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> --- ~ QMPro 1.53 ~ http://alpha.sggw.waw.pl/~woyke/