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In order to mate, the male crawls beneath the female and clings to her so that the two ventral surfaces are in apposition. After dilation and stimulation of the female orifice by insertion and movement of male mouthparts, a spermatophore issuing from the male genital aperture is grasped by the male's mouthparts and transferred to the female genital aperture. [Coxal fluid is emitted by the male during the course of these activities ac. cording to Nuttall and Merriman, but Dr. G. E. Davis and Dr. H. Burgdorfer state (conversation) that they have not observed this. It is possible that coxal fluid may or may not be emitted at this time, due either to copiousness of supply or to degree of excite.
The spermatophore is bulb shaped (Figure 42) as it issues. After the male applies it to the female aperture, contraction and evagination force out the long neck with the capsules (Figure 43) that are inserted into the aperture. Most of the spermatids are forced into the capsules but the bulb remains outside the female aperture and drops off sooner or later. As many as ten bulbs have been seen in situ. The neck dries and twists, making an effective seal at the capsule closue. After five days at 30°C., the now mature s rms escape into the uterus by rupture of the capsule wall. or further details, see Robinson (l942B)i7
As stated below, the initial fertilization usually occurs shortly following melting to the adult stage, and females first feed about two days afterwards. They may feed before mating, presumably chiefly when males are not readily available. How. ever, according to Jobling, the period of time between fertiliza. tion and feeding has no effect upon the period between feeding and oviposition.
Figure /,2. Invaginated, bulh_shaped spermatophore as it issues from male genital aperture. Figure 43. Evaginated spermatophore, with neck and capsules, after having been applied to female uterus.
Generally, ovipositicn only follows a blood mal. For various reasons the interval between feeding and egg laying varies from five to 25 days, although (in tubes in jars with slightly moist cotton, maintained at 29.5°C. to 3093.) the average is six to nine days (Jobling, and others). [speeielists will be interested in Uigglesworth's (1943) brief account of the fate of haemoglobin in ovipositing females.;7
As each egg is emitted from the female genital aperture it _ normally comes in contact with a peculiar glandular organ, gene's organ, that lies dorsally at the base of the capitulum. Gene's organ, which is everted only during ovipositicn, envelops each egg and provides it with a waxy, waterproof coating. Should this organ fail to evert or if any eggs are missed, these shrivel and fail to hatch, even in a humid atmosphere. The waxy coating is soft and viscuous (melting point 5CPC. to 5490., in contrast to cuticular wax, which is hard and crystalline with a melting point of 65°C.). The critical temperature of 0. moubata eggs well covered by this wax is 1.5%. Lees and Beament (19487 We made a detailed study of gene's organ and its secretion, temperature and water loss of eggs, morphology of the female genital tract, structure and chemistry of the egg shell, and permeability of the egg shell.
Eggs are deposited in masses on the soil or in hollows burowed out by the female. It has been stated that the masses are agglutinated. Actually, individual eggs have a somewhat adhesive coating. When a container in which they are kept is jostled they roll about like globules of mercury. This is true also for eggs of numerous other argasids that have been observed.
After ovipositicn, the female 'broods“ over the eggs for some days (Hellman), a phenoenon of unknown function common among argasids. Jobling observed that this "brooding" sometimes con. tinues till the nymphal molt, after which the female may walk about for a time with several nymphs clinging to her.
Dutton and Todd recorded individual batches of ten to twenty eggs, with the greatest total of several batches from a single female numbering 139 eggs. Mbllers (1907) observed a single batch of eighty eggs. Hellman mentioned a lifetime total of 88 eggs and Newstead reported a total of 94 eggs. Records obtained under optimu laboratory coditions have been higher than those secured by
these early field and laboratory workers. Cunliffe observed a female that produced a lifetime total of 535 eggs of which over ninety percent were fertile. In Job]_ing's tests, one female deposited several batches totalling 1,217 eggs and eight other females laid totals of from almost 700 to over 1000 each. Dr.
G. E. Davis a.nd Dr. W. Burgdorfer report (conversation) that the largest mnnber of eggs they have observed in a single oviposition has been 233 and 327, respectively. Mast eggs are laid at night a.nd sometimes nnre than one day is necessary before a fuJ_l batch is deposited.
Six or seven batches, gradually diminishing in mmbers, appear to be usual in one female's lifetime. The amount of the
previous blood meal influences the number of eggs subsequently produced. Jobling noted that the fertility of later batches deCreaseso
In a laboratory study of Q. mubata fertility, Robinson (191.20) found that three egg bete‘lT_ee may be laid after one mating but that egg fertility is considerably increased if mating occurs before each oviposition. Fertility decreases when the interval between mating and oviposition is extended. Oviposition occurs almost without exception only after a blood meal. Eggs show no alteration in fertility when maintained between 22°C. and 32°C., but at 34°C. no larvae emerge. As already stated, I.ees and Bea.ment (191.8) have stated that 45 . is the critical temperature for normal eggs._|7 Robinson recommenced a temperature of 30"C. and a relative humidity of 5% in the breeding chamber for safe and speedy production. He found that a female might deposit a few eggs without a blood meal and that large females produce more than do snnll ones. The range in number of eggs per female per batch in these experiments varied from fifty to 250, with an av. erage of 170. Many females died shortly after their first blood meal; others after depositing their first egg batch.
According to Robinson, females lay over twice as many eggs when sand rather than a flat surface such as filter paper is provided for this purpose, but Dr. G. E. Davis and II‘. V. Burgdorfer report (conversation) that in their experience the opposite is tr\1$o
Egg just deposited
19, Rupture of egg shell
50, Larva hatching
51, Larva with shell, ventral view 52, The same, dorsal view
53, Larva, without shell, dorsal view 54, The same, ventral view
Figure Figure Figure Figure The sam, alternate contraction Figure
and expansion Figure
ORNITHODGKOS MOUBATA EGG AND IARVA
_7A.£‘ter Jobling (1925 )_7