download the PDF here - Amphibian Specialist Group

Figure 6. (left) Ectromelia of Ramanella variegata. Photo Anslem de Silva.
Figure 7. (right) Ectromelia of Euphlyctis cyanophlyctis. Photo Anslem de Silva
4. Possible Viral Infection
During the survey all frog species which are primarily aquatic
such as Euphlyctis cyanophlyctis, E. hexadactylus, Fejervarya
greenii, F. kirtisinghei, F. limnocharis, Hoplobatrachus crassus
and Lankanectes corrugatus were assessed. Only in Euphlyctis
cyanophlyctis did we observe a conspicuous ‘red patch’ above
the eye on the dorsal aspect of the head in some specimens. This
observation was made in many different locations. It was present in
both sexes (Figures 12). Even after death the particular ‘red patch’
was inflamed and distinct (Figure 13).
2. Eye Disease
2.1. A case of small right eye (Microphthalmia) was observed in
a relict frog species, Lankanectes corrugatus (Nyctibatrachidae)
measuring 39 mm from Yagirala (Figure 8).
Figure 12. (left) Red patch in Euphlyctis cyanophlyctis. Photo Anslem de Silva Figure
13. (right) Conspicuous Red patch in a dead frog. Photo Anslem de Silva
Figure 8. (left) Microphthalmia in Lankanectes corrugatus. Photo Anslem de Silva
Figure 9. (right) Opaqueness in left eye Pseudophilautus fulvus. Photo Anslem de
Silva
2.2. Opaqueness in the right eye of a female Fejervarya kirtisinghei
(Manamendra-Arachchi & Gabadage, 1996), measuring 45 mm
from Ambagamuwa (Figure 2).
2.3. Opaqueness in the left eye of a female Pseudophilautus fulvus
(Manamendra-Arachchi & Pethiyagoda, 2005) (Figure 9) measuring
57 mm from Knuckles.
3. Parasitic infections
During the survey we investigated 181 free living specimens of
the Saddled Tree frog Taruga eques that were inhabiting marshes,
forest ponds, agro-wells and vegetable farms from 1600-2300 m
above sea level. Of this sample 31 (30 male and 1 female) specimens
were infected with encysted Proteocephlan plerocercoids, a cestode
(species not yet identified). The highest frequency of occurrence
of this cestode was on the ventral side of the thigh. Only in 2
specimens did we observe a cestode on the forelimb (Figures 10,
11).
Figure 10. (left)Taruga
eques parasitic
infections. Photo
Anslem de Silva
Figure 11. (inset)
Cestodes removed.
Photo Anslem de Silva
5. Agrochemicals and Farming Methods
Modern agricultural methods have been considered a major cause
for deformed frogs as the widely used herbicides, atrazine and
phosphate elevate trematode infections in amphibians (Rohr et
al., 2008).
A wide variety of agrochemicals are used in Sri Lanka in large
quantities in rice fields, vegetable plots and tea plantations.
Invariably, different agrochemicals are applied to the same field at
different stages of cultivation - to kill weeds, condition and enrich
the soil, destroy soil fungus, application of pesticides to control
pests and the addition of chemical fertilizers for growth etc. Thus,
large quantities of agrochemicals are accumulated in the fields.
We observed two incidents in which amphibians and reptiles
were killed with severe skin burns (lesions) a few hours after
fields were sprayed with agrochemicals. This was possibly due to
their sensitive skin having permeability to such chemicals. The
following are the two incidents:
a. A hectare of virgin land was cleared and the soil treated with
a fumigant (Methyl bromide) for new strawberry cultivation at
Udabulathgama (Ambagamuwa). The following morning six
specimens of the caecilian Ichthyophis glutinosus and about 20
fossorial snakes of the Family Uropeltidae (Rhinophis homolepis)
were found dead (de Silva and Dawundasekera, 2010).
b. A quarter hectare tea plantation adjoining the author’s land
in Gampola was sprayed with a herbicide known as Round-up
(Glyphosate) to kill the undergrowth of weeds. Within 5-7 hours
after spraying there were three Ichthyophis glutinosus wriggling
with fresh burn-like wounds (Figure 14) that eventually died (de
Silva, 2009).
In one of two studies conducted at Mihintale (North-Central
Province) 69% of the farmers interviewed had seen dead frogs
and lizards after the application of agrochemicals to paddy fields
(Somathilaka et al., 2010). The other study showed that even the
FrogLog Vol. 98 | September 2011 | 25