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Seasonal distribution of fungi on house sparrows
[5°9 ] Trans. Br. mycol. Soc. 66 (3) 509-516 (1976)
Printed in Great Britain
SEASONAL DISTRIBUTION OF FUNGI ON HOUSE SPARROWS By Z. HUBALEK Institute of Parasitology, Czechoslovak Academy of Sciences, 166 32 Prague, Czechoslovakia
House sparrows (Passer domesticus L.) were netted each month in 1970 and the seasonal variation of fungi on their feathers was followed. A few species were more frequent on these birds in the warm seasons of the year while many other species were more frequent in the cold seasons. The distribution of other fungi was relatively homogeneous during the course of the year. The specific temperature and humidity relations of the fungi and their seasonal distribution in nature were considered to be major factors determining the seasonal variation of occurrence on the birds. The occurrence of microfungi on free-living birds was followed by Heald & Studhalter (1914), Tiffany, Gilman & Murphy (1955), Pugh (1964, 1965, 1966, 1972), Rees (1967), Evans & Prusso (1969), Pugh & Evans (1970a), Mishra & Tewari (1970), Sheridan (1971) and Hubalek (1972a, 1974a, b, d, 1975). Warner & French (1970) studied experimentally the dispersal of selected fungi by migratory birds. Recently, Hubalek (1975) has observed the annual periodicity of Chaetomiaceae on birds, and Hubalek & Balat (1976) have studied the seasonal occurrence of keratinolytic fungi in the nests of Tree Sparrow (Passer montanus). In this paper, an attempt is made to evaluate the seasonal variations of fungi on the feathers of birds. MATERIALS AND METHODS
The site of collections was the hospital garden of a small city Valtice, Czechoslovakia (16° 45' E, 48° 45' N), situated 195 m above sea level. In this country, the house sparrow is a permanently resident bird, although some individuals can exceptionally move to limited distances. During 1970, fourteen house sparrows were netted monthly (except June, August, September and October when 7 specimens were caught each month). The Japan mist nets were disinfected with 1 % water solution of benzododecinyl(dimethyllaurylbenzylammonium)bromide (' Ajatin' Spofa); during the trapping, the nets were periodically sprayed with 3 % formaldehyde. Each captured bird was lifted carefully to avoid contact of its ventral body part with the hand, and the feathers of the belly, vent region, under tail-coverts and ventral part of tail feathers were smeared with a dry sterile cotton-wool swab immediately in the net; from the same sites, except the tail, 10-15 feathers were plucked off with flamed tweezers
and placed in a sterile test-tube. After being ringed, each bird was released. The swabs were smeared on the same day on 2 plates of Sabouraud's glucose agar (SGA) - one subsequently incubated at 26°C, the other at 37° and on 1 plate of SGA supplied with cycloheximide (0'03 %) and chloramphenicol (0'01 %), which was incubated at 26°. The dishes were observed for a period of 3 weeks. The feathers of each bird were placed individually on 5 sites of 2 Petri dishes with 30 g of sifted sterile garden soil (autoclaved 45 min at 133° and then treated with hot-air 2 hat 160°). Each feather was covered separately with a layer of sterile human hair (one pool of mixed hair, shampooed, rinsed, dried, cut to 2-5 mm pieces, submerged for 5 h in diethyl ether at room temperature, boiled 1 min in distilled water, dried and autoclaved 30 min at 130°). The soil in each dish was moistened with 5 ml of sterile distilled water; the dishes were then placed in the dark at 26°, inspected for a period of 10 weeks, re-moistened when necessary. Dishes were discarded when growth of keratinophilic fungi did not start within the first 4-6 weeks. Simultaneously some of the birds' feathers were laid on sterile water agar (2 % agar in distilled water) incubated at 26° and observed for a period of 12 weeks. During the trapping periods, air-borne fungi were also detected in the neighbourhood of the nets: at a height of 60 em above ground, three SGA plates were exposed for 10 min (subsequently incubated at 26°), two SGA plates exposed for 30 min (incubated at 37°), and 2 SGA plates supplied with the antibiotics were exposed 30 min (incubated at 26°). In addition, two dishes with moistened hair-on-soil substrate were exposed for 20 min and incubated subsequently at 26°. Procedures for isolation, cultivation and identi-
Distribution of fungi on house sparrows
51 0
Table
1.
Weather values ( 1970) of the area examined
8'26 18'47 9'7 2 -1 '13
Mean air relative humidity (%) 7 2'3 73'5 79'4 85 '8
15'18 2'47
74'3 81'1
Mean air temperature
Season (m onth s)
CCq
Spring (III- V) Summer (VI- VIII) Autumn (IX- X I) Winter (I, II, XII) Warm (V-X) Cold (I-IV, XI, XII)
Total precipitation (m m) 100'9 21 9'9 131'0 77'1 06 3 '9 222 '0
Maximum da ily wind gusts in Beaufort degrees (averages) 1'4 2 1'03 1'11 1'3 1 1'04 1'39
Roman numerals = months,
tication of fungi have been described previously (Hubalek 1974a). Weather conditions of the area are surveyed in Table 1. RESULTS
Fungi on birds In all, 1615 fungal isolates of 180 species were obtained from feathers of the birds (T able 2 omitting species of low occurrence). The most common species were in decreasing frequency of occurrence; Arthroderma quadrifidum, Alternaria alternata, Chaetomium globosum, C. funicolum, Ctenomyces serratus, Cladosporium herbarum, C. cladosporioides, Aspergillus fumigatus, Chaetomium murorum, Arthroderma ciferrii, Chrysosporium tropicum, Arthrinium phaeospermum, Chaetomium bostrychodes and Arthroderma tuberculatum, all isolated from at least 20 % of the samples. Several human pathogenic species, isolated on a few occasions only, are not included in Table 2. These were (number of isolations in brackets): Absidia corymbifera (Cohn) Sacco Trott (3); Candida albicans (Rob.) Berkh. (2) ; C. parapsilosis (Ashf.) Lang. Tal. (1); Cephalosporium acremonium Cda. (1); Geotrichum candidum Lk. ex Pers. (3); Microsporum gypseum (Bod.) Guiart Grig. (1); Mucor pusillus Lindt (3); Rhizopus oryzae Went Geerl. (6); and Trichophyton ajelloi (Vanbr.) Ajello (1). On evaluating the seasonal distribution of the common fungi on the birds statistically by means of the chi-square test, the fungi fall -in to three groups ; Fungi which occurred on the birds significantly more frequently in the warm seasons of year; Aphanoascus fuluescens, Arthrinium phaeospermum (autumn/summer), Fusarium spp., Phoma sp., Schizosaccharomyces sp., and possibly Alternaria alternata. Fungi which occurred significantly more frequently in the cold seasons: Arthroderma ciferrii,
A. tuberculatum, Aspergillus fumigatus, A. repens, Chaetomium bostrychodes, C. funicolum, Chrysosporium pannorum, Penicillium breoicompactum, Stachybotrys chartarum, Trichoderma viride, and possibly Botrytis cinerea. Fungi with a relatively homogeneous seasonal distribution on the birds; Arthroderma quadrifidum, Chaetomium globosum, C, indicum, C. murorum, Chrysosporium tropicum, Cladosporium cladosporioides, C. herbarum, Ctenomyces serratus, Monilia spp ., Scopulariopsis brevicaulis. An advantage of ringing the birds was the possibility of following changes in the mycoflora of birds re-caught after certain periods of time. In all, fourteen sparrows were captured twice, and 1 bird thrice, during the year. A comparison of the fungi isolated from feathers of this small number of recaptured birds disclosed marked changes in the fungal spectrum which indicate that there are probably very few, if any, true inhabitants (residents) of the bird's plumage, and that most of the fungi could be considered more properly as transients (visitors) of this microhabitat. Dermatomycoses of the birds Skin scales taken from alopetic lesions on the head of 2 subadult females (1'4 % of all the birds examined) caught in July, revealed abundant dichotomously branched, septate and hyaline hyphae 2'0-3'6,lm in diam, but no dermatophyte was isolated from the lesions. In a similar case two years later a secondary mycosis was found due to Cladosporium herbarum joined to bacterial infection caused by Staphylococcus aureus (Hubalek, 1974c). Fungi in the air From the air at the trapping site and during the times of netting birds, a total of 143 fungal isolates of 51 species were obtained in the course of the year 1970 (T able 3). Dominant air-borne fungi were Cladosporium herbarum, Aspergillus fumigatus,
Z. Hubdlek
511
Table 2 . Statistical evaluation (,\" test ) of the seasonal distribution of fungi isolated from feathers of the house sparrow (ma ny less frequent specie s omitted) SumSpring mer (VI(IIIVIII) V) 28 42
Season No. of birds examined Fungi
Total isolates
Autumn (I XXI )
Winter (I , II,
28
42
XII )
Difference
X)
Cold (X I, XII , (I-IV)
56
84
Warm (V-
D ifference
No, of fungal isolates per bird ----A
Fungi in total
161 5
Alternaria alternata (Fr.) Keiss!' 72 Aphanoascus julvescens (Cke.) Apin. 27 Arthrinium phaeospermum (Cda.) Ell. 38 Arthroderma cijerrii Vars . Aj, 43 A. quadrifidum Daws. Gent!' 81 A. tuberculatum Kuehn 28 A rthroderma all speci es 174 Aspergillus fumigatus Fres. 52 A. repens (C da.) de By. 14 128 Aspergillus all spp, Aureobasidium pullulans (de By. ) Am , 16 Botrytis cinerea Pers. ex Fr. 17 Chaetomium bostrychodes Zopf 36 C. junicolum Cke, 55 C. globosum Kze . ex Fr. 69 C. indicum Cda. 27 C. murorum Cda . 49 Chrysosporium pan norum (L k.) Hugh. 27 C. tropicum Carm. 41 Chrysosporium all spp, 101 Cladosporium cladosporioides (F res.) de Vries 53 C. herbarum Lk . ex Fr. 53 Ctenomyces serratus Eid. 54 Fusarium spp. 21 Glioc/adium roseum (L k.) Bain. 17 MOl/ilia spp , 28 Penicillium breuicompactum Dierckx. 14 P. chrysogenum Thorn. 21 P . cyc lopium West!' 17 Pen icillium all spp. 123 Phoma sp . 11 Rhizopus arrhizus Fisch. 18 Rhizopus all spp. 31 Schizosaccharomyces sp. 26 Scopulariopsis brevicaulis (Sacc.) Bain . 24 Stachybotrys chartarum (Ehr. ex Lk.) Hugh. 21 Trich ocladium asperum H arz 11 Trichoderma viride Pers. ex Fr. 24
11'02 0 ,62 0'05 0'29 0'33 c '69 0'3 1 1"48 0'24 0'02 0,62 0'05 0'17 0'3 6 0 '29 0 '57 0'17 0'19 0'3 1 0'29 0'83 0'3 8 0'57 0'40 0'07 0'10 0'24 0'12 0'05 0'21 1'17 0'12 0'10 0'10 0 '12 0'12 0'02 0'02 0 '10
9'79 0'75 0'3 2 0'29 0'04 0'54 0'00 0,68 0'25 0'04 0'54 0'07 0'00 0'21 0 '18 0'39 0' 18 0'43 0'00 0'39 0'64 0'3 2 0'29 0 '54 0 '3 6 0 '04 0'18 0'00 0 '14 0'04 0'5 0 0' 18 0'11 0'11 0'54 0'14 0'04 0'11 0'04
11'75 0'29 0'18 0'54 0'21 0'43 0'07 0'93 0'36 0'04 0'96 0 '14 0'11 0 '18 0'36 0 '43 0'25 0'43 0'14 0'32 o-Bz 0'50 0'25 0 '25 0'18 0 '25 0 '11 0 '07 0'25 0'07 0'68 0'04 0'07 0 '29 0 '11 0 '14 0'04 0 '21 0'11
13'07 0 '4 0 0'26 0'07 0'5 2 0'60 0 '3 1 1'60 0'60 0'26 1'43 0'19 0'17 0 '24 0 ,66 0'52 0'19 0"40 0'24 0'21 0·60 0 '33 0'33 0'36 0'07 0 '12 0 '24 0 '17 0'19 0'12 0'9 8 0'00 0'21 0 '3 8 0' 07 0' 26 0"43 0'02 0 '3 8
*oO*
t
* ** **
t
** ** * ** oO** NT NT
t
**
t t... I
*
t t t t t
** NT
t
NT NT NT
*
*
NT
* oO**
t
***
NT
**
10'02 0 ,62 0'21 0'3 8 0' 07 0'5 0 0'02 0'7 1 0'27 0'04 0,68 0'09 0'05 0'14 0 '23 0'45 0 '2 1 0'38 0'11 0 '3 6 0'73 0'3 8 0'3 6 0'43 0'21 0'11 0 '13 0'00 0'14 0'07 0'55 0'18 0'07 0'16 0'3 8 0'11 0' 02 0'09 0'04
12'54 0"44 0'17 0'20 0"46 0'63 0'32 1,60 0 '44 0'14 1'07 0'13 0'17 0 '33 0 '50 0'52 0 '17 0'33 0'25 0'25 0'71 0'38 0'39 0'36 0 '11 0 '13 0 '25 0'17 0'15 0 '15 1'10 0 '0 1 0 '17 0'26 0'06 0'2 1 0'24 0'07 0 '26
oO**
t t t
oO*oO
toOoOoO oOoOoO
t
*
*
t
* * *
t t t t t t t t t t t t ** t
toOoOoO *oOoO
t toOoO* t
oOoO*
t
**
'Difference' (X' test ): ***, significant at P < 0'001; ** significant at 0'001 :s; P < 0'01 ; * significant at 0 '01 '" P < 0 '05 ; t insignificant (P > 0'05 ); t approaches the limit of P = 005 j NT not tested because of a low number of isolations.
Aureobasidium pullulans, Fusarium sp. and A. alternata. T he mean n u m b er of species per month va ried little d u r in g the year, but two indistinct peaks ar e indicated in spring and autumn. It was of interest to compare st atistically (ch isquare test) the occurrence of the more common fungi on sparrows' feathers and in the atmosphere.
Three groups of fungi were revealed (Table 4) : Fungi relatively more frequent on the fea thers t han in the air : Arthroderma ciferrii, A . quadrifidum, Chaetomium spp ., Chrysosporium spp. and Ctenomyces serratus (all keratinolytic or keratinop hilic fungi ). F ungi relatively more frequent in t h e ai r than
Distribution of fungi on house sparrows
512
Table 3. Fungi isolated from the atmosphere at the trapping site (most fungi not included in Table 2 omitted here) Sum- AuSeason, 1970 Average no. of fungal species per sample ...
Spring mer
Alternaria alternata Aphanoascusfuluescens Arrhrinium phaeospermum Arthroderma quadrifidum Aspergillus candidus A.flavus
Win-
tumn
ter
Fungi
Isolates in total (= 100 %) 1615 143 % of total isolates Alternaria alternata 4'89 4"46 Aphanoascus fuluescens 1·67 1"40 Arthrinium phaeospermum 2'35 0'7 0 Arthroderma ciferrii 0'00 z·67 A. quadrifidum 0'70 5' oZ Arthroderma all spp. 0'7 0 10'77 Aspergillus candidus 0'5 6 3'5 0 Ai fiaous 2·80 0'37 Ai fumigatus 6'Z9 3'22 2,80 A. repens 0·87 A. versicolor 0·80 3'5 0 Aspergillus all spp. 21·68 7'93 Aureobasidium pullulans 5'60 0'99 Botrytis cinerea 1"40 1'05 2·80 Chaetomium all spp. 15'86 Chrysosporium pannorum 1·67 0'70 Chrysosporium all s; p. 6'25 0'7 0 Cladosporium cladosporioides 3'28 2·80 C. herbarum 6'29 3'28 Ctenomyces serratus 0'00 3"35 Fusarium spp. 5'60 1'3 0 Gliocladium spp. 1·61 0'7 0 2,80 Penicillium chrysogenum 1'3 0 7,6z Penicillium all spp. 12'5 8 Phoma spp. 0·68 3'50 Rhizopus spp. 2'10 1'9 2 Scopulariopsis breuicaulis z·80 1"49 Stemphylium spp. 0-31 4'89 Trichoderma oiride 0'00 1'49
14'3
12'5
18'5
12,6
+
+ +
+
+ +
+
+
A. fumigatus A. nidulans
+
A. repens
+ +
Aureobasidium pullulans Botrytis cinerea
Chauomium spp. Chrysosporium pannorum
Cladosporium cladosporioides C. herbarum Fusarium spp. Gliocladium roseum Penicillium breoicompactum P. chrysogenum Pi oxalicum
Phialophora sp. Phoma sp. Rhizopus arrhizus Scopulariopsis breoicaulis
Explanation: +, fungus detected; detected.
Table 4. Comparison of relative abundance of common fungi isolated from feathers of house sparrow and from the atmosphere at the trapping site (X 2 test, the symbols as for Table 2)
+
+ + + + +
+ + fungus not
on the feathers: Aspergillus candidus, A. flavus, A. repens, A. versicolor, Aureobasidium pullulans, Fusarium spp., Penicillium spp., Phoma spp. and Stemphylium spp. Fungi with similar relative frequency on the feathers and in the air: Alternaria alternata, Aphanoascus fuluescens, Arthrinium phaeospermum, Aspergillus fumigatus, Botrytis cinerea, Chrysosporium pannorum, Cladosporium cladosporioides, C. herbarum, Gliocladium spp., Penicillium chrysogenum, Rhizopus spp., Scopulariopsis brevicaulis and Trichoderma viride. The frequency of occurrence of these fungi on the birds reflects to a considerable extent merely the abundance of the fungal diaspores in the environmental atmosphere. The results show, in sum, that the mycoflora of birds' feathers is in many respects distinct from the local mycofiora of the air. Seasonal changes in variables The frequency of occurrence of several fungi showing marked seasonal distribution patterns on feathers of house sparrows has been correlated
Feathers
Air
Difference
t t
t
* * *** *** ***
t
* ** *** ***
t t
*** **
t
:j:
* ***
t t
* ***
t t
***
t
with monthly weather values in Table 5, using the rank correlation method (Kendall, 1943). Temperature The air temperature is the most powerful climatic factor which influences the seasonal occurrence of fungi on the birds; the negative correlation between the frequency of fungi in total and the monthly mean air temperature is highly significant (P < 0'001). Arthroderma ciferrii, Aspergillus spp., Chaetomiurn funicolurn and Trichoderma viride all showed a significant adverse correlation with the seasonal temperature values. Since the optimal growth temperatures for the great majority of fungi are almost identical (2230°), from the ecological point of view a selective action of low and high temperatures on these organisms is more important. The fungi could be classified according to their temperature relations into psychrotolerant (capable of growth below 6°), thermotolerant (capable of growth above 35°) and
Z. Hubdlek Table 5. Correlation of monthly weather values with the monthly occurrence of several common fungi with a marked seasonal pattern of distribution (Kendall's T rank correlation coefficient values) Mean air temperature
Mean air relative humidity
Total precipitation
Maximum daily wind gusts (averages)
-018
+0'5 6
-0'11
+0'4 2
Arthroderma ciferrii A. tuberculatum
-0'70 -0'50
+0'43 +0'14
-0'24 -0'07
+0'24 +0,64
Arthrodema all spp.
-0,66
+0'14
-0'06
+0·67
Aspergillus all spp.
-019
+0'70
-0'33
+0'14
Chaetomium bostrychodes
-0'14
-0'30
+0'5 2
+ 1'00
C. funicolum
-0,80
+01 1
-oAo
+0'43
Penicillium all spp.
-0'44
+0'09
-0'17
+0'5 6
Trichoderma viride
-0'71
+0'71
-0'33
+0'20
Fungi Fungi in total
The significant (P < 0'05) thermophobic (not surviving 10 days at 37°). The results indicate that the psychrotolerant fungi were frequent on the birds in winter; the thermophobic fungi were never found to have a peak of occurrence in summer, whilst the fungi with a summer peak of occurrence were thermotolerant organisms. Humidity The seasonal occurrence of fungi (fungi in total, Aspergillus spp., Chaetomiumfunicolum and Trichoderma viride) on feathers was subject to variations significantly positively correlated with the changes of mean relative humidity of the air, but this correlation was not so marked as with the air temperature. These two abiotic variables, air temperature and humidity, are significantly negatively interrelated. The fungi could be grouped by a commonly accepted classification of Heintzeller (1939) according to the minimum relative humidity necessary for the growth into hygrophilic (minimum r.h. higher than 90 %), mesophilic (80-90 %) and xerophilic (below 80%). It was found that the hygrophilic fungi (Trichoderma viride, Gliocladium roseum, Chaetomium funicolum) were frequent in humid seasons (winter, autumn) but infrequent in dry seasons. Surprisingly, the xerophilic fungi (Aspergillus repens, A. versicolor) were common in winter and autumn; their abundance in those seasons might indicate the colonization of suitable substrata with massive sporulation.
T
Determining climatic factors Temperature Humidity Temperature Wind (Temperature) Temperature Wind Temperature Humidity Wind (Precipitation) Temperature Humidity Wind (Temperature) Temperature Humidity
values italicized.
Wind
The frequency of occurrence of some fungi (Arthroderma spp., A. tuberculatum, Chaetomium spp., C. bostrychodes, Penicillium spp.) was significantly and positively correlated with the intensity of wind gusts (Table 5). Chaetomium spp. and Penicillium spp. are known air-borne and winddispersed fungi. Feather pH Feather samples taken monthly from ventral body parts of the house sparrows were pooled and suspended in a minimal volume of 0'01 % NaCI in distilled water, and the pH values were measured potentiometrically:
Months Feather pH
I 5'5
Months Feather pH
VI 6'3
II 5'4 VII
vnr
6'4
III 5'9
IV 6'1
V 6·8
IX X 4'4
XI 4'7
XII 5'2
It is evident that pH of new feathers after the moulting in August till September was markedly lower and that it increased thereafter up to the values of 6'4-6'8 during the breeding season. Some correlation between the frequency of occurrence of fungi and the acidity of plumage seems possible (the rank correlation coefficient T = - 0'42 approaching the limit of P = o-oy).
Distribution of fungi on house sparrows DISCUSSION
B ird's plumage as microhabitat for fun gi The body temperature of the house sparrow approximates 41 but within the plumage there is a marked temperature gradient ranging from about 40-41 0 (next the skin) and 34-38 0 (partly under the feathers) to 25-30° (out side the surface of the feathers on the under tail-coverts). Such a gradient permits the survival even of thermophobic fungi (for exposure to 3f is lethal) contaminating the outer feathers. On rainy days the average water content of feathers increased from about 10-11 to 13-18 %. A gradient of plumage humidity was evident : on the warmer body parts (belly, flanks) the moisture was low (7-14 %), while it was higher in the under tail-coverts (10-16 %). The minimal moisture suitable for the growth of even xerophilic fungi (such as Aspergillus repens) is 13-14 % of water in a substrate. It follows from this that uninterrupted growth of common fungi in plumage is hardly to be expected. The feather even in vitro is a very restricted substrate [or the fungi (except keratinolytic ones), because only small quantities of easily assimilated compounds other than keratin are present on it (Bolliger & Gross, 1952a, b). Pugh & Evans (1970b) suppose that superficial feather lipids play a role in determining both qualitatively and quantitatively the occurrence of keratinolytic fungi on .birds, Feather fats of starling stimulated Chrysosporium keratinophilum and slightly inhibited Arthroderma uncinatum and Ctenomyces serratu s. Pheasant lipids stimulated A . uncinatum, A. curreyi, and inhibited C. serratus; blackbird's fats stimulated A . curreyi, whereas lipids of pigeon inhibited the growth of that species and of A . uncinatum as well. Baxter & Trotter (1969), however, found very low, if any, inhibition of A. uncinatum by feather fats of pigeon. In our work, the occurrence and a seasonal fluctuation of superficial feather lipids of house sparrow have not been studied. The methods used in this study do not distinguish whether the fungi isolated are actually growing in the plumage or merely caught up in it. In our opinion, most fungi recovered from birds' plumage are deposited there in a dormant state and are not true residents or active inhabitants of th is microhabitat. There are several reasons which support this assumption : the low concentration of easily accessible nutrients, the high temperature - except the outer feathers -, the very low moisture, the violent movements of feathers during flight, the recovery data on recaptured house sparrows, and direct microscopic observations of feathers when only spores are seen. However, the survival
of some fungi on feathers and their dispersal by birds could be long-la sting as was indicated by Warner & French (1970) who recovered viable fungal spores from feathers of birds up to 45 days after their experimental application.
0
Seasonal variations Seasonal fluctuations in occurrence of microfungi on variou s sub strates have been described by many workers. The results are in general agreement that the minimal occurrence of fungi in the mild climatic zone is in summer (i.e. in the season with the highe st temperature and the lowest air humidity ), whereas the peaks are often ob served in autumn, spring or winter; saprophytic fungal colonization has been reported to be mo st efficient when low or moderate air temperatures and sufficient air (and substrate) humidities prevail. In this study, the fungi in total were most frequent on feathers of the birds in the cold seasons of year . The frequency of fungi on birds might reflect the frequency of the occurrence of the se microorganisms in the birds ' environment: On the sites where the birds occur, in their nest s, in the environmental atmosphere. The substrate composition is in general the principal single factor of the distribution of fungi in nature. Therefore the seasonal periodicity of accessible nutrients in nature determines the seasonal fluctuations of fung i in the macroenvironment and in this indirect way also the occurrence of fungi in plumage of birds. However, very effective seasonal factors are also temperature and humidity. Influence of the wind speed and direction on the variations of atmospheric fungi was observed by Isoard et al. ( 1971). Variations of certain fungi on hous e sparrows can be understood on the basis of preceding paragraphs and in accordance with data in the literature (Ackermann, Schmidt & Lenk, 1969; Fassatiova, 1966; Hubalek & Balat, 1974, 1976; Tomsfkova & Novackova, 1970 ; Valla et al., 1969) as follows. (1) Fungi relatively very frequent in the warm season of year. Thermotolerant species : Aphanoascus fuluescens, Schizosaccharomyces sp., Alternaria alternata, Arthrinium pha eospermum, Chrysosporium keratinophilum, C. tropicum and Ctenomyc es serratus. The species mo st common in the air in summer: Fusarium spp., Alternaria alternata. Aphanoascus fuluescens occurs in the nests of tree sparrow most frequently in summer. (2) Fungi relatively very frequent in the cold season of year . Psychrotoleranr or rhermophobic species: Arthroderma ciferrii, A. tuberculatum , A . quadrifidum, A spergillus candidus, A . fumigat us, A . repens, Chaetomium [unicolum, Chrysosporium pannorum, Cladosporium cladosporioides, C. herbarum, Gliocladium roseum, Penicillium chrysogenum,
z.
Hubdlek
P. cyclopium, Stachybotrys chartarum and Trichoderma viride. Hygrophilic species: Chaetomium funicolum, Gliocladium roseum, Rhizopus spp. and T. viride. The species most frequent in the air or in the soil in winter (or spring): Aspergillus [umigatus, A. repens, Aspergillus spp., Chrysosporium pannorum, Gliocladium roseum, and Trichoderma viride. The species which overwinter in the nests of tree sparrow: Arthroderma ciferrii, A. tuberculatum, A. quadrifidum, Aspergillus fumigatus, A. repens, Aureobasidium pullulans, Chaetomium funicolum , Chrysosporium pannorum, Cladosporium cladosporioides, C. herbarum, Gliocladium roseum, Penicillium breoicompactum, P. chrysogenum, P. eye/opium, P . janthinellum, Scopulariopsis candida and T. viride . Chaetomium bostrychodes and Penicillium spp. are anemochorous species, and the wind gusts are most intensive in the cold season.
REFERENCES ACKERMANN, H.-W., SCHMIDT, B. & LENK, V. (1969). Mykologische Untersuchungen von Aussen- und Innenluft in Berlin. Mykosen 12, 309-320. BAXTER, M. & TROTTER, M. D . (1969). The effect of fatty materials extracted from keratins on the growth of fungi, with particular reference to the free fatty acid content. Sabouraudia 7, 199-206. BOLLIGER, A. & GROSS, R. (1952 a). Quantitative studies on some water-soluble organic constituents associated with vertebrate keratin. Australian Journal of Experimental Biology and Medical Sciences 30, 181189. BOLLIGER, A. & GROSS, R. (1952b ). Nitrogenous compounds in the aqueous extract of vertebrate keratinous structures. Australian Journal of Experimental Biology and Medical Sciences 30, 399-408. EVANS, R. N. & PRUSSO, C . D . (1969 ). Spore dispersal by birds. Mycologia 61, 832-835. FASSATIOvA, O. (1966). Bodenmikromyzeten am HUgel Doutnac im Bohrnischen Karst. Preslia 38, 1-14. HEALD, F. D. & STUDHALTER, R. A. (1914). Birds as carriers of the chestnut-blight fungus. Journal of Agrarian Research 2, 405-422. HEINTZELLER, J. (1939). Das Wachstum der Schimmelpilze in Abhangigkeit von den Hydraturverhaltnissen unter verschiedenen Aussenbedingungen. Archiv fur Mikrobiologie 10,93-132. HUBALEK, Z . (1972 a). Keratinophile Pilze an freilebenden Vogeln, Mykosen 15, 207-211. HUBALEK, Z. (1972b). An interesting recovery of House Sparrow (Passer domesticus). Zpravy Ceskoslovenske Ornitologicke Spolecnosti no. 11, 9 (in Czech). HUBALER, Z. (1974a). Fungi associated with free-living birds in Czechoslovakia and Yugoslavia. Prirodovldm! Prdce Ostavu CSAV v Brne, nova series, 8, no. 3,1-62. HUBALEK, Z. (1974b). Dispersal of fungi of the family Chaetomiaceae by free-living birds. I. A survey of records. Ceska Mykologie 28, 65-79.
HUBALEK, Z . (197 4c). Cutaneous staphylococcosis and secondary infection of House Sparrow with the fungus Cladosporium herbarum. Folia Parasitologica, Prague :11, 59-66. HUBALEK, Z. (1974 d). The distribution patterns offungi in free-living birds. Prirodooedne Prdce Ilstaou CSAV v Brne, nova series, 8, no. 9, 1-51. HUBALEK, Z. (1975). Dispersal of fungi of the family Chaetomiaceae by free-living birds. II. Ecological aspects. Ceska Mykologie 29, 46-58. HUBALEK, Z. & BALAT, F . (1974) . The survival of microfungi in the nests of Tree Sparrow (Passer montanu s L. ) in the nest-boxes over the winter season. Mycopathologia et Mycologia Applicata 54, 5 17-530. HUBALEK, Z. & BAUT, F. (1976 ). The seasonal distribution of keratinolytic fungi in the nests of Tree Sparrow (Passer montanus L. ). Zentralblatt fur Bakteriologie, Parasitenkunde, Infektionskrankheiten und Hygiene, II. Abt. 131, 179-197. ISOARD, P., VALLA, G ., DIDILLON, P., MICHEL-BRUN, J., ACHARD, I., COUDERT, J. & FONTANGES, R. (1971). Influence des conditions meteorologiques sur les micrornycetes atmospheriques, au cours d'une etude cinetique de cent heures. Mykosen 14, 213224· KENDALL, M. G. (1943). The advanced theory of statistics, vol. 1. London: Charles Griffin and Co . KORELUs, J. (1947). Study of bird's plumage with special consideration of numbers and weight of their feathers. Vlstnik Ceskoslovenske Zoologicke Spolecnosti 11, 218-234. MISHRA, R. R. & TEWARl, R. P. (1970). Fungal species associated with certain common birds. Science and Culture 36, 350-352. PUGH, G. J. F. (1964). Dispersal of Arthroderma curreyi by birds, and its role in the soil. Sabouraudia 3, 275278. PuGH, G . J. F . (1965). Cellulolytic and keratinophilic fungi recorded on birds. Sabouraudia 4, 85-91. PUGH, G. J. F. (1966). Fungi on birds in India.Journal of Ind ian Botanical Society 45, 296-303. PUGH, G . J. F. (1972 ). The contamination of birds' feathers by fungi. Ibis 114, 172-177. PUGH, G . J. F. & EVANS, M. D. (1970 a). Keratinophilic fungi associated with birds. I. Fungi isolated from feathers, nests and soil. Transactions of the British Mycological Society 54, 233-240. REES, R. G. (1967). Keratinophilic fungi from Queensland. II. Isolations from feathers of wild birds. Sabouraudia 6, 14-18. SHERIDAN, J. E. (1971). The kerosene fungus Amorphotheca resinae as a natural component of the airspora and on bird feathers . New Zealand Journal of Science 14, 1094-1096. TIFFANY, L. H., GILMAN, J. C. & MURPHY, D. R. (1955). Fungi from birds associated with wilted oaks in Iowa. Iowa State College Journal of Science 29, 659-706. TOM~fKovA. & NovA~l
Distribution of fungi on house sparrows VALLA, T., DIDILLON, P., MICHEL-BRUN, J., ISOARD, WARNER, G . M . & FRENCH, D . W . (1970).
516
P., CoUDERT, J. & FONTANGES, R. (1969). Etude de la repartition annuelle, quantitative et qualitative, des micrornycetes atmospheriques de 1aregion Iyonnaise.
Mykosen
12,
Dissemination of fungi by migratory birds ; survival and recovery of fungi from birds. Canadian Journal of Botany 48, 907-910.
447-458.
(Accepted for publication 29 November 1975)
Printed in Great Britain
SEASONAL DISTRIBUTION OF FUNGI ON HOUSE SPARROWS By Z. HUBALEK Institute of Parasitology, Czechoslovak Academy of Sciences, 166 32 Prague, Czechoslovakia
House sparrows (Passer domesticus L.) were netted each month in 1970 and the seasonal variation of fungi on their feathers was followed. A few species were more frequent on these birds in the warm seasons of the year while many other species were more frequent in the cold seasons. The distribution of other fungi was relatively homogeneous during the course of the year. The specific temperature and humidity relations of the fungi and their seasonal distribution in nature were considered to be major factors determining the seasonal variation of occurrence on the birds. The occurrence of microfungi on free-living birds was followed by Heald & Studhalter (1914), Tiffany, Gilman & Murphy (1955), Pugh (1964, 1965, 1966, 1972), Rees (1967), Evans & Prusso (1969), Pugh & Evans (1970a), Mishra & Tewari (1970), Sheridan (1971) and Hubalek (1972a, 1974a, b, d, 1975). Warner & French (1970) studied experimentally the dispersal of selected fungi by migratory birds. Recently, Hubalek (1975) has observed the annual periodicity of Chaetomiaceae on birds, and Hubalek & Balat (1976) have studied the seasonal occurrence of keratinolytic fungi in the nests of Tree Sparrow (Passer montanus). In this paper, an attempt is made to evaluate the seasonal variations of fungi on the feathers of birds. MATERIALS AND METHODS
The site of collections was the hospital garden of a small city Valtice, Czechoslovakia (16° 45' E, 48° 45' N), situated 195 m above sea level. In this country, the house sparrow is a permanently resident bird, although some individuals can exceptionally move to limited distances. During 1970, fourteen house sparrows were netted monthly (except June, August, September and October when 7 specimens were caught each month). The Japan mist nets were disinfected with 1 % water solution of benzododecinyl(dimethyllaurylbenzylammonium)bromide (' Ajatin' Spofa); during the trapping, the nets were periodically sprayed with 3 % formaldehyde. Each captured bird was lifted carefully to avoid contact of its ventral body part with the hand, and the feathers of the belly, vent region, under tail-coverts and ventral part of tail feathers were smeared with a dry sterile cotton-wool swab immediately in the net; from the same sites, except the tail, 10-15 feathers were plucked off with flamed tweezers
and placed in a sterile test-tube. After being ringed, each bird was released. The swabs were smeared on the same day on 2 plates of Sabouraud's glucose agar (SGA) - one subsequently incubated at 26°C, the other at 37° and on 1 plate of SGA supplied with cycloheximide (0'03 %) and chloramphenicol (0'01 %), which was incubated at 26°. The dishes were observed for a period of 3 weeks. The feathers of each bird were placed individually on 5 sites of 2 Petri dishes with 30 g of sifted sterile garden soil (autoclaved 45 min at 133° and then treated with hot-air 2 hat 160°). Each feather was covered separately with a layer of sterile human hair (one pool of mixed hair, shampooed, rinsed, dried, cut to 2-5 mm pieces, submerged for 5 h in diethyl ether at room temperature, boiled 1 min in distilled water, dried and autoclaved 30 min at 130°). The soil in each dish was moistened with 5 ml of sterile distilled water; the dishes were then placed in the dark at 26°, inspected for a period of 10 weeks, re-moistened when necessary. Dishes were discarded when growth of keratinophilic fungi did not start within the first 4-6 weeks. Simultaneously some of the birds' feathers were laid on sterile water agar (2 % agar in distilled water) incubated at 26° and observed for a period of 12 weeks. During the trapping periods, air-borne fungi were also detected in the neighbourhood of the nets: at a height of 60 em above ground, three SGA plates were exposed for 10 min (subsequently incubated at 26°), two SGA plates exposed for 30 min (incubated at 37°), and 2 SGA plates supplied with the antibiotics were exposed 30 min (incubated at 26°). In addition, two dishes with moistened hair-on-soil substrate were exposed for 20 min and incubated subsequently at 26°. Procedures for isolation, cultivation and identi-
Distribution of fungi on house sparrows
51 0
Table
1.
Weather values ( 1970) of the area examined
8'26 18'47 9'7 2 -1 '13
Mean air relative humidity (%) 7 2'3 73'5 79'4 85 '8
15'18 2'47
74'3 81'1
Mean air temperature
Season (m onth s)
CCq
Spring (III- V) Summer (VI- VIII) Autumn (IX- X I) Winter (I, II, XII) Warm (V-X) Cold (I-IV, XI, XII)
Total precipitation (m m) 100'9 21 9'9 131'0 77'1 06 3 '9 222 '0
Maximum da ily wind gusts in Beaufort degrees (averages) 1'4 2 1'03 1'11 1'3 1 1'04 1'39
Roman numerals = months,
tication of fungi have been described previously (Hubalek 1974a). Weather conditions of the area are surveyed in Table 1. RESULTS
Fungi on birds In all, 1615 fungal isolates of 180 species were obtained from feathers of the birds (T able 2 omitting species of low occurrence). The most common species were in decreasing frequency of occurrence; Arthroderma quadrifidum, Alternaria alternata, Chaetomium globosum, C. funicolum, Ctenomyces serratus, Cladosporium herbarum, C. cladosporioides, Aspergillus fumigatus, Chaetomium murorum, Arthroderma ciferrii, Chrysosporium tropicum, Arthrinium phaeospermum, Chaetomium bostrychodes and Arthroderma tuberculatum, all isolated from at least 20 % of the samples. Several human pathogenic species, isolated on a few occasions only, are not included in Table 2. These were (number of isolations in brackets): Absidia corymbifera (Cohn) Sacco Trott (3); Candida albicans (Rob.) Berkh. (2) ; C. parapsilosis (Ashf.) Lang. Tal. (1); Cephalosporium acremonium Cda. (1); Geotrichum candidum Lk. ex Pers. (3); Microsporum gypseum (Bod.) Guiart Grig. (1); Mucor pusillus Lindt (3); Rhizopus oryzae Went Geerl. (6); and Trichophyton ajelloi (Vanbr.) Ajello (1). On evaluating the seasonal distribution of the common fungi on the birds statistically by means of the chi-square test, the fungi fall -in to three groups ; Fungi which occurred on the birds significantly more frequently in the warm seasons of year; Aphanoascus fuluescens, Arthrinium phaeospermum (autumn/summer), Fusarium spp., Phoma sp., Schizosaccharomyces sp., and possibly Alternaria alternata. Fungi which occurred significantly more frequently in the cold seasons: Arthroderma ciferrii,
A. tuberculatum, Aspergillus fumigatus, A. repens, Chaetomium bostrychodes, C. funicolum, Chrysosporium pannorum, Penicillium breoicompactum, Stachybotrys chartarum, Trichoderma viride, and possibly Botrytis cinerea. Fungi with a relatively homogeneous seasonal distribution on the birds; Arthroderma quadrifidum, Chaetomium globosum, C, indicum, C. murorum, Chrysosporium tropicum, Cladosporium cladosporioides, C. herbarum, Ctenomyces serratus, Monilia spp ., Scopulariopsis brevicaulis. An advantage of ringing the birds was the possibility of following changes in the mycoflora of birds re-caught after certain periods of time. In all, fourteen sparrows were captured twice, and 1 bird thrice, during the year. A comparison of the fungi isolated from feathers of this small number of recaptured birds disclosed marked changes in the fungal spectrum which indicate that there are probably very few, if any, true inhabitants (residents) of the bird's plumage, and that most of the fungi could be considered more properly as transients (visitors) of this microhabitat. Dermatomycoses of the birds Skin scales taken from alopetic lesions on the head of 2 subadult females (1'4 % of all the birds examined) caught in July, revealed abundant dichotomously branched, septate and hyaline hyphae 2'0-3'6,lm in diam, but no dermatophyte was isolated from the lesions. In a similar case two years later a secondary mycosis was found due to Cladosporium herbarum joined to bacterial infection caused by Staphylococcus aureus (Hubalek, 1974c). Fungi in the air From the air at the trapping site and during the times of netting birds, a total of 143 fungal isolates of 51 species were obtained in the course of the year 1970 (T able 3). Dominant air-borne fungi were Cladosporium herbarum, Aspergillus fumigatus,
Z. Hubdlek
511
Table 2 . Statistical evaluation (,\" test ) of the seasonal distribution of fungi isolated from feathers of the house sparrow (ma ny less frequent specie s omitted) SumSpring mer (VI(IIIVIII) V) 28 42
Season No. of birds examined Fungi
Total isolates
Autumn (I XXI )
Winter (I , II,
28
42
XII )
Difference
X)
Cold (X I, XII , (I-IV)
56
84
Warm (V-
D ifference
No, of fungal isolates per bird ----A
Fungi in total
161 5
Alternaria alternata (Fr.) Keiss!' 72 Aphanoascus julvescens (Cke.) Apin. 27 Arthrinium phaeospermum (Cda.) Ell. 38 Arthroderma cijerrii Vars . Aj, 43 A. quadrifidum Daws. Gent!' 81 A. tuberculatum Kuehn 28 A rthroderma all speci es 174 Aspergillus fumigatus Fres. 52 A. repens (C da.) de By. 14 128 Aspergillus all spp, Aureobasidium pullulans (de By. ) Am , 16 Botrytis cinerea Pers. ex Fr. 17 Chaetomium bostrychodes Zopf 36 C. junicolum Cke, 55 C. globosum Kze . ex Fr. 69 C. indicum Cda. 27 C. murorum Cda . 49 Chrysosporium pan norum (L k.) Hugh. 27 C. tropicum Carm. 41 Chrysosporium all spp, 101 Cladosporium cladosporioides (F res.) de Vries 53 C. herbarum Lk . ex Fr. 53 Ctenomyces serratus Eid. 54 Fusarium spp. 21 Glioc/adium roseum (L k.) Bain. 17 MOl/ilia spp , 28 Penicillium breuicompactum Dierckx. 14 P. chrysogenum Thorn. 21 P . cyc lopium West!' 17 Pen icillium all spp. 123 Phoma sp . 11 Rhizopus arrhizus Fisch. 18 Rhizopus all spp. 31 Schizosaccharomyces sp. 26 Scopulariopsis brevicaulis (Sacc.) Bain . 24 Stachybotrys chartarum (Ehr. ex Lk.) Hugh. 21 Trich ocladium asperum H arz 11 Trichoderma viride Pers. ex Fr. 24
11'02 0 ,62 0'05 0'29 0'33 c '69 0'3 1 1"48 0'24 0'02 0,62 0'05 0'17 0'3 6 0 '29 0 '57 0'17 0'19 0'3 1 0'29 0'83 0'3 8 0'57 0'40 0'07 0'10 0'24 0'12 0'05 0'21 1'17 0'12 0'10 0'10 0 '12 0'12 0'02 0'02 0 '10
9'79 0'75 0'3 2 0'29 0'04 0'54 0'00 0,68 0'25 0'04 0'54 0'07 0'00 0'21 0 '18 0'39 0' 18 0'43 0'00 0'39 0'64 0'3 2 0'29 0 '54 0 '3 6 0 '04 0'18 0'00 0 '14 0'04 0'5 0 0' 18 0'11 0'11 0'54 0'14 0'04 0'11 0'04
11'75 0'29 0'18 0'54 0'21 0'43 0'07 0'93 0'36 0'04 0'96 0 '14 0'11 0 '18 0'36 0 '43 0'25 0'43 0'14 0'32 o-Bz 0'50 0'25 0 '25 0'18 0 '25 0 '11 0 '07 0'25 0'07 0'68 0'04 0'07 0 '29 0 '11 0 '14 0'04 0 '21 0'11
13'07 0 '4 0 0'26 0'07 0'5 2 0'60 0 '3 1 1'60 0'60 0'26 1'43 0'19 0'17 0 '24 0 ,66 0'52 0'19 0"40 0'24 0'21 0·60 0 '33 0'33 0'36 0'07 0 '12 0 '24 0 '17 0'19 0'12 0'9 8 0'00 0'21 0 '3 8 0' 07 0' 26 0"43 0'02 0 '3 8
*oO*
t
* ** **
t
** ** * ** oO** NT NT
t
**
t t... I
*
t t t t t
** NT
t
NT NT NT
*
*
NT
* oO**
t
***
NT
**
10'02 0 ,62 0'21 0'3 8 0' 07 0'5 0 0'02 0'7 1 0'27 0'04 0,68 0'09 0'05 0'14 0 '23 0'45 0 '2 1 0'38 0'11 0 '3 6 0'73 0'3 8 0'3 6 0'43 0'21 0'11 0 '13 0'00 0'14 0'07 0'55 0'18 0'07 0'16 0'3 8 0'11 0' 02 0'09 0'04
12'54 0"44 0'17 0'20 0"46 0'63 0'32 1,60 0 '44 0'14 1'07 0'13 0'17 0 '33 0 '50 0'52 0 '17 0'33 0'25 0'25 0'71 0'38 0'39 0'36 0 '11 0 '13 0 '25 0'17 0'15 0 '15 1'10 0 '0 1 0 '17 0'26 0'06 0'2 1 0'24 0'07 0 '26
oO**
t t t
oO*oO
toOoOoO oOoOoO
t
*
*
t
* * *
t t t t t t t t t t t t ** t
toOoOoO *oOoO
t toOoO* t
oOoO*
t
**
'Difference' (X' test ): ***, significant at P < 0'001; ** significant at 0'001 :s; P < 0'01 ; * significant at 0 '01 '" P < 0 '05 ; t insignificant (P > 0'05 ); t approaches the limit of P = 005 j NT not tested because of a low number of isolations.
Aureobasidium pullulans, Fusarium sp. and A. alternata. T he mean n u m b er of species per month va ried little d u r in g the year, but two indistinct peaks ar e indicated in spring and autumn. It was of interest to compare st atistically (ch isquare test) the occurrence of the more common fungi on sparrows' feathers and in the atmosphere.
Three groups of fungi were revealed (Table 4) : Fungi relatively more frequent on the fea thers t han in the air : Arthroderma ciferrii, A . quadrifidum, Chaetomium spp ., Chrysosporium spp. and Ctenomyces serratus (all keratinolytic or keratinop hilic fungi ). F ungi relatively more frequent in t h e ai r than
Distribution of fungi on house sparrows
512
Table 3. Fungi isolated from the atmosphere at the trapping site (most fungi not included in Table 2 omitted here) Sum- AuSeason, 1970 Average no. of fungal species per sample ...
Spring mer
Alternaria alternata Aphanoascusfuluescens Arrhrinium phaeospermum Arthroderma quadrifidum Aspergillus candidus A.flavus
Win-
tumn
ter
Fungi
Isolates in total (= 100 %) 1615 143 % of total isolates Alternaria alternata 4'89 4"46 Aphanoascus fuluescens 1·67 1"40 Arthrinium phaeospermum 2'35 0'7 0 Arthroderma ciferrii 0'00 z·67 A. quadrifidum 0'70 5' oZ Arthroderma all spp. 0'7 0 10'77 Aspergillus candidus 0'5 6 3'5 0 Ai fiaous 2·80 0'37 Ai fumigatus 6'Z9 3'22 2,80 A. repens 0·87 A. versicolor 0·80 3'5 0 Aspergillus all spp. 21·68 7'93 Aureobasidium pullulans 5'60 0'99 Botrytis cinerea 1"40 1'05 2·80 Chaetomium all spp. 15'86 Chrysosporium pannorum 1·67 0'70 Chrysosporium all s; p. 6'25 0'7 0 Cladosporium cladosporioides 3'28 2·80 C. herbarum 6'29 3'28 Ctenomyces serratus 0'00 3"35 Fusarium spp. 5'60 1'3 0 Gliocladium spp. 1·61 0'7 0 2,80 Penicillium chrysogenum 1'3 0 7,6z Penicillium all spp. 12'5 8 Phoma spp. 0·68 3'50 Rhizopus spp. 2'10 1'9 2 Scopulariopsis breuicaulis z·80 1"49 Stemphylium spp. 0-31 4'89 Trichoderma oiride 0'00 1'49
14'3
12'5
18'5
12,6
+
+ +
+
+ +
+
+
A. fumigatus A. nidulans
+
A. repens
+ +
Aureobasidium pullulans Botrytis cinerea
Chauomium spp. Chrysosporium pannorum
Cladosporium cladosporioides C. herbarum Fusarium spp. Gliocladium roseum Penicillium breoicompactum P. chrysogenum Pi oxalicum
Phialophora sp. Phoma sp. Rhizopus arrhizus Scopulariopsis breoicaulis
Explanation: +, fungus detected; detected.
Table 4. Comparison of relative abundance of common fungi isolated from feathers of house sparrow and from the atmosphere at the trapping site (X 2 test, the symbols as for Table 2)
+
+ + + + +
+ + fungus not
on the feathers: Aspergillus candidus, A. flavus, A. repens, A. versicolor, Aureobasidium pullulans, Fusarium spp., Penicillium spp., Phoma spp. and Stemphylium spp. Fungi with similar relative frequency on the feathers and in the air: Alternaria alternata, Aphanoascus fuluescens, Arthrinium phaeospermum, Aspergillus fumigatus, Botrytis cinerea, Chrysosporium pannorum, Cladosporium cladosporioides, C. herbarum, Gliocladium spp., Penicillium chrysogenum, Rhizopus spp., Scopulariopsis brevicaulis and Trichoderma viride. The frequency of occurrence of these fungi on the birds reflects to a considerable extent merely the abundance of the fungal diaspores in the environmental atmosphere. The results show, in sum, that the mycoflora of birds' feathers is in many respects distinct from the local mycofiora of the air. Seasonal changes in variables The frequency of occurrence of several fungi showing marked seasonal distribution patterns on feathers of house sparrows has been correlated
Feathers
Air
Difference
t t
t
* * *** *** ***
t
* ** *** ***
t t
*** **
t
:j:
* ***
t t
* ***
t t
***
t
with monthly weather values in Table 5, using the rank correlation method (Kendall, 1943). Temperature The air temperature is the most powerful climatic factor which influences the seasonal occurrence of fungi on the birds; the negative correlation between the frequency of fungi in total and the monthly mean air temperature is highly significant (P < 0'001). Arthroderma ciferrii, Aspergillus spp., Chaetomiurn funicolurn and Trichoderma viride all showed a significant adverse correlation with the seasonal temperature values. Since the optimal growth temperatures for the great majority of fungi are almost identical (2230°), from the ecological point of view a selective action of low and high temperatures on these organisms is more important. The fungi could be classified according to their temperature relations into psychrotolerant (capable of growth below 6°), thermotolerant (capable of growth above 35°) and
Z. Hubdlek Table 5. Correlation of monthly weather values with the monthly occurrence of several common fungi with a marked seasonal pattern of distribution (Kendall's T rank correlation coefficient values) Mean air temperature
Mean air relative humidity
Total precipitation
Maximum daily wind gusts (averages)
-018
+0'5 6
-0'11
+0'4 2
Arthroderma ciferrii A. tuberculatum
-0'70 -0'50
+0'43 +0'14
-0'24 -0'07
+0'24 +0,64
Arthrodema all spp.
-0,66
+0'14
-0'06
+0·67
Aspergillus all spp.
-019
+0'70
-0'33
+0'14
Chaetomium bostrychodes
-0'14
-0'30
+0'5 2
+ 1'00
C. funicolum
-0,80
+01 1
-oAo
+0'43
Penicillium all spp.
-0'44
+0'09
-0'17
+0'5 6
Trichoderma viride
-0'71
+0'71
-0'33
+0'20
Fungi Fungi in total
The significant (P < 0'05) thermophobic (not surviving 10 days at 37°). The results indicate that the psychrotolerant fungi were frequent on the birds in winter; the thermophobic fungi were never found to have a peak of occurrence in summer, whilst the fungi with a summer peak of occurrence were thermotolerant organisms. Humidity The seasonal occurrence of fungi (fungi in total, Aspergillus spp., Chaetomiumfunicolum and Trichoderma viride) on feathers was subject to variations significantly positively correlated with the changes of mean relative humidity of the air, but this correlation was not so marked as with the air temperature. These two abiotic variables, air temperature and humidity, are significantly negatively interrelated. The fungi could be grouped by a commonly accepted classification of Heintzeller (1939) according to the minimum relative humidity necessary for the growth into hygrophilic (minimum r.h. higher than 90 %), mesophilic (80-90 %) and xerophilic (below 80%). It was found that the hygrophilic fungi (Trichoderma viride, Gliocladium roseum, Chaetomium funicolum) were frequent in humid seasons (winter, autumn) but infrequent in dry seasons. Surprisingly, the xerophilic fungi (Aspergillus repens, A. versicolor) were common in winter and autumn; their abundance in those seasons might indicate the colonization of suitable substrata with massive sporulation.
T
Determining climatic factors Temperature Humidity Temperature Wind (Temperature) Temperature Wind Temperature Humidity Wind (Precipitation) Temperature Humidity Wind (Temperature) Temperature Humidity
values italicized.
Wind
The frequency of occurrence of some fungi (Arthroderma spp., A. tuberculatum, Chaetomium spp., C. bostrychodes, Penicillium spp.) was significantly and positively correlated with the intensity of wind gusts (Table 5). Chaetomium spp. and Penicillium spp. are known air-borne and winddispersed fungi. Feather pH Feather samples taken monthly from ventral body parts of the house sparrows were pooled and suspended in a minimal volume of 0'01 % NaCI in distilled water, and the pH values were measured potentiometrically:
Months Feather pH
I 5'5
Months Feather pH
VI 6'3
II 5'4 VII
vnr
6'4
III 5'9
IV 6'1
V 6·8
IX X 4'4
XI 4'7
XII 5'2
It is evident that pH of new feathers after the moulting in August till September was markedly lower and that it increased thereafter up to the values of 6'4-6'8 during the breeding season. Some correlation between the frequency of occurrence of fungi and the acidity of plumage seems possible (the rank correlation coefficient T = - 0'42 approaching the limit of P = o-oy).
Distribution of fungi on house sparrows DISCUSSION
B ird's plumage as microhabitat for fun gi The body temperature of the house sparrow approximates 41 but within the plumage there is a marked temperature gradient ranging from about 40-41 0 (next the skin) and 34-38 0 (partly under the feathers) to 25-30° (out side the surface of the feathers on the under tail-coverts). Such a gradient permits the survival even of thermophobic fungi (for exposure to 3f is lethal) contaminating the outer feathers. On rainy days the average water content of feathers increased from about 10-11 to 13-18 %. A gradient of plumage humidity was evident : on the warmer body parts (belly, flanks) the moisture was low (7-14 %), while it was higher in the under tail-coverts (10-16 %). The minimal moisture suitable for the growth of even xerophilic fungi (such as Aspergillus repens) is 13-14 % of water in a substrate. It follows from this that uninterrupted growth of common fungi in plumage is hardly to be expected. The feather even in vitro is a very restricted substrate [or the fungi (except keratinolytic ones), because only small quantities of easily assimilated compounds other than keratin are present on it (Bolliger & Gross, 1952a, b). Pugh & Evans (1970b) suppose that superficial feather lipids play a role in determining both qualitatively and quantitatively the occurrence of keratinolytic fungi on .birds, Feather fats of starling stimulated Chrysosporium keratinophilum and slightly inhibited Arthroderma uncinatum and Ctenomyces serratu s. Pheasant lipids stimulated A . uncinatum, A. curreyi, and inhibited C. serratus; blackbird's fats stimulated A . curreyi, whereas lipids of pigeon inhibited the growth of that species and of A . uncinatum as well. Baxter & Trotter (1969), however, found very low, if any, inhibition of A. uncinatum by feather fats of pigeon. In our work, the occurrence and a seasonal fluctuation of superficial feather lipids of house sparrow have not been studied. The methods used in this study do not distinguish whether the fungi isolated are actually growing in the plumage or merely caught up in it. In our opinion, most fungi recovered from birds' plumage are deposited there in a dormant state and are not true residents or active inhabitants of th is microhabitat. There are several reasons which support this assumption : the low concentration of easily accessible nutrients, the high temperature - except the outer feathers -, the very low moisture, the violent movements of feathers during flight, the recovery data on recaptured house sparrows, and direct microscopic observations of feathers when only spores are seen. However, the survival
of some fungi on feathers and their dispersal by birds could be long-la sting as was indicated by Warner & French (1970) who recovered viable fungal spores from feathers of birds up to 45 days after their experimental application.
0
Seasonal variations Seasonal fluctuations in occurrence of microfungi on variou s sub strates have been described by many workers. The results are in general agreement that the minimal occurrence of fungi in the mild climatic zone is in summer (i.e. in the season with the highe st temperature and the lowest air humidity ), whereas the peaks are often ob served in autumn, spring or winter; saprophytic fungal colonization has been reported to be mo st efficient when low or moderate air temperatures and sufficient air (and substrate) humidities prevail. In this study, the fungi in total were most frequent on feathers of the birds in the cold seasons of year . The frequency of fungi on birds might reflect the frequency of the occurrence of the se microorganisms in the birds ' environment: On the sites where the birds occur, in their nest s, in the environmental atmosphere. The substrate composition is in general the principal single factor of the distribution of fungi in nature. Therefore the seasonal periodicity of accessible nutrients in nature determines the seasonal fluctuations of fung i in the macroenvironment and in this indirect way also the occurrence of fungi in plumage of birds. However, very effective seasonal factors are also temperature and humidity. Influence of the wind speed and direction on the variations of atmospheric fungi was observed by Isoard et al. ( 1971). Variations of certain fungi on hous e sparrows can be understood on the basis of preceding paragraphs and in accordance with data in the literature (Ackermann, Schmidt & Lenk, 1969; Fassatiova, 1966; Hubalek & Balat, 1974, 1976; Tomsfkova & Novackova, 1970 ; Valla et al., 1969) as follows. (1) Fungi relatively very frequent in the warm season of year. Thermotolerant species : Aphanoascus fuluescens, Schizosaccharomyces sp., Alternaria alternata, Arthrinium pha eospermum, Chrysosporium keratinophilum, C. tropicum and Ctenomyc es serratus. The species mo st common in the air in summer: Fusarium spp., Alternaria alternata. Aphanoascus fuluescens occurs in the nests of tree sparrow most frequently in summer. (2) Fungi relatively very frequent in the cold season of year . Psychrotoleranr or rhermophobic species: Arthroderma ciferrii, A. tuberculatum , A . quadrifidum, A spergillus candidus, A . fumigat us, A . repens, Chaetomium [unicolum, Chrysosporium pannorum, Cladosporium cladosporioides, C. herbarum, Gliocladium roseum, Penicillium chrysogenum,
z.
Hubdlek
P. cyclopium, Stachybotrys chartarum and Trichoderma viride. Hygrophilic species: Chaetomium funicolum, Gliocladium roseum, Rhizopus spp. and T. viride. The species most frequent in the air or in the soil in winter (or spring): Aspergillus [umigatus, A. repens, Aspergillus spp., Chrysosporium pannorum, Gliocladium roseum, and Trichoderma viride. The species which overwinter in the nests of tree sparrow: Arthroderma ciferrii, A. tuberculatum, A. quadrifidum, Aspergillus fumigatus, A. repens, Aureobasidium pullulans, Chaetomium funicolum , Chrysosporium pannorum, Cladosporium cladosporioides, C. herbarum, Gliocladium roseum, Penicillium breoicompactum, P. chrysogenum, P. eye/opium, P . janthinellum, Scopulariopsis candida and T. viride . Chaetomium bostrychodes and Penicillium spp. are anemochorous species, and the wind gusts are most intensive in the cold season.
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447-458.
(Accepted for publication 29 November 1975)