one at each of two urban areas in Catalonia (Spain). The suspected host plant, Platanus sp., is very common as an ornamental at
the collecting sites. This is the second report for the Palaearctic Region, after collections in France (Matocq, 2008).
Key words: faunistics, new record, Iberian Heteroptera, true bugs, allochthonous species, Platanus, plane tree.
The worldwide exchange of goods and tourists facili-
tates the movement of allochthonous species, often re-
ferred to as “aliens”. Italy seems to be the most common
door of entrance to Europe, due to its location in the
middle of the Mediterranean Basin (Jucker et al., 2008).
About 50% of imported species belong to the Hemip-
tera, and are scale-insects or aphids. Among true bugs,
recent examples of imported species are the sycamore
lace bug Corythuca ciliata (Say) (Tingidae) and western
conifer seed bug Leptoglossus occidentalis Heidemann
(Coreidae). Also the American oak lace bug Corythuca
Drake et Maa and azalea lace bug Stephanitis pyrioides
(Scott) have been reported (Jucker et al., 2008), al-
though they seem to be less widespread.
In Catalonia, the most recent reports of allochthonous
species concern L. occidentalis (Ribes et al., 2008), and
a pontomediterranean lygaeid which is expanding its
Identification of Belonochilus numenius
Belonochilus numenius (Say 1832) (Heteroptera Ly-
gaeidae) the sycamore seed bug (common name sug-
gested by Sweet, 2000), belongs to a group species of
family Orsillinae, tribe Orsillini with spiny fore femora,
in which European, African and American species may
be found (Péricart, 2001). In Ashlock’s (1967) key to
world genera of the tribe Orsillini, Belonochilus is
reached through the following characters: mesopleuron
appearing to overlap propleuron, antenniferous tubercle
not produced beyond point of attachment of antenna,
profemora armed with a single spine ventrally, vertex
without carinae, head long, and anteocular length more
than twice length of eye. The genus is monotypic. The
few other species described in, or at one time placed in,
transferred to other genera (Slater, 1964).
In the context of the Palaearctic fauna, B. numenius
can be easily identified. The only other orsilline genus
that has armed profemora is Orsillus. Using Péricart’s
key on euromediterranean Lygaeidae (Péricart, 1998), B.
numenius is easily attributed to subfamily Orsillinae. In
Péricart’s opinion, tribes within the subfamily Orsillinae
have not yet been resolved; thus he does not include a
key to tribes. To include Belonochilus, we propose a
slight amendment in the first step of his generic key:
1 (2) Profemora spiny. Rostrum reaching at least the
middle of the abdomen.
1a (1b) Profemora with 1 spine. Body elongate, not
depressed. Anteocular length more than three times
length of eye ..........................................Belonochilus
1b (1a) Profemora with 3 spines. Body oval-elongate,
depressed. Anteocular length about twice length of
2 (1) Profemora not spiny. Rostrum at most slightly
surpassing the metacoxae.
For remaining couplets, refer to Péricart’s key.
Figures 1, 2 and 3 allow ready identification of B. nu-
B. numenius may complete its biological cycle upon the
seed balls of the sycamore tree Platanus occidentalis L.
(Heidemann, 1902; Wheeler, 1984), which it pierces
(In colour at www.bulletinofinsectology.org)
Figure 3. Lateral view of a male B. numenius. Photo:
(In colour at www.bulletinofinsectology.org)
with its very long rostrum. It is considered a specialist on
sycamores (plane in Europe) (Schuh and Slater, 1995).
Platanus racemosa Nutt., Platanus wrightii S. Wats. and
Platanus mexicana Moric. have been reported as host
trees of B. numenius (Sweet, 2000). This arboreal niche
is considered to be unusual for North American Orsilli-
nae (Sweet, 2000). In some cases, the species may be-
come a pest on ornamental planes, as for example the
London plane (Platanus x acerifolia). Other occasional
host plants are goldenrod (Solidago sp.), giant ragweed
(Ambrosia trifida L.), hackberry (Celtis occidentalis L.)
and willow (Salix sp.) (Wheeler, 1984).
Detailed studies from field samples in Pennsylvania,
and from rearing in laboratory conditions, permitted the
description of life cycle, of egg and fifth instar, as well
as diagnoses for the second to fourth instars (Wheeler,
1984). Overwintering occurs as eggs in the plane tree
seed balls, mainly those fallen on the floor. Only a few
proportion of the first generation population develops in
the fruit heads remaining attached to the tree. Number
of individuals per fruit, either adults or nymphs, ranged
from 0 to more than 50 (average 15/fruit). Hatching be-
gins in the first half of April, until early May. Early in-
stars keep protected inside the fruiting heads. First
adults are found in May 20, and oviposition occurs in
the current-season fruits, more rarely in old fruits re-
maining on the tree, and never in the old fallen fruit
heads. Mating and oviposition of the first generation
lasts until June 10, overlapping with all nymphal stages
of the second generation. At 20 ºC under natural photo-
period, the nymphal period requires an average of 28.8
days. By early October, the species has developed four
generations. Eggs deposited by third and fourth genera-
tion females represent the overwintering stage. Adults
may be found under bark either in autumn or in early
spring, which suggests that overwintering adults may be
found in more southern (warm) localities (Wheeler,
The native area of B. numenius is the Nearctic Region.
Ashlock (1967) summarizes the distribution of B. nu-
menius as restricted to southern Canada, United States
and most of Mexico, between latitudes 15º-45ºN. Slater
(1964) and Ashlock and Slater (1988) give a detailed
list of USA states and Canadian provinces where the
species is known.
B. numenius has been reported for the first time in the
Palaearctic by Matocq (2008), through specimens found
in Corsica and Languedoc. The present work includes
the first records for the Iberian Peninsula (figure 4). The
localities of samples from Catalonia are (UTM projec-
tion is based in the datum Europe 1950, Spain and Por-
1) Castelldefels, UTM 31TDF17, Barcelona province,
Catalonia, Spain, 11 VIII 2008, 1 male. On a wall,
near a row of ornamental Platanus x hybrida. F.
2) Barcelona city, Barceloneta area, UTM 31TDF38,
Barcelona province, Catalonia, Spain, 2 IX 2008, 1
female. On the door of a drugstore. J. J. Pérez De
Gregorio leg., J. Ribes det. et coll.
Figure 4. Localities where B. numenius was collected in Catalonia.
North American specimens, lent by the American Mu-
seum of Natural History of New York, were also stud-
female, 1 male.
2) USA, New York, Columbia Co., Stockport Marsh,
July 1981. R. Schmidt., ex: fruits of Populus del-
and Spain in a very short lapse of time (from August to
October 2008). The origin of the importation has not
been elucidated in any of both reports. As plane trees
are very common as ornamentals, high attention must be
payed to possible new records of the sycamore seed
bug, which may become a pest in parks and urban areas,
although it doesn’t in natural plane tree habitats (Sweet,
As it happened in the past with L. occidentalis and C.
establishment of B. numenius in Europe, and eventually
its noxious effects.
We thank Dr H. Brailovsky (México D.F., México) for
confirming the identity of the species, J. J. Pérez De
Gregorio (Barcelona, Spain) for lending of sample, A.
Masó (Barcelona, Spain) for picture in figure 1, A.
Alma (Torino, Italy), C. Ferraccini (Torino, Italy), and
A. Gogala (Ljubljana, Slovenja) for their help in inquir-
ing about possible previous records of B. numenius, and
L. Mata (Barcelona, Spain) for revision of English text.
of the World (Hemiptera: Heteroptera: Lygaeidae).- Univer-
bugs, pp. 167-245. In: Catalog of the Heteroptera, or true
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Hemiptera recently introduced into Italy.- Bulletin of Insec-
Hétéroptère néarctique, Belonochilus numenius (Say, 1831)
(Hemiptera, Lygaeidae, Orsillinae).- Bulletin de la Société
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Francaise des Sociétés de Sciences Naturelles, Paris, France
Entomological Society, Wageningen, The Netherlands.
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thor, firstname.lastname@example.org), Marta G
, Departament de
tat de Barcelona, Avda Diagonal 645, E-08028 Barcelona
(Catalonia), Spain; Jordi R
de la Ciutadella-Zoologia, Passeig Picasso s/n, E-08003 Bar-
celona (Catalonia), Spain.
Received December 19, 2008. Accepted April 24, 2009.