CHAPTER 3

SECTION 6. Order HYMENOPTERA

Superfamily SIRICOIDEA (horntail wasps)

The first information regarding the horntails of the Kuril Islands is cited by K. Takeuchi (Takeuchi, 1934, 1956). He reports the discovery of only two species, Xiphydria camelus L. and Urocerus antennatus Marl., on the Kurils. The materials we collected have substantially expanded the conception of the fauna of the Kurils horntails, increasing the list of their species to 14. We have published these data (Krivolutskaya, Stroganova, 1966), and they were included in the synoptic study of S. Kuwayama (Kuwayama, 1967) on the entomofauna of the Southern Kurils. All the material was identified by V. K. Stroganova and used by her in writing the generalizing study of the horntails of Siberia (Stroganova, 1968).

The superfamily Siricoidea is represented on the archipelago by two families (Xiphydriidae and Siricidae), which include 6 genera: Euxiphydria (1 species), Xiphydria (5), Sirex (2), Xeris (1), Xoanon (2), and Urocerus (3). It is entirely possible that several additional rare species which are prevalent on adjacent territories, in Japan, on Sakhalin, and Primorskiy Kray, such as Xiphydriola amurensis Sem., X. buyssoni Knw., X. alnivora Mats., X. kawakamii Mats., and X. kuccharonis Mats., will be found. The horntail fauna on the Kurils is negligibly depauperated as compared with the adjacent territories. Almost half the known species of Siberia and the Far East (29), and even a somewhat greater number than in Kamchatka (7) and on Sakhalin (12), live here, but at the same time, so widespread a genus as Tremex is absent.

The horntails are typical sylvan insects; therefore, their distribution on the archipelago is limited to the southern islands, where there are true forests. All 14 species are present on Kunashir, 5 on Iturup, and only 2 on Shikotan. Not one species is known so far on Urup, although it is entirely possible that representatives of the Xiphydriidae, associated with the birch and the alder, as in the north of the range, may be on that island.

Dark coniferous-broadleaved forests and dark coniferous forests serve as the principal habitats of the horntails on the Kuril Islands. The majority of the species are associated with dark conifers, the spruce and the fir. These are Sirex juvencus L., S. ermak Sem., Xeris spectrum L., Xoanon mysta Sem., Urocerus antennatus Marl., U. gigas taiganus Bens., and U. umbra Sem. More often they appear in logging sites on stacks of nonstripped timber, along the margins of old coupes on weakened and wind-thrown trees, and less often in healthy woods with a dense canopy. Habitations of horntails were not found on larch or in cedar elfin wood. By the way, no one has found horntails on Pinus pumila; it is evidently not inhabited by these insects.

Horntails associated with the alder (Xiphydria eborata Knw., X. palaeanarctica Sem., X. jakovlevi Sem. et Guss., X. camelus L.), the birch (Euxiphydria potanini A. Jak., Xiphydria camelus L.), and the maple (Euxiphydria potanini A. Jak., Xiphydria ogasawaria Mats.), are present in stands with a predominance of leafed species. According to our observations, other leafed species were not inhabited by horntails. Xiphydria ogasawarai [sic] Mats. is distinguished by an interesting nutritional specialization. It is linked with the painted maple (Acer pictum) on the Kurils, while on the continent, according to the observations of V. K. Stroganova (1968), it is linked with the Mono maple (Acer mono). Both, according to the data of A. I. Poyarkova (1933), are the most ancient species of maples. The trophic linkages are somewhat altered in some horntails under the islands' conditions. In particular, X. camelus L. develops mainly on birch on the continent, while on the islands the alder is its preferred variety; on the other hand, here it lives much more rarely on the birch.

The majority of the horntails are encountered comparatively infrequently on the Kurils. Only 4 species can be considered common: Xiphydria eborata Knw., X. camelus L., Xeris spectrum L., and Urocerus antennatus Marl. Under favorable conditions they can probably reproduce en masse, but foci were not formed during the years of our observations.

The faunistic composition of the Kuril horntails and the types of their ranges point to an eastern origin of at least 2/3 of the species living on the archipelago. The groups of Ussuri-Island (Xiphydria eborata Knw., X. ogasawaria Mats., X. jakovlevi Sem. et Guss., X. palaeanarctica Sem.) and Manchurian (Euxiphydria potanini A. Jak., Xoanon mysta Sem.) species associated mainly with leafed varieties constitute the basic nucleus of the fauna. The range of the first group is limited by the borders of Primorskiy Kray, partially by the Korean Peninsula, Japan, Sakhalin, and the Southern Kuril Islands. The Manchurian species are somewhat more widespread to the north and west; they are also encountered in the Amur basin, Eastern Siberia, and North China. Xoanon matsumurae Rohwer is distinguished by the narrowest (Sakhalin-Kuril-Japanese) range, but this species requires further specification, as does its range.

Urocerus antennatus Marl., which is prevalent in regions bordering the northern part of the Pacific Ocean, is evidently of Beringian origin: it is known in North America, Sakhalin, the Southern Kurils, the southern spurs of the Sikhote-Alin' mountains, Japan, and mountainous areas of the Korean Peninsula. The range of this horntail has yet to be adequately studied; in particular, it is unknown on Kamchatka, and so far it is unclear whether this involves a discontinuity of the range, or rare incidence on the peninsula.

V. K. Stroganova (1968) assigned U. umbra Sem. to the Eastern Siberian species. However, we are inclined to regard its range to be Southern Okhotsk, since all the known finds of this rare horntail have been made on the territories adjoining the southern part of the Sea of Okhotsk and the mountainous portions of Sikhote-Alin'.

The widely distributed species may be regarded as northern-boreal; they are associated, in the overwhelming majority of instances, with coniferous varieties; Xiphydria camelus L., which develops on the birch and alder, is the only exception. These are horntails which mainly inhabit the taiga zone of Siberia and the northern forests of Europe. Latitudinally they may be differentiated with respect to the extent of their range into the holarctic (Xiphydria camelus L., Xeris spectrum L.), transpalaearctic (Sirex juvencus L., Urocerus gigas taiganus Bens.), and eastern Siberian (Sirex ermak Sem.) species. Urocerus gigas taiganus Bens. gravitates more to the eastern Siberian group, since it is represented by a characteristic eastern subspecies.

In view of the fact that we have previously published the data on nearly all the species collected on the Kuril Islands (collection points, dates, number of specimens), we present a complete list of the Kuril horntails in Table 14.

Family APIDAE (bees)

Subfamily Bombinae (bumblebees)

Bumblebees on the Kuril Islands are not so diverse as are other representatives of the order Hymenoptera. Only 7 species were known here until recently (Sakagami, 1954; Panfilov, 1956). S. Kuwayama (Kuwayama, 1967) added 1 more species and 1 subspecies, and reduced B. florilegus Panf., described by D. V. Panfilov (1956), to a synonym for Bombus japonicus Fr. Our materials have enlarged the list of Kuril bumblebees by 9 additional species, raising its number to 18. All of our collections relating to the subfamily Bombinae have been examined and identified by D. V. Panfilov. Information on the general distribution of particular species has been borrowed from the articles enumerated and the study of A. S. Skorikov (1922).

The bumblebees of the Kuril Range that are known at present have been assigned to two genera - Bombus (17 species) and Psithyrus (1). Of these, 4 species have been defined only to the generic level and require identification. The bumblebees are distributed more evenly throughout the territory of the archipelago than the groups of insects considered above: 6 species have been noted on Shikotan, 10 on Kunashir, 3 on Iturup, 6 on Paramushir, and 4 on Shumshu. Bombus japonicus Fr. is especially widely distributed; it is encountered on all the islands we have examined, as well as on the islands of Ketoi, Rasshua, Shiashkotan, Onekotan, and Alaid; there is no information regarding its being on the Malaya Kuril Range, where seemingly it should be found. Half of the species (9) live on several islands, mainly on two (6). Ten species have been recorded on only one of the islands: 5 on Kunashir, namely B. diversus Smith, B. atrocaudatus Vogt., B. schrenkii Moraw., B. hypnorum calidus Er., and Bombus (Pratobombus) sp. 1; 2 on Shikotan, namely B. tersatus Smith and Bombus (Pratobombus) sp. 2; Bombus (Pyrobombus) sp. on Iturup; Bombus (Pratobombus) sp. 3 on Urup; and B. jonellus Kby. on Paramushir. Two species (B. yezoensis Mats., B. tichenkoi Skor.) have a disrupted range within the limits of the Range: they are known on Kunashir and the northern islands, but are not found on the remaining islands.

The habitats of the bumblebees are quite diverse. They do not manifest strict confinement to certain plant formations, since they are associated with flowering vegetation. Based on our observations, three principal types of eco-areas visited by bumblebees can be distinguished on the Kuril Islands: meadows, forest clearings, and forests. The greatest number of species and number of individuals of each of them are encountered on meadows occupying marine terraces, coastal slopes, lower courses of wide river valleys, and necks. B. japonicus Fr., B. hypocrita Pérez, Bombus (Pratobombus) sp. 2, and some others remain here constantly on the southern islands among the lushly flowering grasses; on the central islands, B. japonicus Fr. and Bombus (Pratobombus) sp. 3; and on the northern islands, B. albocinctus Smith, and B. tichenkoi Skor. and Psithyrus bohemicus Saidl. Bombus japonicus Fr. visits eagerly during the blossoming of the wrinkled rose (Rosa rugosa) scrub, which densely covers the sand dunes along the seacoasts.

Bumblebees are encountered in somewhat smaller numbers in forest clearings, even if they are fairly diverse here, especially in clearings amidst broadleaved-dark coniferous forests, which almost all species from the meadows enter; bumblebees which are characteristic for the forest eco-areas (Bombus hypnorum calidus Er., B. atrocaudatus Vogt., B. konakovi Panf., and on the northern islands, B. jonellus Kby.) are encountered along with them. The fewest bumblebees have been observed in forests with a dense canopy and in thin forests with a Kuril bamboo cover. The ubiquitous B. japonicus Fr. and Bombus (Pratobombus) sp. 2, as well as B. jonellus Kby., B. konakovi Panf., B. albocinctus Smith, and Psithyrus bohemicus Saidl., penetrate here. But bumblebees mainly prefer open areas, well aerated and well warmed by the sun.

These insects attract attention because of their dramatic coloring, rather large sizes, and rapid flight. Some of them (Bombus japonicus Fr., B. albocinctus Smith, B. hypocrita Pérez) are encountered in fairly large numbers; landscape forms are found here and there, and, along with individual representatives of other orders (butterflies, beetles, dipterans), impart distinctive color to the Kuril entomofauna.

We do not have at our disposal data on the bumblebee fauna of Kamchatka, Sakhalin, the continental Far East, and Japan; therefore, it difficult thus far to judge the degree of its paucity. However, it is already possible to compare the notion of the genetic associations of the Kuril bumblebees and the zoogeographic character of their fauna. Based on types of ranges, the bumblebees inhabiting the Kuril Range are divided into four zoogeographical groups: the palaearctic (4 species), the Okhotsk (2), the Manchurian (1) and the island (7).

The palaearctic group consists of the forest species: B. schrenkii Moraw., B. hypnorum calidus Er., B. jonellus Kby., and Psithyrus bohemicus Saidl. Of these, the first is prevalent only within Siberia; the second is represented also by a Siberian subspecies; both of these are rare and noted only on Kunashir; the rest have a wide, transpalaearctic distribution; they are quite common on the northern islands; they are not encountered on the remaining areas of the archipelago. The Okhotsk group is represented by two species: B. tichenkoi Skor. and B. albocinctus Smith. Both are confined mainly to the northern islands, although B. tichenkoi Skor. is also found on Kunashir. The only representative of the Manchurian group is B. sapporoënsis Cocker, known on Sakhalin, in Primorskiy Kray, Northeast China, the Korean Peninsula, and Japan, was found on the southern islands (Kunashir and Shikotan), where it is encountered sporadically. The island group, which combines several subgroups, constitutes the principal nucleus of the Kuril bumblebee fauna: the Kuril-Hokkaido (B. yezoensis Mats., B. japonicus Fr.), the Kuril-Japanese (B. tersatus Smith, B. hypocrita Pérez), the Sakhalin-Kuril-Japanese (B. diversus Smith, B. atrocaudatus Vogt.), and the Kuril (B. konakovi Panf.). Clearly, species as yet unidentified must be assigned to this group.

Two species, the Kuril-Hokkaido B. yezoensis Mats. and the northern Okhotsk B. tichenkoi Skor., which are known on Kunashir and the northernmost islands, but have not been found in the central portion of the Range or even on Iturup, are distinguished by an interesting distribution within the limits of the archipelago. Such a discontinuity of the archipelago may suggest the existence of a land bridge between northern and southern parts of the Range at a particular stage of the geological history, which was subsequently destroyed.

The Kuril-Hokkaido species which do not penetrate south of Hokkaido, despite the fact that they are good fliers and are quite numerous on the Southern Kurils, represent a highly characteristic group. It is difficult to hypothesize that these large, impressive insects would not be noticed in Japan.

Thus, the bumblebee fauna of the Kuril archipelago is highly zoogeographically diverse and is somewhat distinct from other groups of insects.

!1. Bombus (Hortobombus) yezoensis Mats. (=B. (Hortobombus) diversus Smith). K - Tyatino, Gemerling villages; P, Sh - according to the data of Kuwayama (Kuwayama, 1967). A Kuril-Hokkaido species, prevalent on the Northern Kuril Islands, K, and Hokkaido. S. F. Sakagami (Sakagami, 1954) distinguishes the form living on the northern Kurils as a special subspecies B. yezoensis kurilensis.

!2. Bombus (Hortobombus) tersatus Smith. Sh - according to the data of Kuwayama (Kuwayama, 1967); we did not encounter it. A Kuril-Japanese species. Known on Sh, Hokkaido, Honshu.

*3. Bombus (Hortobombus) tichenkoi Scor. K - env. of the villages of Alekhino, Sernovdosk, Golovnino, Kosmodem'yansk; outer dates of collection 6/29-8/27; 12 spec. in all; P - env. of the village of Shelekhovo, Aug. 11, 1964, 2 spec. Inhabits meadows close to sea shores, as well as clearings amid elfin woods and coniferous-broadleaved forests growing on coastal slopes. A northern Okhotsk species, known, in addition to the Kuril Islands, on the east coast of the Kamchatka Peninsula and Karaginskiy Island.

4. Bombus (Diversobombus) diversus Smith. K - between the village of Tyatino and Cape Gemerling, the villages of Yuzhno-Kuril'sk and Golovnino. Cited according to the data of Kuwayama (Kuwayama, 1967). An Island-Sakhalin-Kuril-Japanese species. prevalent on K, Sakhalin, Hokkaido, Sikoku, Kyushu.

*5. Bombus (Diversobombus) atrocaudatus Vogt. (=D. ussuriensis f. atrocaudatus Skor.). Env. of the villages of Alekhino, Sernovdosk, Goryachiy Plyazh, Yuzhno-Kuril'sk, Kosmodem'yansk. Outer dates of detection 6/29-8/27; 14 spec. in all. Encountered primarily in clearings amid dark coniferous-broadleaved forests and dark coniferous forests, more rarely on coastal meadows. A Sakhalin-Kuril-Hokkaido species. Observed only on K within the limits of the Kuril Range.

6. Bombus (Adventirobombus) konakovi Panf. Sh - env. of the village of Malokuril'sk, Cape Kray Sveta, Aug. 21-27, 1964, 9 spec.; I - env. of the villages of Lesozavodsk, Reydovoye, Lesozavodskiy Neck, June 30-Aug. 20, 1963; 16 spec. in all; U - env. of the village of Podgornoye, Aug. 8, 1963; 1 spec. Forest clearings and various types of coniferous-broadleaved forests and elfin wood stands on slopes are the principal habitats. Occasionally encountered on meadows. Has been described on the Kuril Islands and is thus far unknown at other sites; may therefore be considered a Kuril endemic. However, the species independence of this species is doubted by Japanese entomologists (Sakagami, 1954; Kuwayama, 1967), and they identify it with B. schrenkii Morav., to which it is in fact very close.

!7. Bombus (Agrobombus) schrenkii Moraw. K - the villages of Alekhino, Sernovdosk, Golovnino (Kuwayama, 1967). In addition to K, listed on Sakhalin and Siberia. S. Kuwayama cites 2 subspecies of B. schrenkii Moraw. for the Kuril Islands, under the provisional designations ssp. 1 and ssp. 2. The former is prevalent on Sh and I; it is identified with B. konakovi Panf.; the latter is regarded as a special Kunashir subspecies.

8. Bombus (Pratobombus) hypnorum calidus Er. K - env. of the village of Goryachiy Plyazh, July 26, 1961, 1 spec., in a clearing in a dark coniferous-broadleaved forest. Very rare on the Kuril Islands. A transpalaearctic sylvan species, represented by a special subspecies, prevalent to the east of Altai to the Pacific Ocean.

*9. Bombus (Pratobombus) jonellus Kby. P - env. of the city of Severo-Kuril'sk, env. of the village of Shelekhovo, July 16-August 9, 1964, 4 spec.; clearings amid alder elfin wood; meadow vegetation on seaside terraces. A transpalaearctic boreal species, prevalent in the northern part of the Palaearctic, northward to the Arctic Circle.

10. Bombus (Pratobombus) sp. 1. K - Pacific Ocean shore in the region of Petrov Cape, July 27-28, 1964, 3 spec., on meadows along seaside terraces and in forest clearings.

11. Bombus (Pratobombus) sp. 2. Sh - env. of the village of Malokuril'sk, August 21-27, 1963, 13 spec.; inhabits thin broadleaved-dark coniferous forests on mountain slopes.

12. Bombus (Pratobombus) sp. 3. U - env. of the village of Podgornyy, shores of Lake Tokotan, August 8-12, 1963, 3 spec.; meadow vegetation on seaside terraces and slopes.

13. Bombus (Pyrobombus) sp. I - between the village of Kuybyshevo and Kasatka Bay (Kuwayama, 1967).

14. Bombus (s. str.) japonicus Fr. et Wag. (=B. (s. str.) florilegus Panf.). K - Veslovskiy Peninsula, August 7, 1961, 7 spec.; Sh - env. of the villages of Malokuril'sk, Krabovoye, the road to Cape Kray Sveta, August 21-27, 1963, 10 spec. in all; I - env. of the city of Kuril'sk, the flood plain of the Kurilka River, section between the villages of Kuybyshevo and Peschanyy, the village of Goryachiye Klyuchi, env. of the village of Lesozavodsk, the Pacific Ocean coast south of the village of Burevestnik, outer dates of collection 7/1-8/27; 21 spec. in all; U - env. of the village of Podgornyy, shores of Lake Tokotan, August 8-13, 1963, 12 spec. in all; S - env. of the village of Skalistyy; Kostochko Neck, September 8-9, 1963, 12 spec. in all; S. Kuwayama (Kuwayama, 1967) cites places where this species was found on more northern islands as well - Ke, R, Sh, O, A, P, and Shu. Various meadow eco-areas, but mainly meadows on coastal marine terraces, as well as wrinkled rose scrub, are the typical habitats. One of the most numerous bumblebees on the Kuril Range, in places it is a landscape form. In addition to the Kuril Islands, it is encountered on Hokkaido; has not been observed further south.

15. Bombus (s. str.) hypocrita Pérez. (=B. sapporensis Mats.). K - the villages of Yuzhno-Kuril'sk, Goryachiy Plyazh, Sernovdosk; Sh - according to the data of Kuwayama (Kuwayama, 1967). A Kuril-Japanese species; in addition to the Southern Kurils, widespread in Japan (Hokkaido, Honshu, Sikoku, Kyushu).

*16. Bombus (s. str.) sapporoënsis Cocker. (=B. ikonnovici Scor.). K - env. of the village of Alekhino, June 29-August 2, 1963, 13 spec.; Sh - section between village of Malokuril'sk and Krabovoye, August 26, 1963, 2 spec. Encountered on forb meadows. A Manchurian species, known also on Sakhalin, the southern regions of Primorskiy Kray, Northeast China, and the Korean Peninsula.

*17. Bombus (s. str.) albocinctus Smith. P - env. of the city of Severo-Kuril'sk, the northwest coast, env. of the village of Shelekhovo, region of Konusnaya Mountain; outer dates of detection July 16-August 11, 1964, 20 spec. in all; Shu - west coast near the village of Kozyrevsk, July 29, 1964, 3 spec. Representative of the Okhotsk group. Prevalent on the Northern Kurils, the Kamchatka Peninsula, the Okhotsk continental littoral, in Khabarovskiy Kray, in the north of Primorskiy Kray, and on Sakhalin.

*18. Psithyrus (Ashtonpsithyrus) bohemicus Saidl. - the parasitic bumblebee. P - env. of the city of Severo-Kuril'sk, July 16-August 11, 1964, 4 spec.; Shu - env. of the village of Kozyrevsk, July 29, 1964, 1 spec. Encountered singly in clearings amid mixed elfin woods. It is known that the larvae parasitize in the nests of bumblebees. A transpalaearctic boreal species. It evidently penetrated the Northern Kuril Islands from Kamchatka.