By using cytogenetic analysis of larval polytene chromosomes from small samples of the Simulium arcticum complex of black flies (Diptera: Simuliidae) at the Coeur d'Alene River in northern Idaho in 2004 and 2005 we discovered a population that consisted of individuals having sex chromosomes characteristic of S. saxosum, S. arcticum s. s. and combinations of the two. Most taxa of the S. arcticum complex can be identified only on the basis of their well differentiated sex chromosomes, and the presence of larvae having species specific and combinational sex chromosome types presented us with a unique opportunity to further investigate this rare event. This variety of sex chromosome types could be explained if (1) sex-chromosomes in S. saxosum were operating autosomally in S. arcticum s. s. and vice-versa, (2) the combinational types were formed as a result of hybridization or (3) the population was in genetic equilibrium suggesting a unique entity. The latter possibility could be the remnant of an incipient speciation event. We returned to the Coeur d'Alene in the springs of 2009 and 2010 and made more extensive collections. We analyzed all types present for sex chromosome diversity, frequencies of sex chromosome types, tests of Hardy-Weinberg equilibrium for sex chromosomes and the autosomal polymorphism IS-1, and the extent of chromosome pairing and chromocenter morphology between S. saxosum, S. arcticum s.s. and combinational types. Finally, we analyzed additional larvae of the S. arcticum complex from three sites to the west and four sites to the east of the Coeur d'Alene River to determine the geographic distribution of all types. There is no evidence for alternative sex chromosome types of S. saxosum and S. arcticum s. s. acting autosomally, nor is there evidence for hybridization between S. saxosum and S. arcticum s. s. We therefore conclude that the population at the Coeur d'Alene River may be the remnant of a population that gave rise to S. saxosum to the west and to S. arcticum s. s. to the east. This may be a natural example of a remnant population whose types have experienced “mating trials” of different combinations of sex chromosome types that subsequently gave rise to the described siblings via incipient speciation.

Important life history traits of animals may parallel those of their food sources, a factor that plays out at multiple trophic levels, potentially influenced by sexual and temporal variation. Here I evaluate the role of three variables in a system featuring a pair of alternative host plants, a herbivore, and its principal primary parasitoid. My test system consists of the fern-feeding moth Herpetogramma theseusalis (Crambidae) and its principal enemy, the parasitoid wasp Alabagrus texanus (Braconidae), which depend on two distantly related host plants, sensitive Onoclea sensibilis (Dryopteridaceae) and marsh Thelypteris palustris (Thelypteridaceae) ferns. I measured the effects of host plant, sex and yearly variation on several aspects of the mass and development times of the moth and wasp on the two host plants. Although the timing of pupation and eclosion, and length of pupal period, varied from year to year, both the moth and wasp often varied in the same way on the two host plants, with faster development times offset by differences in size. However, intersexual differences in performance by both moth and wasp on time and size-related variables usually exceeded differences in performance on the two host plants, in spite of the sizeable phylogenetic distance between them. Despite their intimate relationship, moth and wasp responses to size and temporal variables differed in several instances, including pupation date, time as a pupa and conversion of pupal to adult biomass. In general, the moths responded more strongly than the wasps to these variables.

The diversity of ground beetles in relation to habitat type was investigated in west-central Illinois from May to Oct. 2005 and 2006 using pitfall traps in six habitats: (1) prairie burned in 2004, (2) prairie burned in 2005, (3) early successional forest, (4) oak-hickory forest burned in 2004, (5) oak-hickory forest burned in 2005 and (6) oak-hickory forest burned in 2006. A total of 2712 ground beetles representing 28 genera and 54 species were collected. A multi-response permutation procedure showed significant differences in ground beetle assemblages among habitat types. Nonmetric multidimensional scaling and analysis of similarity supported the findings of MRPP. Indicator species analysis found significant habitat associations for seven species of carabids in 2005 and eight species in 2006. Forest habitats generally had lower species richness than expected based on rarefaction. The effects of fire on prairie carabid assemblages and detrimental effects on individual species appeared to be short-lived. There was little difference in carabid faunas inhabiting oak-hickory stands with different burn histories, but early successional hardwood forest fragments harbored several carabid indicator species.

Native grass conservation buffers established for grassland birds require periodic disturbance, but disturbance of vegetation and soil may increase abundance and activity of imported fire ants (Solenopsis sp.). This is a concern because fire ants are invasive, often respond positively to disturbance and can be a major cause of nest losses in grassland birds. We experimentally tested if fire ant mound density and foraging activity increased after burning and disking in native grass buffers. In 2008, fall disking increased mound density and foraging activity during the first growing season post-disturbance, but burning did not. In 2009, disking had no effect, but effects of disking the previous season persisted into the second growing season. Prescribed fire, which tends to maintain or increase perennial grass cover, may be a better option than disking for managing native grass buffers where fire ant densities are high.

Prairie restorations are increasingly common throughout the central United States. However, we continue to have little information about which planted species become successfully established, or about the factors potentially limiting establishment. We used a combination of site surveys, field tests and germination testing to examine these issues. We surveyed thirty 4 to 6 y old Conservation Reserve Program (CRP) plantings to quantify the likelihood that planted native species can be found 4–6 y after planting. We then selected a subset of species that had been planted in the CRP sites for use in germination tests and field tests quantifying emergence and seedling survival. We found that nearly one third of the species planted in CRP sites failed to become established and that grasses were more likely to be successful than legumes or nonleguminous forbs. We also found that species with low establishment in the CRP sites often had low emergence rates in the field experiment and low germination rates in germination testing despite differences in seed origin and planting year. Our results suggest that germination may be a major limiting factor in the establishment of some tallgrass prairie species.

The ability of species to establish and persist in multiple habitats is of increasing importance given ecotone shifts following climate change. We examined a sedge (Carex blanda) that primarily occurs in woodlands in Kansas but is reported at low frequency in grasslands. At a Kansas, USA site, we found C. blanda occurred at similar densities across woodland, edge and grassland habitats. Plants differed in morphology: grassland plants were often broader and shorter than woodland plants. We transplanted cloned woodland plants into woodland, edge and grassland habitats. Transplanted plants developed similar height to naturally occurring plants, showing a plastic response. Further, seed number per plant was highest for woodland plants transplanted to grasslands. Both naturally occurring and transplanted plants growing in the grassland also had low disease incidence, suggesting that pathogen presence is affected more by habitat than plant origin. Since light differed greatly among the habitats, we grew cloned plants from each habitat in low and high light in a growth chamber. Regardless of origin, high light plants were broader and shorter than plants growing at low light, again illustrating plasticity. Finally, we examined herbarium records. Ninety percent of Kansas specimens occurred in woodland or edge habitat. Although collection biases are possible, these results suggest a primarily woodland habitat of this species in Kansas. Our results showing “woodland” plants thriving in grasslands illustrates the broad adaptability of this species and raises cautions on simplistic interpretations of habitat distributions.

Due to the paucity of long-term fire chronologies in the upper Midwest, we studied basal cross-sections dating back to 1822 and the impacts of recent fire suppression in pine and oak stands on the Menominee Indian Reservation in northeast Wisconsin. A total of 93 fire events with a fire-return interval (FRI) of 5.9–17.7 y were recorded across all stands before fire suppression activities in 1935. After 1935, we recorded 29 fires. Most stands have only burned 0–3 times since 1935, and only four of 16 stands yielded enough fire years to calculate FRIs. Superposed Epoch Analysis (SEA) determined significantly lower Palmer Drought Severity Index (PDSI) values 1 y before individual fire years. Fire wounding occurred primarily in the dormant season and average tree diameter at time of wounding ranged from 7–30 cm. Current forest composition was dominated by white pine (Pinus strobus L.) and red maple (Acer rubrum L.) overstories, whereas seedlings and saplings were predominantly eastern hemlock (Tsuga canadensis (L). Carrière), witch-hazel (Hamamelis virginiana L.) and sugar maple (A. saccharum Marsh.). Tree species recorded on similar soils in 19th Century General Land Office surveys were mainly aspen (Populus), white pine and eastern hemlock. We conclude that the combination of logging and decreased fire occurrence over the past century resulted in a compositional shift from historic aspen, pine and oak forests towards later successional northern hardwoods.

Since European colonization and subsequent commercialization of Appalachian medicinal and edible plants, millions of kilograms of plant material have been extracted from our forests, with little effort to manage these species as natural resources. Roots and rhizomes of black cohosh, a native Appalachian forest herb, are extensively harvested for treatment of menopausal symptoms. As nearly all cohosh sold commercially is collected from natural populations, the potential for harvest impacts is considerable. To better understand wild-harvest impacts and the likelihood of post-harvest recovery, we studied the effects of 2 to 4 y of experimental harvest on natural black cohosh populations in the George Washington-Jefferson National Forest in southwest Virginia. After 2 to 3 y of intense harvest (66% plant removal), we found significant reductions in foliage area, stem production, and mean and maximum plant height. The effects of moderately intense harvest (33%) were less clear, producing growth measures between, yet not significantly different from, control (non-harvest) and intensively harvested plots. After three successive years of experimental harvest, harvest treatments were terminated to assess population regrowth. Populations experiencing intensive harvest showed no evidence of recovery after 1 y. Results suggest that black cohosh is highly responsive to harvest intensity and that low to moderate harvest intensities and/or longer recovery periods will be necessary for prolonged and sustainable harvests at our study site. While this study has increased our understanding of harvest impacts on black cohosh, continued assessment is needed to determine the sustainability of low to moderate harvest levels and minimum recovery periods necessary for population reestablishment.

Exotic earthworm species that have traditionally been used for composting are purportedly intolerant of low temperatures, which may explain why they are rarely found outside of compost bins in temperate zones of North America. In contrast, numerous exotic European earthworm species have invaded previously earthworm-free temperate forests of North America where they impact native forest communities and ecosystem processes. A European species, Dendrobaena veneta, has recently become prevalent in the vermicomposting and bait industries, and its European origins and anecdotal reports of cold tolerance suggest that this species has the potential to become established in northern climates outside of its native range. Here we compare the survivorship of traditionally used composting species (Eisenia fetida and Perionyx excavatus) to D. veneta, and to a well established invasive European earthworm species (Lumbricus rubellus) at a low temperature (1.5 C) and room temperature (18 C), as a means of assessing the invasiveness of these species. Additionally, we compared the effect of this cold temperature treatment on the number of hatchlings that emerged from E. fetida and D. veneta cocoons. Adult earthworms exhibited near-100% survival in the room-temperature treatment, but survivorship varied appreciably among species in the low-temperature treatment. Perionyx excavatus and E. fetida mortality was similar, and each was greater than that of D. veneta, which was similar to L. rubellus. Dendrobaena veneta cocoons produced more hatchlings than E. fetida overall, and the number of hatchlings decreased in the low-temperature treatment relative to the room-temperature treatment for both species. When temperature corrected hatching rates were examined, the number of hatchlings was still less in the low-temperature treatment relative to the room-temperature treatment, suggesting embryonic mortality and not simply slowed development. Collectively, these results suggest that D. veneta shows greater cold tolerance than E. fetida, a trait that may increase its success as an invader.

Foraging behavior of snails is affected by competition and risk of predation, both of which can be detected by chemical cues in the water. Freshwater snails are able to detect and respond to kairomones, from predators, and chemical cues, such as alarm cues, from other snails. Invasive species, such as the Chinese mystery snail (Cipangopaludina chinensis), are known to affect native species through competition and predation. This study examines the effects of competition and predation risks on the feeding rate of Helisoma trivolvis. Higher densities of competitors cause the snails to increase their feeding rate compared to no competition and low densities of competitive organisms. Presence of crayfish predators causes the snails to decrease their feeding rate and masks the effects of competitor density and type on the feeding rate. This study found no significant difference in feeding rates for the different treatments between the predation and crushed snails experiments, suggesting kairomones are more influential than alarm cues in altering foraging behavior. Despite the effects of Chinese mystery snails on the feeding rate of H. trivolvis, the invasion of Chinese mystery snails is likely to alter the community structure by consuming more algae and possibly increasing the feeding rate of native snails.

Zebra mussel presence and lake water calcium concentrations were compared to determine if a calcium concentration threshold exists which might preclude colonization of zebra mussels in Michigan inland lakes. The shallow littoral zones of nine northern Michigan inland lakes with calcium concentrations near 28.3 mg/L and considered to have had potential zebra mussel introductions through recreational boating were studied. A survey of native unionids was carried out in the lakes for the purpose of establishing a species inventory list for each lake. Zebra mussel densities were determined for lakes where zebra mussels were detected. Water samples were collected and calcium concentrations determined for each study lake. In five softwater lakes (lakes with calcium concentrations <28.3 mg/L), zebra mussels were not found. Zebra mussels had colonized three of four lakes where calcium concentrations were >28.3 mg/L. Five unionid species were found in seven of the nine lakes surveyed. Unionids were present in four of five lakes where calcium concentrations <28.3 mg/L and where zebra mussels were not detected suggesting a possible unionid refuge from zebra mussel induced mortality and/or extirpation in softwater lakes.

The shrimp Macrobrachium ohione (Decapoda, Caridea) was once numerous in the Mississippi River System (MRS) as far north as the Missouri and lower Ohio Rivers but is now abundant only within the lower Mississippi and Atchafalaya Rivers. Adult M. ohione live and breed in fresh water, but larval development occurs in brackish and marine waters, a life history pattern termed amphidromy. A downstream female “hatching” migration may ensure that the stage-1 larvae reach the required salinity in time for the critical molt to stage-2 (first feeding larval stage). This study tested the hypothesis that embryo-bearing females deliver larvae to the estuaries of the Mississippi and Atchafalaya Rivers in Louisiana. To test the prediction of a downstream migration, this investigation examined the reproductive condition and the spatial-temporal distribution of reproductive-sized females during 2008 and 2009. Shrimps were collected by trapping at downstream (Pass A Loutre, Atchafalaya Delta) and upstream (St. Francisville, Butte La Rose) locations within the Mississippi and Atchafalaya Rivers, respectively. During M. ohione's reproductive season, a significantly larger proportion of females incubating embryos at any stage of development were observed downstream in the Atchafalaya River (AR) but not in the Mississippi River (MR). However, in the MR, a positive association between the proportion of females incubating near-hatching embryos and the downstream sample site was found in both years. In the AR, a similar association was found in 2009 but not in 2008. Females with near-spawning ovaries were positively associated with the downstream sites in the MR in 2009 and the AR in 2008. During the reproductive season, females in both the AR and MR were observed with near-spawning ovaries while simultaneously incubating near-hatching embryos. Thus, females may produce multiple broods during the reproductive season. In general, relative abundance (Catch Per Unit Effort) of reproductive-sized females was higher at downstream sites during the reproductive season. However, the predicted seasonal increase into downstream sites was statistically significant only in the AR in 2008. Overall, results of this study support the hypothesis that reproductive females migrate downstream to deliver larvae to the sea in both the AR and MR. Nevertheless, the exact mechanics of the migrations may vary with river characteristics such as length and water velocity.

Fish species from temperate climates exhibit seasonal variation in reproduction triggered by abiotic variables such as day length and temperature. The sailfin molly Poecilia latipinna occupies habitats in the southern temperate zone in North America, but little is known about seasonal patterns in reproductive parameters such as female egg production and male sperm production, especially in spring-fed habitats. Males and females were collected monthly for 21 mo to: (1) examine the seasonal patterns in egg availability, (2) examine the relationship between female size and fecundity, (3) examine seasonal patterns in male sperm availability and (4) examine the relationship between male size and sperm availability. We found that reproductive investment varied seasonally in both males and females in a population of sailfin mollies occupying a spring-fed habitat. Because both egg and sperm production can be energetically costly, individuals may reduce costs associated with reproduction by reducing the availability of ready gametes during the time of year when mating is infrequent.

Environmental niche parameters of breeding ranges for two subspecies in the Orchard Oriole complex (Icterus spurius spurius and I. s. fuertesi) were characterized via ecological niche modeling. Niche models formulated from museum specimen collections largely agree with published breeding ranges of both taxa. Furthermore, our findings identify likely suitable habitat of migratory double breeding in I. s. spurius. Models successfully identify suitable habitat as illustrated by threshold dependent and independent statistical tests and overlap very little in geographic space. Principal component analysis (PCA) identifies two axes explaining 99.0% of variation in the climate data and reveals that each breeding range exhibits unique ecological characteristics, as they occur in nonoverlapping PCA space. Multivariate analysis of variance (MANOVA) identifies significant differences along both axes (PC1, P < 0.0001; PC2, P < 0.0001). A newly formulated metric for niche similarity (I) agrees with PCA and ENM results and, further, indicates that environmental niche differences are more likely a result of differences in habitat availability than habitat preference. Our results may indicate rapid change in environmental niche within the Orchard Oriole group as these taxa have been diverging for approximately 200,000 y. The Orchard Oriole group provides an example of niche lability that contrasts with evidence of niche conservatism between many other Mexican species pairs.

Species that undergo range expansions often exhibit a loss of genetic diversity in populations found at the leading edge of the expansion and show a genetic signal of isolation by distance. We examined the genetic consequences of range expansion on White-winged Dove populations, a species that is undergoing a range and possible demographic expansion in Texas. We genotyped five microsatellite loci and sequenced a segment of mitochondrial DNA and found that White-winged Doves do not exhibit a loss of genetic diversity in recently colonized areas or a genetic signal of a demographic expansion. However, we did find a slight signal of isolation by distance and range expansion based on both nuclear and mitochondrial markers. We suggest that high, multi-directional, ongoing gene flow has removed any loss of diversity caused by range expansion. A conservation implication of our findings is that species that exhibit rapid range expansions with high gene flow are likely to retain their evolutionary potential and resist the effects of environmental fluctuations.

Raccoon ecology is poorly understood in bottomland hardwood systems, despite the fact that bottomland forests are considered high-quality raccoon habitat. We radio-marked 41 raccoons during 2008–2009 and estimated seasonal space use and habitat selection in a bottomland hardwood forest located within the Atchafalaya floodway system in Louisiana. Space use varied seasonally, with home ranges and core areas largest during the breeding season. Forest openings were important when configuring seasonal home ranges, whereas habitat selection within home ranges varied seasonally. The composition of habitats within core use areas was similar to that of home ranges. We concluded that home range size was influenced by reproductive behaviors and seasonal food availability, whereas habitat selection was most influenced by spatio-temporal changes in seasonal food abundance. Raccoons used all available habitat types and landscape heterogeneity is likely important to raccoons when establishing home ranges in bottomland hardwood forest systems.

Riparian sign surveys near bridge crossings are commonly used to detect the presence of river otters. However, the efficacy of using such surveys for determining river otter presence has not been evaluated relative to habitat conditions. We conducted surveys to detect latrines (locations where scats are deposited in riparian areas) from reintroduced populations of river otters at 26 bridge-suites in northern Pennsylvania. A bridge-suite consisted of a bridge site, a random site and a selected site (i.e., high quality site based on several habitat variables), <2.5 km upstream or downstream from the bridge. Sites consisted of both shorelines along a 200-m section of stream or river. Site quality was determined by applying a modified Pattern Recognition model (PATREC) previously developed to provide a probabilistic assessment for predicting the occurrence of river otter latrines based on the presence or absence of certain riparian and riverine habitat features. Sites were surveyed in fall 2003 and spring 2004. Latrines were detected at 19 (73.1%) of the 26 bridge-suites. Of these 19 bridge-suites, 17 (65.3%) were positive for latrines in spring, 15 (57.7%) in the fall and 13 (50.0%) in both seasons. Among the 78 survey sites (i.e., 3 sites per bridge-suite), 32 (41.0%) were positive for latrines [21 sites (26.9%) in spring and 22 sites (28.2%) sites in fall]. Repeated measures logistic regression was used to assess the influence of the covariates season (spring or fall), type of site (i.e., site type: bridge, random or selected) and quality of site (site score) on the probability of detecting latrines. Two models were useful in describing the occurrence of a positive site (i.e., a site with ≥1 latrine), and both included site type as a variable. The odds of a selected site being positive ranged from 7.8 to 9.3 times the odds of random or bridge sites being positive. We concluded that monitoring the presence of river otters based on searching for latrines at bridge or random sites was considerably less effective than by using the a priori selection of surveys areas based on riparian habitat features.

Resident fish exhibited higher short-term resiliency than did non-resident fish to a 100 y flood in a low-gradient stream. In Jun. 2008, a substantial flood (400% higher than mean daily discharge) occurred in the Big Manistee River watershed in Michigan. Pre- and post-flood fish communities were sampled at two sites on Bear Creek, a 4th order tributary of the Big Manistee River. One site was low-gradient and dominated by sand; the second site was higher gradient and dominated by large woody debris and fine gravel. At both sites, post-flood fish communities were similar to pre-flood communities (Morisita's Index (I_m) ≈ 0.8), especially for resident fish (I_m ≈ 0.95). Total Catch Per Unit Effort (CPUE) of non-resident fish declined dramatically (5.2 to 1.4 fish per minute) in post-flood surveys, whereas CPUE of resident fish increased slightly (4.3 to 4.7) post-flood. Individual species response was site-dependent and mixed: CPUE of mottled sculpin and burbot increased post-flood, whereas CPUE of other resident species decreased. Resident non-native (i.e., rainbow trout) and non-resident non-native salmonids (i.e., Chinook salmon) experienced the most negative response, suggesting life-history traits of native fish encompass evolutionary adaptations to better persist through extreme disturbance events as compared to non-native salmonids.

Collections of the earwigfly, Merope tuber Newman (Mecoptera: Meropeidae), have been sparse. Little is known about the life history, behavior or ecology of this elusive mecopteran species. Found only in North America, within eastern forests, increased trapping records have recently demonstrated a previously undetected western expansion for this species. This paper is the first documentation of M. tuber on carrion and in Greene County, Ohio, USA and the second record of specimens collected in western Ohio. Four specimens (two males and two females) were caught using glue traps during Aug. 2010 at a carrion resource, a first trapping occurrence of this type for M. tuber.

We report the Silver Lamprey (Ichthyomyzon unicupis) from Arkansas for the first time. Fifteen adult I. unicuspis attached to paddlefish (Polyodon spathula) were collected in Apr. 2005 from the White River near the confluence of the Black River, Independence and Jackson counties. Twelve (80%) of the I. unicuspis possessed 3 teeth (including the apex) in the anterior row, while the other 3 had 4 teeth in their anterior row; unicuspid teeth arrangement in the lateral row were 3 3 for 11 (73%) lampreys while 4 had 4 4 teeth in the lateral row. Two additional specimens collected in Apr. 1972 and May 1998 from the Buffalo and White rivers in Marion and Prairie counties, respectively, and originally identified as Chestnut Lampreys (Ichthyomyzon castaneus), were re-examined and identified as I. unicuspis. The addition of I unicuspis to the lamprey fauna of Arkansas brings to five the number of species currently occurring in the state.

The discovery and temporal persistence of xanthic phenotypes are reported for an isolated population of the twoline pupfish Cyprinodon bifasciatus, a species endemic to the Cuatro Ciénegas basin, México. During four observations over a 19 mo period, the Escobedita population of C. bifasciatus was found to harbor a low but stable frequency of xanthic individuals (recorded range 3.3–3.7%). Persistence of xanthic phenotypes in this system could reflect relaxed predation pressure, genetic drift in a small population, benign to favorable sexual selection or some combination of these factors. This population provides an exceptional natural laboratory for investigation of evolutionary influences on the frequency of xanthic variants in wild populations.