Publications by EEOB faculty July 1 - July 31

July 24, 2015
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DNA microsatellite analysis of sporophytes of the short-lived moss Physcomitrium pyriforme reveals a predominantly self-fertilizing mating pattern

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Robert A. Klips. 2015. The Bryologist 118(2):200-211. doi: http://dx.doi.org/10.1639/0007-2745-118.2.200

Abstract

Physcomitrium pyriforme (Funariaceae) is a monoicous moss with the potential for producing sporophytes either via outcrossing or intra-gametophytic self-fertilization. A core set of microsatellite markers was identified for use in population genetic studies of this species, and employed to ascertain its mating patterns. An initial collection of 88 sporophytes gathered from widely separated locations in a meadow in central Ohio, U.S.A. was screened for genetic uniformity based on trnL-F DNA sequences, and found to display considerable heterogeneity. Fifty-three members of the largest clearly defined clade were selected for genotyping at 6 variable microsatellite loci having expected heterozygosities ranging from 0.11 to 0.70. Fifty-two individuals (98.2%) were homozygous at all 6 loci, strongly indicative of self-fertilization. Only one individual (1.8%) appeared to be an outcrossed sporophyte, being heterozygous at 4 loci. Twenty-three samples that constituted a second well-marked clade displayed complex microsatellite genotypes strongly suggestive of a polyploid cytotype that, although not readily amenable to further analysis, is also not inconsistent with the predominantly selfing mating pattern exhibited by the 53 others. Male and female branches within gametophyte stems were observed to develop simultaneously or nearly so, and in 4 dense moss clusters within which samples of 8 gametophytes were genotyped, all 8 were found to be identical within each cluster. These results indicate that the overall mating pattern is predominantly selfing, and suggest that the species reproduces principally in what is, in effect, a clonal fashion, via the union of genetically identical gametes. This may be occurring both within and between gametophytes.

Klips Lab


Post-embryonic development in the mite suborder Opilioacarida, with notes on segmental homology in Parasitiformes (Arachnida)

Hans Klompen, Ma. Magdalena Vázquez, Leopoldo Ferreira de Oliveira Bernardi. 2015. Experimental and Applied Acarology. 10.1007/s10493-015-9939-7

Abstract

In order to study homology among the major lineages of the mite (super)order Parasitiformes, developmental patterns in Opilioacarida are documented, emphasizing morphology of the earliest, post-embryonic instars. Developmental patterns are summarized for all external body structures, based on examination of material in four different genera. Development includes an egg, a 6-legged prelarva and larva, three 8-legged nymphal instars, and the adults, for the most complete ontogenetic sequence in Parasitiformes. The prelarva and larva appear to be non-feeding. Examination of cuticular structures over ontogeny allows development of an updated model for body segmentation and sensillar distribution patterns in Opilioacarida. This model includes a body made up of a well-developed ocular segment plus at most 17 additional segments. In the larvae and protonymphs each segment may carry up to six pairs of sensilla (setae or lyrifissures) arranged is distinct series (J, Z, S, Sv, Zv, Jv). The post-protonymphal instars add two more series (R and Rv) but no extra segments. This basic model is compatible with sensillar patterns in other Parasitiformes, leading to the hypothesis that all taxa in that (super)order may have the same segmental ground plan. The substantial segmental distortion implied in the model can be explained using a single process involving differential growth in the coxal regions of all appendage-bearing segments.

Acarology Lab


Research Summary: Dreissenid Mussel Impacts On Plankton Dynamics In Western Lake Erie

Long Jiang, Meng Xia, Stuart A. Ludsin, Edward S. Rutherford, Doran M. Mason, Jose R. Marin Jarrin, Kevin L. Pangle. 2015. Lake Scientist.

Abstract

The ability to describe the distribution and dynamics of plankton communities can benefit both our understanding and management of aquatic ecosystems. For example, indices of plankton community composition and dynamics have been used to track environmental changes in both freshwater and marine ecosystems, as well as assess ecosystem health (e.g., Allinger and Reavie, 2013; Lugoli et al., 2012). Likewise, because higher consumers such as fish depend on plankton as prey during one or more life stages, long-term fisheries dynamics have been linked to shifts in the plankton community (e.g., Beaugrand et al., 2003).

Aquatic Ecology Lab


Reproductive sharing in relation to group and colony-level attributes in a cooperative breeding fish

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Abstract

The degree to which group members share reproduction is dictated by both within-group (e.g. group size and composition) and between-group (e.g. density and position of neighbours) characteristics. While many studies have investigated reproductive patterns within social groups, few have simultaneously explored how within-group and between-group social structure influence these patterns. Here, we investigated how group size and composition, along with territory density and location within the colony, influenced parentage in 36 wild groups of a colonial, cooperatively breeding fish Neolamprologus pulcher. Dominant males sired 76% of offspring in their group, whereas dominant females mothered 82% of offspring in their group. Subordinate reproduction was frequent, occurring in 47% of sampled groups. Subordinate males gained more paternity in groups located in high-density areas and in groups with many subordinate males. Dominant males and females in large groups and in groups with many reproductively mature subordinates had higher rates of parentage loss, but only at the colony edge. Our study provides, to our knowledge, the first comprehensive quantification of reproductive sharing among groups of wild N. pulcher, a model species for the study of cooperation and social behaviour. Further, we demonstrate that the frequency of extra-pair parentage differs across small social and spatial scales.

Hamilton Lab | Gibbs Lab
 


Motivation but not body size influences territorial contest dynamics in a wild cichlid fish

Constance M. O'Connor, Adam R. Reddon, Isaac Y. Ligocki, Jennifer K. Hellmann, Kelly A. Garvy, Susan E. Marsh-Rollo, Ian M. Hamilton, Sigal Balshine. 2015. Animal Behaviour 107:19-29. doi:10.1016/j.anbehav.2015.06.001

Abstract

We studied contests in wild free-living Neolamprologus pulcher, a cooperatively breeding fish. Males were briefly removed from territories, and then engaged in contests with usurping males. The relative size difference between the males had no effect on contest dynamics or outcome. Perceived resource value influenced male aggression. More aggressive fish were more likely to win contests.

Hamilton Lab


Ten+ years gone: Continued degradation of offshore planktonic communities in U.S. waters of Lake Erie's western and central basins (2003–2013)

Douglas D. Kane,Stuart A. Ludsin,Ruth D. Briland,David A. Culver,Mohiuddin Munawar. 2015. Journal of Great Lakes Research. In Press. doi:10.1016/j.jglr.2015.06.002

Abstract

Mounting evidence exists to indicate that Lake Erie is once again experiencing eutrophication. Such signs include increases in both the incidence of harmful algal blooms in the western basin and the re-emergence of large hypoxic areas in bottom waters of the central basin. Towards further assessing Lake Erie's health and the degree to which this ecosystem has become more eutrophic, we calculated a Planktonic Index of Biotic Integrity (P-IBI) for the western and central basins of Lake Erie during 2003–2013 and compared values to P-IBI values from previous periods of heightened eutrophy (1970) and the recovery from eutrophy (1995–2002). As expected, P-IBI scores in the eutrophic/hypereutrophic range (< 3) have predominated in both the western and central basins during 2003–2013. This decline in P-IBI scores (and hence, ecosystem health), however, has been more evident in the western basin than in the central basin.

Aquatic Ecology Lab


Continuous activity and no cycling of clock genes in the Antarctic midge during the polar summer

Alena Kobelkova, Shin G. Goto, Justin T. Peyton, Tomoko Ikeno, Richard E. Lee Jr., David L. Denlinger. 2015. Journal of Insect Physiology 81:90-96. doi:10.1016/j.jinsphys.2015.07.008

Abstract

The extreme seasonal shifts of day length in polar regions, ranging from constant light in the summer to constant darkness in the winter, pose an intriguing environment for probing activity rhythms and the functioning of circadian clocks. Here, we monitor locomotor activity during the summer on the Antarctic Peninsula and under laboratory conditions, as well as the accompanying patterns of clock gene expression in the Antarctic midge, the only insect endemic to Antarctica. Larvae and adults are most active during the warmest portion of the day, but at a constant temperature they remain continuously active regardless of the photoregime, and activity also persists in constant darkness. The canonical clock genes period, timeless, Clock, and vrille are expressed in the head but we detected no cycling of expression in either the field or under diverse photoregimes in the laboratory. The timekeeping function of the clock has possibly been lost, enabling the midge to opportunistically exploit the unpredictable availability of permissive thermal conditions for growth, development, and reproduction during the short summer in Antarctica.

Denlinger Lab