close

Вход

Забыли?

вход по аккаунту

?

The longevity of sperm in the female bat.

код для вставкиСкачать
THE LONGEVITY O F SPERM I N T H E F E M A L E BAT
G. EDGAE FOLK, JR.
Biological Laboratories, Harvard University, Cunzbridge, Massacliusetis
OSE
PLATE (FIVE FIGURES)
.For many years students of reproduction have been interested in the process of fertilization in the bat. It has been
suspected that in certain northern species the sperm from fall
inseminations a r e carried over winter by the female and may
fertilize ova produced by ovulation at the time of resumed
activity in spring. The only exact information concerning
longevity of sperm in either the male or the female bat, is that
of Courrier ('27), later confirmed by Nakano ('28). These
workers state they have found sperm in the epididymis of the
male bat 7 months after cessation of spermatogenesis. It has
been repeatedly stated that the problem of the longevity of
sperm in the female reproductive tract must be attacked by
the direct method of isolating female bats during hibernation.
Investigators attempting to use this method have been handicapped by the difficulty of keeping bats over a period of months
in a state of hibernation.
Most investigators of the longevity of sperm have had to
use an indirect approach. The history of their work is summarized in the review of Hartman ('33). According to this
author, Eimer (1879) found sperm in the tract of female
Vesperugo (Nyctalus) noctula all winter, but failed to report
whether the females had been isolated from males. Guthrie
( ' 3 3 a ) and Guthric and Jeffei*s ( '38 c ) by collecting specimens
at all seasons and by producing artificial ovulation by injection
of hypophyseal extract, showed that female Myotis 1. lucifngus
arid Pipistrellus subflavus a r e probably not inseminated in
December or January, but that in February spring inseminations have started. Most other American investigators have
103
104
G. KUGAR F O L K , JR.
\\~orBctlwith the geiius llyotis, but I4:vaiis ('38) records finding spermatozoa in the u t e i u of Eptesicas f. fuscus in niiclwiitter. EIerluiit ( '34) obtaiiied fei?ilizltion and emlwyos iii
t lie B el giaii s c 1x1ti iic 1)ut f o 11owiiig i 1itluc e cl o r 11la t ioii, us ii t g
specimeiis takcii iii Iiil~i~iiatioii
iii lute ,January. It is importaiit t o note tliat in tlre 1oc;ilitics \\-lici.e tllese woi~lierscwllectccl
material, bats copulatc most of tlic wintcr (€Iai.tmaii aiid
Cuyler, '2T ; €Iat.tmaii, '33) and iiisemiiiatioii might ha\-c talieii
l)lace shortly before collection.
During the wiiiter aiitl spriiig of 1939 ail attcm1,t n'as iiiatlc
to test tlie longeritp of spei.m iii tlie genital tract of female
bats by the methocl of isolatiiig them from iilales cliiriiig Iiibcriiatioit. A t the siiggestioii of 111.. 1). 1;. Gi%iii, tlic big I)ro\\-ii
h t , Kptcnicus f . fuseus w a s c m l h y e d , iiiasiiiuch a s this species
is probably the most I iaid y availahlc f o r such cspcrimeiits.
His furtlier assistaiice iii tlie prolilcm and that of 111..Heriiim
B a l i i i aiid A h . Robe1.t Holden w a s much a1)l)iwiatecl. 1 am
very iiiiicli iiiclebtcd to I'rofs. Alcleii K. Dawsoii aiicl l~iigli
Hoadlcy, mlio were liiiitl eiiougli to esamiiie the sectioiied material aiicl assist in its iiiterpretatioii.
EXL'ERIRIENTS
Five female B;ptcv4cus were takcii in hibernation a t El:lline, Versliii*e, Veimoiit, o n ,Jaiiuai*y 8, 1939. The\.- n c r e
ljacliclil in a container swrouiicled by ice aiid removed to a
i*efrigerated mom at the Harvard Biological Lahoixtoiies,
wlicrc they remained in hiberiiatioii, isolatetl fi-oiii all iiiales,
from January 8th to April 7th. Tlie tem1)cratui.e of tlie colcli'oorii varied from 40" t o 42.5" F., occasionall\.- going clowii to
38". Since tlic average wiiitci. temperature of many S e w
13higlaiit3 caves is about 40", the 1aboratoi.y coiiclitioiis (10 iiot
seeiii f a r from normal. Probably tliei*e would be greater estrcnics of teiiiperature variatioii in normal places of hiberliation. At no time dui*iiigor after tlic period of Iiibci*iiation in
tlic laboratoiy, ~ 7 a st1iei.e any possibility of contact between
male bats aiicl the five ca1)tivc female bats.
LONGEVITY OF BAT
105
smxnr
The cage iii wliich tlie bats m r e kept measulml 2 by 1 by 11
feet and was kept constantly dark. A large pan of water into
which was suspended a cloth towel prevented tlic bats from
desiccating, a difficulty experienced by previous worliers. Two
of the hats apparently did not m o ~ efor over 2 montlis, while
Ihe tliiaee others changed their positions about oiicc a week.
On April 7th the five bats were removed to a large, dark
cage with ample water supply, mhicli mas maintained a t about
’78”F. They wei-e fed a t first by hand, but soon learned to
catch blowflies released in their cage and to eat a quantity of
iiieal woi’ms and anesthetized blowflies and fruit flies from the
floor. The bats, apparently in good Iicalth, were killecl as
indicated in table 1.
TABLE 1
Szcniiiiary of bats Pillrtl
4
8
22
29
30
Old
Old
Old
First year
First ?ear
A t autopsy no signs of pregnancy were evident in the rcproductive tract of any bat cxccljt that of tlie one killed on
Bl)ril 28th. The two killed 011 May 6th sliowed little wear on
tlic teeth, indicatiiig that they w c i probably
~
first year femalcs
and thus had not mated in the fall. Only the pi-egiiant re1)i.otlactive tract will be considered in this 1pnl)er. The otlicl. tracts
will he described aiitl cliscussctl in detail iii coiiiiectioii ~ i t l i
futu1.e ivork on the i d a t i o n of resumed activity aiid o\wlation
in Eptcsicus f. fuscns.
The bat killed on Api‘il 28th contained a much enlai*gecl
uterus ( s e e fig. 1). 011151 thcl right horn was satisfactorilp sectioncd. It coiitaiiied two blastoclermic vesicles, one a t least
106
G. EDGAR FOLK, J R .
containing an embryo in a late primitive streak or early head
process stage ; and another slightly older, which may be in the
first somite stage (see figs. 2 and 3). Examination of the left
horn by gross dissection at the time of removal of the reproductive tract rendered it unsuitable for sectioning.
The exact age of the embryos under discussion cannot be
determined until more is known about the ovulatory cycles of
this species. A detailed study of the ovary of Myotus 1. lucifugus and Myotis grisescens has been made by Guthrie and
Jeffers ( '38 b), who have found that during the winter a single
tertiary follicle persists in one ovary of each bat, the follicle
rapidly increasing in size just before ovulation in A4pril.
Guthrie found that many Myotis which were brought from
hibernation into a warm room in late winter, would ovulate
in 24 hours. I f this observation also applies t o Eptesicus f.
fuseus, the embryos would be about 20 days old. Without
question the sperm which produced these embryos remained
in the female bat during the 90 days it was held in artificial
hibernation. From observations on Myotis wintering in caves
of western Missouri, Guthrie ( '33 b) showed that if these bats
become active, the sperm stored in the female tracts are phagocytized and eliminated. It is possible that the pregnant
Eptesicus was one of the two which did not move during
hibernation for over 2 months and therefore the sperm which
it stored remained. A further conjecture is that if female
Eptesicus hibernating in their normal environment in New
England remain inactive, they may retain sperm over a long
peri0d.l
Guthrie ( '33 b) found as many a s seven large follicles in the
two ovaries of Eptesicus f. fuscus collected in winter in Missouri. Guthrie also records that on March 4, 1933, a female
that had been in the laboratory for 8 days, had ovulated and
contained six tuba1 eggs; another in captivity 2 weeks, had
'During a n extended study of hibernating bats in a New York cave (unpub
lished) I observed t h a t i n the case of Myotis 1. lucifngus the usual hibernating
condition was one of periodic activity, but occasional bats would remain dormant
for two and three months.
107
LONGEVITY O F BAT SPERM
at least four tuba1 eggs. Evans ('38) states that in each ovary
of specimens of Eptesicus f. fuscus that lie examined in winter
in southern Xinnesota, there was one follicle much larger than
the others, measuring: about one-third the diameter of the
entire ovary. Evans thus implied that there would be but one
ovum released from each ovary. Sirice two embryos werc
found in the right horn of the pregnant Eptesicns from Vermont, more than one ovum must have been released from tlie
right ovary. This fact is verified by the presence of two clefiiiitive corpora lutea in the riglit ovary (see figs. 4 and 5).
I n the left ovary there is good evidence for tlie presence of
three corpoi*a lutca. Griffin (in 1)ress) and Poolc ('32)
state that Eptesicus f. fuscus usually produces two young, but
not more. Tliese observers do not mention whctiicr the enihryos clcvclop iii one 1101.11, 01' both lioi.iis, of tlie utcim.'
The details of tlie reproductive cycle of I~~ptesicus
f . fuscus
a r e yet t o be investigated, but it is certain that one female of
this species, kept i n hibernation under ai3ificial coi~ditioiis
from ,January 8th to April 7th, isolated from any male bat,
coiitaiiicd two embryos on April 28th.
LITERATURE CITED
COURKIER,R.
1927 Rtude sur la d6terminisnic des caiact6rcs s c ~ u e l ssecondaires
ehez quelques inaininif~res& actirit6 tcsticu1:rire phriodique. Arch. de
Riol., 1'. 3 7 , pp. 173-334.
EINER,TH. 1879 Uebcr die Fortpflanzung der Fledcrmause. Zool. Anz., Bd. 2 ,
S. 425.
EVANS,C. A. 1938 Observations on hil)rrnatlng bats with espCcia1 refercnce t o
rcproduction and splenic adaptation. Anier. Nat., ~ o l .7 2 , pp. 480-484.
GRIFFIS, D. R. Notes on tlic life liistoiics ot iVew Englnutl C : I T C )):its. J . Manlni,rl
(ill ]IICW).
GUTIIRIE,MARYJ. 1933 a Notes on the seasonal movemcnts and habits of some
cave hats. J. Mammal., vol. 14, pp. 1-19.
1933 b The reproductive cycles of some cave bats. J. Mammal.,
V O ~ .14, pp. 199-2163.
G U ~ W R I E~,I A R EJ., A N D KA~TIIARINE
I<. JEFFERS 1938 h Growth of follicles in
the ovaries of the hat Myotis lucifugus lucifugus. Anat. RK., xol. 71,
pp. 477-4963.
~
~
_
_
.
~
~
~
_
~
_ _
p l o f . (:luvt~1 31. Allclr has called attention to a. ~ c c . o l dof a fenr:llr Eptc>sicus
f . fusc.119 collected on L \ l , 1 i l 2 , \\111cli cout:t~nctl foul 2 niiii. twibiyos, t u o 111 each
I l o i i i of thc utciiis (F. Ha11)t'r, 1999, a. M:1111111. TOI. 10, 1)~).
8!)).
~
~
108
G. EDGAR FOLK, JR.
GUTRRIE,MARYJ., A N D KATHARINE
R. JEFFERS
1938 c The ovaries of the bat
Myotis lacifugus lucifugus after injection of hypophgseal extract.
Anat. Rec., vol. 72, pp. 11-36.
HARTMAN,
C. G. 1933 On the survival of spermatozoa in the female genital
tract of the bat. Quart. Rev. Biol., vol. 8, pp. 185-193.
KARTMAN,
C. G., AND W. I<. CUYLER 1927 I s the supposed long life of the bat
spermatozoa fact or fable? (Abst.) Anat. Rec., vol. 35, p. 39.
HERLAXT,
M. 1934 Recherches sur les potentialites de developpement des oeufs
obtenus par ovulation provoquke chez la chauve-souris en hibernation.
Bull. Acad. Roy. de Belgique, T. 20, pp. 359-366.
NAICANO,
0. 1928 Ueber die Verteilung des Glykogens bei den zyklischcn Veranderungen in den Geschlechtsorgnnen der Fledermaus und iiber die
Nahrungsaufnahme der Spermien in den weiblichen Geschlectswegen.
Folia Anat. Japon., Bd. 6, S. 777-828.
POOLE,
E. L. 1932 Survey of the mammals of Berks County, Pennsylvania.
Reading public museum and art gallery. Bull. no. 3.
PLATE 1
EXPLANATION OF FIGURES
1 Reproductive tract of pregiiant Eptesicus f . fuscus showing right horn of
uterus containing the embryos, surrounding the right ovary, with uterine tube
and cervix attached. The left ovary and dissected left horn of the uterus is also
shown. X 2.6.
2 Uterine lumen containing the embryo which may be in the first somite stage.
Transrerse section. X 32.
3 The embryo in figure 2 shown under higher magnification. x 93.
4 Section through right ovary of pregnant Eptesicus f . fuscus showing two
corpora lutea, A and B. X 60.
5 Cells of corpora lutea in figure 4 shown under higher magnification. x 293.
PLATE 1
LOXGEVITY O F BAT S P E R M
G . EDGAR FOLK, JR.
109
Документ
Категория
Без категории
Просмотров
0
Размер файла
393 Кб
Теги
bat, longevity, female, sperm
1/--страниц
Пожаловаться на содержимое документа