J. Med. Ent. Vol. 3, no. 1: 29-35 15 April 1966

NOTES ON REPRODUCTIVE BEHAVIOR IN THE DERMANYSSIDAE 1 (ACARINA: )

By James H. Oliver, Jr.2

Abstract: Various aspects of reproductive behavior were colonies for several years and thus have been subjected investigated in the gqllinae, Ophionyssus to the selection that inevitably accompanies laboratory Downloaded from https://academic.oup.com/jme/article/3/1/29/864276 by guest on 30 September 2021 natricis, Ornithonyssus bacoti, and Ornithonys$us sylviarum. rearing. Some" out-crossing" occurred, however, Results of observations and experiments were compared on in the O. natricis colonies when snakes infested with such topics as: the effect of mating on feeding, oviposition mites from other sources were added. and longevity of the females; effect of feeding on mating; The maintenance and handling techniques for each site of mating; longevity of spermatozoa in the female; and multiple mated females' effect on sex ratio of progeny. of the four colonies have been given in detail by Oliver et at. (1963) and Oliver (1965). Ornithonyssus Information on the reproductive behavior of parasitic bacoti was reared on white rats, Op. natricis on many mesostigmatid mites is meager. This is especially species of snakes, young chickens (1 day to several evident when studies requiring the rearing of such weeks old) were used as hosts for the two species of species are attempted. Clearly one must know some- bird mites, D. gallinae and Or. sylviarum. The mites thing of the reproductive behavior of a species before used in experiments on reproductive behavior were its population structure and dynamics can be under- removed from the stock colonies as nymphs and isolated stood. The present study, while not definitive, adds individually to make certain they had not mated. to our knowledge of the reproductive behavior of four During experiments the mites were kept in zipper species of dermanyssid mites. boxes (clear plastic cylinders: height=2.5 cm; dia- meter=3.2 em) in which small strips of moist filter MATERIALS AND METHODS paper had been placed. The four species of mites used in this study were The feeding and recovery of experimental mites maintained in laboratory colonies in cages described presented a problem which was solved only to varying by Camin & Ehrlich (1960), Oliver et at. (1963) and degrees, depending upon the species. Ornithonyssus Oliver (1965). The colonies of the chicken mite, bacoti was fed on the closely shaved tail of a white (DeGeer), the tropical rat mite, laboratory rat. The tail and the mites were confined Ornithonyssus bacoti (Hirst), and the snake mite, in a glass tube slightly larger than the tail. The two Ophionyssus natricis (Gervais), were kept at ••room species of bird mites, D. gallinae and Or. sylviarum, conditions" (18-26°C, 10-35% R.H.). Oliver (1965) were experimentally fed and recovered by placing them pointed out, however, that the humidity in the colonies on chickens (1-7 days old) which had been placed in was higher due to periodic additions of water to the quart paper containers. Immediately after placing " nesting" materials, the moats, and from the urine the mites on the chick, white paper towels were and feces of the host . The colony of the crumpled and placed around the chick. Upon en- northern fowl mite, Ornithonyssus sylviarum (Cane- gorgement the mite~ left the host and were collected c strini & Fanzago), was kept in an incubator at 25 C on the towels. and 80% R.H. All four species have been in laboratory The experimental feeding and recovery of the snake mite was similar to that employed by Oliver et al. 1. Contribution number 1264 from the Department of (1963) and consists of placing mites in the ear cavity Entomology, University of Kansas. This paper is from of a lizard (Anolis caroline1tsis) and covering the open- a thesis presented to the Graduate School of the Univer- ing to this cavity with a fine mesh bolting cloth fastened sity of Kansas in partial fulfillment of the requirements with Pliobond Cement (available from W. J. Ruscoe for the degree of Doctor of Philosophy. The investiga- Co., Akron, Ohio, U.S.A.). Upon repletion, the mites tion was supported in part by Public Health Service Re- were removed from the ears. search Grant, AI 02487, from the National Institute of Allergy and Infectious Diseases (Principal Investigator: Oliver et at. (1963) and Oliver (1965) have shown that J. H. Camin). in the four species of mites used in this study partheno- 2. Division of Entomology and Acarology, University of genetically produced eggs that were always haploid California, Berkeley. (except 4 of 79 eggs of the snake mite). If a female D. 30 J. Med. Ent. Vol. 3, no. 1 gallinae oviposited, it could be assumed that she had an additional feeding before laying eggs; however, mated, and, if females of the other three species pro- some did oviposit after the first meal. Once a female duced any diploid eggs, it was highly probable that they began ovipositing, she continued to do so after each were no longer virgins. Conversely, D. gallinae females feeding for as long as she lived. If the number of that failed to produce eggs after feeding several times eggs produced after each meal is plotted against the could be assumed to be virgins and this same assump- number of meals, a normal curve is approximated. tion may be made for macronyssine females that pro- The largest number of eggs was produced after the duced only haploid eggs. This rationale was used third, fourth, and fifth feedings. The relatively large throughout the experiments reported below. number of eggs produced after the eighth feeding (Table 2) is probably not significant because of the OBSERVATIONS AND EXPERIMENTS small sample involved. Egg laying results obtained Relationship of mating, feeding, and egg production from 40 females indicated that the total mean num- Downloaded from https://academic.oup.com/jme/article/3/1/29/864276 by guest on 30 September 2021 Mating was not a necessary prerequisite to feeding ber of eggs produced per female, under our laboratory in any of the 4 species of mites tested. Mating was a conditions, was 23. One female, which fed a total of necessary prerequisite to oviposition in D. gallinae, eight times, laid 29 eggs before she escaped. At best, but the 3 macronyssine species readily oviposited the reproductive potential of D. gallinae does not ap- without mating. Many virgin female D. gallinae were proach that of the snake mite and the tropical rat mite. exposed to hosts on several occasions and, although There was no significant difference in the snake mite most of them fed, none oviposited. On the other or the tropical rat mite between the percentage of hand, subsequent to feeding almost all mated females virgins and mated females that fed and laid eggs. produced eggs. Oviposition in the snake mite depends on the degree Mated and virgin female D. gallinae appeared to of engorgement, varying from 1 or 2 to 30 eggs. A differ in their feeding responses, i.e. fewer virgins fed comparison of the number of eggs laid by virgin and than mated females (Table 1), but statistical analysis mated females after a single blood meal shows that showed that this apparent difference was not significant mating does not influence the number of eggs pro- at the 5% level. Nevertheless, whereas mating may not determine whether or not the mite feeds, it signi- Table 2. Mean number of eggs produced per ficantly affects the extent of engorgement in D. gallinae. adult Dermanyssus gallinae. However, even mated females rarely engorged to reple- No. of Ovipositing Mean No. of eggs per tion at the first feeding; a greater number became feedings females female per feeding fully engorged at the second feeding; and following 1 13 1.46 the third and subsequent meals, mated females almost 2 29 3.11 invariably fed to repletion. Virgin females rarely 3 22 3.95 engorged completely even after several exposures to 4 13 3.71 the hosts. 5 11 3.95 In D. gallinae the number of eggs laid after each 6 8 2.50 blood meal varied (Table 2). Many adult females did 7 8 1.66 8 2 3.00 not oviposit after their first blood meal and required

Table 1. Effects of mating on feeding behavior of Dermanyssus gallinae.

Virgin Females Mated Females

Exposure to Mites recovered Mites Mites % Mites recovered Mites Mites 0',0 hostl from hosts2 fed unfed feeding from hosts2 fed unfed feeding First 91 69 22 75.8 46 39 7 84.8 Second 55 38 17 69.0 36 29 7 80.6 Third 30 24 6 80.0 25 24 1 96.0 Fourth 28 19 9 68.0 14 13 1 92.9 Fifth 19 18 1 94.7 12 11 1 91.7 Sixth 18 18 o 100.0 11 10 1 90.9 Seventh 15 10 5 66.6 8 8 o 100.0 Eighth 12 9 3 75.0 6 5 1 83.3 Ninth 8 5 3 62.5 Tenth 5 4 1 80.0

1. Mites were exposed to hosts at approximately weekly intervals. 2. The progressive decrease in sample size with successive exposures was due to mortality and loss. 1966 Oliver: Reproduction behavior in Dermanyssidae 31 duced, and since the number of eggs produced is matings would have on egg production and sex ratio. positively correlated with the degree of engorgement, Twelve female nymphs were removed from the stock mating does not influence feeding. This greater varia- colony of D. gallinae, placed separately into zipper tion in number of eggs laid after each feeding in Op. boxes and allowed to molt. One day after the females natricis as compared with D. gallinae may be the result molted, 3 males were added to each container. A of several factors. Probably chief among these is 3 male to 1 female ratio was maintained for 4 days, that Op. natricis fed more slowly, usually requiring after which the females were removed and offered a approximately 5 days at room conditions to become meal. Eleven of the 12 mites placed on the chick were replete, whereas D. gallinae became replete in 5-30 recovered. Nine of the 11 had fed and 7 of the 9 min. It should be emphasized that in the experi- that had fed also oviposited. After the mites were mental feeding of Op. natricis the ear of Anolis carolin- recovered from the host they were isolated separately ensis was utilized as a feeding chamber, and this lizard in containers, where they remained undisturbed for Downloaded from https://academic.oup.com/jme/article/3/1/29/864276 by guest on 30 September 2021 is an abnormal host to the mite. No attempt was 36 hrs. At the end of this period one male was added made to determine the mean number of eggs produced to each zipper box containing a female and kept in per female during her entire life, but the total number the container for 1 week. The 10 surviving females produced by each of a few females under our experi- were offered a second blood meal and all fed, 9 feeding mental conditions were 51, 40, 36, and 39. Camin enough to oviposit. (1953) reported that females of this species would No significant difference in egg production was noted produce a total of 60 to 80 eggs when exposed continu- between the females that had had the opportunity to ously to a snake. mate several times and those that were mated only Ornithonyssus bacoti produced 1 to 12 eggs after once. The mean number of eggs produced per ovi- each blood meal. Mated females produced a mean positing female after the first meal was 1.7 in the of 6.6 eggs after a single blood meal, and virgins laid multiple mating experiment while it was 1.5 in the a mean of 4.5. These data were based on counts of other. The mean number of eggs produced after the eggs from 17 mated females and 27 virgins and most second meal was 3.9 in the former and 3.1 for the of the counts were taken after the first or second blood once mated females. As previously mentioned, the meal. For this reason, the means given here are pro- haploid to diploid ratio of eggs produced by once bably slightly lower than they would have been if mated females was approximately 1: 1. The pre- counts had been taken after later blood meals. sumed multiplemated females laid 29 haploid and 18 Ornithonyssus sylviarum produced 1 to 5 eggs after diploid eggs, which is not significantly different from a single blood meal. The mated females laid a mean a 1: 1 ratio (0.5< P< .10). It should be emphasized of 3.7 and the virgins a mean of 2.6 eggs. The counts again, however, that there is no way to be certain were obtained from only four virgins and eight mated that all or any of the females in this experiment actually females and were taken after the first or second blood mated more than once, even though they had the meals. The data here are meager and may not reflect opportunity to do so. A few cases were observed in the true situation; however, Sikes & Chamberlain which a female was seen to be embraced by a male (1954) found that 1 to 5 eggs, 2 or 3 more often, were on 2 different occasions, but it is not known whether produced after each meal and Combs & Lancaster the female was actually fecundated on both of these (1965) agreed. The oviposition habits of Or. sylviarum occaSIOns. were difficult to observe and were different from Ten pairs (adult males and female nymphs) of Op. those of the other species utilized in this investigation. natricis were removed from the stock colony. Each Omithonyssus sylviarum tended to remain on the host pair was placed separately into a zipper box and left much more than did the other three species. Although undisturbed until the females had molted, at which Or. sylviarum fed rapidly (within 5-30 min) it usually time two additional males were added to each container did not engorge to repletion at each feeding, but re- bringing the male to female ratio to 3: 1. This ratio mained on the host and fed intermittently. For this was maintained for several days and then the females reason, when females were isolated from the host were placed in the ear cavities of lizards to feed. Un- they seldom were fully engorged and laid only a few fortunately, only 1 female fed sufficiently to oviposit. eggs. Chromosome determinations were obtained on 10 of Single pair matings of D. gallinae, Op. natricis and the 12 eggs that she produced, 4 being haploid and 6 Or. bacoti all produced approximately equal numbers diploid. Once again the n to 2n ratio approximated of male and female determined eggs. Since virgin a 1: I ratio. The lack of a greater number of females D. gallinae do not oviposit and mating does not deter- ovipositing prevents a comparison of egg production mine whether or not Op. natricis and Or. bacoti lay between assumed multiple mated and once mated eggs, the question arose as to what effect multiple females. 32 }. Med. Ent. Vol. 3, no. 1

Results of experiments and observations on the 2 mite number three laid a haploid egg, and a fifth mite species just mentioned suggested that, if females werc also laid 1 haploid egg. Thus 5 of the 20 mites (25%) actually impregnated several times, then the supposed laid 8 eggs, 4 haploid, 3 diploid, and 1 undetermined. increase in sperm did not alter the usual n to 2n ratio None of the mites in the control group oviposited. observed of eggs of once mated females. The 15 experimental mites that were still alive 1 The number of times males may mate effectively is week later were offered a third blood meal and 13 of an important factor in sex determination and popula- them fed enough to oviposit. One died shortly after tion structure. Although males have been observed being recovered from the host and upon dissection re- apparently mating several times with different females vealed a completely formed haploid egg. The mean (D. gallinae and Op. natricis), it is unknown whether number of eggs produced by each ovipositing mite or not these matings resulted in the actual transfer of was 1.6 after the second meal, 3.8 after the third, and spermatophores. 4.2 after the fourth meal. As before, none of the Downloaded from https://academic.oup.com/jme/article/3/1/29/864276 by guest on 30 September 2021 Mating apparently did not affect the longevity of mites in the control group produced any eggs. females of D. gallinae, Op. natricis and Or. bacoti. I t is especially interesting that in the experiment on Skaliy & Hayes, (1949) and Camin (1953) came to the oviposition stimulus in D. gallinae the mean numbers same conclusion when working with Or. bacoti and of eggs deposited following the third and fourth meals Gp. natricis, respectively. agree closely with comparable means listed (Table 2) Females of the 3 macronyssine species used in for females that were mated prior to their first meal this study do not oviposit until a certain minimum (i.e. 3.8 vs. 4.0 respectively for the third, and 4.2 vs. amount of blood is engorged, but as already noted 3.7 respectively for the fourth meal). It should be mating is not necessary to initiate oviposition. Al- emphasized that whereas the females from the experi- though feeding is required before oviposition can be- ment on oviposition rate (Table 2) had fed and ovi- gin, there might be additional stimuli required for egg posited 4 times, those from the experiment on oviposi- laying. The actual oviposition stimulus is unknown. tion stimulus had fed 4 times, but none had oviposited That is to say, it may be a sensory stimulus of gut after their first feeding and only a few had oviposited distention alone, or it may be a nutritional stimulus after their second meal. This failure to oviposit, of that causes oviposition to begin. Probably both factors course, was due to the lack of contact with males until plus others are necessary for oviposition. immediately after the second meal. From these results In an attempt to determine the prerequisites for it appears that the number and/or the extent of meals oviposition in D. gallinae the following experiment is more important than the number of times the females was performed. Thirty virgin females were allowed have oviposited in determining the number of eggs 2 blood meals each. The amount of engorgement laid after each subsequent meal. varied and some females took only small amounts of In D. gallinae mating and engorgement together blood while others appeared replete. Although other initiate oviposition. Apparently, if the mites en- experiments and observations have established that gorged to a certain degree, eggs started forming but virgins do not oviposit even though some are apparently did not complete development unless mating occurred. fully engorged, 10 of the 30 virgins in the present Eggs were sometimes seen in the body of recently en- experiment were utilized as additional controls. Some gorged virgin females and several of the mites deposited of the randomly selected controls were fully engorged eggs within a few hours subsequent to mating. It is while others had taken only small amounts of blood. doubtful that the eggs could complete their entire The 20 experimental mites also had fed to varying development in such a short period. Conversely, degrees. One male was placed in a zipper box with mated females did not begin oviposition until an each experimental virgin female immediately after the undetermined minimum quantity of blood had been females were recovered from the host following their ingested. second blood meal. The males had not fed for at least 8 days. The control group was not exposed to Mating Activity males. Camin (1953) reported that males of Op. natricis Upon addition of males to containers with females, would no longer mate successfully with virgin females immediate mating was observed in many cases. that were more than 1/7 engorged, about 3 X their Within 2 days subsequent to the addition of the males, unfed weight. He also stated that females could not 4 of the 20 (20%) experimental females had laid a produce eggs until they were about 1/3 engorged and, total of 6 eggs. Mite number one laid 2, both diploid; therefore, virgins that had oviposited would not mate mite number two laid 2 eggs, both haploid; mite subsequently. Such behavior could affect sex ratio number three laid 1 egg, diploid; and mite number and population dynamics, inasmuch as it had been four laid 1 egg, which was abortive. The next day, demonstrated that virgin females of this species feed 1966 Oliver: Reproduction behavior in Dermanyssidae 33

as readily and produce as many eggs as mated females, from the host and 8 of them had fed. None of these but have only male progeny. Consequently, the effects laid eggs. This experiment indicates that virgin of engorgement and oviposition on subsequent mating female D. gallinae, fed to varying degrees, will mate were investigated in D. gallinae, Op. natrieis and Or. successfully after having had two blood meals. baeoti, using chromosome counts in early embryos to Ten virgin female Op. natrieis were placed in the ascertain whether or not mating had occurred. ears of several lizards (A. carolinensis) to feed. Four Fifty-two nymphal females and adult males of D. of the 10 fed and oviposited, laying from 5 to 24 gallinae were removed from the stock colony and each haploid eggs each. One male was added to each mite was isolated in a separate container. Forty-six zipper box containing a female, and the mites readily females molted successfully and, 3 days later were embraced. One of the mites had not completed the placed on a young chick. All 46 virgins were re- egg laying period and laid 3 eggs subsequent to the covered and 32 had fed. As expected, none of these " embracing" by the male. All 3 of these eggs were Downloaded from https://academic.oup.com/jme/article/3/1/29/864276 by guest on 30 September 2021 mites oviposited. One week later, 31 of these mites haploid. Unfortunately, all 4 of these females died were again offered a blood meal and 30 of them fed before it was possible to have them feed again and and again none oviposited. The 30 virgins, which had produce another series of eggs. Because of this and fed twice, were randomly separated into 2 groups; because all 3 of the eggs laid after mating were haploid, a control group of 10 and an experimental group of several more O. natricis virgins were isolated. 20. Both groups contained mites that had engorged Eight virgins were placed in the ear cavities of lizards to varying degrees. Each mite was kept in a separate and 5 fed successfully. They laid a total of 43 eggs, container and 1 male was added to each of the 20 all haploid. The number of eggs laid per female zipper boxes containing the experimental mites. In ranged from 7 to 10. Several days subsequent to several instances the males immediately embraced the the termination of the egg-laying period, each female females; 10 of the 20 had males clasping them within was placed into a container with 2 males and allowed 1 hr. Thus, in D. gallinae, males are attracted to to coinhabit the container for 5 days. Males definitely females and females will accept males after the females mounted some of the females but were not observed have had 2 blood meals. In addition, although the mating with all females. All of the females were extent of engorgement of the females varied consider- approximately 1/3 to 1/2 engorged and had similar ably, this did not seem to affect their mating success. histories. Following the 5 days of exposure to the To determine whether the matings resulted in the males, the 5 females were offered another blood meal females actually b'ecoming inseminated, the experiment and 3 accepted. After becoming replete the 3 mites was continued. The males and females were allowed began laying eggs. One produced 21, another 26, to coinhabit the same container for 5 days, then the and the third laid 18 eggs. Chromosome counts were males in the 20 containers were redistributed so that obtained from 16 of the 21, and 22 of the 26 eggs they were exposed to different females. After being produced by mites one and two, respectively. All exposed to a second male for 24-30 hrs, all the females proved to be haploid. Counts obtained from 14 of and males were placed together on a young chick, the 18 eggs produced by the third mite showed seven where they remained for approximately 12 hrs. This to be haploid and seven diploid. moving of males to different females should have These results partly confirm and partly refute the precluded the chance of incompatability between any report of Camin (1953) on Op. natricis. Mating suc- one male and female. The control group, which was cess does appear to be affected by engorgement and not not exposed to males, was fed at the same time as the all females mate successfully after having oviposited. experimental mites. Up to this point, 1 female in In unfed virgins, if given the opportunity, mating the control group and 4 in the experimental group success approaches 100%. However, it has been had died, while 1 of the experimental group escaped. demonstrated that females of this species do sometimes All 15 remaining experimental females were re- mate after engorgement and may even mate successfully covered from the host and 14 of them had fed. Thir- after having produced eggs. teen of the 14 oviposited, indicating that they had Data on the mating success of Or. baeoti after mated. It was confirmed that fertilization had taken engorgement and oviposition are meager. One virgin place because 11 of the 13 ovipositing mites produced female had fed 3 times and laid a total of 12 eggs, both haploid and diploid eggs. The 2 that laid only all haploid. After occupying a zipper box with a haploid eggs could not be interpreted as unfertilized male for 4 days, she was offered another blood meal. because 1 produced only 1 egg and the other produced Subsequent to feeding she produced 5 eggs, 2 of which only 3 eggs. The single mite that fed but did not were diploid. While these latter data were too scanty oviposit appeared to be abnormal and died 5 days to indicate the frequency of such an occurrence, they after feeding. All 9 of the control mites were recovered did demonstrate that successful mating could occur 34 J. Med. Ent. Vol. 3, no. 1

with a female that had fed several times and under- frequencies of " off the host II and "on the host" gone oviposition. Similar data on Or. sylviarum are matings (90.9% and 41.7%) mentioned above are not yet available. probably somewhat misleading because accessibility For practical reasons in the maintenance of stock of mates on and off hosts, in the experimental set-up, colonies and when designing certain kinds of experi- were not equivalent, nor were the times permitted for ments, it would be advantageous to know whether mating. mating occurs on or off the host or in both places. It would seem that mating would probably occur off Sperm longevity the host since these species, except Or. sylviarum, Because sperm longevity and sperm depletion in are nest parasites (nidi coles) and spend most of their the female are potentially important factors in deter- time off the host. Observations made on mites from mining sex ratios in the 4 species of mites used here samples of "nesting" material from colonies of D. the following observations are given. Forty-three Downloaded from https://academic.oup.com/jme/article/3/1/29/864276 by guest on 30 September 2021 gallinae, Op. natricis and Or. bacoti revealed many female D. gallinae were each fed 7 times over a 50 adult males riding and embracing female nymphs and day period, and at the end of this period diploid eggs adults. This behavior has also been observed on the were still being produced. These mites had been ex- host in Op. natricis. To test whether females were posed to males only once, prior to their first feeding. actually fecundated off or on the host in D. gallinae, These observations indicated that sperm probably do 40 pairs (adult males and female nymphs) were removed not become depleted or die during the life span of the from the stock colony. The 40 pairs were separated female. into 2 groups, 1 group being given the opportunity to More than 12 female Op. natricis were fed twice, mate off the host and the other on the host. The some laying as many as 51 eggs over a 21 day period. former group was placed in 8 zipper boxes, 1 pair At the end of this period diploid eggs were still being per box in 5 boxes and 5 pairs per box in the other formed. These females were exposed to males only 3 boxes. Following an undisturbed period of 6 days, once and this was prior to their first blood meal. As 16 adult females were recovered alive and placed on in D. gallinae, sperm remained alive and in good a chick. Care was taken to exclude all males. Four- supply in the females throughout their lives; however, teen of the 16 mites were recovered and each had fed, this may not hold true in a natural environment. Camin but none oviposited. Because D. gallinae females do (1953) reported that Op. natricis live 10 days longer not always oviposit after the first meal, the 14 mites and lay 10-30 more eggs than observed in the present were offered a second meal 1 week later. Of the 14 study when reared on snakes, the normal host. There- offered a second meal, 3 died and 11 fed. Ten of fore, I probably missed the last 1/6 to 1/3 of the these oviposited, indicating that they had mated off potential eggs and do not know whether or not sperm the host. would have died or become depleted during that time. The other 20 pairs (adult males and female nymphs) Even though D. gallinae was reared on the normal of D. gallinae were tested to determine whether or not host, laboratory handling and conditions probably mating also occurs on the host. Immediately upon affected the longevity and total egg production in this removal from the colony, the female nymphs were iso- species too. Harrison (1962) reported that D. gallinae lated singly into separate containers. They were could survive without food for 36 weeks at 25"C and undisturbed for 7 days and at the end of this period 80% R.H. Kirkwood (1963) verified that some D. 17 had successfully molted and were active. The 17 gallinae could live for 34 weeks without a blood meal, virgins were placed on the head of the chick and 17 but only 21, 2, and 48% of the adults remained males were immediately added to the same area. alive after 8 weeks when stored at 100C, room tem- They were allowed to remain this way for approximate- perature, and in a " chicken hut" respectively. The ly 8 hr. Sixteen of the 17 females were recovered, 15 temperature of the " chicken hut II varied considerably having fed. None of these mites oviposited. One depending on the time of the year. Because of this, week later 13 mites were still alive and they were again I can say only that the sperm of D. gallinae remained offered a blood meal. Twelve of the 13 mites were alive and in good supply in the female for at least 7 recovered alive and all 12 had fed. Only 5 of these weeks under laboratory conditions; the same may be produced eggs. said for sperm of O. natricis for a period of at least 3 The results of these two experiments suggest that weeks. mating occurs both off the host and on the host, but perhaps more often off the host (i.e. 90% of the mites SUMMARY

in the "off the host II mating experiment were Mating did not affect the percentage of Ophionyssus fecundated whereas 41.7% were fecundated in the natricis and Ornithonyssus bacoti females which fed or

"on the host II mating experiments). The relative oviposited. In Dermanyssus gall£nae the number of 1966 Oliver: Reproduction behavior in Dermanyssidae 35

mites that fed was unaffected by mating, but there and this paper. I should like to thank also Drs H. V. was an effect on the amount of blood imbibed. Long- Daly and D. P. Furman, University of California, evity of females was not affected by mating in any of Berkeley, for their critical review of this paper. the three species. Many mated females of D. gal/inae did not oviposit LITERATURE CITED after their first blood meal. The mean number of Camin, J. H. 1953. Observations on the life history eggs produced per ovipositing female gradually in- and sensory behavior of the snake mite, Ophionyssus creased after each blood meal. The greatest numbers natricis (Gervais) (Acarina: Macronyssidae). Chi- were produced after the third, fourth and fifth feedings cago Acad. Sci. Spec. Publ. 10: 1-75. and decreased subsequent to the fifth feeding. Ophio- Camin, J. H. & P. R. Ehrlich. 1960. A cage for nyssus nutricis produced more eggs after each meal maintaining stock colonies of paraistic mites and than did either of the other species and Or. bacoti their hosts. J. Parasitol. 46(1): 109-11. Downloaded from https://academic.oup.com/jme/article/3/1/29/864276 by guest on 30 September 2021 produced more than D. gal/inae. Combs, R. L. & J. L. Lancaster, Jr. 1965. The One engorged Op. natricis virgin, which had ovi- biology of the northern fowl mite. Ark. Agr. posited, mated and subsequently deposited haploid Exp. Sta. Rep. Ser. 138: 3-10. and diploid eggs. However, unfed virgins of all 4 Harrison, I. R. 1962. The biology of poultry red species investigated appeared to be more attractive mite (Dermanyssus gal/inae) and its control with to males. contact and systemic insecticides. Proc. XIth Mating occurred both on and off the host in D. Internat. Entomol. Cong., Vienna 1960: 469-73. gallinae and Gp. natricis. No experiments were con- Kirkwood, A. 1963. Longevity of the mites Derm- ducted on Or. bacoti but mating off the host was ob- anyssus gal/inae and Liponyssus sylviarum. Exp. served. Once the females were impregnated, at least Parasitol. 14(3): 358-66. in D. gallinae and Op. natricis, they continued produc- Oliver, J. H. 1965. Karyotypes and sex determina- ing haploid and dipliod eggs throughout life. How- tion in some dermanyssid mites (Acarina: Mesos- ever, because Op. natricis was reared on an abnormal tigmata). Ann. Ent. Soc. Am. 58(4): 567-73. host species, longevity and fecundity were probably Oliver, J. H., J. H. Camin & R. C. Jackson. 1963. reduced. Sperm lived at least 50 days in female D. Sex determination in the snake mite Ophionyssus gallinae. There was no difference in the haplo-dip- natricis (Gervais) (Acarina: Dermanyssidae). loid egg ratio produced by presumed multiple mated Acarologia 5(2): 180-84. D. gallinae and Gp. natricis females when compared Sikes, R. K. & R. W. Chamberlain. 1954. Labora- to once mated females. tory observations on three species of bird mites. No attempt was made to find the specific oviposition J. Parasitol. 40: 691-97. stimulus in each of the four species, but apparently Skaliy, P. & W. J. Hayes. 1949. The biology of a certain minimum amount of blood must be engorged Liponyssus bacoti (Hirst, 1913) (Acarina: Liponys- before eggs are laid. Moreover, in D. gallinae mating, sidae). Am. J. Trop. Med. 29: 759-72. too, must take place before females will oviposit. Strandtmann, R. W. & G. W. Wharton. 1958. A Acknowledgments: It is a sincere pleasure to manual of mesostigmatid mites parasitic on acknowledge Professor J. H. Cam in, University of Kan- vertebrates. Contribution No.4, Institute of sas, for his encouragement and aid during the course Acarology, Univ. Md., 399 pp. of this reseach and for his critical review of the thesis