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