperatures. We conclude that resource stoichiometry plays a key role in how copepod survival and growth are impacted by temperature, and that ontogeny mediates these responses. Our results suggest that as the extent of warming oceans and phytoplankton nutrient limitation increase, copepod survival and the growth of early life stages may decline.

Assistive technology evaluations: Remote-microphone technology for children with Autism Spectrum Disorder.

The goal of this study was to conduct assistive technology evaluations on 12 children diagnosed with Autism Spectrum Disorder (ASD) to evaluate the potential benefits of remote-microphone (RM) technology. A single group, within-subjects design was utilized to explore individual and group data from functional questionnaires and behavioral test measures administered, designed to assess school- and home-based listening abilities, once with and once without RM technology. Because some of the children were unable to complete the behavioral test measures, particular focus was given to the functional questionnaires completed by primary teachers, participants, and parents. Behavioral test measures with and without the RM technology included speech recognition in noise, auditory comprehension, and acceptable noise levels. The individual and group teacher (n=8-9), parent (n=8-9), and participant (n=9) questionnaire ratings revealed substantially less listening difficulty when RM technology was used compared to the no-device ratings. On the behavioral measures, individual data revealed varied findings, which will be discussed in detail in the results section. However, on average, the use of the RM technology resulted in improvements in speech recognition in noise (4.6dB improvement) in eight children, higher auditory working memory and comprehension scores (12-13 point improvement) in seven children, and acceptance of poorer signal-to-noise ratios (8.6dB improvement) in five children. The individual and group data from this study suggest that RM technology may improve auditory function in children with ASD in the classroom, at home, and in social situations. However, variability in the data and the inability of some children to complete the behavioral measures indicates that individualized assistive technology evaluations including functional questionnaires will be necessary to determine if the RM technology will be of benefit to a particular child who has ASD.

Personal FM systems for children with autism spectrum disorders (ASD) and/or attention-deficit hyperactivity disorder (ADHD): an initial investigation.

UNLABELLED: The goal of this initial investigation was to examine the potential benefit of a frequency modulation (FM) system for 11 children diagnosed with autism spectrum disorders (ASD), attention-deficit hyperactivity disorder (ADHD), or both disorders through measures of speech recognition performance in noise, observed classroom behavior, and teacher-rated educational risk and listening behaviors. Use of the FM system resulted in significant average improvements in speech recognition in noise for the children with ASD and ADHD as well as large effect sizes. When compared to typically functioning peers, children with ASD and ADHD had significantly poorer average speech recognition performance in noise without the FM system but comparable average performance when the FM system was used. Similarly, classroom observations yielded a significant increase in on-task behaviors and large effect sizes when the FM system was in use during two separate trial periods. Although teacher ratings on questionnaires showed no significant improvement in the average level of educational risk of participants, they did indicate significant improvement in average listening behaviors during two trial periods with the FM system. Given the significantly better speech recognition in noise, increased on-task behaviors, and improved teacher ratings of listening behaviors with the FM system, these devices may be a viable option for children who have ASD and ADHD in the classroom. However, an individual evaluation including audiological testing and a functional evaluation in the child's primary learning environment will be necessary to determine the benefit of an FM system for a particular student. LEARNING OUTCOMES: 1. The reader will be able to describe the potential benefit of FM systems for children with ASD and/or ADHD. 2. The reader will be able to identify on-task versus off-task listening behaviors in children with ASD and/or ADHD. 3. The reader will be able to explain the components of a successful pre-fit education program that may be necessary prior to fitting an FM system in children with ASD.

Induction of persistent colitis by a human commensal, enterotoxigenic Bacteroides fragilis, in wild-type C57BL/6 mice.

Enterotoxigenic Bacteroides fragilis (ETBF) causes diarrhea and is implicated in inflammatory bowel diseases and colorectal cancer. The only known ETBF virulence factor is the Bacteroides fragilis toxin (BFT), which induces E-cadherin cleavage, interleukin-8 secretion, and epithelial cell proliferation. A murine model for ETBF has not been characterized. Specific pathogen-free (SPF) C57BL/6J or germfree 129S6/SvEv mice were orally inoculated with wild-type ETBF (WT-ETBF) strains, a nontoxigenic WT strain of B. fragilis (WT-NTBF), WT-NTBF overexpressing bft (rETBF), or WT-NTBF overexpressing a biologically inactive mutated bft (rNTBF). In SPF and germfree mice, ETBF caused colitis but was lethal only in germfree mice. Colonic histopathology demonstrated mucosal thickening with inflammatory cell infiltration, crypt abscesses, and epithelial cell exfoliation, erosion, and ulceration. SPF mice colonized with rETBF mimicked WT-ETBF, whereas rNTBF caused no histopathology. Intestinal epithelial E-cadherin was rapidly cleaved in vivo in WT-ETBF-colonized mice and in vitro in intestinal tissues cultured with purified BFT. ETBF mice colonized for 16 months exhibited persistent colitis. BFT did not directly induce lymphocyte proliferation, dendritic cell stimulation, or Toll-like receptor activation. In conclusion, WT-ETBF induced acute then persistent colitis in SPF mice and rapidly lethal colitis in WT germfree mice. Our data support the hypothesis that chronic colonization with the human commensal ETBF can induce persistent, subclinical colitis in humans.

Molecular phylogeny reveals extensive ancient and ongoing radiations in a snapping shrimp species complex (Crustacea, Alpheidae, Alpheus armillatus).

Tropical marine habitats often harbor high biodiversity, including many cryptic taxa. Though the prevalence of cryptic marine taxa is well known, the evolutionary histories of these groups remain poorly understood. The snapping shrimp genus Alpheus is a good model for such investigations, as cryptic species complexes are very common, indicating widespread genetic diversification with little or no morphological change. Here, we present an extensive phylogeographic investigation of the diversified amphi-American Alpheus armillatus species complex, with geographic sampling in the Caribbean Sea, Gulf of Mexico, Florida, Brazil, and the tropical Eastern Pacific. Sequence data from two mitochondrial genes (16SrRNA and cytochrome oxidase I) and one nuclear gene (myosin heavy chain) provide strong evidence for division of the species complex into six major clades, with extensive substructure within each clade. Our total data set suggests that the A. armillatus complex includes no less than 19 putative divergent lineages, 11 in the Western Atlantic and 8 in the Eastern Pacific. Estimates of divergence times from Bayesian analyses indicate that the radiation of the species complex began approximately 10 MYA with the most recent divergences among subclades dating to within the last 3 MY. Furthermore, individuals from the six major clades had broadly overlapping geographic distributions, which may reflect secondary contact among previously isolated lineages, and have apparently undergone several changes in superficial coloration, which is typically the most pronounced phenotypic character distinguishing lineages. In addition, the extensive substructure within clades indicates a great deal of molecular diversification following the rise of the Isthmus of Panama. In summary, this investigation reflects substantial biodiversity concealed by morphological similarity, and suggests that both ancient and ongoing divergences have contributed to the generation of this biodiversity. It also underlines the necessity to work with the most complete data set possible, which includes comprehensive and wide-ranging sampling of taxa.

Distance communication of sexual status in the crayfish Orconectes quinebaugensis: female sexual history mediates male and female behavior.

Chemical communication plays an important role in mediating social interactions of many taxa, particularly arthropods. Many individuals communicate information about their reproductive status to potential mates through distance and/or contact pheromones, an ability that may be advantageous to both signalers and receivers. In this paper, we describe tests of two hypotheses on the role of distance communication in the reproductive behaviors of crayfish (Orconectes quinebaugensis). First, we hypothesized that male crayfish would show stronger attraction towards virgin females (females with no viable sperm) than towards non-virgin females because of the fitness costs (to males) associated with sperm competition. Second, we hypothesized that female crayfish should show differential responses to mature male signals depending on their own sexual history: virgin females should be more strongly attracted to male signals than should non-virgin females because they must mate at least once to be able to fertilize eggs in the spring. Data from two Y-maze experiments yielded support for both hypotheses: males were attracted to signals from virgin females, but not to signals from non-virgins. Likewise, virgin females were attracted to signals from males, but non-virgin females were not. We discuss our data in the context of the potential costs and benefits of mate searching and suggest that distance chemical communication of sexual status may be particularly advantageous when the costs of mate searching are high.

Genetic and morphological evidence for substantial hidden biodiversity in a freshwater crayfish species complex.

North America is a center of biodiversity for freshwater crayfish, with >300 described species, mostly in the family Cambaridae. However, the phylogenetic and phylogeographic relationships among these taxa are poorly understood, despite their ubiquitous occurrence in North American freshwater habitats. Here, we target the geographically widespread Orconectesvirilis and its sister taxa for genetic and morphological investigation. We used sequence data from two mitochondrial genes (16S rRNA and cytochrome oxidase I) and from one nuclear gene (glyceraldehyde-3-phosphate dehydrogenase), as well as morphological data from the male gonopod, to gain insights into phylogenetic relationships among individuals collected in the northeastern United States, where this taxon is considered to be invasive, and from Kansas. Our data reveal evidence for three cryptic species in our collections, in addition to O.virilis sensu stricto; all four clades are separated by both mitochondrial and nuclear sequence data. In addition, two of the newly discovered species, O.sp. nov. A and O.sp. nov. B, are distinguishable from O.virilis by significant differences in gonopod morphology (no data on gonopod morphology were available for O.sp. nov. C). O.sp. nov. A was collected at numerous sites in Massachusetts; additional sampling is required to determine if this species is native to New England. Two other taxa, O.sp. nov. B and O.sp. nov. C, were both collected from sites in eastern Kansas, and historically have probably been considered to be O.nais. In summary, this investigation indicates that this species complex may harbor a great deal of unknown biodiversity over the rest of its described range, and suggests that further attention to the phylogenetics and phylogeography of North American crayfishes may yield interesting insights into the evolution of biodiversity.

Cryptic biodiversity and phylogeographical patterns in a snapping shrimp species complex.

Recent investigations suggest that marine biodiversity may be much higher than earlier estimates, and an important hidden source of diversity in marine systems is the phenomenon of cryptic species complexes. Such complexes are informative models for research into the evolutionary processes that govern species compositions of marine fauna. The snapping shrimp genera Alpheus and Synalpheus are known to harbour large numbers of cryptic species; here, I characterize the genetic structure of the Alpheus armillatus species complex in the northern Caribbean, west Atlantic, and Gulf of Mexico using mitochondrial and nuclear sequence data. Over this geographical region, the complex harbours at least three lineages that are probable reproductively isolated species; all major lineages diverged subsequent to the close of the Isthmus of Panama. Only one lineage was present in the Gulf of Mexico, whereas outside the Gulf of Mexico there was no clear tendency for lineage dominance by geographical region, as most sites were populated by shrimp from at least two lineages. However, within each lineage, there was strong evidence of population genetic differentiation between geographical regions. All lineages showed strong signals of demographic expansion, and one lineage showed sharply reduced genetic diversity, suggestive of past population bottlenecks or recently founded populations with low gene flow from other sites. These results show that evolutionary processes leading to divergence and speciation have been common and recent in the snapping shrimp, and suggest that connectivity among shrimp populations may be limited.

Large differences between LINE-1 amplification rates in the human and chimpanzee lineages.

The genomic evolution and causes of phenotypic variation among humans and great apes remain largely unknown, although the phylogenetic relationships among them have been extensively explored. Previous studies that focus on differences at the amino acid and nucleotide sequence levels have revealed a high degree of similarity between humans and chimpanzees, suggesting that other types of genomic change may have contributed to the relatively large phenotypic differences between them. For example, the activity of long interspersed element 1 (LINE-1) retrotransposons may impose significant changes on genomic structure and function and, consequently, on phenotype. Here we investigate the relative rates of LINE-1 amplification in the lineages leading to humans, bonobos (Pan paniscus), and chimpanzees (P. troglodytes). Our data indicate that LINE-1 insertions have accumulated at significantly greater rates in bonobos and chimpanzees than in humans, provide insights into the timing of major LINE-1 amplification events during great ape evolution, and identify a Pan-specific LINE-1 subfamily.