L'état des connaissances taxonomiques sur le genre Nysius (Hemiptera: Lygaeidae: Orsillinae)

Le 11 févrir 2020, j'ai reçu un courrier intéressant de Docteur G. E. E. Scudder concernant l'état des connaissances taxonomiques des espèces du genre Nysius et voici ce qui est écrit:

Thank you for sending me your email address, and the photograph of
Aradus insolitus Van Duzee that you collected and record from Quebec.

I have checked, and I do not have any bed bugs, that you said you sent
me. However, I have some other Heteroptera, mostly Nysius, that you sent
me on 6 March 2006.  I will return these when I am able to pack parcels.
You should have received, by email, the pdf of the two papers that I
coauthored with the new Quebec records. I am having some problems with
Nysius identifications. Eric Maw at the CNC has been coordinating some
bar-coding of Nysius species, trying to sort out some of the problems.
So far, the data obtained are rather confusing.

Baber (1947), Moore (1950), Beique & Robert (1965) and Slater (1964),
recorded N. angustatus Uhler, N. ericae (Schill.), N. thymi (Wolff) and
N. groenlandicus (Zett.) from Quebec. However, Ashlock (1977) reported
that North American N. ericae was in fact really N. niger Baker, and
said that N. ericae and N. niger were best separated by the shape of the
female spermatheca. Thereafter, Larochelle  (1984) and Henry &
Froeschner (1988) reported N. niger instead of N. ericae from Quebec.

In our preliminary bar-coding of N. niger, we found that those sorted
into two groups. This suggests that there may be two types of N. niger
in North America. We need to do more research on this problem.

With regard to N. groenlandicus that Barber (1947)reported from Bradore
in Quebec, Böcher (1976, 1978) said that the species did not occur in
North America, a fact noted by Danks (1987, Arctic Arthropods p. 425).
We have bar-coded specimens from Greenland determined as N.
groenlandicus by Claus Rasmusson, and found that these have a bar-code
like specimens we have from Churchill, Manitoba. However, our bar-coding
results from other Greenland specimens suggests that there may be two
forms of N. groenlandicus in Greenland. We need to check this further by
looking at more specimens. The PEI specimens in the CNC determined as N.
groenlandicus by L.A. Kelton, are in fact N. angustatus.

I see that Schmitz and Péricart (1993) believe that N. groenlandicus may
be a subspecies of N. ericae. In fact, Péricart (1999 Faune de France
84A:218) accepts this suggestion. However, Péricart (2001 in Aukema and
Riegert, Catalogue of the Heteroptera of the Palaearctic Region) says
that this taxon needs further discussion, noting that American authors
and Vinokurov consider that it is a good species. Péricart (2001) says
that a study of populations from arctic parts of Eurasia and America is
necessary. So far, we have not examined the specimens from Bradore in
Quebec.

The Greenland specimens have bucculae, not fading out posteriorly, as in
N. niger. Instead, the bucculae in N. groenlandicus are like N.
angustatus, that is they have bucculae that are only slightly narrow
posteriorly and end abruptly or even form a small, but distinctly
rounded subanulate point, while the first labial segment in N.
angustatus is slightly shorter than the bucculae; in N. groenlandicus
the first labial segment projects slightly beyond the end of the
bucculae, although not usually as much as illustrated by Wagner (1958,
Comment Biol. 19(2): Fig. 4h, p. 11) or Vinokurov (1988, Heteroptera of
Yakatia , Fig. 557, p. 188). The corium and the membrane are more or
less broadly infuscate, and the surface of the corium is densely coated
with fine setae, but is usually divided of longer erect setae. The male
genital capsule has a lateral spur, similar to N. ericae, as illustrated
by Wagner (1958) p. 13, Fig. 42, or Vinokurov (1988) on page 188, Fig.
558.

Specimens of N. groenlandicus from the Sondrestrom Air Base in
Greenland, were illustrated in Larson and Scudder (2018).

I am not sure about the records of N. thymi from Canada. I reported N.
thymi from the Yukon, but noted it was because the specimens keyed to
this species in Barber (1947). I am not sure that these are true N.
thymi because they look different from the specimens I have from
England, determined by the late G.E. Woodroffe. We have not so far been
able to bar-code fresh specimens of N. thymi from Europe, but have had
to rely on gene-bank data from Germany (Bavaria and Brandenburg).

Finally, we borrowed some type material of N. grandis Baker from the
USNM, but were unable to get barcode data from them. I have seen
specimens from Alberta, named and illustrated in Larson and Scudder
(2018), but am not sure that I can always recognize this species. Barber
(1947) reported N. grandis as closely related to N. angustatus, and said
they differed for the most part with relative rather than positive
features. However, since the species was described from Colorado, and I
have seen many specimens from this state, in the CNC, I have labeled
these as N. grandis. Barber (1947) also reports N. grandis from
Churchill in Manitoba, and south through Mexico to Panama, but the
Churchill record was queried by Larson and Scudder (2018).

I have not yet worked much on N. insoletus Barber, but Barber (1947)
reports it from Utah and Colorado, and I reported it from Idaho
(Scudder, 2013). Barber (1947) says that N. insoletus most closely
resembles N. angustatus, and is best distinguished by the difference in
colour, size, and has more elevated bucculae, longer antennae, and more
distinctly elevated veins in the corium.

The Nysius specimens that you sent on 6 March 2006, appear to be N.
angustatus, and I have labeled them as such. However, I did not dissect
them, and relied on the shape of the bucculae and costal margin of the
corium, and the length of the first segment of the labium.

Posted by jeanfrancoisroch jeanfrancoisroch, September 30, 2020 13:36

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