evidence of seasonal reproduction in two species of cuban...

Evidence of seasonal

reproduction

in two species of Cuban

anurans

Yamilka Rodríguez-Gómez, Ana Sanz-Ochotorena,

Manuel Iturriaga-Monsisbay, Roxana Rodríguez-Ortíz,

Javier Torres-López

Our research group

Our research group

Collaboration

Distribution of amphibians in Cuba

Amphibia

Gymnophiona

or Apoda

(cecilias)

Urodela

or Caudata

(salamanders)

Anura

(frogs and toads)

Eleutherodactylidae

(Eleutherodactylus)

Bufonidae

(Peltophryne)

Hylidae

(Osteopilus septentrionalis)

Ranidae

(Lithobates catesbeianus)

95% of

endemism

Amphibian species studied

E. riparius

E. goini

E. casparii

E. varleyi

E. atkinsi

E. planirostris

E. thomasi E. dimidiatus E. pinarensis

Eleutherodactylus 15 -50 mm snout-vent lenght (SVL)

Amphibian species studied

Osteopilus septentrionalis

SVL 76-130 mm

Amphibian species studied

Backgrounds

Why do we select these two species?

Backgrounds

Relationship of some environmental

variables with the reproductive status

of gonads.

Histological analysis of gonads

which evidences or not their maturity

Backgrounds

As reproduction in amphibians is

generally regulated by climatic

variables, it has been suggested that

amphibians in the Caribbean could

reproduce throughout the year, given

the stability of high temperatures,

humidity, and the absence of true

seasons.

Backgrounds

R a i n y s e a s o n

Dry season Dry season

Main goal

Main goal

The aim of this work was to check

whether the annual gonadal

development of two amphibian

species is continuous or seasonal in

Cuba, and related to climatic

variables such as temperature,

relative humidity and precipitations.

Materials and methods

Three adults females and males of each

species were collected once a month

during one year

Materials and methods

in Havana

E. planirostris

in Matanzas

O. septentrionalis

During each sampling event:

Temperatures were recorded in situ with a

thermometer (to the nearest 0.1°C) and

checking with Centro del Clima, Instituto de

Meteorología de Cuba.

The average monthly rainfall was obtained

by the Instituto Nacional de Recursos

Hidraulicos (INRH).

Materials and methods

Materials and methods

• The weight of gonad data did not meet the normality of

the data according to the Kolmogorov-Smirnov normality

test. A nonparametric ANOVA was performed, Kruskal-

Wallis.

• A trend graph was constructed to describe and relate

environmental variables to reproductive activity.

Dissection of specimen

Extraction of gonads

Weighing of gonads

Materials and methods

• Fixation

• Dehydration

• Cleared up

• Inclusion

• Cut

• Staining

Processing of tissue samples:

The reproductive status in both females and males was verified

using classical histological techniques:

Materials and methods

Results and discussion

• Analysis of the variation of the weight of gonads during a year in E. planirostris

• Relationship between environmental variables and the reproductive state of the gonads in O. septentrionalis

• Histological evidence on both species

Results and discussion

Females

Annual weight dynamics of ovaries of adult females of

E. planirostris

Results and discussion

Males

Annual weight dynamics of testicles of adult males of

E. planirostris

Results and discussion

Females

Relationship between environmental variables and gonadal

states of O. septentrionalis females

Results and discussion

Males

Relationship between environmental variables and gonadal

states of O. septentrionalis males

Results and discussion

Ovaries

Ovaries of E. planirostris where oocytes are shown at all stages of development. H-E

The arrow points to the central cavity of the ovary.

Feb.

Jul.

Abr.

Results and discussion

Testicles

Testicles of E. planirostris in different stages of development. H-E

Sperm cysts

Results and discussion

Ovaries

Ovaries of O. septentrionalis where oocytes are shown at all stages of development. H-E

Dec.

Jul.

Mar.

Results and discussion

Testicles

Cysts of

spermatogonia

and sperm

Testicles of O. septentrionalis in different stages of development. H-E

Results and discussion

Is the annual development of

gonads of these two species

continuous or seasonal?

The populations of Eleutherodactylus planirostris

and Osteopilus septentrionalis from western Cuba

show a seasonally cyclic reproductive pattern, similar

to that of anurans from temperate and tropical

regions with a marked seasonality.

The environmental conditions that exist in western

Cuba might induce this type of pattern, which has

been well reported in other Cuban tetrapods.

Conclusions

Acknowledgment:

Nanobiology Lab, UNAM, Mexico

Histopathology Lab, CIREN, Cuba

Pathological Anatomy Lab, “R. González Coro” Hospital, Cuba