.,. OVIPOSITION AND INCUBATION IN BOOPHILUS DECOLORATUS (KOCH, 1844) (ACARINA: IXODIDAE)* , (/) (/) 60 ~0 100

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1 Onderstepoort J. vet. Res. 44 (1), 13-2 (1977) OVPOSTON AND NCUBATON N BOOPHLUS DECOLORATUS (KOCH, 1844) (ACARNA: XODDAE)* J. G. H. LONDT(l), Department of Entomology, Veterinary Research nstitte, Onderstepoort ABSTRACT LONDT, J. G. H., Oviposition and incbation in Boophils decolorats (Koch, 1844) (Acarina: xodidae). Onderstepoort Jornal of Veterinary Research 44 (1), 13-2 (1977). Stdies on the dration of the oviposition and incbation periods of Boophils deco/orats (Koch, 1844) revealed that these non-parasitic periods are temperatre dependent, increase in temperatre casing shortening of the periods. Hmidity had no effect on the dration of either the oviposition or the incbation periods. The relation beteen the mass of engorged female ticks and that of the eggs they prodced as fond to be linear. The viability of eggs prodced dring the first 13 days of oviposition (at 26 oq as greater than that of eggs laid sbseqently. The critical temperatre for B. decolorats eggs as fond to be 42 oc and they ere shon to be nable to take p ater vapor from damp atmospheres. Both temperatre and hmidity affected the hatch of eggs. A simple model of the relations beteen the physical factors of the environment and the varios biological phenomena stdied has been given. Resme LA PONTE ET LNCUBATON CHEZ LA TQUE, BOOPHLUS DECOLORATUS Des etdes portant sr a dnfe de a ponte et cel/e de a periode dincbation de a tiqe Boophils decolorats (Koch, 1844) ant revele qe ces periodes non-parasitaires dependent de a temperatre, /elevation de celleci determinant n raccorcissement de ces periodes. Lhmidite na acn e.ffet sr a dree de ces periodes. Le rapport entre le poids des tiqesfemel/es apres /ingestion complete d sang et celi de lers oefs est lim!aire. La viabilite des oefs ponds pendant les 13 premiers jors de a ponte (a 26 C) depasse cel/e des oefs ponds pls tard. La temperatre critiqe des oefs se site a 42 C. Les oefs sont incapables dabsorbes de a vaper dne atmosphere hmide. Leclosion des oefs est inflencee par a temperatre et lhmidite. Later presente n modele simple exprimant le rapport entre les caracteres physiqes d milie et les differents phenomenes biologiqes qi ant ete etdies. NTRODUCTON Detailed information concerning the life cycle of Boophils decolorats (Koch, 1844) has only recently become available. The athor and his co-orkers have pblished acconts of the anatomy and parasitic life cycle of this species (Arthr & Londt, 1973), its preoviposition period (Londt, 1974), the embryonic development of the larvae (Londt, 1975), gonad development and gametogenesis (Londt & Spickett, 1976), and the adlt males fertiliation capacity (Londt, 1976). n addition the distribtion of larvae in cattle pastres and their.climbing behavior on grass stems and ater balance ere discssed by Londt & Whitehead, The oviposition and incbation periods, hoever, have not yet been described. Knoledge of the dration of these periods is important hen the possibilities of "Pastre Spelling" as a means of controlling this one-host species are considered or hn an attempt is made to design acaricide bioassay techniqes involving engorged adlt female ticks. OVPOSTON PEROD The relation beteen engorged female mass and the mass of eggs prodced Tenty-one semi-engorged female ticks, selected for their ide range in sie, ere plled off a laboratory infested Gernsey calf, mass measred and alloed to oviposit in tbes held in an incbator (26 oc; 95% R.H.). The relation beteen female mass and that of the eggs they prodced (Fig. 1) is linear and similar to that demonstrated for a nmber of other tick species, inclding Amblyomma americanm (Gladney & Drmmond, 197); A. maclatm (Drmmond & Whetstone, 197); A. hebraem (Norval, 1974) ; Anocentor nitens (Drmmond, Whetstone, Ernst & Gladney, 1969); Boophils micropls * This investigation as ndertaken at the Tick Research Unit, Rhodes University, Grahamston, Cape Province ( 1 ) Present address: Natal Msem, Loop St., Pietermaritbrg, Natal Received 26 October 1976-Editor (Stherst, 1971); Hyalomma aegyptim (Seatman, 1968); H. anatolicm (Sno & Arthr, 1966) and Rhipicephals sangines (Seatman, 1967). The minimm mass a female mst attain before eggs are prodced as abot 17 mg. This implies that, as nengorged females have a mean mass of 1, 4 mg (Arthr & Londt, 1973), a blood meal of approximately 16 mg is reqired for egg prodction , E \.J 1 t- 8...J <i :E LL.. LL (/) (/) <i :E 2./.,..,,.,. - /!/ 2 4,, 6 1 MASS OF EGGS PRODUCED C mg) FG. 1 The relation beteen the mass of Boophils decolorats female ticks and that of the eggs they prodce The inflence of constant temperatre and hmidity conditions on the pattern of oviposition and dration of oviposition period The inflence of constant temperatre and hmidity conditions on the oviposition period of B. decolorats females as stdied, 6 different temperatres and 3 13

2 OVPOSTON AND NCUBATON N BOOPHLUS DECOLORATUS (KOCH, 1844) different hmidity levels being sed (Table ). The reslts of mass measring daily collections of eggs from all the females stdied are shon in Fig. 2 a-e. TABLE 1 Combinations of temperatre, relative hmidity and satration deficit sed to stdy the inflence of these parameters on oviposition and incbation periods in Boophils decolorats Temperatre Relative hmidity Satration deficit (OC) (% R.H.) (mm Hg) beteen temperatre and egg otpt is shon in Fig. 5. There appears to be a tendency for ticks to prodce more eggs at high temperatres than at lo. Hoever, as the variation abot the means as great, this relationship is qestionable. The relation beteen satration deficit and egg otpt (Fig. 6) is again difficlt to interpret. t appears to be affected by temperatre, so it is sggested that hmidity does not inflence total egg otpt by female B. decolorats ticks. 1 9, , , , , , , , , , , , , , , , , ,71 No oviposition took place at 1 C. The oviposition patterns for females laying at 38 C, 32 oc and 26 oc ere very similar. Egg prodction sally reached a peak on the 3rd day, althogh in a fe instances this peak occrred either on the 2nd or the 4th day after laying began (Fig. 2 a-c). Egg prodction then decreased fairly rapidly and finally ceased abot Day 13 (range: 7-16 days). At 2 oc and 15 oc respectively no clearly defined peaks of egg prodction ere fond (Fig. 2 d-e), althogh it as still evident that the majority of eggs ere prodced dring the first half of the oviposition period. The relation beteen temperatre and the dration of the oviposition period, clearly illstrated in Fig. 3, shos that the dration of oviposition remains fairly constant at temperatres of 26 oc and higher, hile loer temperatres have the effect of extending the oviposition period from 18, 3 days at 2 oc to 32,2 days at 15 C. The relation beteen satration deficit and the dration of the oviposition period (Fig. 4) is more difficlt to interpret. The data plotted in Fig. 4 sggest that the oviposition period is possibly extended by a decrease in satration deficit (i.e. an increase in hmidity). This relation is not real, hoever, for the same reasons given by Londt (1974) hen discssing the effects of satration deficit on the preoviposition period of B. decolorats. t is obvios that there is an overriding effect of temperatre and that the inflence of hmidity is minimal. This sggestion is spported by the information contained in Fig. 2 a-e, here egg prodction crves plotted for each hmidity level are very similar at each temperatre level. To assess the effects of temperatre and hmidity on the total egg otpt of female ticks, the mass of eggs per milligramme of engorged female mass as calclated for each tick to eliminate any effects of female sie or degree of engorgement. The relation :: Q. en 3 j---t----lib----< _j <!) <!) 2 <!) t5 1 :: Q. 1., o,. -. _-o_ c OVPOSTON PEROD C DAYS) FG. 2 a-e The inflence of constant temperatre and hmidity on the oviposition pattern of Boophils decolorats. Data collected at 9% R.H. e--e ; 7% R.H. ----; 5% R.H. + + The inflence of natrally flctating temperatres and hmidities on oviposition To batches of flly fed B. decolorats females ere confined in open-ended plastic tbes by means of fine gae and placed together ith a thermohygrograph in a Stephensons screen standing on the grond in a cattle pastre on the farm, Upper Gletyn, near Grahamston. B. decolorats larvae had previosly been collected in this pastre. These ticks ere examined daily, their eggs removed and mass measred. The daily flctations in egg prodction in both batches of females are given (Fig. 7) and the dration of the oviposition period of each female shon (Table 2). a b d 14

3 J. G. H. LONDT 4,8 r. 3 " " - E ",6 -- :: a_ Q Ui a_ > 2 1 t t E... ll,4 " E -- => a_,2 => (.!) (.!) TEMPERATURE ( C} FG. 3 The relation beteen temperatre and the oviposition period dration of Boophils decolorats. Data collected at 9;/,; R.H. e; 7;/,; R.H. ; 5/;; R.H.. The horiontal lines indicate means; open boxes indicate one standard deviation abot the mean and vertical lines the range at each temperatre level TEMPERATURE C C} FG. 5 1 :1e relation beteen temperatre a nd egg otpt by Boophils decolorats. Data collected at 9% R.H. e ; 7;/,; R.H. ; 5/;; R.H.. Horiontal lines indicate means and vertical lines range at each temperatre 4 RELATVE HUMDTY% /:, 15 /:, :: 2 [] /::;. /:, => 3 " M!:i 26 [).:1 (J :: /::;. ll /::;. 2 ll 1::. Q :: Jl tj a_ 32 l!j (]::, L 38 a_ [) l!j (]::, 1::. M ffi (]::, [) l!j [] 1 (J (J a_ (]::, l!j > [) SATURAT ON DEFCT ( mm Hg),8 /::;. <1 [) " i:j.,6 /::;. -;;; " <1[] E ll..: [] A l!j E l!j... (]::, g},,4 [) l!j " /:, HUMDTY /o E (J v j [) 15 /:, => n.. =>,2 /:, (] 2 [] /::;. => (.!) /::;. (.!)!:i 26 [) A (J :: 32 l!j (]::, L SATURATON DEFCT Cmm Hg ) FG. 4 The relation beteen satration deficit and the oviposition period dration of Boophils decolorats 15 FG. 6 The relation beteen satration deficit and egg otpt by Boophils decolorats

4 OVPOSTON AND NCUBATON N BOOPHLUS DECOLORATUS (KOCH, 1844) TABLE 2 The oviposition periods, in days, of Boophils deco/orats females laying nder natrally flctating macroclimatic conditions No. of female Mean.... Dration of oviposition period (days) Batch Batch The mean mass of eggs prodced flctated from day to day, the flctations being directly related to temperatre changes expressed as daily hor degrees above a baseline of 1 oc (Fig. 7). To assess the possible effects that flctations of relative hmidity and satration deficit had on oviposition, the nmber of relative hmidity nits (i.e. hor % R.H. nits above a baseline of 5% R.H.) and the nmber of satration deficit nits (i.e. hor mm Hg nits above a baseline of ero) ere calclated for each 24-hor period and plotted together ith the flctations in hor degrees (Fig. 8). The flctations of relative hmidity nits (hor % R.H. nits) ere the converse of temperatre and satration deficit y 14 J 13 - N 9 ::::> 8 ::: 7 a.. CJ) 6 <.!) <.!) 5 LL. 4 CJ) 3 2 <l: 1 l nits, as old be expected, otherise all 3 physical parameters folloed the same pattern. As oviposition stdies nder controlled laboratory conditions shoed that egg prodction is not dependent on hmidity, it can be accepted that the flctations in oviposition illstrated in Fig. 7 are the direct conseqence of temperatre flctations. NCUBATON PEROD The viability of eggs prodced on different days of the oviposition period Boophils microp/s eggs laid toards the end of the oviposition period yielded a loer percentage hatch than those prodced dring the first fe days (Hitchcock, 1955). t as therefore decided to determine the viability of eggs laid on sccessive days throghot the oviposition period of B. deco/orats. Eggs ere collected daily from 1 flly engorged female ticks and placed in separate glass vials in an incbator (26 oc; 95% R.H.) to hatch. When hatching had ceased, the percentage hatch of each egg batch as determined and then plotted against the day on hich the eggs ere prodced (Fig. 9). Except for Day 8, for hich a mean hatch of 82% as recorded, eggs laid over the first 13 days of the oviposition period yielded hatches of over 95%. The percentage hatch of eggs prodced after Day 13 decreased progressively; of those laid on Day 19 (the last day of the oviposition period) jst nder 1% hatched. The reasons for this decrease in hatch have not been established bt the decrease cold be de to any of the folloing factors:. A possible decrease in the spply of ntrients to the eggs dring their formation in the ovaries. 2. A possible decrease in the ater content of the eggs dring their formation. 3. A possible decrease in the efficiency of Genes organ in the aterproofing of eggs. 4. A possible breakdon of the fertiliation mechanism... ; : t. 4 ftl (j) :: ftl ftl 3CJ),..._ ll CT < ) c TME CDAYS) FlG. 7 The oviposition patterns of Boophils decolorats females <e e = Batch 1; -- = Batch 2), in relation to natral daily flctations in hor degrees (above 1 C} ( ) 16

5 J. G. H. LONDT,14 i, U"l Clo > 1 a: 5soo t:: :::16 >- 1- i5 4 > i=; 2 a: i TME CDAYSJ FG. 8 The interactions beteen temperatre (h ocabove l C, ),relative hmidity (h % R.H. above 5% R.H., e-.-.-.e) and satration... deficit (h mm Hg above ero, - ---) dring stdies on oviposition by Boophils decolorats nder natrally flctating climatic conditions \ 1 :., \ <.!> <.!> ll. 4 <.!> <l: 1- ::... 2 <l: :::E.. : \ :: \ : /\ i " ol : :, DAY OF OVPOSTON PEROD ON WHCH EGGS WERE LAD FG. 9 The percentage hatch of Boophils decolorats eggs in relation to the day on hich they ere laid 17 Critical temperatre of cticlar ax layer of eggs The critical temperatre is the temperatre at hich the protective ax molecles covering the cticle are reorientated, ith conseqent loss of ater from the tick. Lees & Beament (1 948) determined the critical temperatres of the egg axes of 6 tick species, as follos: xodes ricins 35 oc;. canisga 42,5 oc; Dermacentor andersoni 43 oc; Hyalomma savignyi 44 oc; Ornithodoros mobata 45 oc and. delanoei acins 46 C. The critical temperatre of B. deco/orats eggs as established by mass measring egg batches before and after exposre for 1 hor, to different temperatres. The reslts obtained indicate a critical temperatre of 42 oc (Fig. 1 ). Londt & Whitehead (1972) recorded temperatres of this order in field sitations here vegetation cover as limited and here no B. decolorats larvae ere ever collected. t is possible that eggs prodced by adlt female ticks in sitations here temperatres of 42 oc or over are experienced, old lose ater very rapidly and die. The ptake of ater vapor by eggs Londt (1975) demonstrated that B. decolorats eggs lost ater at all hmidity levels belo 1% R.H. and that sccessfl development of the embryos as entirely dependent on the rate at hich ater as lost. Eggs losing more than abot 35% of their initial mass throgh ater evaporation did not complete embryonic development. n previos stdies it as shon that B. decolorats larvae ere able to take p ater vapor hen the atmospheric hmidity exceeded 7% R.H. and imbibe free ater throgh their mothparts (Londt & Whitehead, 1972). No information has been available to date regarding the ptake of ater vapor by eggs. To assess the ability of B. decolorats eggs to take p ater vapor, 4 batches ere mass measred and placed in an incbator (26 C) in 4 different hmidity chambers: 95% R.H. (1, 3 mm Hg); 8/o R.H. (5,4 mm Hg); 6% R.H. (1,2 mm Hg) and 4% R.H. (1 5, mm Hg). After 24 hors all the egg batches ere

6 OVPOSTON AND NCUBATON N BOOPHLUS DECOLORATUS (KOCH, 1844) again mass measred, transferred to the 95 /o R.H. chamber and thereafter mass measred at 24 hor intervals. The reslts (Fig. 1 ) sho that, dring the first 24 hors, eggs held at 95/o R.H. increased slightly in mass hereas the rest all lost mass : the loer the hmidity the greater the loss recorded. After their transfer to 95 % R.H., none of the egg batches increased markedly in mass; so they are apparently nable to take p ater vapor from damp atmospheres. This means that the egg stage of B. deco!orats is more sensitive to desiccation than the larval stage, a fact that may have important implications in ftre biological and ecological research on these ticks. ::: :::> 2 r (l) <( 2 LL ;:! ::: Q._ <( 2 3 CR TCAL TEMPERATU RE TEMP ERATURE ( C) 5 55 FG. 1 The mean percentage mass lost by Boophils deco/orats eggs exposed to constant temperatre vales beteen 35 oc and 55 oc for hor. Critical temperatre of 42 oc is indicated The inflence of constant temperatre and hmidity conditions on egg development and hatch To assess the inflence of different combinations of temperatre and hmidity on the dration of the incbation period of B. decolorats eggs and the larval yield, batches of eggs ere exposed to the same 18 combinations of temperatre and hmidity sed in ork on the oviposition period (Table 1). All vials ere examined daily and the length of the incbation period recorded hen the first larvae hatched. Three eeks later all larvae and eggs ere conted and the percentage hatch determined. The relation beteen temperatre and incbation period dration is shon in Fig. 12 and that beteen satration deficit and incbation period dration in Fig. 13. No hatch took place at oc, 15 oc and 38 oc. At 2 oc only eggs held at 9/o R.H. hatched hile at 26 oc and 32 oc only eggs held at 9/o R.H. and 7/o R.H. hatched. The incbation period as extended by a decrease in temperatre. Again it can be seen that temperatre has an overriding effect and that hmidity has no inflence on the incbation period dration. r (l) + 5 REL ATVE ALL EGGS HELD AT 95 % R H HUMDTY 1,. AS SHOWN <i ::: <( 2 LL ;:! -1 ::: Q._ <( TME CHOURS) FG. The effects of placing Boophils decolorats eggs in a damp atmosphere (95% R.H.) after an initial 24 hor period in of 4 different relative hmidity levels. The temperatre as 26 oc throghot While considering the effects of temperatre and satration deficit on egg hatch (Fig. 4-5), it is evident that there is a definite satration deficit dependence and an apparent, possibly indirect, temperatre dependence. Temperatre inflences the dration of the incbation period and eggs held at lo temperatres ill have longer to lose ater throgh evaporation before they hatch. At similar satration deficit levels, eggs may develop into larvae at 32 oc hereas they may not be able to complete development at 2 oc becase this old take mch longer. t is possible, therefore, that the reslts shon in Fig. 14 and 15 reflect another limiting factor sch as the ater content of the eggs. DSCUSSON The effects of temperatre and hmidity on varios aspects of the non-parasitic life cycle of B. decolorats reported in this and previos pblications (Londt, 1974, 1975) may be smmaried by means of a model (Fig. 16) resembling that described by Macleod ( 1962) for the dynamic commnity relations in hich /. ricins participates. Each disc represents a measrable parameter. A clockise rotation of any disc means an increase in the effect of the parameter involved. t is important to note that the main drive for the model is throgh the physical factors 18

7 6 t *------t : J. G. H. LONDT 5 4 oc 3 g co ::::J 2 LL 4 ;:! :: 2 t TEMPERATURE C C) FG. 12 The relation beteen temperatre and incbation period dration of Boophils decolorats eggs. Data collected at 9% R.H. e and 7% R.H..A. Eggs held at 5% R.H. failed to hatch. For convenience means at each temperatre level have been joined oc 3 CD ::::J 2 :: ::::J :: :::;: RELATVE HUMDTY% X X X 15 X X X 2 X X 26 X 32 X &. 38 X X X X = NO HATCH TEMPERATURE C C) FG. 14 The relation beteen temperatre and the percentage hatch of Boophils decolorats eggs. Data collected at 9/,; R.H. e and 7% R.H..A. For convenience means at each temperatre level have been joined (/) LL :: 1,\ 8 \ \ f \ \{..,.-, \ \ \ \ \ \ ; 2i:; :. ; -:k- 1"\ \ :: ::::J :: :::;: RELATVE HUMDTY% [] [) & L----r--L_------L SATURATON DEFCT C mm Hg) FG. 13 The relation beteen satration deficit and incbation period dration of Boophils decolorats eggs 19.h--+-.A-@ l SATURATON DEFCT Cmm Hg) FG. 15 The relation beteen satration deficit and the percentage hatch of Boophils decolorats eggs. Means for data at each temperatre level have been joined

8 OVPOSTON AND NCUBATON N BOOPHLUS DECOLORATUS (KOCH, 1844) of the environment. This means that a change in temperatre reslts in a change in metabolic rate bt that the reverse is impossible. Ths it can be seen that, ith temperatre increase, relative hmidity decreases and satration deficit increases. Temperatre increase also cases a decrease in the drations of the non-parasitic phases (preoviposition, oviposition and incbation periods), presmably by increasing the metabolic rate of the ticks. A rise in temperatre also appears to increase the total egg prodction by female ticks, presmably becase the metabolic rate and efficiency of food tiliation increase. A rise in satration deficit, hich cold be cased by a rise in temperatre, reslts in increased ater loss from tick eggs; this directly affects the percentage hatch of the eggs. FG. 16 A model of the interactions beteen the physica factors of the environment (temperatre, relative hmidity and satration deficit) and varios parameters investigated dring a stdy of the biology of Boophils decolorats ACKNOWLEDGEMENTS Sincere thanks are extended to Professors G. B. Whitehead, B. R. Allanson (both of Rhodes University, Soth Africa) and Don R. Arthr (University of London, Kings College) for their constrctive criticism throghot all stages of this ork hich formed part of a dissertation for the degree of Doctor of Philosophy aarded by Rhodes University. This stdy as made possible throgh the financial spport given to the Tick Research Unit, Grahamston, by the Livestock and Meat ndstries Control Board, The Mohair Board, The Rhodes University Fondation Trst and the Department of Agricltral Technical Services. REFERENCES ARTHUR, D. R. & LONDT, J. G. H., The parasitic cycle of Boophils decolorats (Koch, 1844) (Acarina : xodidae). Jornal of the Entomological Society of Sothern Africa 37, DRUMMOND, R.. & WHETSTONE, T. M., 197. Oviposition in the Glf Coast Tick. Jornal of Economic Entomology 63, DRUMMOND, R.., WHETSTONE, T. M., ERNST, S. E. & GLADNEY, W. J., Laboratory stdy on Anocentor nitens (Nemann) (Acarina : xodidae) the tropical horse tick. Jornal of Medical Entomology 6, GLADNEY, W. J. & DRUMMOND, R.., 197. Mating behavior and reprodction of the lone star tick, Amblyomma americanm. Annals of the Entomological Society of America 63, HTCHCOCK, L. F., Stdies on the non-parasitic stages of the cattle tick Boophils micropls (Canestrini) (Acarina : xodidae). Astralian Jornal of Zoology 3, LEES, A. D. & BEAMENT, J. W. L., An egg-axing organ in ticks. Qarterly Jornal of Microscopical Science 89, LONDT, J. G. H., The preoviposition period of Boophils decolorats (Koch, 1844) (Acarina: xodidae). Jornal of the Entomological Society of Sothern Africa 37, LONDT, J. G. H., A rapid spectrophotometric method for the monitoring of embryonic development in ticks (Acarina : xodoidea). Onderstepoort Jornal of Veterinary Research 42, LONDT, J. G. H., Fertiliation capacity of Boophils decolorats (Koch, 1844) (Acarina: xodidae). Onderstepoort Jornal of Veterinary Research 43, LONDT, J. G. H. & SPCKETT, A. M., Gonad development and gametogenesis in Boophils decolorats (Koch, 1844) (Acarina: Metastriata: xodidae). Onderstepoort Jornal of Veterinary Research 43, LONDT, J. G. H. & WHTEHEAD, G. B., Ecological stdies of larval ticks in Soth Africa (Acarina: xodidae). Parasitology 65, MAEOD, J., Ticks and disease in domestic stock in Great Britain. Symposim of the Zoological Society of London 6, NORVAL, R. A. 1., The life cycle of Amblyomma hebraem (Koch, 1844) (Acarina: xodidae). Jornal of the Entomological Society of Sothern Africa 37, SNOW, K. R. & ARTHUR, D. R., Oviposition in Hyalomma anatolicm anatolicm (Koch, 1844) (xodoidea: xodidae). Parasitology 56, SUTHERST; R. W., An experimental investigation into the effects of flooding on the ixodid tick Boophils micropls (Canestrini). Oecologia 6, SWEATMAN, G. K., Physical and biological factors affecting the longevity and oviposition of engorged Rhipicephals sangines female ticks. Jornal of Parasitology 53, SWEATMAN, G. K., Temperatre and hmidity effects on the oviposition of Hyalomma aegyptim ticks of different engorgement eights. Jornal of Medical Entomology 5, Printed by and obtainable from The Government Printer, Private Bag X85, Pretoria, 1 2