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TAXONOMY AND BIONOMICS OF THE
VESPA TROPICA GROUP (HYM., VESPINAE)
BY MICHAEL E. ARCHER
of
Vespa tropica (Linnaeus, 1758) is a common and widespread hornet
south-eastern Asia which until recently (Kojima, 1982) was con-
sidered a single species. This paper reports on taxonomic, distributional and bionomic studies of Vespa tropica resulting in the recognition of three species. These three species, designated the Vespa
tropica species group, can be readily recognised from other Vespa
species by the elongated first gastral tergum (fig. 1 A) and the lateral
apical margin of the clypeus produced as a blunt triangular projection
(fig. 1 C). Both these character states are derived so the V. tropica
species group is monphyletic (Archer, unpublished).
This paper attempts to reduce the number of colour subspecies by
eliminating polytopic subspecies and synonymising 'subspecies',
which are really microgeographic races, with their macrogeographic
race or subspecies. In addition informal names are proposed to replace
the subspecies names.
TAXONOMY
The taxonomy of the Vespa tropica species group has been largely
determined by Bequaert (1936) and van der Vecht (1957, 1959) although these two authors considered that the species group consisted
of one species, namely V. tropica, which was divided into 15 colour
subspecies.
Bequaert (1936) showed that du Buysson (1904,1905) confused two
V. cincta Fabricius,, 1775, viz.: V. tropica and V. afftnis
Linnaeus, 1764. Bequaert (L936) selected the oldest specific name
available from Sphex tropica, Linnaeus, 1758. Van der Vecht (1957)
found the holotype of Sphex tropica and showed that it came from
Java. Under V. tropica, Bequaert (1936) included the eight colour
varieties: deusta Lepeletier, 1836, ducalis Smith, 1852, eulemoides du
Buysson, 1905, esakii Sonan, 1925,, philippinensis de Saussure, 1854,
pulchra du Buysson, 1905, sorror du Buysson, 1905, trisignata P€rez,
1910 and described three new colour varieties: anthracina, haematospecies under
des and loochooensis.
Van der Vecht (1957) raised the status of Bequaert's (1936) varieties
to subspecies and described two new subspecies by separating leefmansi from tropica and trimeres from trisignata. He recognised that
the subspecies unicolor Smith, 1864 was distinct from deusta, and that
the variety soror was not a subspecies of V. tropica as suggested by
Bequaert (1936) but a subspecies of V. mandarinia Smith, 1852. Van
der Vecht (1959) introduced the new subspecies pseudosoror to replace
soror for the appropriate specimens of V. tropica.
25th November, 1991
Yol.l27
(1991)
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226
Kojima & Reyes (1984) described the subspecies cebuana but Starr
(1989) found that the types of cebuana represented a colour anomaly
and synonymised it with anthracina.
Kojima (1982) found that the subspecies philippinensis and anthracina were sympatric in distribution and that females of philippinensis
were separable from V. tropica on a structural character, and therefore
raised philippinensis to specific rank.
I have found that within the geographical distribution of the subspecies trimeres, the subspecies trisignata is found in two widely
separated areas of the island of Ceram and south-eastern New Guinea.
The more widespread subspecies trimeres has given rise to the polytopic subspecies trisignata tn at least two geographical areas. To avoid
the use of the polytopic subspecies concept it is proposed that the
subspecies trisignatabe a new synonym of the subspecies trimeres.
Also I have found that the subspecies ducalis and pseudosoror are
sympatric with the subspecies haematodes and leefmansi in North and
South Vietnam and southern China but remain distinct colour forms.
V. tropica should lose several colour subspecies which can be grouped
together as the species V. ducalis (Table 1). The species V. tropica of
Bequaert and van der Vecht can now be seen as consisting of three
species (Table 1).
Wilson & Brown (1953) put forward arguments that the subspecies
nomenclature should not be used and the subspecies categories be
replaced by a brief statement of locality or range of distribution. Such a
set of informal names is proposed for the eight colour subspecies of I/.
tropica (Table 1). The distribution (fig.2 A) and recognition of the
eight informal colour forms can be described as follows.
TABLE 1. THE SPECIES OF THE V. TROPICA SPECIES GROUP, TOGETHER
WITH THE- SUBSPECIES AND INFORMAL COLOUR FORM NAMES.
Subspecies
Species
Informal colour form name
ducalis
1. ducalis to include new synonyms
lo ochoo e ns is and p s e udos oror
2. pulchra to include new synonym esakii
Chinese
philippinensis
none
none
1. anthracina
south Philippine
2.
3.
4.
5.
6.
Andaman
Indian-Chinese
Malayan
Sulawesi-New Britain
tropica
deusta
eulemoides
haematodes
Japanese
north Philippine
leefmansi
trimeres to include new synonym
trisignata
7. tropica
Javan
8. unicolor
Buruan
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The Indian and south Chinese colour form (: Indian-Chinese colour form) is characterised by reddish markings on the head and thorax and has the first gastral tergum black
and the second gastral tergum orange. The reddish markings on the head and thorax
become black in the colour form found in Indo-China, Malaysia, Sumatra and Borneo
(: Malayan colour form) although the Indian-Chinese and Malayan colour forms have a
wide area of overlap with intermediate colour forms from Sikkim to Thailand. In the
Malayan colour form the orange of the second gastral tergum sometimes extends onto
the third gastral tergum while in the colour form from the Andaman and Nicobar Islands
(: Andaman colour form) all the gastral terga are orange except for the first and reddish
marks appear again on the head and thorax. The Java and Bali colour form (: Javan
colour form) is similar but darker than the Malayan colour form. In particular the second
gastral sternum is mainly orange on the Malayan colour form but mainly black on the
Javan colour form. The colour form from Sulawesi, Flores and Sumba to New Britain
(: Sulawesi-New Britain colour form) has the orange of the second gastral tergum
extending onto the first gastral tergum to a varying extent. Melanic colour forms are
found in the north Philippine Islands (: north Philippine colour form), south Philippine
and Palawan Islands (: south Philippine colour form) and the island of Buru (: Buruan
colour form). The north Philippine colour form has its wings a uniform brown with a
yellow tinge while the south Philippine and Buruan colour forms, which are indis-
tinguishable from each other, have their wings strongly darkened in the basal half but
apically are like the north Philippine colour form.
Concerning V. ducalis I have found examples of the nominate subspecies from mainland China which are similar to the subspecies
loochooensrs and which can, therefore, be considered a synonym of
the nominate subspecies. Similarly the subspecies pseudosoror, which
I have found to be present in Taiwan, Hainan island, southern China
and Vietnam, can be considered as part of the subspecies ducalis and
hence a synonym of the nominate subspecies. The subspecies esakii,
which occurs within the geographical distribution of the subspecies
pulchra may be considered a race of the subspecies pulchra and hence
a new synonym of the subspecies pulchra. Thus V. ducali^t would seem
to consist of two rather similar subspecies (Table 1). The two subspecies may be distinguished as follows. The central transverse markings on the first and second gastral terga of the subspecies pulchra are
black, but are brown or reddish in the subspecies ducalis. The mesoscutellum is entirely yellow or reddish-brown in the subspecies ducalis
but mainly black with some reddish-brown marks in the subspecies
pulchra. The geographical distribution of V. ducalis is shown in
tig.2 B. The two subspecies names may be replaced by the following
informal colour form names (Table 2): the Chinese, Taiwan and
Vietnam colour forms (: Chinese colour form) and the Japanese and
Korean colour forms (: Japanese colour form). Specimens of an intermediate coloration are found in Korea and U.S.S.R. (southern Ussuriland). Bequaert (1936) indicated that the Japanese colour form extended into northern China.
The distribution of V. philippinensis (fig. 2 C) is endemic to the
Philippine Islands and has been recorded on Luzon, Leyte, Samar and
Negros.
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228
PTC
A
c
tropica group. A, dorsal view of first gastral tergum; B, lateral view
Fig. 1.
-Vespa
(PTC : pretegula carina); C, front view of clypeus (LAA : lateral apical
of pronotum
angle); D, ventral view of the sixth (6) and seventh (7) gastral sterna of the male.
V. tropica, V. ducalis and V. philippinensis can be separated from all
other species of Vespa by the following combination of characters of
which L, 3 and 4 are considered derived and2 and 5 primitive (Archer,
unpublished).
1. First
gastral tergum long, as seen from above, about half as long or longer than wide
(fig. 1A).
2. Pretegula carina complete (fig. 1 B).
3. Lateral apical margin of the clypeus produced
as a
blunt triangular projection, greater
than a semicircle (fig. 1 C).
In addition the following male characters should also be used.
4. Apical margin of the seventh gastral sternum slightly concave (fig. 1 D).
5. Apical margin of the sixth gastral sternum with one shallow emargination, less than a
semicircle (fig. 1 D).
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229
The three species may be separated with the following key.
1 Vertex black. First three
2
gastral terga mainly or extensively orange-yellow. On the
.... philippinensis
male the left eye touches the clypeal margin
Vertex often not black; if black then the first three gastral terga either all black or only
one or two terga with orange-yellow bands or markings. On the male the left eye does
....... 2
not touch the clypeal margin
Yertex usually black; if not black the second gastral tergum entirely or orange-yellow
s;;;i ;;;ffi ;t;h ;;; ;; ;;;; u""0, r".i';i;;:T!-;
- n;;;;; ;;, bi;;k S;;";;
..
band
ducalis
apical orange-yellow
Kojima (1982) found that the pronotum of the female in dorsal view
is moderately convex laterally on V. philippinensis but less convex or
often nearly straight on V. tropica and V. ducalis.
NESTING BIOLOGY
The nesting biology of V. ducalis is well known from a study of the
Japanese colour form in southern Japan (Matsuura, 1984). Nests are
found in covered aerial positions or in large cavities underground.
Matsuura (1980, pers. comm.), from a sample of.72 nest sites, found 25
in attics, 7 in hollow trees, 9 in other covered aerial sites and 31
underground. Martin (pers. comm., 1990) found three nests on the
Ryukyu Islands, Japan of which one was inside a hollow log, one in a
small rock cave and one underground. Yamane, So (1977) found nests
in Japan in hollow trees and underground and in Taiwan in attics and
underground. Sonan (1929) found nests of V. ducalis in Taiwan in the
gaps of the walls of dwelling houses.
Over-wintering queens emerge from the end of May until early June
and the nest is founded by a single queen from early to mid-June. The
first workers emerge by the end of July and the sexuals by late August.
The queen usually dies in August and the demise of the colony is from
late September until early October. There are about four months of
colonial activity and this may be considered a short cycle.
The queen nest consists of a comb of up to 35-40 cells, covered by
an envelope shaped like an inverted bowl with a wide ventral opening.
The mature nest has two or three combs of about L70 cells although
some have over 300 cells. The envelope consists of a few plate-like
sheets with imperfect air pockets and its wide basal opening exposes
the lowermost comb.
The mean developmental period of a worker is 35-36 days (eggs 6
days, larvae l2-I3 days, sealed brood 17 days). The mean length of life
of an adult worker is 35 days with most workers having died by their
50th day. The average colony probably produces about 45 workers, 40
males and 45 queens although as many as 71 workers, 6L males and 75
queens has been recorded from one colony. The maximum mean
number of workers found in a colony is about 15 although up to 40
workers have been found. Thus the colonies of V. ducalis are rather
small. Matsuura (1983) also reported that the Chinese colour form of V.
230
ducalis
ENTOMOLOGIST'S MONTHLY MAGAZINE
in Taiwan and south China produced small
nests
like
the
Japanese colour form.
V. ducali.r seems to be dependent on the brood
of polistine wasps,
particularly Polistes jadwigae Dalle Torre, as a source of food.
Matsuura & Yamane (198a) related the four month duration and small
size of colonies of V. ducalis to the four month nesting cycle of Polistes
colonies and the low density of Polistes colonies in any one area. They
estimated that a colony of V. ducalis would need 150-200 Polistes
colonies for full development.
Sakagami & Fukushima (1957) also give information about the nesting behaviour of the Japanese colour form of V. ducalis (which agrees
with that given by Matsuura, 1984), and note the small nest size, with
each comb rarely consisting of more than 100 cells. Yamane, So (1977)
reported nest data which agreed with that given by Matsuura (1984).
The only available information about the nesting biology of V.
philippinensis is from the examination of an underground colony by
Starr (1987), Starr & Jacobson (1990) taken at the end of September.
The nest consisted of four combs with 1560 cells and was estimated to
have produced 1480 adults although a cell was never used to produce
more than one adult. Large and small cells were clearly discernible.
Each sex showed a bimodal size distribution although the size difference between males was not aS clear aS that between gynes and
workers. This colony was clearly much larger than any recorded f.or V.
ducalis.
Little information is available on the nesting biology of. V. tropica.
Pagden (1952) recorded the Malayan colour form as building its nest
inside aerial structures, e.g. hollow trees, under roofs and underground. Chan (1972) also recorded the Malayan colour form as building
its nests inside aerial structures such as roofs or inside artificial structures such as sheds and boxes. Kojima (1982) recorded a colony of the
north Philippine colour form in the hollow of a dead log which was
partially covered by soil. Matsuura (1983) recorded a nest of the
Malayan colour form in a river bank with some of the envelope visible.
Starr & Jacobson (1990) found six colonies of the north Philippine
colour form nesting underground; the three colonies that were dug up
being 10-20 cm below the surface of the ground.
Matsuura & Yamane (1984) reported that colonies of the Malayan
colour form in central Sumatra could be initiated by more than one
queen and that colonies may contain two to six queens even after the
emergence of the workers.
The nest of V. tropica found by Kojima (1982) in late August consisted of three combs of about 2600 cells. Chan (1972) showed a
photograph of a nest of two or possibly three combs and over 200 cells
are visible on the lowermost comb. Matsuura &" Yamane (1984)
reported that the nests of the Malayan colour form contained 5-6000
cells and produced 500-1000 queens. One nest contained 5667 cells and
ENTOMOLOGIST'S MONTHLY MAGAZINE
23r
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ENTOMOLOGIST'S MONTHLY MAGAZINE
711 workers, 62 males and 245 queens (Matsuura 1983).
Yamane, Sk (1974) found that workers and queens of V. tropica of
the Indian-Chinese colour form were difficult to distinguish by size.
Starr (1987) also referred to the difficulty of separating workers and
queens of the north and south Philippine colour forms because of the
presence of intermediate sized individuals. In this respect V. tropica
differs from V. philippinensis where workers and queens are readily
distinguished.
Van der Vecht (1957) summarised several observations recording
thatV. tropica preys on a variety of social Vespidae including Polistes,
Ropalidia, Parischnogaster and Stenogaster. Matsuura (1983) also
recorded the dependence of V. tropica on the larvae and sealed brood
of the Polistinae and Stenogastrinae. The use of such prey is similar to
that of V. ducalis.
Clearly the mature nest size of V. ducalis is small in comparison with
those of. V. philippinensis and V. tropica. These characteristics could
be species specific or a consequence of V. ducalis'only having been
studied in a temperate region and V. philippinensis and V. tropica in
tropical regions. Study of V. tropica and V. ducalis in their overlap
areas of North and South Vietnam and southern China should resolve
this problem.
REFERENCES
Bequaert, J,, 1936, The common Oriental hornets, Vespa tropica and Vespa ffinis,
and their color forms, Treubia, 15:329-351. Buysson, R. du, 1904, Monographie des
gu6pes ouVespa. Annls Soc. ent. Fr.,72:260-288;1905, Monographie des gudpes ou
Vespa. Annls Soc. ent. Fr.,73'.485-556, 565-634. Chan, K.L., 1972, The hornets of
Singapore: their identification, biology and control, Singapore med. 1., 13: 178-187.
Kojima, J.,7982, The genus Vespa in the Philippines (Hymenoptera, Vespidae), KontyA,
50: 434-444. Kojima, J. & Reyes, S.G., 1984, A new subspecies of Vespa tropica from
Cebu Island, the Philippines (Hymenoptera, Vespidae). Kontytt, 52:260-261. Matsuura,
M." 1983, Tropical hornets and honey bees, Insectarium, 20: 4-9; 1984, Comparative
biology of the five Japanese species of the genus Vespa (Hymenoptera, Vespidae), Bull.
Fac. Agric. Mie Univ.,69: 1-131. Matsuura, M. & Yamane, Sk., 1984, Comparative
ethology of the Vespine Wasps, Hokkaido Univ. Press. Pagden, H.T., 1.952, Hornets in
Malaya, Malay. Nat. J., 7: 78-83. Sakagami, S.F. & Fukushima, K., 1957, Some
biological observations on a hornet, Vespa tropica var. pulchra (Du Buysson), with
special reference to its dependence on Polistes wasps (Hymenoptera), Treubia,24:
73-82. Sonan, J.,1929, Research on Taiwan wasps. Trans. nat. Hist. Soc. Formosa, 19:
136-1.49. Starr, C.K., 1987, A colony of the hornet Vespa philippinensrs (Hymenoptera:
Vespidae), Insectes soc., 34'. 7-9; 1989, More on Vespa tropica subspecies. Sphecos, 18:
6-7. Starr, C.K. & Jacobson, R.S., 1990, Nest structure in Philippine Hornets (Hymenoptera, Vespidae, Vespa spp.). Jap. J. Ent.,58'. 125-1,43. Vecht, J. van der, 1957, The
Vespinae of the Indo-Malayan and Papuan areas (Hymenoptera, Vespidae), Zool. Verh.,
Leiden,34: 1-83; 1959, Notes on Oriental Vespidae, including some species from China
and Japan (Hymenoptera, Vespidae), Zool. Meded. Leiden, 36:205-232. Wilson, E.O.
& Brown, W.L., 1953, The subspecies poncept and its taxonomic applications, Sys/.
Zool., 2: 97-1.1.1. Yamane, Sk., 1974, On the genus Vespa (Hymenoptera, Vespidae)
from Nepal. Kontytt, 42:29-39. Yamane, So., 1977, Collecting techniques for Vespa
nests, Seibutsukyozai, 12: 42-59.
University College of Ripon and York St John, Lord Mayors Walk, York YO3 7EX.
Iuly 3rd,7990.