The eyes of stalk-eyed flies (Diopsidae) are positioned at the end of rigid peduncles ('stalks') protruding laterally from the head. Eye-stalk length varies within the family and, in some species, varies between males and females. Larger eye-stalks in males result from sexual selection for longer stalks, a trait that increases male reproductive success. In the present study, we examined whether an increase in eye-stalk length results in an adjustment of wing size and shape to deal with the burden of bearing an exaggerated 'ornament'. We compared wing morphology among ten species of stalk-eyed flies that differ in eye-span and the degree of sexual dimorphism. Mass-specific wing length differed between males and females in seven out of the ten species. Nondimensional wing shape parameters differed between the species (P < 0.001), but mostly did not differ between males and females of the same species. Dimorphism in eye-span closely correlated with dimorphism in wing length (r = 0.89, P < 0.001) and the correlation remained significant (r = 0.81, P = 0.006) after correcting for phylogenetic relationships. Once corrected for phylogenetic relatedness, the mass-specific wing length of males (but not females) was weakly correlated with mass-specific eye-span (r = 0.66, P = 0.042). We propose that the observed proportional increase in wing length associated with increased eye-span can facilitate aerial manoeuverability, which would otherwise be handicapped by the elevated moment of inertia imposed by the wider head.

BackgroundPolymorphisms of single amino acid repeats (SARPs) are a potential source of genetic variation for rapidly evolving morphological traits. Here, we characterize variation in and test for an association between SARPs and head shape, a trait under strong sexual selection, in the stalk-eyed fly, Teleopsis dalmanni. Using an annotated expressed sequence tag database developed from eye-antennal imaginal disc tissues in T. dalmanni we identified 98 genes containing nine or more consecutive copies of a single amino acid. We then quantify variation in length and allelic diversity for 32 codon and 15 noncodon repeat regions in a large outbred population. We also assessed the frequency with which amino acid repeats are either gained or lost by identifying sequence similarities between T. dalmanni SARP loci and their orthologs in Drosophila melanogaster. Finally, to identify SARP containing genes that may influence head development we conducted a two-generation association study after assortatively mating for extreme relative eyespan.ResultsWe found that glutamine repeats occur more often than expected by amino acid abundance among 3,400 head development genes in T. dalmanni and D. melanogaster. Furthermore, glutamine repeats occur disproportionately in transcription factors. Loci with glutamine repeats exhibit heterozygosities and allelic diversities that do not differ from noncoding dinucleotide microsatellites, including greater variation among X-linked than autosomal regions. In the majority of cases, repeat tracts did not overlap between T. dalmanni and D. melanogaster indicating that large glutamine repeats are gained or lost frequently during Dipteran evolution. Analysis of covariance reveals a significant effect of parental genotype on mean progeny eyespan, with body length as a covariate, at six SARP loci [CG33692, ptip, band4.1 inhibitor LRP interactor, corto, 3531953:1, and ecdysone-induced protein 75B (Eip75B)]. Mixed model analysis of covariance using the eyespan of siblings segregating for repeat length variation confirms that significant genotype-phenotype associations exist for at least one sex at five of these loci and for one gene, CG33692, longer repeats were associated with longer relative eyespan in both sexes.ConclusionAmong genes expressed during head development in stalk-eyed flies, long codon repeats typically contain glutamine, occur in transcription factors and exhibit high levels of heterozygosity. Furthermore, the presence of significant associations within families between repeat length and head shape indicates that six genes, or genes linked to them, contribute genetic variation to the development of this extremely sexually dimorphic trait.

The authors recently discovered that 15 out of the 421 flies measured in the above mentioned study were erroneously measured twice at different time points of the data collection process. Therefore the correct sample size for this analysis (without repeated sampling) should have been 406 flies. The 15 flies that were measured twice belonged to one species (Diasemopsis meigenii) and included 7 male flies and 8 females. A re-calculation of the entire statistical analysis, this time with the correct sample size confirmed that the inflated sample size for D. meigenii had negligible effect on statistical values and did not change any of the results or conclusions reported in the paper.For the sake of accuracy we provide the corrected averages for D. meigenii below and these should be used instead of the ones presented for D. meigenii (DM) in figure 4.The authors regret any inconvenience that might have resulted from this error. Means ± 1 SD of measurements from 20 males and 20 females of D. meigenii Diasemopsis meigeniiBody mass [mg] Wing length [mm] Eye span [mm] Wing area [mm 2 ] Males

Understanding the role of green space in urban-suburban landscapes is becoming critical for bird conservation because of rampant habitat loss and conversion. Although not natural habitat, golf courses could play a role in bird conservation if they support breeding populations of some native species, yet scientists remain skeptical. In 2003-2009, we measured reproduction of Eastern Bluebirds {Siala sialis) in Virginia on golf courses and surrounding reference habitats, of the type that would have been present had golf courses not been developed on these sites (e.g., recreational parks, cemeteries, agriculture land, and college campus). We monitored >650 nest boxes and 2,255 nest attempts {n = 1,363 golf course, n = 892 reference site). We used an information-theoretic modeling approach to evaluate whether conditions on golf courses affected timing of breeding, investment, or nest productivity compared with nearby reference sites. We found that Eastern Bluebirds breeding on golf courses reproduced as well as those breeding in other disturbed habitats. Habitat type had no effect on initial reproductive investment, including date of clutch initiation or clutch size (jc = 4 eggs). During incubation and hatching, eggs in nests on golf courses had higher hatching rates (80%) and brood sizes {x = 4.0 nestlings brood"') than nests on reference sites (75% hatching rate; x = 3.8 nestlings brood"'). Mortality of older nestlings was also lower on golf courses and, on average, golf course nests produced 0.3 more fledglings than nests on reference sites. Thus, within a matrix of human-dominated habitats, golf courses may support productive populations of some avian species that can tolerate moderate levels of disturbance, like Eastern Bluebirds. Éxito Reproductivo de Sialia sialis en Campos de Golf SuburbanosRESUMEN.-Comprender el papel del espacio verde en paisajes urbanos-suburbanos se está haciendo crítico para la conservación de las aves debido a la marcada pérdida y conversión de habitats. Aunque no son habitats naturales, los campos de golf podrían desempeñar un papel en la conservación de las aves si éstos sostienen poblaciones reproductoras de algunas especies nativas, pero los científicos son aun escépticos al respecto. En 2003-2009, medimos la reproducción de Siala sialis en campos de golf en Virgina y en ambientes circundantes de referencia correspondientes al tipo de habitat que habría estado presente si no se hubieran desarrollado los campos de golf en esos sitios (e.g., parques recreacionales, cementerios, áreas agricolas, campus universitario). Monitoreamos más de 650 cajas de anidación y 2255 intentos de anidación (n = 1363 en campos de golf, n = 892 en sitios de referencia). Empleamos un enfoque de modelamiento basado en teoría de la información para evaluar si las condiciones de los campos de golf afectaban el momento en que tenía lugar la reproducción, la inversión reproductiva o la productividad de los nidos en comparación con sitios de referencia cercanos. Encontramos que los individuos que se reproducen en...