P ROCEEDINGS, 193 1 19

Drosophila funebris as a Host of the Fungus Stigmatomyces

H UG H L EECH

u N IVERSITY OF BRITISH COLUMBIA

On F ebruary 10 th, 193 1, a Drosophilid fl y appeared un m y bed room w indow. ~O \N D rosophilid s a re apt to turn up on a ny winduw at any lime o f the vear a nd somehow a h\-avs li nd t heir wav into m v c\'ani de j:lr. l1ut this o n-e was nut behavin g Cj ulte normally ; it- had e i t il e ~ been ~ >u t: the nig ht before and had fa ll en into a dust heap, or it was decidedly ill. Therefore I made cel-tain that it entered my poison bottle immediatelv. l"pon examinatiun later, the t-l y wa s found to be quite heavily infested wi t h what seemed li ke m inute, s woll en, yell ow ish bristles pm ­ jecting at odd angles irom its body- not at a ll n o r~11al bri stles of D iptera and certainly not the a rma ture o f the norma ll y smooth-looking Droso­ phila. Professor Spencer of the Department of Zoology a t the U ni ve rsity, to whom I submitted the t-l y, suggested that the "bri stles" were probably the fruiting bodies of a species of Laboulbeniaceae a nd this was verified by P rofessor F. Dickson of t he Depa rtment o f Hota ny. A ny form of li fe that mig ht turn out to be parasitic on is \\'orth investi gating so I l()okedup references on this g rowth and fuund that the fungi of the Laboulbeniaceae a re rather cl osely related to the mildews, and thoug h in a ll cases, a re so small a s to necessitate t he :.t id o f a microscope in studying them, yet a re exceeding ly interesting be­ cause of thei r peculi a r habits. Approximately 152 species have been de­ scribed up to t he present, belong ing- to 28 genera and t heir clistri buti onal records show a few unl y in E urope, a few in the tropics of Asi:.t , A fri ca and America, but a compa ratively la rge number of species in l\orth A merica. The known species li ve on insects, particul a rly those t hat a rc found in damp places or a re entirely acquatic such as certain Diptera, ~e ur op t era and Coleoptera. They seem to favour beetles especially as husts possibly because of the fact that nlany beetles hiberna te as adults a nd so a re admirably adapted to ca lTy ing the fungi through the winter. Armed with t hi s informa tion. a sea l-ch was made of the house in w hich the diseased had appeared and several more in fested specim ens were founc! on the windm.\-s in the ha sem ent. A further search showed that this species of (-Iy was breeding in a mixture of rotten potato anc! ca rrot vvh ich was lying in a corner. Curiously enoug h, another species uf D rosophi lid Av was much more num erou s in the basement and proved to be breeding i;l the same materia l but specim ens tOlWc! were entirely free o f the fung us. One of my references, H a rshberger, states (a) that t hese fungi do not annoy or in a ny wav hurt their host s and (b) that they a re otten exceeding ly specifi c in their attachment, being in some cases attached 20 B. C. ENTOMOLOGICAL SOCIETY seems to extend this information for in connecti on w ith the first poir.t (a) in a ll cases the were very obvi osul y bothered by the fun.gp:i and kept incessantly rubbing as much of their bodies as they could reach with their legs. Moreover, in the cases o f the more heavil y in­ fe sted Aie s, there appeared to be a very definite weakening of the hosts whi ch were sluggish, and w hen kept in confinement with uninfested fli es caug ht in the same basement, died very much m o re quickly than the latter. T hi s mig ht, however, be attributed to the fact tha t the infested Aies were probably considerably older than the others. ] n connecti on with the second point (b) namely specificity of attachment on the host, in a ll cases examined the fungus seemed capable of g ruwing on any parts o f the Ai es' bodi es except on the w ings and perhaps on t he eyes. Professur Dicksun vvas kind enoug h t o trace out the material se­ cured and te ll s m e tha t the parasite belongs to the genus Stigmatomyces o f which one species Baeri attacks h o u sef~i es in E urope (Germa ny) and in ;\orth A m eri ca. Anothe l- species of the same genus has been reported as occulTing on fiies of the genus a nd on the same species as those in m y coll ections whi ch] traced out to funebris in Sturtevant's (1921) key. .

T o work out the hi story o f this fungus a nd its method of a ttaching itself to the Hi es, I am maintaining culonies of funebris (whi ch is re­ po rted chi e Ay as breeding in vineg'a r vats but also in decaying matter especially in material which has been preserved in formalin and has dried out) and P rofessor Dickson in investigating the sporulation a nd g rowth of the fung us. U ntil further w' ork has been done, we cannot defin itely state the na me o f this species o f Stigmatomyces which differs from m ost of the m embers of the Order Laboulbeniaceae in being a n aerial form and in being so large as to be readily perceptible to the naked eve.

Acknowledgment. I w ish to off er thanks to Dr. F. Dickson for hel p in connection w ith t hi s fung us ; to Dr. J. H. McDunnoug h of the Canadian National Museum a t Ottawa to whom specimens o f the Aies were sent a nd throug h him, to D r. J. M . A ld ri ch who veri fied our identificati on of it as being Droso, phila funebris. ·

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