Descriptions of Three New Species of Nearctic Ctenopelmatinae (Hymenoptera: Ichneumonidae)

Three new species of Ctenopelmatinae are described from series obtained from rearings of yellowheaded spruce sawfly larvae, Pikonema alaskensis (Rohwer)

Synopsis of biological control for European fruit lecanium (Parthenolecanium corni) by parasitoids in North America and preliminary findings in hybrid hazelnut orchards

The European fruit lecanium, Parthenolecanium corni (Bouché) (Hemiptera: Coccidae) is a native insect to North America that causes significant damage to a large variety of fruit and ornamental trees worldwide. Here we provide a summary of the insect’s worldwide distribution and synopsis of all the Hymenopteran parasitoid wasps found to parasitize P. corni in North America from past literature. Additionally, a preliminary parasitoid survey of P. corni was carried out in two hybrid hazel (Corylus avellana × C. americana) plantings as hazelnuts represent a potential new crop for the region. European fruit lecanium, Parthenolecanium corni (Bouché) (Hemiptera: Coccidae), were collected over two sample days in July 2022 from two hybrid hazelnut plantings and their parasitoid fauna recorded. Parasitism rates of P. corni were estimated for hymenopterous parasitoids as well as the entomophagous fungus Ophiocordyceps clavulata (Ascomycota: Hypocreales: Ophiocordycipitaceae). Hymenopterous parasitoids were identified to the lowest taxonomic level possible. Relationships between parasitism rates (a binomial response) and P. corni density (the predictor variable) were analyzed using binomial generalized linear models. Parthenolecanium corni experienced high parasitism rates: 24.0% by hymenopteran parasitoids, and 63.4% by entomophagous fungi, giving a combined parasitism rate of 87.4%. Wasp and fungal parasitism exhibited contrasting density-dependent relationships. Plants with higher densities of scales experienced lower parasitism rates from hymenopteran parasitoids, but higher scale densities experienced higher parasitism rates from O. clavulata. Further research is needed over the whole adult female life stage of P. corni to learn more about these ecological relationships that could be of great benefit to hybrid hazelnut growers if P. corni becomes a significant pest

Bark Beetle (Coleoptera: Curculionidae: Scolytinae) Community Structure in Northeastern and Central Minnesota

Large-scale surveys of forest insects provide two distinct benefits: the detection of invasive and exotic species that cause millions of dollars of damage annually to forest and ornamental industries, and the addition of a wealth of species distribution and diversity information to the scientific community. We intensively surveyed the Northeast and East-central regions of Minnesota from 2006-2008 for invasive/exotic and native Scolytinae using Lindgren funnel traps baited with one of four lures (a/β-pinene, ultra-high-release ethanol [EtOH], EtOH+a-pinene, and Ips 3-part). We captured 16,841 scolytines (representing 25 genera) of which over 40% were Ips pini (Say) and Ips grandicollis (Eichhoff). We found two exotic Scolytinae, Scolytus multistriatus (Marsham) and Scolytus schevyrewi Semenov, both of which had previously been recorded in Minnesota. Two native species, Conophthorus coniperda (Schwarz) and Crypturgus pusillus (Gyllenhal), were reported for the first time in Minnesota. Non-metric multi- dimensional scaling and analysis of similarities indicate that lure types capture different Scolytinae communities, while year, weather pattern and region factors were not significant. We also report the seasonal phenology of the seven most abundantly captured species; Dendroctonus valens LeConte, Hylastes porculus Erichson, Hylurgops rugipennis pinifex (Fitch),I. grandicollis, I. pini, Orthotomicus caelatus (Eichhoff) and Pityophthorus spp. Eichhoff

Bark Beetle (Coleoptera: Curculionidae: Scolytinae) Community Structure in Northeastern and Central Minnesota

Large-scale surveys of forest insects provide two distinct benefits: the detection of invasive and exotic species that cause millions of dollars of damage annually to forest and ornamental industries, and the addition of a wealth of species distribution and diversity information to the scientific community. We intensively surveyed the Northeast and East-central regions of Minnesota from 2006-2008 for invasive/exotic and native Scolytinae using Lindgren funnel traps baited with one of four lures (a/β-pinene, ultra-high-release ethanol [EtOH], EtOH+a-pinene, and Ips 3-part). We captured 16,841 scolytines (representing 25 genera) of which over 40% were Ips pini (Say) and Ips grandicollis (Eichhoff). We found two exotic Scolytinae, Scolytus multistriatus (Marsham) and Scolytus schevyrewi Semenov, both of which had previously been recorded in Minnesota. Two native species, Conophthorus coniperda (Schwarz) and Crypturgus pusillus (Gyllenhal), were reported for the first time in Minnesota. Non-metric multi- dimensional scaling and analysis of similarities indicate that lure types capture different Scolytinae communities, while year, weather pattern and region factors were not significant. We also report the seasonal phenology of the seven most abundantly captured species; Dendroctonus valens LeConte, Hylastes porculus Erichson, Hylurgops rugipennis pinifex (Fitch),I. grandicollis, I. pini, Orthotomicus caelatus (Eichhoff) and Pityophthorus spp. Eichhoff

Discoveries from a Near-infrared Proper Motion Survey using Multi-epoch 2MASS Data

We have conducted a 4030-square-deg near-infrared proper motion survey using multi-epoch data from the Two Micron All-Sky Survey (2MASS). We find 2778 proper motion candidates, 647 of which are not listed in SIMBAD. After comparison to DSS images, we find that 107 of our proper motion candidates lack counterparts at B-, R-, and I-bands and are thus 2MASS-only detections. We present results of spectroscopic follow-up of 188 targets that include the infrared-only sources along with selected optical-counterpart sources with faint reduced proper motions or interesting colors. We also establish a set of near-infrared spectroscopic standards with which to anchor near-infrared classifications for our objects. Among the discoveries are six young field brown dwarfs, five "red L" dwarfs, three L-type subdwarfs, twelve M-type subdwarfs, eight "blue L" dwarfs, and several T dwarfs. We further refine the definitions of these exotic classes to aid future identification of similar objects. We examine their kinematics and find that both the "blue L" and "red L" dwarfs appear to be drawn from a relatively old population. This survey provides a glimpse of the kinds of research that will be possible through time-domain infrared projects such as the UKIDSS Large Area Survey, various VISTA surveys, and WISE, and also through z- or y-band enabled, multi-epoch surveys such as Pan-STARRS and LSST.Comment: To appear in the September 2010 issue of The Astrophysical Journal, Supplement Serie

A Census of the Young Cluster IC 348

We present a new census of the stellar and substellar members of the young cluster IC 348. We have obtained images at I and Z for a 42'x28' field encompassing the cluster and have combined these measurements with previous optical and near-infrared photometry. From spectroscopy of candidate cluster members appearing in these data, we have identified 122 new members, 15 of which have spectral types of M6.5-M9, corresponding to masses of 0.08-0.015 M_sun by recent evolutionary models. The latest census for IC 348 now contains a total of 288 members, 23 of which are later than M6 and thus are likely to be brown dwarfs. From an extinction-limited sample of members (A_V<=4) for a 16'x14' field centered on the cluster, we construct an IMF that is unbiased in mass and nearly complete for M/M_sun>=0.03 (<=M8). In logarithmic units where the Salpeter slope is 1.35, the mass function for IC 348 rises from high masses down to a solar mass, rises more slowly down to a maximum at 0.1-0.2 M_sun, and then declines into the substellar regime. In comparison, the similarly-derived IMF for Taurus from Briceno et al. and Luhman et al. rises quickly to a peak near 0.8 M_sun and steadily declines to lower masses. The distinctive shapes of the IMFs in IC 348 and Taurus are reflected in the distributions of spectral types, which peak at M5 and K7, respectively. These data provide compelling, model-independent evidence for a significant variation of the IMF with star-forming conditions.Comment: 47 pages, 14 figures, 3rd para of 4.5.3 has been added, this is final version in press at ApJ, also found at http://cfa-www.harvard.edu/sfgroup/preprints.htm

Prospecting in ultracool dwarfs : Measuring the metallicities of mid- and late-m dwarfs

© 2014. The American Astronomical Society. All rights reserved.Metallicity is a fundamental parameter that contributes to the physical characteristics of a star. The low temperatures and complex molecules present in M dwarf atmospheres make it difficult to measure their metallicities using techniques that have been commonly used for Sun-like stars. Although there has been significant progress in developing empirical methods to measure M dwarf metallicities over the last few years, these techniques have been developed primarily for early- to mid-M dwarfs. We present a method to measure the metallicity of mid- to late-M dwarfs from moderate resolution (R ∼ 2000) K-band (≃ 2.2 μm) spectra. We calibrate our formula using 44 wide binaries containing an F, G, K, or early-M primary of known metallicity and a mid- to late-M dwarf companion. We show that similar features and techniques used for early-M dwarfs are still effective for late-M dwarfs. Our revised calibration is accurate to ∼0.07 dex for M4.5-M9.5 dwarfs with -0.58 <[Fe/H] <+0.56 and shows no systematic trends with spectral type, metallicity, or the method used to determine the primary star metallicity. We show that our method gives consistent metallicities for the components of M+M wide binaries. We verify that our new formula works for unresolved binaries by combining spectra of single stars. Lastly, we show that our calibration gives consistent metallicities with the Mann et al. study for overlapping (M4-M5) stars, establishing that the two calibrations can be used in combination to determine metallicities across the entire M dwarf sequence.Peer reviewe

Spitzer/IRAC Photometry of M, L, and T Dwarfs

We present the results of a program to acquire photometry for eighty-six late-M, L, and T dwarfs using the Infrared Array Camera (IRAC) on the Spitzer Space Telescope. We examine the behavior of these cool dwarfs in various color-color and color-magnitude diagrams composed of near-IR and IRAC data. The T dwarfs exhibit the most distinctive positions in these diagrams. In M_5.8 versus [5.8]-[8.0], the IRAC data for T dwarfs are not monotonic in either magnitude or color, giving the clearest indication yet that the T dwarfs are not a one parameter family in Teff. Because metallicity does not vary enough in the solar neighborhood to act as the second parameter, the most likely candidate then is gravity, which in turn translates to mass. Among objects with similar spectral type, the range of mass suggested by our sample is about a factor of five (~70 M_Jup to ~15 M_Jup), with the less massive objects making up the younger members of the sample. We also find the IRAC 4.5 micron fluxes to be lower than expected, from which we infer a stronger CO fundamental band at ~4.67 microns. This suggests that equilibrium CH_4/CO chemistry underestimates the abundance of CO in T dwarf atmospheres, confirming earlier results based on M-band observations from the ground. In combining IRAC photometry with near-IR JHK photometry and parallax data, we find the combination of Ks, IRAC 3.6 micron, and 4.5 micron bands to provide the best color-color discrimination for a wide range of M, L, and T dwarfs. Also noteworthy is the M_Ks versus Ks-[4.5] relation, which shows a smooth progression over spectral type and splits the M, L, and T types cleanly.Comment: 32 pages, 18 figures, accepted for publication to ApJ: revised to adjust acknowledgments, add a few more references, and the correct typographical errors in text and tables 1 and 3 (note as binaries sds0926+5847 and 2ma1553+1532

Detection of brown dwarf-like objects in the core of NGC3603

We use near-infrared data obtained with the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope to identify objects having the colors of brown dwarfs (BDs) in the field of the massive galactic cluster NGC 3603. These are identified through use of a combination of narrow and medium band filters spanning the J and H bands, and which are particularly sensitive to the presence of the 1.3-1.5{\mu}m H2O molecular band - unique to BDs. We provide a calibration of the relationship between effective temperature and color for both field stars and for BDs. This photometric method provides effective temperatures for BDs to an accuracy of {\pm}350K relative to spectroscopic techniques. This accuracy is shown to be not significantly affected by either stellar surface gravity or uncertainties in the interstellar extinction. We identify nine objects having effective temperature between 1700 and 2200 K, typical of BDs, observed J-band magnitudes in the range 19.5-21.5, and that are strongly clustered towards the luminous core of NGC 3603. However, if these are located at the distance of the cluster, they are far too luminous to be normal BDs. We argue that it is unlikely that these objects are either artifacts of our dataset, normal field BDs/M-type giants or extra-galactic contaminants and, therefore, might represent a new class of stars having the effective temperatures of BDs but with luminosities of more massive stars. We explore the interesting scenario in which these objects would be normal stars that have recently tidally ingested a Hot Jupiter, the remnants of which are providing a short-lived extended photosphere to the central star. In this case, we would expect them to show the signature of fast rotation.Comment: 26 Pages, 8 Figures, Accepted for publication on Ap

Clouds in the Coldest Brown Dwarfs: FIRE Spectroscopy of Ross 458C

Condensate clouds are a salient feature of L dwarf atmospheres, but have been assumed to play little role in shaping the spectra of the coldest T-type brown dwarfs. Here we report evidence of condensate opacity in the near-infrared spectrum of the brown dwarf candidate Ross 458C, obtained with the Folded-Port Infrared Echellette (FIRE) spectrograph at the Magellan Telescopes. These data verify the low-temperature nature of this source, indicating a T8 spectral classification, log Lbol/Lsun = -5.62+/-0.03, Teff = 650+/-25 K, and a mass at or below the deuterium burning limit. The data also reveal enhanced emission at K-band associated with youth (low surface gravity) and supersolar metallicity, reflecting the properties of the Ross 458 system (age = 150-800 Myr, [Fe/H] = +0.2 to +0.3). We present fits of FIRE data for Ross 458C, the T9 dwarf ULAS J133553.45+113005.2, and the blue T7.5 dwarf SDSS J141624.08+134826.7B, to cloudless and cloudy spectral models from Saumon & Marley. For Ross 458C we confirm a low surface gravity and supersolar metallicity, while the temperature differs depending on the presence (635 [+25,-35] K) or absence (760 [+70,-45] K) of cloud extinction. ULAS J1335+1130 and SDSS J1416+1348B have similar temperatures (595 [+25,-45] K), but distinct surface gravities (log g = 4.0-4.5 cgs versus 5.0-5.5 cgs) and metallicities ([M/H] ~ +0.2 versus -0.2). In all three cases, cloudy models provide better fits to the spectral data, significantly so for Ross 458C. These results indicate that clouds are an important opacity source in the spectra of young cold T dwarfs, and should be considered when characterizing the spectra of planetary-mass objects in young clusters and directly-imaged exoplanets. The characteristics of Ross 458C suggest it could itself be regarded as a planet, albeit one whose cosmogony does not conform with current planet formation theories.Comment: Accepted for publication to ApJ: 18 pages, 11 figures in emulateapj forma