Farris, S. H.

English

Journal of the Entomological Society of British Columbia

30 PIlOC. ENTOMOL. Soc. Burr. COL1: MIlIA, VOL. 62 (1965 ), DEC. 1, 1965 References Bishopp, F. C. and Trembley, H. L. (1945). Distribution and hosts of certain North American ticks. J. Parasitology 31: 1-54. Cooley, R. A. (1938). The genera Dermacentor and Otocentor (Ixodidae) in the United States, with studies in variation. U.S. Nat. Inst. Health Bull. 171: 89 pp. Cowan, I. McTaggart (1944). Parasites, Diseases and Injuries of Game Animals in Banff, Jasper, and Kootenay National Parks. Canada Dept. of Mines and Resources. Gregson, J. D. (1958). Host susceptibility to paralysis by the tick Dermacentor andersoni Stiles (Acarina: Ixodidae). Canad. Ent. 90 (7): 421-424. Klebenow, D. A. (1965). A montane forest winter deer habitat in Western Montana. J. Wildl. Mgmt. 29: 27-33. Milne, A. (1949). The ecology of the sheep tick, Ixodes ricinus L. Host relationships of the tick. Parasitology" 39: 167-172. Riek, R. F. (1962). Studies on the reactions of animals to infestations with ticks. Aust. J. Agric. Res. 13: 532-550. Trager, W. (1939). Acquired immunity in ticks. J. Parasitology 25: 57-81. Wilkinson, P. R. (1962). Selection of cattle for tick resistance, and the effects of herds of different susceptibility on Boophilus populations. Aust. J. Agric. Res. 13: 974-983. Wilkinson, P . R. (1964). Factors affecting distribution of the Rocky Mountain wood tick (Dermacentor andersoni Stiles) in British Columbia. (Abstract). Bull. Eco!. Soc. America 45: 53. REPOSITORIES OF SYMBIOTIC FUNGUS IN THE AMBROSIA BEETLE Monllrthrum stutellllre LEC. (COLEOPTERA :SCOL YTI DAE) By S. H. FARRIS Department of Forestry of Canada Forest Research Laboratory, Victoria, B.C. Introduction Specialized structures or mycangia that contain symbiotic fungi have been identified by several workers in a number of scolytid ambrosia beetles. Since Francke - Gro.;;mann (1956a) first described structures with this function in Trypodendron lineatum Oliv., workers have report-ed mycangia in other s p e c i e s (Francke - Grosmann, 1956b, 1958; Fernando, 1960; Schedl, 1962; Finne-gan, 1963; Farris, 1963; Batra, 1963) . Only females of most species possess these structures but in eorthylus punctatissimus Zimm. (Finnegan, 1963) , Gnathotrichus retusus Lec., and G. sulcatus Lec. (Farris, 1963) only males have mycangia. Batra (1963), working with Monar-thrum taciatum Say and M. mali Fitch found mycangia to be enlarge-ments of the forecoxal cavit.ies in the female beetles. Because of this and the previous work of Francke-Gros-mann and Batra (Francke-Gros-mann, 1963) with these two species of Monarthrum it seemed reasonable to suspect that Monarthr1lm scuteZ-lare Lec. would possess mycangia ~n a similar position. This insect attacks logs or weakened trees of the genus Quercus from British Columbia south to California (Chamberlin, 1958), its host on Vancouver Island being Q. garryana DougI. Materials and Methods Adult beetles were excavated from their host and either l"ill- fixed in alcoholic Bouin's solution for section-ing or stored a live in a refrigerator for dissecting and culturi.ng later. Specimens for sectioning were de-hydrated with tertiary bntyl alcohol (Johansen, 1940), embedded with Fisher 's "Tissuemat," and serial sag-ittal sections were cut at 15 and 20 microns on a rotary microtome. The sections were treated with a modified Gram-Weigert stain (Leach, 1940) and counter stained with eosin Y, previously used by Fernando (1960), PROC. E "'TOllIOL. Soc. BUIT. COLlJlIWrA, VOL. 62 (1965), DEC. 1, 1965 Illustrations Fig. 1.-Sagittal section, 15 microns, of a whole 'i? M. scutellare stained with a modified Gram-Weigert stain, showing the location (cc) of the mycangia . 22X. Fig. 2.-Sagittal section, 20 microns, of the enlarged 'i? forecoxal cavity (cc), stained with a modified Gram-Weigert stain to show the fungous cells (fc), glandular tissue (gc), brush (b) and coxal indentation (ci). 180X. Fig. 3.-Sagittal section, 15 microns, of a ~ coxal cavity (cc). 180X. Fig. 4.-Ventral view of ~ and 'i? M. scutellare adults with forecoxae removed to show whitish fungous layer (£1) and complete median ridge in 'i? (mr), and the lack of same in ~. 20X. Symbol Legend cc -Coxal cavity £1 -Fungous layer gc -Gland cells b -Brush ci -Coxal indentation fc -Fungous cells mr -Median ridge fcx -Forecoxae 31 32 PHOC. E N T 0 Jl10L. Soc. BIl),!". C OL1,;M HIA , V OL 62 ( 1965), D EC. 1, 1965 Farris (1963) and Farris and Funk (1965) , to differentiate fungous de-posits from other tissue in beetle sections. To corroborate findings in the stained se::!tions, the forecoxae were removed from refrigerated beetles of both sexes and the coxal cavities examined under a dissecting micro-scope. Cultures were made from the cavity contents and the fungns iden-tified as Monilia brunnea Verrall (Funk,1965). Results and Discussion Stamed sagittal sections of female beetles showed enlargem~ ~1 ~s .')f the fore coxal cavities (Figs. 1 alld 2) containing blue and pink coloured fungous material consisting of glob-ose cells and short hyphal filaments (Fig. 2) . The male forecoxal cav-ities were not enlarged (Fig. 3) a nd did not contain fungous material. The meso coxal and metacoxal cavities of both sexes were not enlarged and likewise contained no fungous ma-terial. A whitish layer of fungous material was visible when the fore-coxae of the female were removed from their sockets. This was absent in the male (Fig. 4). After staining with the modified Gram-Weigert stain and eosin Y, some of the globose fungal cells found in the forecoxal cavities show-ed a Gram-positive reaction by re-tair.ing the blue stain, and others showed a Gram-negative reaction by turning pink. When these cells were viewed under polarized light, a por-tion of the walls of the Gram-positive cells was birefringent but no bire-fringence was seen in the Gram-negative cells. The significance of the birefringence is unknown. Fresh fungous material taken from the coxal cavities showed no birefring-ence. The median ridge between the forecoxal ca vi ties of the female is complete, forming part of the my-cangial wall (Fig. 4) separating the two cavities. This ridge is incom-plete in the male (Fig. 4) . The fungous cells are not contained in a structure with a separate spe-ci a lized opening as in T . Uneatum, but lie in a loosely compressed hemis-pherical cake in the cavity (Fig. 2). Within the anterior wall of the cavity in the femal e there is a series of gland cells which appear to lead into the cavity (Fig. 2), but these are absent or greatly reduced in the ma le. In her work with several species of a mbrosia beetles Francke-Grosmann suggested th:1t secretions from similar cells a re ben eficial to the fungous spores . Possibly the gland cells serve a simila r fun ction in M. scutellare. Not only are the female cavities enlarged, making a place for fungus transport, but the forecoxae have a slight indentation which makes the cavity even larger (Fig. 2) . At the anterior edge of this indentation, opposite the glandular tissue, there arises a sci erotized group of bristles forming a brush (Fig. 2) . The bristle.3 are pOinted or bent away from the main body of fungous cells. The orientation of the brush on the coxae indicates that it could move the fungous cells forward and out of the cavity when the beetle walks about in its gallery, thus inoculating the host with the fungus. Schedl (1962) has described simi-lar mycangia and methods of host inoculation in the ambrosia beetles Pterocyclon brasiliensis Schedl and P. nudum Schedl, both from Brazil. Summary Adult female beetles of Monar-thrum scuteZZare Lec. carry symbiotic fungi in mycangia. These are en-largements of the foreco:{al cavities similar to those described by Batra (1963) for other members of the genus. Male beetles do not have these structures. PROC. E :'ITOMOL. Soc. BRIT. COLU ~[BIA, VOL. 62 (1965), DEC. 1, 1965 33 Acknowledgements I gratefully acknowledge the advice received from Dr. J. A. Chapman during this investigation and his assistance in collecting the insect material. Mr. G. R. Hopping, formerly' of the Forest Entomol-ogy and Pathology Laboratory, Calgary, Alberta, kindly identified the beetles. I also wish to thank Dr. A. Funk for cultur-ing the coxal cavity contents; Mr. A. Hedlin and Mr. E. D. A. Dyer for reviewing the manuscript, and Mr. A. Craigmyle for the photographic work. References Batra, Lekh R. 1963. Ecology of ambrosia fungi and their dissemination by beetles. Trans. Kans. Acad. Sci . 66: 213·236. Chamberlin, W. J. 1958. The Scolytoidea of the Northwest· Oregon. Washington, Idaho and British Columbia. Oregon State Monogr. Corvallis (;:,Lu'::. Ent.) 2: 205 pp. Farris, S. H. 1963. Ambrosia fungus storage in two species of Gnathotrichus Eichhoff (Coleoptera: Scolytidae). Can ad. Ent. 95: 257-259. Farris, S. H. and A. Funk. 1965. Repositories of symbiotic fungus in the ambrosia beetle Platypus wilsoni Swaine (Coleoptera: Platypodidae) . Canad. Ent. 97: 527·532. Fernando, E. F. W. 1960. Storage and transmission of ambrosia fungus in the adult Xyleborus fornicatus Eich. (Coleoptera: Scolytidae). Ann. Mag. Nat. Hist. Ser. 13 (2): 475·480. Finnegan, R. J. 1963. The storage of ambrosia fungus spores by the Pitted Ambrosia Beetle, Corthylus punctatissimus Zimm. (Coleoptera: Scolytidae). Canad. Ent. 95: 137-139. Francke·Grosmann, H. 1956a. Zur Ubertrangung der Nahrpilze bei Ambrosiakafern . Naturwissenchaften 43 (12): 286-287. Francke·Grosmann, H. 1956b. Hautdrtisen als trager der Pilzsymbiose bei Ambrosia· kafern. Z. Morph u . Okol Tiere, 45: 275-308. Francke-Grosmann, H. 1958. Uber die Ambrosiazucht holzbrtitender Ipiden im Hinblick auf das System. 14. Verhand. der Deutschen Gesell. f. angewandte Ent. 1957. 139-144. Francke·Grosmann, H. 1963. Some new aspects in forest entomology. Ann. Rev. Ent. 8: 415-483. Funk, A. 1965. The symbiotic fungi of certain ambrosia beetles in British Columbia. Can. J. Bot. In press. Johansen, D. A. 1940. Plant Microtechnique. First Ed. McGraw-Hill Book Company Inc. New York and London. Leach, J. G. 1940. Insect transmission of plant diseases. First Ed. McGraw·Hill Book Co., Inc., New York and London. Schedl, Wolfgang. 1962. Ein Beitrag zur Kenntnis de Pilztibertragungsweise bei xylomycetophagen Scolytiden (Coleoptera). Sitzungsberichten der Osterr. Akademie der Wissenschaften, Mathern. - Naturw. Kl., Abt. 1. 171 Bd., 8. bis 10. Heft.: 363-387. Springer-Verlag, Wien. 

Repositories of symbiotic fungus in the ambrosia beetle Monarthrum scutellare Lec. (Coleoptera: Scolytidae)

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Repositories of symbiotic fungus in the ambrosia beetle Monarthrum scutellare Lec. (Coleoptera: Scolytidae)

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Journal of the Entomological Society of British Columbia