Black Sexton Beetle Nicrophorus humator

Historically the role of sextons included grave-digging so I assume this is the origin of the term sexton beetle when it applies to species that bury the carrion their larvae feed on.

This is the sexton beetle that I catch in my moth trap most frequently.

Black Sexton Beetle Nicrophorus humator, North Elmham (Norfolk, UK), 15th May 2019

As their vernacular name suggests, Black Sexton Beetles are normally black (except for the orange club to their antennae). Indeed neither Duff nor Hackston make any provision for brown ones in their keys. However I'm sure this must be this species, and I have found a couple of other similar individuals online. I wondered if this might be teneral but I kept hold of the beetle so I could double-check it really was this species and it had not begun to darken up at all by the time it died, so I wonder if it might simply be an unusual colour variant?

Black Sexton Beetle Nicrophorus humator, North Elmham (Norfolk, UK), 31st July 2024

Under its account for this species, the NatureSpot wesbite states that there are several sexton beetles in the UK but this is the only all black species (apart from the orange tips to its antennae). If Necrodes littoralis is not a sexton beetle then this is perfectly correct, and it makes good sense not to treat Necrodes as sexton beetles as, unlike Nicrophorus, I don't believe they bury the carrion they feed on. However Necrodes littoralis is often called the Shore Sexton Beetle implying that some authors do treat it as one of the sexton beetles.

As a beetle newbie who had previously identified both "Black Sexton Beetle" and "Shore Sexton Beetle" from other books that used those vernacular names, I referred to NatureSpot to refresh my memory about how to identify them and took the statement to mean that all the large black "sexton" beetles that I was seeing with orange tips to the antennae must be Black Sexton Beetles. I only realised my error after a couple of years or so when it I started to realise that there were clear differences between the beetles that I was identifying as Black Sexton Beetles, including in the shape of their antennae, and that surely two different species were involved.

I had photographed some so was able to correct or confirm those records when I realised my mistake but I ended up having to ditch all of those records for which I had no photos or specimens. At least the difference in antennal club shape is so glaringly obvious it's easy to identify these from photos. The more prominently ridged elytra of littoralis, the outer ridges being bent around the prominent tubercles at about two thirds, seems to be another obvious difference from humator.

Black Sexton Beetle Nicrophorus humator, North Elmham (Norfolk, UK), 15th October 2018

Black Sexton Beetle Nicrophorus humator, North Elmham (Norfolk, UK), 15th May 2021

Black Sexton Beetle Nicrophorus humator, North Elmham (Norfolk, UK), 29th March 2017

Black Sexton Beetle Nicrophorus humator, North Elmham (Norfolk, UK), 21st April 2016

Black Sexton Beetle Nicrophorus humator, North Elmham (Norfolk, UK), 27th March 2018

Black Sexton Beetle Nicrophorus humator, North Elmham (Norfolk, UK), 28th March 2015

Black Sexton Beetle Nicrophorus humator, North Elmham (Norfolk, UK), 11th July 2018

Black Sexton Beetle Nicrophorus humator, North Elmham (Norfolk, UK), 11th October 2018

Black Sexton Beetle Nicrophorus humator, Cranberry Rough (Norfolk, UK), 1st May 2016

Black Sexton Beetle Nicrophorus humator, North Elmham Cathedral Meadows (Norfolk, UK), 22nd April 2019

Black Sexton Beetle Nicrophorus humator, Wendling Beck Environment Project (Norfolk, UK), 1st September 2021

Black Sexton Beetle Nicrophorus humator, Tresidder (Cornwall, UK), 6th October 2020

Black Sexton Beetle Nicrophorus humator, Weston Park (Norfolk, UK), 25th June 2011

Black Sexton Beetle Nicrophorus humator, North Elmham (Norfolk, UK), 10th April 2015

Black Sexton Beetle Nicrophorus humator, Wendling Beck Environment Project (Norfolk, UK), 1st May 2022

Black Sexton Beetle Nicrophorus humator, Felbrigg (Norfolk, UK), 30th March 2012

Black Sexton Beetle Nicrophorus humator, North Elmham (Norfolk, UK), 1st May 2016

Black Sexton Beetle Nicrophorus humator, North Elmham (Norfolk, UK), 11th April 2020

Black Sexton Beetle Nicrophorus humator, North Elmham (Norfolk, UK), 11th April 2022

Black Sexton Beetle Nicrophorus humator, North Elmham (Norfolk, UK), 28th March 2021

Black Sexton Beetle Nicrophorus humator, North Elmham (Norfolk, UK), 5th April 2020

Black Sexton Beetle Nicrophorus humator, North Elmham (Norfolk, UK), 12th October 2018

Black Sexton Beetle Nicrophorus humator, Bawdeswell (Norfolk, UK), 15th August 2008

Black Sexton Beetle Nicrophorus humator, Bawdeswell (Norfolk, UK), 24th August 2012

Black Sexton Beetle Nicrophorus humator, Bawdeswell (Norfolk, UK), 4th April 2011

Black Sexton Beetle Nicrophorus humator, Bawdeswell (Norfolk, UK), 29th March 2011

Black Sexton Beetle Nicrophorus humator, North Elmham Cathedral Meadows (Norfolk, UK), 8th October 2021