I

Asiatic Herpetological Research

February 1992"

Vol. 4, pp. 62-67]

Female Reproductive Cycle and Embryonic Development of the Chinese
Mamushi (Agkistrodon blomhoffii brevicaudusY

MEHUA HUANG YUMIN CAO FENGXUE ZHU AND YUNFANG QU
11l

11,,

Zhejiang Medical University, Hangzhou, China

Abstract. -Agkistrodon blomhoffii brevicaudus is a species of snake with seasonal reproduction. The
female annual reproductive cycle is as follows: vitellogenesis begins in late March or early April;ovulation is in middle June and parturition is in middle or late August, or in early September. Thegestation period lasts for about 65-75 days. By ovoviviparity, the Chinese Mamushi produces one clutch
and a weight of 2.0 toper year. In each clutch, there are 5 to 20 juveniles with a length of 154 to 203
5.3 g. The size of fat bodies is inversely proportional to that of the vitellogenesis. The fat bodies werelarger in March and before hibernation (about November ) than in the other months. The process ofembryonic development is described by the external morphological investigation on 73 1 embryos from 82

mmfemales.

Key words:

Reptilia, Serpentes, Agkistrodon blomhoffi brevicaudus,Chinese Mamushi, reproduction,embryonic development

Tiantai County, Zhejiang Province, andwere bred in our snake garden. FromIntroduction

The Chinese Mamuashi (Agkistrodon
distributed

blomhoffii brevicaudus)
mainly over southern Liaoning, Hebei,
Jiangsu, Anhui, Zhejiang, Jiangxi,
northern Fujian, Taiwan, Hubei, Shaanxi(southern part of the Qinling Mountains),
southeastern Gansu, Sichuan and Guizhou
provinces in China. It is also scattered overthe Korean peninsula. It is a species of
poisonous snake with a high medical value,
so it attracts many scientists' attention.
This paper reports the female reproductive
iscycle, embryonic development andreproduction of" the Chinese Mamushi. It is
hoped that this paper will serve as areference material for research inreproductive biology and thebreeding of snakes.

artificialMethods

March 1984 to December 1986, 178
females (about 5 females per month) wereinvestigated. Each snake was measured in
total length(SVL+TL) and total weight.

The number and the size of follicles orembryos, as well as the weight of theovaries and fat bodies, were examined bydissection. The pH value, whether sperms
were stored up or not and the sperms'
activity in the oviducts were determined
too. All the above were done in order tounderstand seasonal variation of sex
glands, ovulation and mating. From 1984
to 1987 in the gestation season (June, Julyand August) 82 mature female snakes wereoperated on and 731 embryos wereobtained. The conditions of embryonicdevelopment were based on the studying of
the external morphology of the embryos
removed from the gravid females at regularintervals throughout the gestation period.

Mature female Chinese Mamushi (A.
blomhoffii brevicaudus), 447-680 mm(mean 530 mm) in length and 31-120 g(mean 67 g) in weight, were collected from

Another 10 gravid females were bred apartto observe their rate of reproduction.

Results
The Female Reproductive Cycle+This publication combines material previously

published in Chinese by Huang et al. (1990) withadditional discussion.

(Ci1

QQ9 hv Avtntir* //^rn^M/^oir/j/ ftfwnrrhI.

The seasonal variation of ovary weight.
ovary weight is expressed byTheAsiatic Herpetological ResearchFebruary 1992

Vol. 4, p. 63

5.00.

ff
Coefficient of Ovary
4.50-1

Coefficient of Fat

4.00 -j
3.50 -j
3.00 -j
2.50-=

2.001.50

1.00

0.50 A
0.00
Jan.

FIG. 1.

Feb.

,.— .,...

|--« -|Mar.

May

April

-- June,-,July|-«
Aug.

|

Oct.

Sept.

r|

Dec

Nov.

Seasonal variation of ovary and fat body weight in Agkistrodon blomhoffd brevicaudus.

multiplying the coefficient of ovary (theratio of wet weight of a pair of ovaries to(after parturition),that of total body weight of each individual)

hibernation).

times 100 to take the form of a percentage.
Figure 1 shows the seasonal variation. The
eggs of the ovary were transferred to theoviduct in mid June. The coefficient ofovary reached the lowest point in July andthen increased gradually. From late March
to April in the next year, with vitellogenesis
occuring, the coefficient of ovary rose
obviously. It reached its top value in Mayor June.

The seasonal variation of fat bodies.
The weight of fat bodies is expressed by//.

multiplying the coefficient of fat (the ratioof the wet weight of fat body to that of thetotal body weight of each individual) times
100 to take the form of a percentage.
Figure 2 shows its seasonal variation withtwo peaks in March and November. There
was an inverse correlation between
vitellogenesis and fat body size. Fat bodies
enlarged in spring, reduced in September

until

graduallyand then increased

November(beforeThe seasonal variation offollicle types.
Developing ovarian follicles were divided
into three classes by their size and location.
Previtellogenic follicles were designated as///.

class

1,vitellogenic ovarian follicles asclass 2, and oviductal eggs as class 3.

ChineseThe

Mamushi(A.
blomhoffiibrevicaudus) is a species with annual snake
reproduction. All the mature females haveclass 1 follicles with a diameter of 0.5 to
10.0 mm, with a transparent or white color
and round or oval shape. In April class 1
follicles were at their maximum in number.
On the average, there were 25 class
1

The larger the size ofthe female, the larger the number of class 1
follicles it had. The largest female was 680
follicles per female.

mm in length and 120 g in weight, and had69

previtellogenic

spring, vitellogenesis

follicles.

Inbegan and follicles

grew rapidly. Some of the class 1 follicles

Asiatic Herpetological ResearchVol. 4, p. 64

February 1992

35.

D

30-

Previtellogenic Follicles— Vitellogenic Follicles-A— Oviductal Eggs

m-0

O

25o
20ID

§

15-S 10g

O
H

—

5-a

B—-H

S

h-B

H

01

Jan.

1

1Feb.

Mar.

11AprilMay

11June

July

1Aug.

11Sept.

Oct.

1Nov.

Dec.

FIG. 2. Seasonal variation of follicle and egg size in Agkistrodon blomhoffii brevicaudus.

were transformed into class 2 follicles withyellow color, oval shape, and long
diameters between 11.0-25.0 mm. They
only existed from April to June. Whenfollicles reached the largest value in about
middle June, ovulation occured. The dateof the earliest ovulation took place on June
16.
Class 3 eggs were present in theoviducts from middle June to late August.
The maximum diameter of an egg was 28.0mm. The pH in the oviducts was 7.26+0.6

The blastopore was still visible. Then theneural groove appeared and expanded at theThe amniotic fold wascephalic end.
raisedanteriorly toward the head
sharply
and covered more than half the embryo.
After that the posterior amniotic fold wasbeginning to cover the tail bud. The neuraltube was formed by the fusion of the neuralfolds.
The amnion was closed. The
allantois bulged slightly and was notinflated. The first rudiments of the heartand optic vesicles were formed (Huang et

Embryonic Development

The development of

the external
morphology is described as follows. In
middle June ovulation occurred, and eggs
transferred to the oviducts. Fertilizationand development took place. A small oval
blastodisk divided on the large ellipsoidal
yolk mass to form the blastula. ThenIn early July theallantois began to inflate. The heart took aal.,

1989, stages 4-9).

"U" shape and began to beat. The caudal
part of the embryo began to coil. Lans
placodes invaginated. The mandibular
segment and the auditory pits were visible.
Branchial clefts were formed with thegastrulation proceeded to form a blastopore
marking the posterior end of the embryonicappearance of the nasal pits. The eye waslightly pigmented. Furthermore, the heart
was shaped like an "S". Then both theventricle and auricle were distinguishable.

shield (Huang et al., 1989, stages 1-3). In
late June the neural plate raised and folded.

The cloacal mound was visible and therudiment of the hemipenes appeared. The

February 1992

TABLE 1.

Asiatic Herpetological Research

Reproductive data on 10 adult female Agkistrodon blomhoffi brevicaudus.

Adult Females

Vol. 4, p. 65

Asiatic Herpetological ResearchVol. 4, p. 66

type (Lin et al., in press), which isfound only in temperate and subtropicalregions. Spermatogenesis begins in spring
after hibernation and spermiogenesis begins
in summer. The spermatozoa are stored
throughout the winter in the epididymis andvas deferens of the male or in the oviductsof the female. According to Saint Girons(1966), the reproductive cycle of female
snakes has annual types A-F-G andbiennial types B-C-D. By our observation
firstChinese Mamushithe{A. blomhoffiibrevicaudus) is thought to be the annual
type F. Its mating season is spring (Aprilor May) and ovulation occurs regularly in
middle June, while spermatogenesis is theaestival type. Sperm are stored in winter inthe vas deferens of the male or in the female

Sperm ofoviducts if there is fall mating.
the Chinese Mamushi (A. blomhoffiibrevicaudus) may be stored in the oviducts
and kept available for about three years (Huet al., 1966). This characteristic is of great
benefit to the survivialship of the Chinese

Mamushi 04. blomhoffii brevicaudus).

February 1992

lineatum) from St. Louis, Missouri, USA,the same result was obtained by Krohmer
and Aldridge (1985). All die females in ourexperiment were mature with a length ofand a weight of over 3 1
more than 447
a positive correlation
Therewaseach.
gbetween the number of yolking follicles orembryos and female length. The average
number of embryos from 82 females wasten. Seventy one percent of the females
400-500
long contained less than ten
75% of the females 500whileembryos,
contained
more than ten
600
longmmmmmm

embryos.

Chinese Mamushi iswhichis evolved fromovoviviparous,

TheIV.

It is said to be an adaptation tovariable environments where stochastic
events jeopardize egg survivorship. But
Seigel and Ford (1987) thought it also hadsome disadvantages, including lower clutch
frequency, more mortality risks to theoviparity.

parent, less intake of food and higher
metabolic cost of the parent. The clutch

mass of ovoviviparous snakes is smaller
Several investigators have found an
inverse correlation between reproduction(vitelogenesis) and fat body size in snakes(Seigel and Ford, 1987). In snakes withTheof oviparous snakes.
costsofreproduction (heart
physiologicalrate and oxygen consumption) significantlyannual reproduction

found thatovoviviparous snakes.
pregnant snakes cease feeding during thelast period of gestation, so they were thin
and weak after parturition. If they did not
gain enough food in time, they would bedead during hibernation or by the next
However we think thatspring.

II.

(e.g.

Opheodrysaestivus), fat bodies enlarge in spring,reach a low point in early to middle summer(egg-laying) and then increase gradually
until hiberntion. In species with biennial orVipera berus
and Crotalus viridis, fat body reserves arelowest at the time of parturition (Macartneyand Gregory, 1988; Seigel and Ford,triennial reproduction, e.g.

1987). Seasonal variation of fat bodies ofthe Chinese Mamushi 04. blomhoffiibrevicaudus) is similar to the above
observation. There are two peaks in March

thanthatincreased

duringovoviviparity

ispregnancy

moreinWefavorableinprotecting the filial generation because thesurvival rate is much higher in the Chinese

Mamushi (A. blomhoffii brevicaudus). In
our experiment the survival rate reached 9099%.

(spring) and November (hibernation). The
low point is in September (at the time ofAcknowledgmentsparturition).
III.

The sexual maturity of the Chinese

Mamushi (A. blomhoffii brevicaudus) isattained in 2-3 years. Jin et al. (1983)
mentioned that vitellogenesis began in thesecond spring after birth (20 months old),
350-484
long and 20-60 g in weight.

mmIn theLined Snake (TropidoclonionThis study was supported by a grant
the National Natural Science
Foundation of China and the Education
Commission of Zhejiang Province, China.
We are very grateful to Mr. Fumine Dongfor breeding the snakes and to Miss Fanfromand Mr. Jinxiang Yuan forcommenting on and typing the manuscript.

Yang

Asiatic Herpetological ResearchFebruary 1992

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Snake

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