AM>From: Aaron Morris <[log in to unmask]>
>Date: Fri, 18 Oct 1996 10:50:01 EDT
>Subject: Yet another mite!?!?
AM>Discussion on APIS-L has mentioned another scourge on the horizon.
>This is news to me. Anyone have any details, such as what this mite
For drawings and information try:
http://alpha.sggw.waw.pl/~woyke/
Some of the information you will find at this site in Poland:
Adult Tropilaelaps clareae males can feed and survive
for two weeks
J. Woyke1*, S. Chen2
* 1 Institute of Apicultural Research, Chinese Academy of
Agricultural Sciences, Xiang Shan, Beijing, China;
Present address: Bee Division, Agricultural University
- SGGW, 166 Nowoursynowska, 02-787 Warsaw, Poland.
2 Institute of Animal and Veterinary Sciences, Beijing
Academy of Agricultural and Forestry Sciences, Beijing,
China.
.SUMMARY
The distal part of the chelicerae of the mouthparts of the
adult Tropilaelaps clareae male is modified into a long,
sinuous spermatodactyl. Therefore it is described, that
adult T. clareae male can not feed.
Adult T. clareae males were collected from comb cells
with emerging Apis mellifera workers. The male mites were
released in an incubator on different substrates. No one
male survived 2 days, after the mites were released into
empty test tubes or on bee larvae 4 days old. However, 29 -
50% of them were still alive the 6th day after the males
were released on bee pupae. Some males survived 13 days.
This seems to indicate that adult T. clareae males can feed.
The different surviving on various developmental stages of
honeybee may be explained by different ectohormons present
on the epidermis of honeybee larvae and pupae.
Keywords: Tropilaelaps clareae, survival of mites, males of
T. clareae
INTRODUCTION
Tropilaelaps clareae is more dangerous parasitic mite of
Apis mellifera, than Varroa jcobsonii is (Woyke 1984).
Therefore it is important to know its biology.
Woyke (1984, 1985) found, that T. clareae can survive
on adult A. mellifera honeybees for 2 days only. On this
basis control method without the use of any drugs was
elaborated. Koeniger and Muzaffar (1988) reported that T.
clareae mites survived on adult workers of three Apis
species also for only 25 to 57 hrs. T. clareae females lay
the first eggs 48 - 52 hrs after cell sealing (Woyke 1989,
Wei 1992). The average development time of the mites is 4.8
days (Wei 1989) or 4.4 days (Chen and Li 1993). As a result
first adult T. clareae males appear on A. mellifera brood
15 - 17 days after bee egg was laid, (Ritter and Ritter
1988). Thus, they have to survive in worker brood cells for
at least 5 days, and in drone cells 3 days longer. The males
emerge from the cells together with the bees and are found
on comb surface in ratio 1.0 : 1.8 (Woyke 1989). They
survive in bee colony without brood for two days (Woyke
1985). However, in colonies with brood they can survive up
to 5 days after emerging from the cells (Rath at al 1991).
This would mean, that some mites are able to survive for 10
days, after reaching the imago stage. How it can occure is
not known. The males mate with the females inside sealed
brood cells, as well as outside (Woyke 1994). Therefore, it
is important to know, how long the males can survive outside
sealed brood cells on different development stages of
honeybee.
The females enter new brood cells within 2 days after
emerging from the previous one (Woyke 1987a). T. clareae
males do not enter brood cells to be sealed. According to
Griffiths (1988) female chelicerae function as a pair of
formidable piercing, grasping structures. Therefore it seems
strange, that adult T. clareae females can not survive on
honeybee larvae 3 days old, although they can feed and
survive for 4 weeks on bee larvae 4 days old (Woyke 1993).
The distal part of the chelicerae of adult male, the movable
chela is modified into a long, sinuous spermatodactyl
(Delfinado and Baker 1961, Kitprasert 1984). Consequently,
it is described (Akratanakul 1987) and accepted (J~druszuk
1992), that adult T. clareae male can not feed.
It is very important to know whether adult T. clareae
males can feed and survive on open bee brood. If they could,
open bee brood could be damaged. Furthermore, the sex ratio
of mites moving freely on comb surface may be the result of
different ability to feed and survive on open bee brood and
not the reflection of sex ratio in the offspring.
It is not known, whether adult T. clareae males are
eliminated from bee colonies because they are unable to
feed, or for some other reasons.
Therefore it was investigated whether T. clareae males
can survive for several days without feeding, or on which
developmental stage of honeybee they can survive.
To study the biology in vitro also requires to know
whether, or on which developmental stage of honeybee T.
clareae male can survive.
MATERIAL AND METHODS
The investigations were conducted independently by both
authors. Woyke conducted the investigations in the Institute
of Apicultural Research of the Chinese Academy of
Agricultural Sciences in Beijing in July and August 1992.
Chen, in the Institute of Animal and Veterinary Sciences of
Beijing Academy of Agricultural and Forestry Sciences from
August to December 1992.
Woyke collected adult T. clareae mites from comb cells
with A. mellifera ligustica workers emerging in his
presence. When more mites were needed, sealings were removed
from comb cells with workers ready to emerge. Catching mites
with wet brush was avoided. Instead, forceps with thin
points were used. The points were placed near both sides of
a running mite. As a result the mite entered on one point.
Next, that point was approached to the inside wall of an
empty glass test tube, where the mite descended. The mites
were sexed upon the shape of the epigynial plate.
The male mites were released on the following
substrates: 1. Empty glass tubes (0.8 x 4 cm) without food;
2. Small Petri dishes (diameter 6 cm) with small piece of
brood comb (2 x 2 cm) with 5-6 larvae 4 days old. The combs
were cut along the foundation, so that larvae were present
on one side of the combs only. The length of the cells was
shortened. In a pilot experiment a trial was made to feed
the larvae with mixed food. However, this was not necessary,
since all larvae were alive the next day without feeding.
Together 25 dishes with 2 males in each were investigated.
3. Eighteen males were released into 18 individual glass
test tubes (0.8 x 4 cm) containing bee pupae with white-pink
eyes. Nine males were released June 24 (series 1) and the
other nine one week later (series 2). When some bee pupae
showed some development irregularities, they were exchanged
for new ones of similar age. Bee pupae were not parasitized
by T. clareae before being used in this experiment.
Individual records of male survival were conducted each day.
Petri dishes and test tubes were kept in an incubator at
34oC. Daily measurements showed outside air temperature
around 30oC and humidity 90 - 100%. The humidity in the
vessels in incubator must have been a little lower.
Chen investigated survival of adult T. clareae males on
A. m. ligustica honeybee pupae. The males originated from
another experiment concerning reproduction and development
time of T. clareae. When the young worker bee in a glass
tube was ready to emerge, T. clareae males, reared in the
laboratory, were transferred onto worker pupae with pink
eyes in glass tubes 0.6 cm in diameter and 3 cm long. The
tubes were sealed with a sheet of wax foundation. Two small
holes were made in each wax lid. The tubes were located in
an incubator at 34oC with a dish with water at the bottom.
The humidity in the incubator was 70 - 74%. The survival of
males was inspected daily. The rearing of the mites in the
previous experiment (where from the males originated) was
conducted in the same conditions.
RESULTS
Table 1 shows, that no one T. clareae mite was alive the
next day, after the males were released into empty test
tubes. Out of 30 males released on larvae 4 days old, 2 only
survived till the next day. None male survived after 48 h.
Out of 18 males released by Woyke on bee pupae, all of
them were alive the second day and 89% after 48 h. Without
statistical calculation it is obvious, that during the two
first days considerably more males survived on pupae than on
larvae, or empty test tubes.
Results presented in table 2 show, that out of 18 males
reared by Woyke, 9 (50%) were still alive the 8th day. The
binomial 95% confidence interval for 9 mites surviving out
of 18 is 0.25 - 0.75. This means, that in a large number of
similar experiments, the survival of 5 - 14 mites (18 x 0.25
= 4.5 to 18 x 0.75 = 13.5) can be expected till the 8th day .
The 11th day, still 4 (22%) mites were alive. The
binomial 95% confidence interval for 4 out of 18 indicates,
that 1 - 8 males could be expected to survive till the 11th
day.
Two (11%) males survived till the 13th day. The
binomial 95% confidence interval indicates, that in many
repetitions survival of 0.2 - 6 males can be expected till
the 13th day. Some mites may survive probably for even
longer period. No alive male was found the 14th day of
observation.
Results obtained by Chen show, that out of 7 males 3
(43%) survived till the next day. The binomial 95%
confidence interval shows, that survival of 1 (14%) to 5
(71%) males may be expected in many repetitions. Two males
(29%) survived till the 6th day. The binomial 95% confidence
interval indicates, that survival of 1 to 5 males may be
expected till that day. The last male survived till the 7th
day. The average survival was 2.7 days. The percentage
survival till the 6th day and the binomial 95% confidence
interval for data of Woyke are 50%; and 28% - 75% and of
Chen are 29% and 14% - 71% respectively. Both results
overlap each other, although origin of the males was very
different.
The survival rate of adult T. clareae males in Chen
experiment was lower, than that in Woyke experiment. This
was probably caused by different origin of the males. Chen
showed in a parallel experiment on survival of females, that
the maternal ones originating from a honeybee colony
survived on bee pupae on the average for 30 days, while the
new female generation reared in an incubator survived on the
average for only 21 days.
All the above results show, that adult T. clareae
males can not survive for several days without feeding. They
do not survive on bee larvae 4 days old either. However,
the males are able to survive for several days on bee pupae.
Some survived on the pupae up to 13 days after emerging from
brood cells.
DISCUSSION
Increasing the number of T. clareae males released on bee
pupae could change the mean survival, however it could not
change at all the main conclusion, that adult T. clareae
males can survive on bee pupae up to two weeks. This
indicates, that some males are able to live up to 18 days
after reaching the imago stage. Some males survived on bee
pupae more than 10 times longer, than others in the same
conditions without any food. This seems to indicate that
adult T. clareae males are able to feed on bee pupae. Two
possibilities may occur. Either the male can pierce somehow
the epidermis, despite the chelae of the chelicerae are
modified into spermatodactyls, or the male feeds on some
liquids through the oral opening of the hypognathum.
Interesting is the phenomenon, that the males did not
survive on bee larvae beyond the 2nd day. The epidermis of
bee larvae is softer than that of pupae, and the females can
feed and survive on larvae 4 days old for 4 weeks. It is
suggested, that the different survival results of the males
may be caused by the different ectohormones present on the
epidermis of both bee developmental stages (Koeniger and
Veith, 1984; Trouiller et al, 1991; Nation et al, 1992).
However, this was not supported by any data. Thus, the
reaction for the same stimuli may be different in both sexes
of T. clareae mites.
It is not expected that T. clareae male would enter a
comb cell with larva and survive till the prepupa or pupa
stage. However, in infested colonies, bee workers open many
cells with pupae infested by mites. In these circumstances
adult T. clareae males could feed and survive for several
days after emerging from brood cells.
The results explain, that some adult T. clareae males
are eliminated from bee colonies with open brood within 2
days not because they are not able to survive longer, but
because they do not find bee pupae on which they could
survive for several days.
ACKNOWLEDGMENTS
The first author would like to thank very much prof. Jin
Zhen-Ming the director of the Institute of Apicultural
Research of the Chinese Academy of Agricultural Sciences in
Beijing for providing the facilities to conduct the
investigations, prof. Huang Shuang-Xiu, the vice-director of
that institute for her inestimable help in every respect,
and Mr Zhang Yao-Gang for the technical assistance. He would
like to thank also the United Nation Development Program in
China, Senior Technical Advisers Recruitment (STAR) for the
financial support, which was obtained through China
International Center for Economic & Technical Exchanges
(CICETE).
REFERENCES
Akratanakul, P (1987) Honeybee diseases and enemies in Asia:
a practical guide. FAO Agricultural Service Bulletin
68/5, Rome; 51 pp.
Delfinado, M D; Baker, E W (1961) Tropilaelaps, a new genus
of mite from the Philippines (Laelaptidae [s.lat.]:
Acarina). Fieldiana. Zoology 44(7): 53-58
Chen, S; Li, L (1993) Development of Tropilaelaps clareae.
33 Intern Congr Apimondia, Beijing:
Griffiths, D A (1988) Functional morphology of the
mouthparts of Varroa jacobsoni and Tropilaelaps clareae
as a basis for the interpretation of their life-styles.
In Needham, G R; Page R E Jr; Delfinado-Baker, M;
Bowman, C E (eds) Africanized Honey Bees and Bee Mites.
Ellis Horwood Ltd, Chichester; pp 479-486
Jedruszuk, A (1992) [Bee diseases not present in Poland
(Polish)]] Pszczelarstwo 43(11): 7-9
Kitprasert, C (1984) Biology and systematics of the
parasitic bee mite. MS thesis; Kasetsart
University, Thailand (Eng. summary) 70pp.
Koeniger, N; Muzaffar, N (1988) Lifespan of the parasitic
honeybee mite, Tropilaelaps clareae, on Apis cerana,
dorsata, and mellifera. Journal of Apicultural Research
27(4): 207-212
Koeniger, N; Veith; H J (1984) Specifit t eines
Brutpheromones und Bruterkennung bei der Honigbiene
(Apis mellifera L.). Apidologie 15(2): 205-210
Nation, J L; Sanford, M T; Milne, K (1992) Cuticular
hydrocarbons from Varroa jacobsoni. Experimental &
Applied Acarology 16(4): 331-344
Rath, W, Delfinado-Baker, M; Drescher, W (1991) Observations
of the mating behavior, sex ratio, phoresy and
dispersal of Tropilaelaps clareae (Acari:
Laelapidae). International Journal of Acarology
17(3): 201-208
Ritter, W; Schneider-Ritter, U (1988) Differences in
biology and means of controling Varroa jacobsoni and
Tropilaelaps clareae, two novel parasitc mites of Apis
mellifera. In GR Needham, G R; Page R E Jr;Delfinado-
Baker, M; Bowman, C E (eds) Africanized Honey Bees and
Bee Mites. Ellis Horwood Ltd, Chichester;pp 387-395
Trouiller, J; Arnold, G; Le Conte, Y; Masson, C (1991)
Temporal pheromonal and kairomonal secretion in the
brood of honeybees. Naturwissenschaften 78: 368-370
Wei, H (1992) Study on generative characteristics of
Tropilaelaps clareae Delfinado et Baker (Acari:
Laelapidae). 19 International Congress of Entomology,
Beijing: 675
Woyke, J (1984) Survival and prophylactic control of
Tropilaelaps clareae infesting Apis mellifera
colonies in Afghanistan. Apidologie 15(4): 421-434
Woyke, J (1985) Further investigation into control of the
parasite bee mite Tropilaelaps clareae without
medication. Journal of Apicultural Research 24(3): 250-
254
Woyke, J (1987a) Length of stay of the parasitic mite
Tropilaelaps clareae outside sealed honeybee brood
cells as a basis for its effective control. Journal of
Apicultural Research 26(2): 104-109
Woyke, J (1987b) Comparative population dynnamics of
Ttropilaelaps clareae and Varroa jacobsoni mites on
honeybees Journal of Apicultural Research 26(3): 196-
202
Woyke, J (1989) Change in shape of Tropilaelaps clareae
females and the onset of egg laying. Journal of
Apicultural Research 28(4); 196-200
Woyke, J (1993) Tropilaelaps clareae females can survive for
four weeks when given open bee brood of Apis mellifera.
Journal of Apicultural Research 33(1):21-25
Woyke, J (1994) Mating behavior of the parasitic honeybee
mite Tropilaelaps clareae. Experimental & Applied
Acarology 18: 723-733
.
TABLE 1. Survival of adult Tropilaelaps clareae
males on different substrates.
_________________________________________________
No % survived
Substrate mites 24h 48h
_________________________________________________
Empty test tubes 17 0.0 0.0
4 day old larvae 30 6.7 0.0
Pupae 18 100.0 88.9
TABLE 2. Survival of adult T. clareae males reared on
honeybee pupae by Woyke and Chen.
______________________________________________________
Days Woyke Chen
______________________________________________________
No investigated
0 18 7
Percent survived
1 100 100
2 100 43
3 89 23
4 78 23
5 50 23
6 50 23
7 50 14
8 50 0
9 39
10 22
11 22
12 11
13 11
14 0
<end of paper>
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