EXPERIMENTAL PARASITOLOGY 42, 282-288
Ornithodoros
(1977)
moubata:
Breeding
In Vitro
CHRISTRINE K. A. MANGO International
Centre
of Insect
Physiology
and Ecology,
Nairobi,
Kenya
AND
RACHEL GALUN Israel
Institute (Accepted
for Biological
Research,
for publication
Ness-Ziona,
21 December
Israel
1976)
R. 1977. Ornithodoros moubata: Bre#eding in u&o. MANGO, C. K. A., AND GALUN, Experimental Parasitology 4.2, 282-288. In vitro breeding of Ornithodoros moubata (Murray) was achieved by feeding the ticks on defibrinated porcine and bovine blood through bat’s wing membrane. On either type of blood, the life cycle was completed and the ticks reached equa1 weights and consumed equa1 meaIs. On porcine bIood, a higher number of eggs was produced, and nymphs matured after a fewer number of instars and had shorter intermolt periods than on bovine blood. Ticks bred on rabbit exhibit better utilization of rabbit blood for egg production than ‘of porcine or bovine blood. INDEX DESCRIPTORS: Ticks; Ornithodoros moubata (Murray); Eyeless tampan; Atari; Argasidae; In vitro breeding; Bovine blood; Porcine bIood; Bat’s wing membrane.
The membrane feeding technique for ticks was developed by Tarshis (1958) and we have followed his technique using bat’s wing membrane (Youdeowei and Mango 1975). Ticks feed more readily through bat’s wing membrane than through any other known membrane. Ticks were fed at all stages on either bovine or porcine blood. The effects of rabbit blood on reproduction were also tested. The number of eggs laid and hatched, the number of nymphs developing, the length of intermolt periods, and preoviposition and incubation periods were all used as parameters for evaluation of the suitability of the method.
INTRODUCTION
The sterile male technique for eradicating or controlling hematophagous arthropods depends ‘on their large-scale production and this in turn requires many living hosts. In order to produce cheaper insects, attempts are being made to dispense with live hosts by feeding insects ,artificially through membranes. Laboratory colonies of tsetse flies fed through membrane ‘on bovine, horse, and pig blood are now maintained at the Tsetse Research Laborat’ory at Langford (Langley and Pimley 1975) and at IAEA Laboratory in Vienna (Mews, Baumgartner, Luger, and Offori, 1976). For ‘chemical identification of ticks’ pherhormones, omones and developmental large numbers of ticks at synchronized ages are required. We therefore ‘attempted to establish ,a membrane-fed colony of the tick Ornithodoros moubata at our laborat’ory as a supply for such studies.
MATERIALS
AND METHODS
Ticks from a strain of Ornithodoros moubata maintained on rabbits for many generati’ons in the l’aboratory were used. They
originated
from
warthog
burrows
at
282 Copyright All rights
0 1977 by Academic of reproduction in any
Press, Inc. form reserved.
ISSN
0014-4894
Ornithodoros
Moubata:
Nairobi National Park. They were kept at constant room temperature of 28 C and 84% relative humidity. The feeding apparatus consisted ‘of plastic cylinders, 44 mm in diameter Band77 mm high, open at both e&s. The bat’s wing membrane was stretched ‘across ‘one end and firmly attached to the sides of the cylinder by means of cellotape or masking tape. The sides of the cylinders were also completely ‘covered with black polyethylene in ‘order to enhance feeding of the ticks in the dark. Batches of 25 ticks were weighed and released into the cylinders which were then stoo,d in petri ,dishes containing defibrinated porcine or bovine blood. The petri dishes rested on a Photax photographic ,dish warmer adjusted to give a constant temperature of ab’out 38 C.
BREEDING
of Bovine
283
To assess the effects of the source of blood on the reproduction of 0. moubata, the ticks were fed through membrane on bovine and porcine blood which was defibrinated by means of glass beads. Samples of 40 l-month-old virgin females were weighed either individually or in batches. They were then fed through bat’s wing membrane on porcine or bovine defibrinated blood until they were fully engorged. The ticks were then weighed immediately and 24 hr later when emission of coxal fluid was almost completed. The weights of the blood meal ingested by individual ticks were calculated. The ticks were placed with fully engorged males and then kept in pairs in test tubes and observed daily for egg laying, and later the eggs were checked daily for
TABLE Effects
In V&o
I
and Porcine Blood on the Reproduction of Bovine- and Porcine-Reared Omithodoros moubata Ticks Fed through a Membrane Source of blood
Significance of differences
Mean f
SE
Bovine Porcine
42.40 f 47.83 f
1.60 2.70
-
Weight of fully engorged female ticks (mg)
Bovine Porcine
175.55 f 178.15 f
6.22 17.63
-
Weight of blood meal ingested per female tick (mg)
Bovine Porcine
132.53 f 6.22 131.15 rt 17.65
-
Number
Bovine Porcine
5.48 79.78 f 147.0 zt 15.49
P < 0.001
Weight
of unfed female ticks (mg)
of eggs laid per female tick
Number of eggs per milligram of blood ingested
Bovine Porcine
0.59 f
0.03
1.10 f
0.06
Preoviposition
Bovine Porcine
18.95 i 13.32 f
1.77 0.76
P < 0.05
Bovine Porcine
22.52 f 14.54 f
1.69 0.51
P < 0.001
Bovine Porcine
21.86 f 107.92 f
3.40 15.79
P < 0.001
Bovine Porcine
26.47 f
3.85
P < 0.001
61.34 f
5.72
Incubation
Number
period
period
of nymphs
(days)
(days)
per female tick
Percent,age of hatchability
P < 0.001
284
MANGO AND GALUN TABLE Effects
of Bovine
II
and Porcine Blood on Reproduction Reared on Porcine Blood5
of Ornithodoros
Mean f
Source of blood
moubata
SE
Significance of differences
Bovine Porcine
60.60 z!z 3.70 54.28 rt 3.31
-
Weight of fully engorged female ticks (mg)
Bovine Porcine
290.68 i 12.25 284.98 zk 15.05
-
Weight of blood meal ingested per female tick (mg)
Bovine Porcine
233.18 Z?C15.05 230.80 zk 15.15
-
Number
Bovine Porcine
173.77 f 283.10 i
Weight
of unfed female ticks
(mg)
of eggs laid per female tick
9.60 17.35
P < 0.001
0.06 0.04
P < 0.001
Number of eggs per milligram of blood ingested
Bovine Porcine
Preoviposition
Bovine Porcine
10.82 f 11.28 f
0.24 0.39
-
Bovine Porcine
15.47 f 13.15 f
0.61 0.25
P < 0.01
Bovine Porcine
145.22 f 249.73 f
8.78 18.03
P < 0.001
Bovine Porcine
85.93 f 84.77 i
2.71 3.02
-
Incubation
Number
period
period
(days)
of nymphs
Percentage
(days)
per female tick
of hatchability
a Each sample included
0.83 i 1.26 zt
40 ticks.
hatching. The total number of eggs laid per tick and the resulting number of nymphs were obtained by counting the nymphs and the dead eggs. Preoviposition and incubation perio’ds were calculated from the recorded dates when the eggs were laid and hatched. In one experiment, rabbit blood was also tested. To investigate the effects of porcine and bovine blood on development of 0. moubata, equal numbers of first-stage nymph offsprings of females fed on porcine or bovine blood were raised on Noneof the two types ‘of blood. The fed nymphs were checked daily for molting and mortality. The last-stage nymphs were also weighed before and after feeding on porcine or bovine blood.
RESULTS
Reproduction Table I shows the results of porcine and bovine blood-reared ticks fed son porcine and bovine blood, respectively. There was no significant difference in the weight of the unfed adult Ornithodoros moubata tick whether it was reared ‘on b’ovine or porcine blood. The size of the blood meal ingested was equal for the two types of blood. However, the size of blood meal ingested, the mean number ‘of eggs laid per female tick, percentage Iof hatchability of eggs, ;and number ‘of nymphs of the ticks fed on porcine blood were significantly higher than those ,of ticks fed on bovine blood.
Ornithodoros
Moubata: TABLE
Effects
In Vitro
BREEDING
III
of Rabbit, Porcine, and Bovine Blood on the Reproduction Ornithcdoros moubata Ticks Reared on Rabbits& Source of blood
Mean f
SE
Significance of differences
of
Remarks
P < 0.001
Rabbit-fed ticks significantly bigger than either bovineor porcine-fed ticks.
236.43 f 10.93 278.48 f 14.93 238.13 31 13.02
P < 0.05
Porcine-fed ticks significantly heavier than either bovineor rabbit-fed ticks.
Rabbit Porcine Bovine
136.43 f 203.35 f 165.13 f
10.93 14.93 13.02
P < 0.01
Porcine meals significantly greater than rabbit and bovine meals.
Number of eggs laid per female tick
Rabbit Porcine Bovine
206.62 f 12.12 224.0 f 16.23 151.11 jz 14.82
P < 0.01
Ticks fed on porcine and rabbit blood laid more eggs than those on bovine blood.
Number of eggs per milligram of blood ingested
Rabbit Porcine Bovine
0.10 0.06 0.08
P < 0.001
Number of eggs per milligram of blood ingested significantly higher among ticks fed on rabbit than those on bovine and porcine blood.
Preoviposition
Rabbit Porcine Bovine
9.61 zk 0.74 13.30 f 0.75 15.39 f 0.93
P < 0.001
Preoviposition period was significantly shorter in ticks fed on rabbit blood than in those on bovine blood.
Rabbit Porcine Bovine
14.22 =I= 0.50 15.20 * 0.23 14.64 f 0.38
-
per
Rabbit Porcine Bovine
185.0 f 13.03 178.28 zk 14.83 112.26 f 13.51
P < 0.01
Significantly more nymphs from ticks fed on rabbit and porcine blood.
of hatchability
Rabbit Porcine Bovine
P < 0.001
Hatchabilit,y from ticks fed on rabbit blood was significantly higher than ticks fed on bovine blood.
Rabbit Porcine Bovine
103.58 f 79.75 f 77.65 f
Weight of fully engorged female ticks (mg)
Rabbit Porcine Bovine
Weight of blood meal ingested per female tick (mg)
Weight
of unfed females
Incubation
period (days)
period
Number of nymphs female t,ick
Percentage
(mg)
a Each sample included
1.59 f 1.19 f 1.02 f
87.90 & 76.29 f 66.41 +
5.19 4.55 3.10
2.79 3.59 5.15
40 ticks.
In order to compare the effects of the diet of immature stages son reproduction, treks reared on porcine blood were divi,ded into two groups; one was fed on bovine, the other on porcine blood. The results
which were analyzed by Student t test are shown in Table II. The mean weights of the unfed and the fully engorged ,and the blood meals of females fed on bovine and porcine blood were not significantly differ-
286
MANGO
AND
TABLE Percentage Number
Ornithodoros
IV
moubata Ticks Reaching
Maturity
after Each Molt
of instars
3
4
5
6
>6
Percentage reaching maturity within six instars
F 111~
0 0
3.6 16.8
13.3 13.5
10.4 4.6 >
21.4
62.2
16.4
M F
0 0
0 0
0.2 5.0
3.2 4.2 >
31.2
12.6
56.2
Porcine Bovine
of Surviving
GALUN
Mortality (%)
6 M = males; F = females.
ent. Nevertheless, the mean numbers of eggs laid per female ticks, and thus eggs per milligram of blood ingested, were significantly higher in ticks fed ‘on porcine blood than in those fed on bovine blood, Although the preoviposition period and percentage of hatchability were not significantly different among the Pw’o groups, the incubation period was significantly shorter and the mean number of nymphs per female was higher among ticks fed on porcine blood than those fed on bovine blood. Table III shows the effects of rabbit, porcine, and bovine blood on the reproduction of 0. moubuta. Unlike the ticks in the previous two experiments, the ticks used in this experiment were reared on rabbits. Even though the ticks fed on rabbit blood were all significantly larger than those fed on either porcine #orb’ovine blood, the mean weight of the blood meal ‘of females fed on porcine blood was significantly higher than that of either rabbit or bovine blood fed females, and the mean number of eggs laid by either females fed on rabbit or porcine blood was significantly higher than that of bovine blood-fed females. The mean number of eggs per milligram of blood of females fed on rabbit blood is significantly higher than that of either ‘ticks fed on porcine or b’ovine blood. There was no significant ,difference in incubation periods of
the three groups. The bovine blood-fed ticks produced significantly less nymphs, and the percentage of hatchability was also significantly lower than in either rabbit or porcine blood-fed ticks. Developwnt Table IV shows development of OrrCthodoros moubata nymphs on the two sources of blo’od. Nymphs fed son porcine blood started maturing earlier by one stage and by the sixth molt many more had matured (62.2% ) than the bovine-fed nymphs (12.6% ). High mortality was evident among nymphs fed on bmovine blood. When the last-stage nymphs were weighed, both unfed and fed weights were comparable. Within each instar, the development was invariably faster on porcine than on bovine blood (Fig. 1). DISCUSSION
Though feeding ‘of ticks through membrane has been previously described (Tarshis 1958; Galun and Kindler 1965), to the best of our knowledge this is the first successful achievement of a complete life cycle by the artificial feeding of ticks. In all the experiments, porcine blood was consistently good in Ornithodoros moubata egg and nymph output regardless of the diet or host on which the ticks had been raised.
Omithodoros
Moubata:
BREEDING
In
3rd stage
2nd stage nymphs
287
Vitro
nymphs
100 bovine ,-e-e
73 u 3 P s
I
0
Period
4th
stage
after
blood meal
nymphs
(days)
5th
stage nymphs
100
100
porcine P 3 s
.e
w-ebovine
s
25
0 Period
after
25
0 blood meal
(days)
6th stage nymphs 100 porcine
0 Period
FIG. 1. Effects nymphs
fed through
of porcine and bovine bat’s wing membrane.
25 after
blood
When ticks of mean equal unfed body weights were fed on bovine and porcine blood, they took almost equal blood meals but the ticks fed on porcine blood produced
blood meal
(days)
on development
of Ornithodoros
moubata
significantly more eggs than the bovine-fed ticks; i.e., the number of eggs per milligram of blood ingested was significantly higher on porcine blood than son bovine blood.
288
MANGO AND GALUN
Either the bovine blood has a smaller amount of the necessary ingredients for egg formation or the tick is unable to convert the blood meal into usable ingredients. The fact that egg ‘output ‘of ticks fed on bovine blood improved when the ticks used had been reared on a better diet, like living rabbit
Ornithodoros
(1977)
moubata:
Breeding
In Vitro
CHRISTRINE K. A. MANGO International
Centre
of Insect
Physiology
and Ecology,
Nairobi,
Kenya
AND
RACHEL GALUN Israel
Institute (Accepted
for Biological
Research,
for publication
Ness-Ziona,
21 December
Israel
1976)
R. 1977. Ornithodoros moubata: Bre#eding in u&o. MANGO, C. K. A., AND GALUN, Experimental Parasitology 4.2, 282-288. In vitro breeding of Ornithodoros moubata (Murray) was achieved by feeding the ticks on defibrinated porcine and bovine blood through bat’s wing membrane. On either type of blood, the life cycle was completed and the ticks reached equa1 weights and consumed equa1 meaIs. On porcine bIood, a higher number of eggs was produced, and nymphs matured after a fewer number of instars and had shorter intermolt periods than on bovine blood. Ticks bred on rabbit exhibit better utilization of rabbit blood for egg production than ‘of porcine or bovine blood. INDEX DESCRIPTORS: Ticks; Ornithodoros moubata (Murray); Eyeless tampan; Atari; Argasidae; In vitro breeding; Bovine blood; Porcine bIood; Bat’s wing membrane.
The membrane feeding technique for ticks was developed by Tarshis (1958) and we have followed his technique using bat’s wing membrane (Youdeowei and Mango 1975). Ticks feed more readily through bat’s wing membrane than through any other known membrane. Ticks were fed at all stages on either bovine or porcine blood. The effects of rabbit blood on reproduction were also tested. The number of eggs laid and hatched, the number of nymphs developing, the length of intermolt periods, and preoviposition and incubation periods were all used as parameters for evaluation of the suitability of the method.
INTRODUCTION
The sterile male technique for eradicating or controlling hematophagous arthropods depends ‘on their large-scale production and this in turn requires many living hosts. In order to produce cheaper insects, attempts are being made to dispense with live hosts by feeding insects ,artificially through membranes. Laboratory colonies of tsetse flies fed through membrane ‘on bovine, horse, and pig blood are now maintained at the Tsetse Research Laborat’ory at Langford (Langley and Pimley 1975) and at IAEA Laboratory in Vienna (Mews, Baumgartner, Luger, and Offori, 1976). For ‘chemical identification of ticks’ pherhormones, omones and developmental large numbers of ticks at synchronized ages are required. We therefore ‘attempted to establish ,a membrane-fed colony of the tick Ornithodoros moubata at our laborat’ory as a supply for such studies.
MATERIALS
AND METHODS
Ticks from a strain of Ornithodoros moubata maintained on rabbits for many generati’ons in the l’aboratory were used. They
originated
from
warthog
burrows
at
282 Copyright All rights
0 1977 by Academic of reproduction in any
Press, Inc. form reserved.
ISSN
0014-4894
Ornithodoros
Moubata:
Nairobi National Park. They were kept at constant room temperature of 28 C and 84% relative humidity. The feeding apparatus consisted ‘of plastic cylinders, 44 mm in diameter Band77 mm high, open at both e&s. The bat’s wing membrane was stretched ‘across ‘one end and firmly attached to the sides of the cylinder by means of cellotape or masking tape. The sides of the cylinders were also completely ‘covered with black polyethylene in ‘order to enhance feeding of the ticks in the dark. Batches of 25 ticks were weighed and released into the cylinders which were then stoo,d in petri ,dishes containing defibrinated porcine or bovine blood. The petri dishes rested on a Photax photographic ,dish warmer adjusted to give a constant temperature of ab’out 38 C.
BREEDING
of Bovine
283
To assess the effects of the source of blood on the reproduction of 0. moubata, the ticks were fed through membrane on bovine and porcine blood which was defibrinated by means of glass beads. Samples of 40 l-month-old virgin females were weighed either individually or in batches. They were then fed through bat’s wing membrane on porcine or bovine defibrinated blood until they were fully engorged. The ticks were then weighed immediately and 24 hr later when emission of coxal fluid was almost completed. The weights of the blood meal ingested by individual ticks were calculated. The ticks were placed with fully engorged males and then kept in pairs in test tubes and observed daily for egg laying, and later the eggs were checked daily for
TABLE Effects
In V&o
I
and Porcine Blood on the Reproduction of Bovine- and Porcine-Reared Omithodoros moubata Ticks Fed through a Membrane Source of blood
Significance of differences
Mean f
SE
Bovine Porcine
42.40 f 47.83 f
1.60 2.70
-
Weight of fully engorged female ticks (mg)
Bovine Porcine
175.55 f 178.15 f
6.22 17.63
-
Weight of blood meal ingested per female tick (mg)
Bovine Porcine
132.53 f 6.22 131.15 rt 17.65
-
Number
Bovine Porcine
5.48 79.78 f 147.0 zt 15.49
P < 0.001
Weight
of unfed female ticks (mg)
of eggs laid per female tick
Number of eggs per milligram of blood ingested
Bovine Porcine
0.59 f
0.03
1.10 f
0.06
Preoviposition
Bovine Porcine
18.95 i 13.32 f
1.77 0.76
P < 0.05
Bovine Porcine
22.52 f 14.54 f
1.69 0.51
P < 0.001
Bovine Porcine
21.86 f 107.92 f
3.40 15.79
P < 0.001
Bovine Porcine
26.47 f
3.85
P < 0.001
61.34 f
5.72
Incubation
Number
period
period
of nymphs
(days)
(days)
per female tick
Percent,age of hatchability
P < 0.001
284
MANGO AND GALUN TABLE Effects
of Bovine
II
and Porcine Blood on Reproduction Reared on Porcine Blood5
of Ornithodoros
Mean f
Source of blood
moubata
SE
Significance of differences
Bovine Porcine
60.60 z!z 3.70 54.28 rt 3.31
-
Weight of fully engorged female ticks (mg)
Bovine Porcine
290.68 i 12.25 284.98 zk 15.05
-
Weight of blood meal ingested per female tick (mg)
Bovine Porcine
233.18 Z?C15.05 230.80 zk 15.15
-
Number
Bovine Porcine
173.77 f 283.10 i
Weight
of unfed female ticks
(mg)
of eggs laid per female tick
9.60 17.35
P < 0.001
0.06 0.04
P < 0.001
Number of eggs per milligram of blood ingested
Bovine Porcine
Preoviposition
Bovine Porcine
10.82 f 11.28 f
0.24 0.39
-
Bovine Porcine
15.47 f 13.15 f
0.61 0.25
P < 0.01
Bovine Porcine
145.22 f 249.73 f
8.78 18.03
P < 0.001
Bovine Porcine
85.93 f 84.77 i
2.71 3.02
-
Incubation
Number
period
period
(days)
of nymphs
Percentage
(days)
per female tick
of hatchability
a Each sample included
0.83 i 1.26 zt
40 ticks.
hatching. The total number of eggs laid per tick and the resulting number of nymphs were obtained by counting the nymphs and the dead eggs. Preoviposition and incubation perio’ds were calculated from the recorded dates when the eggs were laid and hatched. In one experiment, rabbit blood was also tested. To investigate the effects of porcine and bovine blood on development of 0. moubata, equal numbers of first-stage nymph offsprings of females fed on porcine or bovine blood were raised on Noneof the two types ‘of blood. The fed nymphs were checked daily for molting and mortality. The last-stage nymphs were also weighed before and after feeding on porcine or bovine blood.
RESULTS
Reproduction Table I shows the results of porcine and bovine blood-reared ticks fed son porcine and bovine blood, respectively. There was no significant difference in the weight of the unfed adult Ornithodoros moubata tick whether it was reared ‘on b’ovine or porcine blood. The size of the blood meal ingested was equal for the two types of blood. However, the size of blood meal ingested, the mean number ‘of eggs laid per female tick, percentage Iof hatchability of eggs, ;and number ‘of nymphs of the ticks fed on porcine blood were significantly higher than those ,of ticks fed on bovine blood.
Ornithodoros
Moubata: TABLE
Effects
In Vitro
BREEDING
III
of Rabbit, Porcine, and Bovine Blood on the Reproduction Ornithcdoros moubata Ticks Reared on Rabbits& Source of blood
Mean f
SE
Significance of differences
of
Remarks
P < 0.001
Rabbit-fed ticks significantly bigger than either bovineor porcine-fed ticks.
236.43 f 10.93 278.48 f 14.93 238.13 31 13.02
P < 0.05
Porcine-fed ticks significantly heavier than either bovineor rabbit-fed ticks.
Rabbit Porcine Bovine
136.43 f 203.35 f 165.13 f
10.93 14.93 13.02
P < 0.01
Porcine meals significantly greater than rabbit and bovine meals.
Number of eggs laid per female tick
Rabbit Porcine Bovine
206.62 f 12.12 224.0 f 16.23 151.11 jz 14.82
P < 0.01
Ticks fed on porcine and rabbit blood laid more eggs than those on bovine blood.
Number of eggs per milligram of blood ingested
Rabbit Porcine Bovine
0.10 0.06 0.08
P < 0.001
Number of eggs per milligram of blood ingested significantly higher among ticks fed on rabbit than those on bovine and porcine blood.
Preoviposition
Rabbit Porcine Bovine
9.61 zk 0.74 13.30 f 0.75 15.39 f 0.93
P < 0.001
Preoviposition period was significantly shorter in ticks fed on rabbit blood than in those on bovine blood.
Rabbit Porcine Bovine
14.22 =I= 0.50 15.20 * 0.23 14.64 f 0.38
-
per
Rabbit Porcine Bovine
185.0 f 13.03 178.28 zk 14.83 112.26 f 13.51
P < 0.01
Significantly more nymphs from ticks fed on rabbit and porcine blood.
of hatchability
Rabbit Porcine Bovine
P < 0.001
Hatchabilit,y from ticks fed on rabbit blood was significantly higher than ticks fed on bovine blood.
Rabbit Porcine Bovine
103.58 f 79.75 f 77.65 f
Weight of fully engorged female ticks (mg)
Rabbit Porcine Bovine
Weight of blood meal ingested per female tick (mg)
Weight
of unfed females
Incubation
period (days)
period
Number of nymphs female t,ick
Percentage
(mg)
a Each sample included
1.59 f 1.19 f 1.02 f
87.90 & 76.29 f 66.41 +
5.19 4.55 3.10
2.79 3.59 5.15
40 ticks.
In order to compare the effects of the diet of immature stages son reproduction, treks reared on porcine blood were divi,ded into two groups; one was fed on bovine, the other on porcine blood. The results
which were analyzed by Student t test are shown in Table II. The mean weights of the unfed and the fully engorged ,and the blood meals of females fed on bovine and porcine blood were not significantly differ-
286
MANGO
AND
TABLE Percentage Number
Ornithodoros
IV
moubata Ticks Reaching
Maturity
after Each Molt
of instars
3
4
5
6
>6
Percentage reaching maturity within six instars
F 111~
0 0
3.6 16.8
13.3 13.5
10.4 4.6 >
21.4
62.2
16.4
M F
0 0
0 0
0.2 5.0
3.2 4.2 >
31.2
12.6
56.2
Porcine Bovine
of Surviving
GALUN
Mortality (%)
6 M = males; F = females.
ent. Nevertheless, the mean numbers of eggs laid per female ticks, and thus eggs per milligram of blood ingested, were significantly higher in ticks fed ‘on porcine blood than in those fed on bovine blood, Although the preoviposition period and percentage of hatchability were not significantly different among the Pw’o groups, the incubation period was significantly shorter and the mean number of nymphs per female was higher among ticks fed on porcine blood than those fed on bovine blood. Table III shows the effects of rabbit, porcine, and bovine blood on the reproduction of 0. moubuta. Unlike the ticks in the previous two experiments, the ticks used in this experiment were reared on rabbits. Even though the ticks fed on rabbit blood were all significantly larger than those fed on either porcine #orb’ovine blood, the mean weight of the blood meal ‘of females fed on porcine blood was significantly higher than that of either rabbit or bovine blood fed females, and the mean number of eggs laid by either females fed on rabbit or porcine blood was significantly higher than that of bovine blood-fed females. The mean number of eggs per milligram of blood of females fed on rabbit blood is significantly higher than that of either ‘ticks fed on porcine or b’ovine blood. There was no significant ,difference in incubation periods of
the three groups. The bovine blood-fed ticks produced significantly less nymphs, and the percentage of hatchability was also significantly lower than in either rabbit or porcine blood-fed ticks. Developwnt Table IV shows development of OrrCthodoros moubata nymphs on the two sources of blo’od. Nymphs fed son porcine blood started maturing earlier by one stage and by the sixth molt many more had matured (62.2% ) than the bovine-fed nymphs (12.6% ). High mortality was evident among nymphs fed on bmovine blood. When the last-stage nymphs were weighed, both unfed and fed weights were comparable. Within each instar, the development was invariably faster on porcine than on bovine blood (Fig. 1). DISCUSSION
Though feeding ‘of ticks through membrane has been previously described (Tarshis 1958; Galun and Kindler 1965), to the best of our knowledge this is the first successful achievement of a complete life cycle by the artificial feeding of ticks. In all the experiments, porcine blood was consistently good in Ornithodoros moubata egg and nymph output regardless of the diet or host on which the ticks had been raised.
Omithodoros
Moubata:
BREEDING
In
3rd stage
2nd stage nymphs
287
Vitro
nymphs
100 bovine ,-e-e
73 u 3 P s
I
0
Period
4th
stage
after
blood meal
nymphs
(days)
5th
stage nymphs
100
100
porcine P 3 s
.e
w-ebovine
s
25
0 Period
after
25
0 blood meal
(days)
6th stage nymphs 100 porcine
0 Period
FIG. 1. Effects nymphs
fed through
of porcine and bovine bat’s wing membrane.
25 after
blood
When ticks of mean equal unfed body weights were fed on bovine and porcine blood, they took almost equal blood meals but the ticks fed on porcine blood produced
blood meal
(days)
on development
of Ornithodoros
moubata
significantly more eggs than the bovine-fed ticks; i.e., the number of eggs per milligram of blood ingested was significantly higher on porcine blood than son bovine blood.
288
MANGO AND GALUN
Either the bovine blood has a smaller amount of the necessary ingredients for egg formation or the tick is unable to convert the blood meal into usable ingredients. The fact that egg ‘output ‘of ticks fed on bovine blood improved when the ticks used had been reared on a better diet, like living rabbit
