Texas Forestry Paper No. 4

Computer reduces cruise-data compilation errorhttps://scholarworks.sfasu.edu/texas_forestry_papers/1005/thumbnail.jp

Sexual conflict and cryptic female choice in the black field cricket, Teleogryllus commodus

The prevalence and evolutionary consequences of cryptic female choice (CFC) remain highly controversial, not least because the processes underlying its expression are often concealed within the female reproductive tract. However, even when female discrimination is relatively easy to observe, as in numerous insect species with externally attached spermatophores, it is often difficult to demonstrate directional CFC for certain male phenotypes over others. Using a biological assay to separate male crickets into attractive or unattractive categories, we demonstrate that females strongly discriminate against unattractive males by removing their spermatophores before insemination can be completed. This results in significantly more sperm being transferred by attractive males than unattractive males. Males respond to CFC by mate-guarding females after copulation, which increases the spermatophore retention of both attractive and unattractive males. Interestingly, unattractive males who suffered earlier interruption of sperm transfer benefited more from mate guarding and guarded females more vigilantly than attractive males. Our results suggest that post-copulatory mate guarding has evolved via sexual conflict over insemination times rather than through genetic benefits of biasing paternity toward vigorous males, as has been previously suggested

Forestry Bulletin No. 6: Point-Sampling from Two Angles

Point-sampling is a valuable tool in the kit of the practicing forester. It is employed for permanent and temporary sampling and for growth studies. Since the concept of point-sampling is new in American forestry, different approaches have been employed to explain its application.https://scholarworks.sfasu.edu/forestrybulletins/1023/thumbnail.jp

Discovery of an introduced Florida Flagfish (\u3ci\u3eJordanella floridae\u3c/i\u3e) population in Coastal Mississippi

The recent discovery of Jordanella floridae (Florida Flagfish) in Harrison County, Mississippi represents the first known occurrence of the species in the state. Native along the Atlantic and Gulf Coasts of Florida from Jacksonville to Tallahassee, this species has been introduced outside of its range via aquarium introductions. We hypothesize that an aquarium introduction was also the source of the newly discovered population, which has persisted at the location since 2020. Multiple collections of the species have been taken from a small waterbody which has a direct connection to the Tchoutacabouffa River (25mm-47mm TL). While it is unknown if this represents the only population in the system, further surveys should be conducted to determine population numbers at the site of collection, the extent of the invasion within the Tchoutacabouffa, and the impact to the native fish fauna

Spatial Patterns and Sequential Sampling Plans for Estimating Densities of Stink Bugs (Hemiptera: Pentatomidae) in Soybean in the North Central Region of the United States

Stink bugs are an emerging threat to soybean (Fabales: Fabaceae) in the North Central Region of the United States. Consequently, region-specific scouting recommendations for stink bugs are needed. The aim of this study was to characterize the spatial pattern and to develop sampling plans to estimate stink bug population density in soybean fields. In 2016 and 2017, 125 fields distributed across nine states were sampled using sweep nets. Regression analyses were used to determine the effects of stink bug species [Chinavia hilaris (Say) (Hemiptera: Pentatomidae) and Euschistus spp. (Hemiptera: Pentatomidae)], life stages (nymphs and adults), and field locations (edge and interior) on spatial pattern as represented by variance–mean relationships. Results showed that stink bugs were aggregated. Sequential sampling plans were developed for each combination of species, life stage, and location and for all the data combined. Results for required sample size showed that an average of 40–42 sample units (sets of 25 sweeps) would be necessary to achieve a precision of 0.25 for stink bug densities commonly encountered across the region. However, based on the observed geographic gradient of stink bug densities, more practical sample sizes (5–10 sample units) may be sufficient in states in the southeastern part of the region, whereas impractical sample sizes (\u3e100 sample units) may be required in the northwestern part of the region. Our findings provide research-based sampling recommendations for estimating densities of these emerging pests in soybean

The Indirect Benefits of Mating with Attractive Males Outweigh the Direct Costs

The fitness consequences of mate choice are a source of ongoing debate in evolutionary biology. Recent theory predicts that indirect benefits of female choice due to offspring inheriting superior genes are likely to be negated when there are direct costs associated with choice, including any costs of mating with attractive males. To estimate the fitness consequences of mating with males of varying attractiveness, we housed female house crickets, Acheta domesticus, with either attractive or unattractive males and measured a variety of direct and indirect fitness components. These fitness components were combined to give relative estimates of the number of grandchildren produced and the intrinsic rate of increase (relative net fitness). We found that females mated to attractive males incur a substantial survival cost. However, these costs are cancelled out and may be outweighed by the benefits of having offspring with elevated fitness. This benefit is due predominantly, but not exclusively, to the effect of an increase in sons' attractiveness. Our results suggest that the direct costs that females experience when mating with attractive males can be outweighed by indirect benefits. They also reveal the value of estimating the net fitness consequences of a mating strategy by including measures of offspring quality in estimates of fitness

Quantifying non-star formation associated 8um dust emission in NGC 628

Combining Ha and IRAC images of the nearby spiral galaxy NGC 628, we find that between 30-43% of its 8um dust emission is not related to recent star formation. Contributions from dust heated by young stars are separated by identifying HII regions in the Ha map and using these areas as a mask to determine the 8um dust emission that must be due to heating by older stars. Corrections are made for sub-detection-threshold HII regions, photons escaping from HII regions and for young stars not directly associated to HII regions (i.e. 10-100 Myr old stars). A simple model confirms this amount of 8um emission can be expected given dust and PAH absorption cross-sections, a realistic star-formation history, and the observed optical extinction values. A Fourier power spectrum analysis indicates that the 8um dust emission is more diffuse than the Ha emission (and similar to observed HI), supporting our analysis that much of the 8um-emitting dust is heated by older stars. The 8um dust-to-Ha emission ratio declines with galactocentric radius both within and outside of HII regions, probably due to a radial increase in disk transparency. In the course of this work, we have also found that intrinsic diffuse Ha fractions may be lower than previously thought in galaxies, if the differential extinction between HII regions and diffuse regions is taken into account.Comment: 14 pages, 11 figures, accepted in Ap

Pancreatic cysts suspected to be branch duct intraductal papillary mucinous neoplasm without concerning features have low risk for development of pancreatic cancer.

BackgroundThe risk of developing pancreatic cancer is uncertain in patients with clinically suspected branch duct intraductal papillary mucinous neoplasm (BD-IPMN) based on the "high-risk stigmata" or "worrisome features" criteria proposed in the 2012 international consensus guidelines ("Fukuoka criteria").MethodsRetrospective case series involving patients referred for endoscopic ultrasound (EUS) of indeterminate pancreatic cysts with clinical and EUS features consistent with BD-IPMN. Rates of pancreatic cancer occurring at any location in the pancreas were compared between groups of patients with one or more Fukuoka criteria ("Highest-Risk Group", HRG) and those without these criteria ("Lowest-Risk Group", LRG).ResultsAfter exclusions, 661 patients comprised the final cohort (250 HRG and 411 LRG patients), 62% female with an average age of 67 years and 4 years of follow up. Pancreatic cancer, primarily adenocarcinoma, occurred in 60 patients (59 HRG, 1 LRG). Prevalent cancers diagnosed during EUS, immediate surgery, or first year of follow up were found in 48/661 (7.3%) of cohort and exclusively in HRG (33/77, 42.3%). Using Kaplan-Meier method, the cumulative incidence of cancer at 7 years was 28% in HRG and 1.2% in LRG patients (P<0.001).ConclusionsThis study supports using Fukuoka criteria to stratify the immediate and long-term risks of pancreatic cancer in presumptive BD-IPMN. The risk of pancreatic cancer was highest during the first year and occurred exclusively in those with "high-risk stigmata" or "worrisome features" criteria. After the first year all BD-IPMN continued to have a low but persistent cancer risk

Forestry Bulletin No. 5: Continuous Forest Inventory with Punch Card Machines for a Small Property

A study on forestry inventory with punched card machines for a small property.https://scholarworks.sfasu.edu/forestrybulletins/1004/thumbnail.jp