Corrections to the literature: Three recently published records for Nicrophorus (Coleoptera: Staphylinidae: Silphinae) deemed erroneous
by Derek S. Sikes1
Abstract
During the last decade three occurrence records for three species of Nicrophorus—N. guttula, from Sitka Alaska, USA, N. hebes from Alaska, and N. hybridus from Whitehorse, Yukon, Canada—were published, which are likely erroneous because no reliable evidence suggests these species occur or occurred in these regions. This short note provides details, comments, and species distribution modeling analyses on these records and concludes all three are erroneous.
Introduction
Species of the genus Nicrophorus, commonly called burying beetles in North America, are relatively well known, large-bodied beetles (Anderson and Peck 1985) now in the family Staphylinidae (Cai et al. 2022). Despite peer-reviewed publications being the gold standard for reliable scientific information, errors do make it into print and, when found, are best corrected. Herein, three such records are addressed—while admitting the much greater difficulty of demonstrating the absence, relative to the presence, of a species from a region. One approach to this problem is to attempt to answer the question of whether the climate of a region is suitable for a species based on an understanding of the climate from where it is known to occur. Thus, a niche modeling, aka species distribution modeling, analysis was undertaken to help quantify the likelihood of two of these questionable records.
Methods
Species Distribution Modeling
The basics of the protocols in Oliver (2021) and Waraniak (2018) were followed using the 19 bioclimatic variables available from the WorldClim 2.0 database which contain the averages for the years 1970–2000 at 2.5 minutes resolution (~5 km) (Fick and Hijmans 2017). The bioclim (Nix 1986, Booth et al. 2014) model in the dismo 1.3-5 package (Hijmans et al. 2021) for R v.4.0.2 (R Core Team 2020) was used with the presence-only occurrence data for N. hybridus and N. guttula. The R script for the N. guttula analysis is provided as an appendix. The occurrence data files for the R analyses presented herein are available at https://doi.org/10.6084/m9.figshare.19401131. These data came from the collections and literature sources listed in Table 1. Those with DSS as the source are available in more complete form at http://dx.doi.org/10.5061/dryad.mr221 from Sikes and Venables (2013). Those with GBIF as the source are listed below in the literature cited as GBIF.org (2022c) and GBIF.org (2022a).
| Collection or Publication | Source |
|---|---|
| Albuquerque [MSBA] | GBIF |
| Anderson & Peck (1985) | literature |
| Backlund & Marrone (1997) | literature |
| Berkeley [EMEC] | DSS, GBIF |
| Boulder [UCM, UCMC] | GBIF |
| Budapest [HNHM] | DSS |
| Cambridge [MCZC] | DSS |
| Chicago [CHAS] | GBIF |
| Chicago [FMNH] | DSS, GBIF |
| Cincinnati [CMC] | GBIF |
| Cochrane [CEIC] | DSS |
| College Station [TAMU] | DSS, GBIF |
| Columbus [OSUC] | DSS |
| Denver [DMNS] | GBIF |
| Ebina -Nishikawa private coll [MNC] | DSS |
| Edinburgh [RSME] | DSS |
| Fairbanks [DSSC] | DSS |
| Fairbanks [UAM] | GBIF |
| Flagstaff [NAUF, CPMAB] | GBIF |
| Fort Collins [CSUC] | GBIF |
| Frankfurt [SMFD] | DSS |
| Hatch (1945) | Literature |
| iNaturalist | GBIF |
| Jalisco [CZUG] | GBIF |
| Las Cruces [NMSU] | GBIF |
| Los Angeles [LACM, IP] | GBIF |
| Los Angeles [LACM, RLB] | GBIF |
| Los Angeles [LACM] | DSS |
| Logan [EMUS] | DSS |
| New Haven [PMNH] | DSS |
| New York [AMNH] | DSS |
| Norman [OMNH, RINVRT] | GBIF |
| Ohio [OSUC] | GBIF |
| Peck & Anderson (1985) | Literature |
| Peck & Kaulbars (1987) | Literature |
| Philadelphia [ANSP] | DSS |
| Provo (BYUC) | DSS |
| San Diego [SDNHM] | GBIF |
| Santa Barbara [SBMNH] | GBIF |
| Santa Barbara [UCSB, IZC] | GBIF |
| St. Paul [UMSP] | DSS |
| Tempe [ASU, ASUHIC] | GBIF |
| Tempe [ASU, NEON-IV] | GBIF |
| University Park [PSUC] | GBIF |
| Vancouver [UBCZ] | GBIF |
| Washington D.C. [USNM] | DSS, GBIF |
| Wien [Wolfgang Barries Private Coll.] | DSS |
Results
Nicrophorus hebes Kirby
Based on molecular, ecological, breeding trial, and morphological data, Sikes et al. (2016) recognized this species as valid and elevated it to species status from a junior synonym under Nicrophorus vespilloides Herbst. Nicrophorus hebes is distritibuted widely within eastern and central Canada and, to date, there is no evidence that Nicrophorus hebes occurs west of about 120° longitude or north of about 61° latitude in the Nearctic. It is thus absent from northwestern Canada and Alaska. Nevertheless, this species was accidentally reported from Alaska by Meeds (2021) who, while reviewing literature relevant to forensic entomology for Alaska, misunderstood the information presented in Sikes et al. (2016).
Nicrophorus hybridus Hatch & Angell
Bygarski and LeBlanc (2013), presenting on forensic entomological research conducted in Whitehorse, Yukon Territory (60° 43’ N, 135° 03’ W) reported the species N. hybridus from their samples. This species has never been confirmed north of 53° latitude and is relatively difficult to distinguish from Nicrophorus investigator (magnified lateral and ventral views are needed). Nicrophorus investigator is a widespread and common species in northern regions of the Nearctic and Palearctic so any records of N. hyrbidus north of 53° latitude are likely misidentifications of N. investigator, as suggested for this case by Sampson and Sikes (2020). There are numerous records of N. investigator north of 60° latitude in both the Nearctic and Palearctic, with maximum latitude records at 69°N in Norway and 67°N in Yukon Territory (Anderson and Peck 1985, Sikes and Venables 2013).
Climate change is expected to expand many species’ ranges polewards (Stafford et al. 2013) so N. hybridus records north of 53° latitude may increase in likelihood as the planet warms. Any such records would need confirmation by careful study of voucher specimens and use of appropriate keys (e.g., Anderson and Peck 1985) by someone experienced with identification of Nicrophorus.
Backlund and Marrone (1997) reported N. hybridus from sandy grasslands and scattered cottonwood stands in South Dakota. Peck and Kaulbars (1987) reported this species from prairie, sage steppe, and montane meadow. Anderson and Peck (1985) indicated it occurs in prairies and dry inland valleys. The ecoregion data of Olson et al. (2001), as mapped in SimpleMappr (Shorthouse 2010) (data not shown), indicate it occurs primarily in grasslands, shrub steppe, montane and foothills forests and parklands east of the Rocky Mountains but some records are known from west of these mountains in coastal forest ecoregions—presumably in drier inland grassland and shrub valleys. All these habitats and climates are quite different from the subarctic boreal habitats of the Whitehorse region.
Using presence-only data for N. hybridus a niche model for this species was estimated which shows Whitehorse to have habitat unsuitable for this species (Figure 1), thus making it far more likely that the specimens in question were actually N. investigator.
Figure 1: Map of records for Nicrophorus hybridus Hatch & Angell showing observations (red dots) and habitat suitability probability (colors, see key) based on presence-only niche modeling using the bioclim algorithm in the dismo package in R.
Nicrophorus guttula Motschulsky
Bousquet et al. (2013) in their checklist of the beetles of Canada and Alaska, reported N. guttula from Alaska because the type locality of this species is Sitka, Alaska (57° N). Sikes et al. (2002) had addressed this issue and concluded the type locality was likely based on an error. Aside from the type locality description there have been no other records of this species reported from Sitka or anywhere in southeast Alaska, despite relatively extensive beetle collections having been made there, including 408 records of Nicrophorus from southeast Alaska—with the only Nicrophorus species being N. investigator and N. defodiens (GBIF.org 2022c). The northernmost, verified record (specimen identified by S. Peck) for N. guttula is from Riske Creek in southern British Columbia at 51.9° (GBIF.org 2022b). However, this northernmost record appears to be an outlier, because 97% of records are south of 50°N (Sikes and Venables 2013 (total n = 294), GBIF.org 2022a (total n = 1328)). Note that in Sikes and Venables (2013) there is a record from 55°N that, upon inspection, was revealed to be incorrectly georeferenced—its locality data said only “British Columbia” with no further geoprecision and it had thus been georeferenced to the approximate center of the province. I therefore deleted that record’s geocoordinates.
Using presence-only data for N. guttula a niche model for this species was estimated which shows southeast Alaska to have unsuitable habitat for this species (Figure 2), making the likelihood very low that the type locality of Sitka is correct. The correct type locality is presumably somewhere along the northwestern coast of California, Oregon, or Washington. Many beetle specimens from this coastline, and Alaska, made their way to Europe via Russian naturalists in the mid 1800s and confusion over collection data is quite plausible.
Figure 2: Map of records for Nicrophorus guttula Motschulsky showing observations (red dots) and habitat suitability probability (colors, see key) based on presence-only niche modeling using the bioclim algorithm in the dismo package in R.
Finally, how is it that this error was published in a work (Bousquet et al. 2013) on which I, a specialist on both the beetles of Alaska and the genus Nicrophorus, was a co-author? The answer is that the Alaskan record for this species was added to the draft, without consulting me, after I had finished and submitted my edits. Nevertheless, I was curious how likely such a record was and these analyses helped lay this question to rest.
Acknowledgments
I thank the curators and collections staff who helped arrange loans of specimens for study from the collections listed in Table 1 and those who helped digitize data shared with GBIF.org, including those who submitted relevant iNaturalist observations.
Appendix: R script for Niche Modeling
# Species distribution modeling for Nicrophorus guttula
# Derek Sikes, dssikes@alaska.edu
# 2022-01-17
install.packages("dismo")
install.packages("maptools")
install.packages("rgdal")
install.packages("raster")
install.packages("sp")
library("sp")
library("raster")
library("maptools")
library("rgdal")
library("dismo")
# getData did not work to download the bioclimatic data from Worldclim so these were downloaded manually from https://www.worldclim.org/data/worldclim21.html they appeared in the following directory Users/dssikes/Downloads/wc2.1_2.5m_bio
> path <- file.path("/Users/dssikes/Downloads/wc2.1_2.5m_bio")
> files <- list.files(path, pattern='tif$', full.names=TRUE )
> files
[1] "/Users/dssikes/Downloads/wc2.1_2.5m_bio/wc2.1_2.5m_bio_1.tif"
[2] "/Users/dssikes/Downloads/wc2.1_2.5m_bio/wc2.1_2.5m_bio_10.tif"
[3] "/Users/dssikes/Downloads/wc2.1_2.5m_bio/wc2.1_2.5m_bio_11.tif"
[4] "/Users/dssikes/Downloads/wc2.1_2.5m_bio/wc2.1_2.5m_bio_12.tif"
[5] "/Users/dssikes/Downloads/wc2.1_2.5m_bio/wc2.1_2.5m_bio_13.tif"
[6] "/Users/dssikes/Downloads/wc2.1_2.5m_bio/wc2.1_2.5m_bio_14.tif"
[7] "/Users/dssikes/Downloads/wc2.1_2.5m_bio/wc2.1_2.5m_bio_15.tif"
[8] "/Users/dssikes/Downloads/wc2.1_2.5m_bio/wc2.1_2.5m_bio_16.tif"
[9] "/Users/dssikes/Downloads/wc2.1_2.5m_bio/wc2.1_2.5m_bio_17.tif"
[10] "/Users/dssikes/Downloads/wc2.1_2.5m_bio/wc2.1_2.5m_bio_18.tif"
[11] "/Users/dssikes/Downloads/wc2.1_2.5m_bio/wc2.1_2.5m_bio_19.tif"
[12] "/Users/dssikes/Downloads/wc2.1_2.5m_bio/wc2.1_2.5m_bio_2.tif"
[13] "/Users/dssikes/Downloads/wc2.1_2.5m_bio/wc2.1_2.5m_bio_3.tif"
[14] "/Users/dssikes/Downloads/wc2.1_2.5m_bio/wc2.1_2.5m_bio_4.tif"
[15] "/Users/dssikes/Downloads/wc2.1_2.5m_bio/wc2.1_2.5m_bio_5.tif"
[16] "/Users/dssikes/Downloads/wc2.1_2.5m_bio/wc2.1_2.5m_bio_6.tif"
[17] "/Users/dssikes/Downloads/wc2.1_2.5m_bio/wc2.1_2.5m_bio_7.tif"
[18] "/Users/dssikes/Downloads/wc2.1_2.5m_bio/wc2.1_2.5m_bio_8.tif"
[19] "/Users/dssikes/Downloads/wc2.1_2.5m_bio/wc2.1_2.5m_bio_9.tif"
> predictors <- stack(files)
> predictors
class : RasterStack
dimensions : 4320, 8640, 37324800, 19 (nrow, ncol, ncell, nlayers)
resolution : 0.04166667, 0.04166667 (x, y)
extent : -180, 180, -90, 90 (xmin, xmax, ymin, ymax)
crs : +proj=longlat +datum=WGS84 +no_defs
names : wc2.1_2.5m_bio_1, wc2.1_2.5m_bio_10, wc2.1_2.5m_bio_11, wc2.1_2.5m_bio_12, wc2.1_2.5m_bio_13, wc2.1_2.5m_bio_14, wc2.1_2.5m_bio_15, wc2.1_2.5m_bio_16, wc2.1_2.5m_bio_17, wc2.1_2.5m_bio_18, wc2.1_2.5m_bio_19, wc2.1_2.5m_bio_2, wc2.1_2.5m_bio_3, wc2.1_2.5m_bio_4, wc2.1_2.5m_bio_5, ...
min values : -54.759167, -38.162666, -66.380669, 0.000000, 0.000000, 0.000000, 0.000000, 0.000000, 0.000000, 0.000000, 0.000000, 1.000000, 9.063088, 0.000000, -30.760000, ...
max values : 31.16667, 38.50467, 29.29167, 11246.00000, 2768.00000, 507.00000, 230.69151, 6174.00000, 1560.00000, 5608.00000, 5230.00000, 21.97300, 100.00000, 2377.62402, 48.46000, ...
# the Nicrophorus guttula data were taken from the data prepared for Sikes and Venables (2013) and GBIF.org (2022c). These were prepared as a .csv file with two columns of data separated by a comma (decimalLongitude, decimalLatitude). Note that R will throw an error if the first column is latitude and the second is longitude - these must be reversed. The following loads the observed data.
> guttula <- read.csv("~/Documents/ ALASKA/ PROJECTS/2022-AKES-Nicro corrections/niche modeling attempts/GBIFandDSS guttula data/guttula.csv")
> View(guttula)
# the following builds the model by using climate data from the observed records
> obspred <- extract(predictors, guttula) # extracts bioclim data for each of our data points
> bioclim.model <- bioclim(obspred)
> predictions <- predict(predictors, bioclim.model)
# the following makes the map of the modeled expected distribution
> plot(predictions, xlim=c(-150, -80), ylim=c(25, 60))
# the following adds the observed data to the expected on the map
> points(guttula, col = "red", pch = 20, cex = 0.75) References
University of Alaska Museum, 1962 Yukon Dr., University of Alaska Fairbanks, Fairbanks, AK 99775, dssikes@alaska.edu↩︎